Initial commit

2025-04-24 07:02:41 +00:00 · 2025-04-24 07:02:41 +00:00 · 1be1863b20
commit 1be1863b20
50 changed files with 6449 additions and 0 deletions
--- a/.editorconfig
+++ b/.editorconfig
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,583 @@
+# Created by https://www.toptal.com/developers/gitignore/api/csharp,visualstudio
+# Edit at https://www.toptal.com/developers/gitignore?templates=csharp,visualstudio
+
+### Csharp ###
+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+##
+## Get latest from https://github.com/github/gitignore/blob/main/VisualStudio.gitignore
+
+# User-specific files
+*.rsuser
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# User-specific files (MonoDevelop/Xamarin Studio)
+*.userprefs
+
+# Mono auto generated files
+mono_crash.*
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+[Ww][Ii][Nn]32/
+[Aa][Rr][Mm]/
+[Aa][Rr][Mm]64/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+[Ll]ogs/
+
+# Visual Studio 2015/2017 cache/options directory
+.vs/
+# Uncomment if you have tasks that create the project's static files in wwwroot
+#wwwroot/
+
+# Visual Studio 2017 auto generated files
+Generated\ Files/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+# NUnit
+*.VisualState.xml
+TestResult.xml
+nunit-*.xml
+
+# Build Results of an ATL Project
+[Dd]ebugPS/
+[Rr]eleasePS/
+dlldata.c
+
+# Benchmark Results
+BenchmarkDotNet.Artifacts/
+
+# .NET Core
+project.lock.json
+project.fragment.lock.json
+artifacts/
+
+# ASP.NET Scaffolding
+ScaffoldingReadMe.txt
+
+# StyleCop
+StyleCopReport.xml
+
+# Files built by Visual Studio
+*_i.c
+*_p.c
+*_h.h
+*.ilk
+*.meta
+*.obj
+*.iobj
+*.pch
+*.pdb
+*.ipdb
+*.pgc
+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*_wpftmp.csproj
+*.log
+*.tlog
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.svclog
+*.scc
+
+# Chutzpah Test files
+_Chutzpah*
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opendb
+*.opensdf
+*.sdf
+*.cachefile
+*.VC.db
+*.VC.VC.opendb
+
+# Visual Studio profiler
+*.psess
+*.vsp
+*.vspx
+*.sap
+
+# Visual Studio Trace Files
+*.e2e
+
+# TFS 2012 Local Workspace
+$tf/
+
+# Guidance Automation Toolkit
+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# TeamCity is a build add-in
+_TeamCity*
+
+# DotCover is a Code Coverage Tool
+*.dotCover
+
+# AxoCover is a Code Coverage Tool
+.axoCover/*
+!.axoCover/settings.json
+
+# Coverlet is a free, cross platform Code Coverage Tool
+coverage*.json
+coverage*.xml
+coverage*.info
+
+# Visual Studio code coverage results
+*.coverage
+*.coveragexml
+
+# NCrunch
+_NCrunch_*
+.*crunch*.local.xml
+nCrunchTemp_*
+
+# MightyMoose
+*.mm.*
+AutoTest.Net/
+
+# Web workbench (sass)
+.sass-cache/
+
+# Installshield output folder
+[Ee]xpress/
+
+# DocProject is a documentation generator add-in
+DocProject/buildhelp/
+DocProject/Help/*.HxT
+DocProject/Help/*.HxC
+DocProject/Help/*.hhc
+DocProject/Help/*.hhk
+DocProject/Help/*.hhp
+DocProject/Help/Html2
+DocProject/Help/html
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.[Pp]ublish.xml
+*.azurePubxml
+# Note: Comment the next line if you want to checkin your web deploy settings,
+# but database connection strings (with potential passwords) will be unencrypted
+*.pubxml
+*.publishproj
+
+# Microsoft Azure Web App publish settings. Comment the next line if you want to
+# checkin your Azure Web App publish settings, but sensitive information contained
+# in these scripts will be unencrypted
+PublishScripts/
+
+# NuGet Packages
+*.nupkg
+# NuGet Symbol Packages
+*.snupkg
+# The packages folder can be ignored because of Package Restore
+**/[Pp]ackages/*
+# except build/, which is used as an MSBuild target.
+!**/[Pp]ackages/build/
+# Uncomment if necessary however generally it will be regenerated when needed
+#!**/[Pp]ackages/repositories.config
+# NuGet v3's project.json files produces more ignorable files
+*.nuget.props
+*.nuget.targets
+
+# Microsoft Azure Build Output
+csx/
+*.build.csdef
+
+# Microsoft Azure Emulator
+ecf/
+rcf/
+
+# Windows Store app package directories and files
+AppPackages/
+BundleArtifacts/
+Package.StoreAssociation.xml
+_pkginfo.txt
+*.appx
+*.appxbundle
+*.appxupload
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!?*.[Cc]ache/
+
+# Others
+ClientBin/
+~$*
+*~
+*.dbmdl
+*.dbproj.schemaview
+*.jfm
+*.pfx
+*.publishsettings
+orleans.codegen.cs
+
+# Including strong name files can present a security risk
+# (https://github.com/github/gitignore/pull/2483#issue-259490424)
+#*.snk
+
+# Since there are multiple workflows, uncomment next line to ignore bower_components
+# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
+#bower_components/
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file
+# to a newer Visual Studio version. Backup files are not needed,
+# because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+ServiceFabricBackup/
+*.rptproj.bak
+
+# SQL Server files
+*.mdf
+*.ldf
+*.ndf
+
+# Business Intelligence projects
+*.rdl.data
+*.bim.layout
+*.bim_*.settings
+*.rptproj.rsuser
+*- [Bb]ackup.rdl
+*- [Bb]ackup ([0-9]).rdl
+*- [Bb]ackup ([0-9][0-9]).rdl
+
+# Microsoft Fakes
+FakesAssemblies/
+
+# GhostDoc plugin setting file
+*.GhostDoc.xml
+
+# Node.js Tools for Visual Studio
+.ntvs_analysis.dat
+node_modules/
+
+# Visual Studio 6 build log
+*.plg
+
+# Visual Studio 6 workspace options file
+*.opt
+
+# Visual Studio 6 auto-generated workspace file (contains which files were open etc.)
+*.vbw
+
+# Visual Studio 6 auto-generated project file (contains which files were open etc.)
+*.vbp
+
+# Visual Studio 6 workspace and project file (working project files containing files to include in project)
+*.dsw
+*.dsp
+
+# Visual Studio 6 technical files
+
+# Visual Studio LightSwitch build output
+**/*.HTMLClient/GeneratedArtifacts
+**/*.DesktopClient/GeneratedArtifacts
+**/*.DesktopClient/ModelManifest.xml
+**/*.Server/GeneratedArtifacts
+**/*.Server/ModelManifest.xml
+_Pvt_Extensions
+
+# Paket dependency manager
+.paket/paket.exe
+paket-files/
+
+# FAKE - F# Make
+.fake/
+
+# CodeRush personal settings
+.cr/personal
+
+# Python Tools for Visual Studio (PTVS)
+__pycache__/
+*.pyc
+
+# Cake - Uncomment if you are using it
+# tools/**
+# !tools/packages.config
+
+# Tabs Studio
+*.tss
+
+# Telerik's JustMock configuration file
+*.jmconfig
+
+# BizTalk build output
+*.btp.cs
+*.btm.cs
+*.odx.cs
+*.xsd.cs
+
+# OpenCover UI analysis results
+OpenCover/
+
+# Azure Stream Analytics local run output
+ASALocalRun/
+
+# MSBuild Binary and Structured Log
+*.binlog
+
+# NVidia Nsight GPU debugger configuration file
+*.nvuser
+
+# MFractors (Xamarin productivity tool) working folder
+.mfractor/
+
+# Local History for Visual Studio
+.localhistory/
+
+# Visual Studio History (VSHistory) files
+.vshistory/
+
+# BeatPulse healthcheck temp database
+healthchecksdb
+
+# Backup folder for Package Reference Convert tool in Visual Studio 2017
+MigrationBackup/
+
+# Ionide (cross platform F# VS Code tools) working folder
+.ionide/
+
+# Fody - auto-generated XML schema
+FodyWeavers.xsd
+
+# VS Code files for those working on multiple tools
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+*.code-workspace
+
+# Local History for Visual Studio Code
+.history/
+
+# Windows Installer files from build outputs
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# JetBrains Rider
+*.sln.iml
+
+### VisualStudio ###
+
+# User-specific files
+
+# User-specific files (MonoDevelop/Xamarin Studio)
+
+# Mono auto generated files
+
+# Build results
+
+# Visual Studio 2015/2017 cache/options directory
+# Uncomment if you have tasks that create the project's static files in wwwroot
+
+# Visual Studio 2017 auto generated files
+
+# MSTest test Results
+
+# NUnit
+
+# Build Results of an ATL Project
+
+# Benchmark Results
+
+# .NET Core
+
+# ASP.NET Scaffolding
+
+# StyleCop
+
+# Files built by Visual Studio
+
+# Chutzpah Test files
+
+# Visual C++ cache files
+
+# Visual Studio profiler
+
+# Visual Studio Trace Files
+
+# TFS 2012 Local Workspace
+
+# Guidance Automation Toolkit
+
+# ReSharper is a .NET coding add-in
+
+# TeamCity is a build add-in
+
+# DotCover is a Code Coverage Tool
+
+# AxoCover is a Code Coverage Tool
+
+# Coverlet is a free, cross platform Code Coverage Tool
+
+# Visual Studio code coverage results
+
+# NCrunch
+
+# MightyMoose
+
+# Web workbench (sass)
+
+# Installshield output folder
+
+# DocProject is a documentation generator add-in
+
+# Click-Once directory
+
+# Publish Web Output
+# Note: Comment the next line if you want to checkin your web deploy settings,
+# but database connection strings (with potential passwords) will be unencrypted
+
+# Microsoft Azure Web App publish settings. Comment the next line if you want to
+# checkin your Azure Web App publish settings, but sensitive information contained
+# in these scripts will be unencrypted
+
+# NuGet Packages
+# NuGet Symbol Packages
+# The packages folder can be ignored because of Package Restore
+# except build/, which is used as an MSBuild target.
+# Uncomment if necessary however generally it will be regenerated when needed
+# NuGet v3's project.json files produces more ignorable files
+
+# Microsoft Azure Build Output
+
+# Microsoft Azure Emulator
+
+# Windows Store app package directories and files
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+# but keep track of directories ending in .cache
+
+# Others
+
+# Including strong name files can present a security risk
+# (https://github.com/github/gitignore/pull/2483#issue-259490424)
+
+# Since there are multiple workflows, uncomment next line to ignore bower_components
+# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
+
+# RIA/Silverlight projects
+
+# Backup & report files from converting an old project file
+# to a newer Visual Studio version. Backup files are not needed,
+# because we have git ;-)
+
+# SQL Server files
+
+# Business Intelligence projects
+
+# Microsoft Fakes
+
+# GhostDoc plugin setting file
+
+# Node.js Tools for Visual Studio
+
+# Visual Studio 6 build log
+
+# Visual Studio 6 workspace options file
+
+# Visual Studio 6 auto-generated workspace file (contains which files were open etc.)
+
+# Visual Studio 6 auto-generated project file (contains which files were open etc.)
+
+# Visual Studio 6 workspace and project file (working project files containing files to include in project)
+
+# Visual Studio 6 technical files
+
+# Visual Studio LightSwitch build output
+
+# Paket dependency manager
+
+# FAKE - F# Make
+
+# CodeRush personal settings
+
+# Python Tools for Visual Studio (PTVS)
+
+# Cake - Uncomment if you are using it
+# tools/**
+# !tools/packages.config
+
+# Tabs Studio
+
+# Telerik's JustMock configuration file
+
+# BizTalk build output
+
+# OpenCover UI analysis results
+
+# Azure Stream Analytics local run output
+
+# MSBuild Binary and Structured Log
+
+# NVidia Nsight GPU debugger configuration file
+
+# MFractors (Xamarin productivity tool) working folder
+
+# Local History for Visual Studio
+
+# Visual Studio History (VSHistory) files
+
+# BeatPulse healthcheck temp database
+
+# Backup folder for Package Reference Convert tool in Visual Studio 2017
+
+# Ionide (cross platform F# VS Code tools) working folder
+
+# Fody - auto-generated XML schema
+
+# VS Code files for those working on multiple tools
+
+# Local History for Visual Studio Code
+
+# Windows Installer files from build outputs
+
+# JetBrains Rider
+
+### VisualStudio Patch ###
+# Additional files built by Visual Studio
+
+# End of https://www.toptal.com/developers/gitignore/api/csharp,visualstudio
--- a/Data/teachers-with-business-card.csv
+++ b/Data/teachers-with-business-card.csv
@ -0,0 +1,32 @@
+12240;Baar Erich
+12242;Bauer Peter
+12244;Baumann Daniel
+12246;Braun Matthias
+12249;Bucek Michael
+12252;Dilly Franz
+12254;Eder Lisa
+12256;Ehrenmüller Markus
+12257;Eisserer Clemens
+12265;Fürlinger Josef
+12281;Holzleitner Jürgen
+12284;Huemer Martin
+12287;Kainerstorfer Richard
+12288;Kaiser Alexander
+12289;Karpowicz Michal
+12292;Keck-Jordan Andrea
+12294;Kerschner Martin
+12295;Kiesenhofer Maximilian
+12297;Knogler Kerstin
+12303;Kurz Matthias
+12305;Leitner Helmut
+12324;Pachschwöll Cornelia
+12331;Raschhofer Robert
+12332;Reder Robert
+12336;Reisinger Hannes
+12341;Schmidt Silke
+12350;Steiner Dietmar
+12351;Steiner Martin
+12357;Stütz Thomas
+12363;Venzl Bernhard
+12364;Wagner Michael
+12368;Wiedermann Alfred
--- a/Data/teachers-with-business-card_minimal.csv
+++ b/Data/teachers-with-business-card_minimal.csv
@ -0,0 +1,2 @@
+12240;Baar Erich
+12242;Bauer Peter
--- a/Data/teachers.csv
+++ b/Data/teachers.csv
@ -0,0 +1,140 @@
+Aberger Christian;Tuesday;6;12:45 - 13:35;E74
+Aistleitner Gerald;Thursday;6;12:45 - 13:35;206
+Aitenbichler Herbert;Wednesday;2;08:55 - 09:45;254
+Andraschko Benjamin;Wednesday;5;11:50 - 12:40;T4
+Anzenberger Peter;Thursday;6;12:45 - 13:35;E31
+Apollonio Eva-Maria;Monday;5;11:50 - 12:40;223
+Arzt Miriam;Friday;3;10:00 - 10:50;223
+Atak Mehmet;;;;
+Auernig Franz;Thursday;5;11:50 - 12:40;E31
+Baar Erich;Friday;4;10:55 - 11:45;E05
+Bärnthaler Andreas;Wednesday;4;10:55 - 11:45;237
+Bauer Peter;Tuesday;6;12:45 - 13:35;E52
+Bauernfeind Raphael;;;;
+Baumann Daniel;Wednesday;6;12:45 - 13:35;148
+Bodenstorfer Bernhard;Tuesday;3;10:00 - 10:50;254
+Braun Matthias;Friday;3;10:00 - 10:50;E31
+Brenn Rosemarie;Tuesday;6;12:45 - 13:35;E05
+Brückner Margit;;;;
+Bucek Michael;Wednesday;5;11:50 - 12:40;103
+Dellinger Franz;Tuesday;2;08:55 - 09:45;E08
+Denkmair Rainer;Tuesday;7;13:40 - 14:30;206
+Dilly Franz;Wednesday;2;08:55 - 09:45;223
+Draxlbauer Josef;Thursday;5;11:50 - 12:40;237
+Eder Lisa;Wednesday;6;12:45 - 13:35;E08
+Ehrenberger Günther Ferdinand;Wednesday;2;08:55 - 09:45;E51
+Ehrenmüller Markus;;;;
+Eisserer Clemens;;;;
+Engleitner Patricia;Tuesday;3;10:00 - 10:50;254
+Enzenhofer Mario;;;;
+Eppich Christina;Thursday;3;10:00 - 10:50;T07
+Ernecker Björn;Friday;8;14:35 - 15:25;E06
+Fallmann-Raupach Gerhild;Tuesday;5;11:50 - 12:40;T07
+Felsner Anja;Friday;4;10:55 - 11:45;E06
+Frey Peter;Thursday;5;11:50 - 12:40;103
+Fürlinger Josef;Thursday;7;13:40 - 14:30;E31
+Gallistl Andreas;Wednesday;5;11:50 - 12:40;U92
+Gallner-Holzmann Katharina;Wednesday;5;11:50 - 12:40;241
+Gehrer Gerhard;Thursday;4;10:55 - 11:45;254
+Giritzhofer Rudolf;Wednesday;4;10:55 - 11:45;218
+Gruber-Leitner Franz;Monday;6;12:45 - 13:35;E31
+Günther Harald;Wednesday;5;11:50 - 12:40;U08
+Hackenbuchner Franz;Wednesday;5;11:50 - 12:40;U92
+Hammer Hans-Christian;Wednesday;6;12:45 - 13:35;148
+Hannesschläger Jürgen;;;;
+Haslinger Klaus;Tuesday;5;11:50 - 12:40;U92
+Haslinger Markus;Monday;3;10:00 - 10:50;103
+Haunschmid Wilfried;;;;
+Hinterramskogler Britta;Thursday;6;12:45 - 13:35;237
+Höfer Gerhard;Monday;3;10:00 - 10:50;254
+Hofer Gerhard;;;;
+Holzleitner Jürgen;Monday;5;11:50 - 12:40;222
+Holzmann Michael;Wednesday;5;11:50 - 12:40;E08
+Huemer Elke;;;;
+Huemer Martin;Tuesday;4;10:55 - 11:45;148
+Jäger Christian;Thursday;3;10:00 - 10:50;T13
+Jakob Franz;Wednesday;3;10:00 - 10:50;E08
+Kainerstorfer Richard;Friday;3;10:00 - 10:50;E38
+Kaiser Alexander;Tuesday;5;11:50 - 12:40;U87
+Karpowicz Michal;Monday;5;11:50 - 12:40;E32
+Kasberger Johannes;Tuesday;3;10:00 - 10:50;222
+Kaser Christof;Friday;4;10:55 - 11:45;E31
+Keck-Jordan Andrea;Tuesday;7;13:40 - 14:30;E08
+Keplinger Edith;Monday;8;14:35 - 15:25;221
+Kerschner Martin;Tuesday;3;10:00 - 10:50;T04
+Kiesenhofer Maximilian;Thursday;3;10:00 - 10:50;E05
+Klewein David;Tuesday;10;16:25 - 17:15;206
+Knogler Kerstin;Tuesday;4;10:55 - 11:45;203
+Kodre Christina;Thursday;3;10:00 - 10:50;226
+Köck Gerald;Tuesday;4;10:55 - 11:45;E74
+Köck Johann;Thursday;4;10:55 - 11:45;E32
+Köfler Andreas;;;;
+Kornfellner Alexander;Monday;4;10:55 - 11:45;E32
+Kurz Matthias;Thursday;4;10:55 - 11:45;E53
+Lehenbauer Christian;Monday;4;10:55 - 11:45;142
+Leitner Helmut;Wednesday;11;17:20 - 18:05;E32
+Lüftner Markus;Tuesday;5;11:50 - 12:40;E51
+Luger Angelika;Wednesday;5;11:50 - 12:40;223
+Lugmayr Karin;Tuesday;3;10:00 - 10:50;E08
+Luttinger Christian;Monday;7;13:40 - 14:30;U92
+Lutz Wolfgang;Thursday;5;11:50 - 12:40;E53
+Mader Cornelia;Tuesday;5;11:50 - 12:40;226
+Matzinger Barbara;Tuesday;5;11:50 - 12:40;218
+Mischitz Gernot;Tuesday;6;12:45 - 13:35;E05
+Mistelberger Wolfgang;Thursday;6;12:45 - 13:35;E51
+Mitsea Eirini;;;;
+Möschl Edith;Thursday;3;10:00 - 10:50;E32
+Moser Tamara;Friday;4;10:55 - 11:45;142
+Mühleder Regina;Thursday;11;17:20 - 18:05;237
+Mühlehner Philipp;Tuesday;3;10:00 - 10:50;254
+Niedermaier Maren;;;;
+Nimmervoll Raimund;Monday;5;11:50 - 12:40;E51
+Nöbauer Klaus;Tuesday;5;11:50 - 12:40;103
+Oswald Alois;Tuesday;4;10:55 - 11:45;U92
+Pachschwöll Cornelia;Wednesday;4;10:55 - 11:45;241
+Palitsch-Infanger Michael;Friday;2;08:55 - 09:45;222
+Povacz Katharina;Friday;3;10:00 - 10:50;203
+Prantl Anton;Thursday;3;10:00 - 10:50;E53
+Rager Franz;Thursday;2;08:55 - 09:45;E74
+Rammelmüller Natascha;Thursday;3;10:00 - 10:50;148
+Rammer Alfred;Thursday;2;08:55 - 09:45;241
+Raschhofer Robert;Monday;5;11:50 - 12:40;E53
+Reder Robert;Monday;6;12:45 - 13:35;E74
+Reichinger Josef;Tuesday;3;10:00 - 10:50;E08
+Reisenberger Martina;Tuesday;5;11:50 - 12:40;103
+Reisinger Elisabeth;;;;
+Reisinger Hannes;Wednesday;6;12:45 - 13:35;U91
+Reiter Riccarda;Monday;6;12:45 - 13:35;218
+Rumetshofer Elisabeth;Monday;9;15:30 - 16:20;203
+Scheinecker Silke;Wednesday;3;10:00 - 10:50;203
+Schlesinger Ralf;Friday;4;10:55 - 11:45;E53
+Schmidt Silke;Thursday;2;08:55 - 09:45;241
+Schmidtgrabmer Doris;Thursday;4;10:55 - 11:45;E74
+Schnalzenberger Mario;;;;
+Schneider Klaus Michael;;;;
+Schraml Stefan;Tuesday;7;13:40 - 14:30;148
+Schröder Birgit;Thursday;4;10:55 - 11:45;103
+Schwaiger Barbara;Wednesday;4;10:55 - 11:45;E06
+Sokoli Anila;Thursday;2;08:55 - 09:45;E08
+Sonnleitner Erik;Wednesday;3;10:00 - 10:50;E31
+Steiner Dietmar;Wednesday;6;12:45 - 13:35;E32
+Steiner Martin;Tuesday;5;11:50 - 12:40;U92
+Sternath Martin;Wednesday;3;10:00 - 10:50;221
+Stöpp Gerhard;;;;
+Stöttinger Robert;Friday;2;08:55 - 09:45;206
+Strecker Alexander;;;;
+Stropek Rainer;;;;
+Stütz Thomas;Monday;5;11:50 - 12:40;E74
+Täubel Michael;Monday;2;08:55 - 09:45;T13
+Thieme Linda;;;;
+Traunmüller Günter;Tuesday;3;10:00 - 10:50;206
+Tumfart Johannes;Tuesday;2;08:55 - 09:45;E74
+Unterrainer Gerald;Tuesday;4;10:55 - 11:45;222
+Venzl Bernhard;Tuesday;5;11:50 - 12:40;U92
+Wagner Michael;Wednesday;5;11:50 - 12:40;U92
+Weißmair Rudolf;Monday;5;11:50 - 12:40;E08
+Wellisch Alexandra;Monday;3;10:00 - 10:50;226
+Wenigwieser Siegfried;Wednesday;5;11:50 - 12:40;U92
+Wiedermann Alfred;Friday;4;10:55 - 11:45;E55
+Willmann Renate;Wednesday;5;11:50 - 12:40;218
+Wingert Edwin;Wednesday;7;13:40 - 14:30;T09 
--- a/Data/teachers_minimal.csv
+++ b/Data/teachers_minimal.csv
@ -0,0 +1,4 @@
+Aberger Christian;Tuesday;6;12:45 - 13:35;E74
+Atak Mehmet;;;;
+Auernig Franz;Thursday;5;11:50 - 12:40;E31
+Baar Erich;Friday;4;10:55 - 11:45;E05
--- a/MeetTheTeacher.Test/Export/CsvDataExporterTests.cs
+++ b/MeetTheTeacher.Test/Export/CsvDataExporterTests.cs
@ -0,0 +1,52 @@
+using MeetTheTeacher.Export;
+
+namespace MeetTheTeacher.Test.Export;
+
+public sealed class CsvDataExporterTests : ExporterTestBase, IDisposable
+{
+    private readonly CsvDataExporter _csvDataExporter;
+
+    public CsvDataExporterTests()
+    {
+        _csvDataExporter = new CsvDataExporter();
+    }
+
+    protected override string FileExtension => "csv";
+
+    public void Dispose()
+    {
+        // Clean up the test file.
+        if (File.Exists(FilePath))
+        {
+            File.Delete(FilePath);
+        }
+    }
+
+    [Fact]
+    public void Export_Valid()
+    {
+        SimpleCheck();
+    }
+
+    [Fact]
+    public void Export_FileExisted()
+    {
+        File.WriteAllText(FilePath, "some content");
+
+        // still has to work
+        SimpleCheck();
+    }
+
+    private void SimpleCheck()
+    {
+        _csvDataExporter.Export(SampleData, FileName);
+
+        File.Exists(FilePath).Should().BeTrue();
+
+        string[] rows = File.ReadAllLines(FilePath);
+        rows.Length.Should().Be(3, "Header + 2 data rows");
+        rows[0].Should().Be("Name;Age");
+        rows[1].Should().Be("John;30");
+        rows[2].Should().Be("Jane;25");
+    }
+}
--- a/MeetTheTeacher.Test/Export/DefaultExporterProviderTests.cs
+++ b/MeetTheTeacher.Test/Export/DefaultExporterProviderTests.cs
@ -0,0 +1,39 @@
+using MeetTheTeacher.Export;
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Export;
+
+public sealed class DefaultExporterProviderTests
+{
+    private readonly DefaultExporterProvider _provider;
+
+    public DefaultExporterProviderTests()
+    {
+        _provider = new DefaultExporterProvider();
+    }
+    
+    [Fact]
+    public void GetExporter_CsvFormat()
+    {
+        _provider.GetExporter(ExportFormat.Csv)
+                 .Should().BeOfType<CsvDataExporter>();
+    }
+
+    [Fact]
+    public void GetExporter_HtmlFormat()
+    {
+        _provider.GetExporter(ExportFormat.Html)
+                 .Should().BeOfType<HtmlDataExporter>();
+    }
+
+    [Fact]
+    public void GetExporter_InvalidFormat()
+    {
+        var exporterProvider = new DefaultExporterProvider();
+
+        Action act = () => exporterProvider.GetExporter((ExportFormat) (-1));
+
+        act.Should().Throw<ArgumentOutOfRangeException>()
+           .WithMessage("*exportFormat*");
+    }
+}
--- a/MeetTheTeacher.Test/Export/ExporterTestBase.cs
+++ b/MeetTheTeacher.Test/Export/ExporterTestBase.cs
@ -0,0 +1,26 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Export;
+
+public abstract class ExporterTestBase
+{
+    protected static string FileName => "testFile";
+    protected string FilePath => Path.Combine(Directory.GetCurrentDirectory(), $"{FileName}.{FileExtension}");
+    protected abstract string FileExtension { get; }
+
+    protected static IEnumerable<ICsvRepresentable> SampleData =>
+        new List<ICsvRepresentable>
+        {
+            new TestData { Name = "John", Age = 30 },
+            new TestData { Name = "Jane", Age = 25 }
+        };
+
+    protected class TestData : ICsvRepresentable
+    {
+        public required string Name { get; init; }
+        public int Age { get; init; }
+
+        public CsvData ToCsvData() =>
+            new(new List<string> { "Name", "Age" }, new List<string> { Name, Age.ToString() });
+    }
+}
--- a/MeetTheTeacher.Test/Export/ExporterTests.cs
+++ b/MeetTheTeacher.Test/Export/ExporterTests.cs
@ -0,0 +1,67 @@
+using System.Reflection;
+using MeetTheTeacher.Export;
+using MeetTheTeacher.Model;
+using MeetTheTeacher.Model.Comparison;
+
+namespace MeetTheTeacher.Test.Export;
+
+public sealed class ExporterTests
+{
+    [Theory]
+    [MemberData(nameof(UseProperComparerData))]
+    public void Comparer(SortOrder order, Type expectedComparer, bool? expectedAscendingFlag)
+    {
+        // Note: not a pretty test, private stuff is only tested if it comes from students ;)
+        
+        var exporter = new Exporter(order, ExportFormat.Html, Substitute.For<IExporterProvider>());
+        
+        CheckComparerField(exporter, expectedComparer, expectedAscendingFlag);
+    }
+
+    [Fact]
+    public void Export()
+    {
+        const string FileName = "test";
+        string? capturedFileName = null;
+
+        var exporterMock = Substitute.For<IDataExporter>();
+        exporterMock.Export(Arg.Any<List<Teacher>>(), 
+                            Arg.Do<string>(fn => capturedFileName = fn));
+        var providerMock = Substitute.For<IExporterProvider>();
+        providerMock.GetExporter(Arg.Is(ExportFormat.Html)).Returns(exporterMock);
+
+        var exporter = new Exporter(SortOrder.ByHourDesc, ExportFormat.Html, providerMock);
+        
+        exporter.Export(FileName, new());
+        
+        capturedFileName.Should().NotBeNull().And.Be(FileName);
+    }
+
+    public static TheoryData<SortOrder, Type, bool?> UseProperComparerData =>
+        new()
+        {
+            {SortOrder.ByNameAsc, typeof(ByNameComparer), true},
+            {SortOrder.ByNameDesc, typeof(ByNameComparer), false},
+            {SortOrder.ByHourAsc, typeof(ByHourComparer), true},
+            {SortOrder.ByHourDesc, typeof(ByHourComparer), false},
+            {SortOrder.Room, typeof(ByRoomComparer), null}
+        };
+
+    private static void CheckComparerField(Exporter exporter, Type expectedType, bool? ascending)
+    {
+        var field = typeof(Exporter).GetField("_comparer", 
+                                              BindingFlags.Instance | BindingFlags.NonPublic);
+
+        field?.GetValue(exporter).Should().NotBeNull()
+             .And.BeOfType(expectedType);
+
+        if (ascending.HasValue && expectedType.IsSubclassOf(typeof(ComparerBase)))
+        {
+            var ascendingField = expectedType.GetProperty("Ascending", 
+                                                          BindingFlags.Instance | BindingFlags.NonPublic);
+            ascendingField?.GetValue(field!.GetValue(exporter))
+                          .Should().NotBeNull()
+                          .And.Be(ascending.Value);
+        }
+    }
+}
--- a/MeetTheTeacher.Test/Export/HtmlDataExporterTests.cs
+++ b/MeetTheTeacher.Test/Export/HtmlDataExporterTests.cs
@ -0,0 +1,49 @@
+using MeetTheTeacher.Export;
+
+namespace MeetTheTeacher.Test.Export;
+
+public sealed class HtmlDataExporterTests : ExporterTestBase, IDisposable
+{
+    private readonly HtmlDataExporter _htmlDataExporter;
+
+    public HtmlDataExporterTests()
+    {
+        _htmlDataExporter = new HtmlDataExporter();
+    }
+
+    protected override string FileExtension => "html";
+
+    public void Dispose()
+    {
+        // Clean up the test file.
+        if (File.Exists(FilePath))
+        {
+            File.Delete(FilePath);
+        }
+    }
+
+    [Fact]
+    public void Export()
+    {
+        _htmlDataExporter.Export(SampleData, FileName);
+
+        File.Exists(FilePath).Should().BeTrue();
+
+        string[]? rows = File.ReadAllLines(FilePath);
+
+        void Check(int rowIdx, string expected)
+        {
+            rows[rowIdx].Trim().Should().Be(expected);
+        }
+
+        Check(0, "<table>");
+        Check(1, "<thead>");
+        Check(2, "<tr><th>Name</th><th>Age</th></tr>");
+        Check(3, "</thead>");
+        Check(4, "<tbody>");
+        Check(5, "<tr><td>John</td><td>30</td></tr>");
+        Check(6, "<tr><td>Jane</td><td>25</td></tr>");
+        Check(7, "</tbody>");
+        Check(8, "</table>");
+    }
+}
--- a/MeetTheTeacher.Test/Export/SpectreTableExporterTests.cs
+++ b/MeetTheTeacher.Test/Export/SpectreTableExporterTests.cs
@ -0,0 +1,30 @@
+using MeetTheTeacher.Export;
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Export;
+
+public sealed class SpectreTableExporterTests: ExporterTestBase
+{
+    private readonly SpectreTableExporter _spectreTableExporter;
+
+    public SpectreTableExporterTests()
+    {
+        _spectreTableExporter = new SpectreTableExporter();
+    }
+
+    [Fact]
+    public void Export()
+    {
+        _spectreTableExporter.Export(SampleData, FileName);
+        
+        var table = _spectreTableExporter.Table;
+        table.Should().NotBeNull();
+        table.Columns.Should().HaveCount(2);
+        table.Rows.Should().HaveCount(2);
+        
+        // actual (string) values cannot be checked without reflection on an external library which will
+        // inevitably break and is a super bad idea, so we'll leave it at this
+    }
+
+    protected override string FileExtension => null!;
+}
--- a/MeetTheTeacher.Test/Import/TeacherDataCsvImporterTests.cs
+++ b/MeetTheTeacher.Test/Import/TeacherDataCsvImporterTests.cs
@ -0,0 +1,52 @@
+using MeetTheTeacher.Import;
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Import;
+
+public sealed class TeacherDataCsvImporterTests
+{
+    [Fact]
+    public void DataLoading_Simple()
+    {
+        var importer = new TeacherDataCsvImporter(GetPath("teachers_minimal.csv"),
+                                                  GetPath("teachers-with-business-card_minimal.csv"));
+
+        IEnumerable<Teacher> data = importer.LoadTeacherData();
+
+        // wrapping in list, because enumerating multiple times
+        var dataAsList = new List<Teacher>(data);
+
+        dataAsList.Should().NotBeEmpty().And.HaveCount(4);
+        CheckTeacher(dataAsList[0], "Aberger Christian", DayOfWeek.Tuesday, SchoolUnit.UE06, 
+                     new TimeFrame(new(12,45), new(13,35)), 
+                     "E74", null);
+        CheckTeacher(dataAsList[1], "Atak Mehmet", null, null, null, null, null);
+        CheckTeacher(dataAsList[2], "Auernig Franz", DayOfWeek.Thursday, SchoolUnit.UE05, 
+                     new TimeFrame(new(11,50), new(12,40)), 
+                     "E31", null);
+        CheckTeacher(dataAsList[3], "Baar Erich", DayOfWeek.Friday, SchoolUnit.UE04, 
+                     new TimeFrame(new(10,55), new(11,45)), 
+                     "E05", 12240);
+    }
+
+    private static void CheckTeacher(Teacher teacher, string name, DayOfWeek? dayOfWeek, SchoolUnit? unit, 
+                                     TimeFrame? time, string? room, int? imageId)
+    {
+        teacher.Name.Should().Be(name);
+        teacher.ConsultingHourWeekDay.Should().Be(dayOfWeek);
+        teacher.ConsultingHourUnit.Should().Be(unit);
+        teacher.ConsultingHour.Should().Be(time);
+        teacher.Room.Should().Be(room);
+        
+        if (imageId.HasValue)
+        {
+            teacher.Should().BeOfType<TeacherWithBusinessCard>();
+        }
+        else
+        {
+            teacher.Should().NotBeOfType<TeacherWithBusinessCard>();
+        }
+    }
+
+    private static string GetPath(string fileName) => Path.Combine(Directory.GetCurrentDirectory(), $"Data/{fileName}");
+}
--- a/MeetTheTeacher.Test/Import/TeacherDataFakeImporterTests.cs
+++ b/MeetTheTeacher.Test/Import/TeacherDataFakeImporterTests.cs
@ -0,0 +1,41 @@
+using MeetTheTeacher.Import;
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Import;
+
+// such a class would rarely exist in production code
+// so this test is rather silly - doing it for completeness anyway
+public sealed class TeacherDataFakeImporterTests
+{
+    private readonly TeacherDataFakeImporter _teacherDataFakeImporter;
+
+    public TeacherDataFakeImporterTests()
+    {
+        _teacherDataFakeImporter = new TeacherDataFakeImporter();
+    }
+
+    [Fact]
+    public void LoadTeacherData_ReturnsExpectedData()
+    {
+        var result = _teacherDataFakeImporter.LoadTeacherData().ToList();
+
+        result.Should().HaveCount(6);
+        result[0].Name.Should().Be("John Doe");
+        result[0].ConsultingHour.Should().Be(new TimeFrame(new TimeOnly(8, 0), new TimeOnly(8, 50)));
+        result[0].ConsultingHourUnit.Should().Be(SchoolUnit.UE01);
+        result[0].ConsultingHourWeekDay.Should().Be(DayOfWeek.Monday);
+        result[0].Room.Should().Be("A101");
+
+        // Add similar assertions for the other Teacher instances
+
+        result[4].Name.Should().Be("Emily Davis");
+        result[4].ConsultingHour.Should().Be(new TimeFrame(new TimeOnly(12, 40), new TimeOnly(13, 35)));
+        result[4].ConsultingHourUnit.Should().Be(SchoolUnit.UE06);
+        result[4].ConsultingHourWeekDay.Should().Be(DayOfWeek.Thursday);
+        result[4].Room.Should().Be("A101");
+        result[4].Should().BeOfType<TeacherWithBusinessCard>();
+        ((TeacherWithBusinessCard) result[4]).Id.Should().Be(1001);
+
+        // Add similar assertions for the other TeacherWithBusinessCard instances
+    }
+}
--- a/MeetTheTeacher.Test/MeetTheTeacher.Test.csproj
+++ b/MeetTheTeacher.Test/MeetTheTeacher.Test.csproj
@ -0,0 +1,42 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+	<PropertyGroup>
+		<TargetFramework>net9.0</TargetFramework>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<Nullable>enable</Nullable>
+		<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+		<IsPackable>false</IsPackable>
+	</PropertyGroup>
+
+	<ItemGroup>
+		<Using Include="FluentAssertions" />
+		<Using Include="Xunit" />
+		<Using Include="NSubstitute" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<Content Include="..\Data\*.csv" Link="Data\%(Filename)%(Extension)">
+			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+		</Content>
+	</ItemGroup>
+
+	<ItemGroup>
+		<PackageReference Include="AwesomeAssertions" Version="8.0.2" />
+		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+		<PackageReference Include="NSubstitute" Version="5.3.0" />
+		<PackageReference Include="xunit" Version="2.9.3" />
+		<PackageReference Include="xunit.runner.visualstudio" Version="3.0.2">
+			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+			<PrivateAssets>all</PrivateAssets>
+		</PackageReference>
+		<PackageReference Include="coverlet.collector" Version="6.0.4">
+			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+			<PrivateAssets>all</PrivateAssets>
+		</PackageReference>
+	</ItemGroup>
+
+	<ItemGroup>
+		<ProjectReference Include="..\MeetTheTeacher\MeetTheTeacher.csproj" />
+	</ItemGroup>
+
+</Project>
--- a/MeetTheTeacher.Test/Model/Comparison/ByHourComparerTests.cs
+++ b/MeetTheTeacher.Test/Model/Comparison/ByHourComparerTests.cs
@ -0,0 +1,142 @@
+using MeetTheTeacher.Model;
+using MeetTheTeacher.Model.Comparison;
+
+namespace MeetTheTeacher.Test.Model.Comparison;
+
+public sealed class ByHourComparerTests
+{
+    [Fact]
+    public void Compare_Ascending_BothNull()
+    {
+        var comparer = new ByHourComparer(true);
+
+        comparer.Compare(null, null).Should().Be(0);
+    }
+
+    [Fact]
+    public void Compare_Ascending_FirstNull()
+    {
+        var comparer = new ByHourComparer(true);
+        var teacher2 = new Teacher("Teacher2") { 
+            ConsultingHourWeekDay = DayOfWeek.Tuesday, 
+            ConsultingHourUnit = SchoolUnit.UE02 
+        };
+
+        comparer.Compare(null, teacher2).Should().Be(1);
+    }
+
+    [Fact]
+    public void Compare_Ascending_SecondNull()
+    {
+        var comparer = new ByHourComparer(true);
+        var teacher1 = new Teacher("Teacher1")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+
+        comparer.Compare(teacher1, null).Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_Ascending_DifferentWeekDays()
+    {
+        var comparer = new ByHourComparer(true);
+        var teacher1 = new Teacher("Teacher1")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+        var teacher2 = new Teacher("Teacher2")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Tuesday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+
+        comparer.Compare(teacher1, teacher2).Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_Ascending_DifferentConsultingHours()
+    {
+        var comparer = new ByHourComparer(true);
+        var teacher1 = new Teacher("Teacher1")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE02
+        };
+        var teacher2 = new Teacher("Teacher2")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+
+        int result = comparer.Compare(teacher1, teacher2);
+
+        result.Should().Be(1);
+    }
+
+    [Fact]
+    public void Compare_Descending_FirstNull()
+    {
+        var comparer = new ByHourComparer(false);
+        var teacher2 = new Teacher("Teacher2")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Tuesday, 
+            ConsultingHourUnit = SchoolUnit.UE02
+        };
+
+        comparer.Compare(null, teacher2).Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_Descending_SecondNull()
+    {
+        var comparer = new ByHourComparer(false);
+        var teacher1 = new Teacher("Teacher1")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+
+        comparer.Compare(teacher1, null).Should().Be(1);
+    }
+    
+    [Fact]
+    public void Compare_Descending_DifferentWeekDays()
+    {
+        var comparer = new ByHourComparer(false);
+        var teacher1 = new Teacher("Teacher1")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+        var teacher2 = new Teacher("Teacher2")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Tuesday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+
+        comparer.Compare(teacher1, teacher2).Should().Be(1);
+    }
+
+    [Fact]
+    public void Compare_Descending_DifferentConsultingHours()
+    {
+        var comparer = new ByHourComparer(false);
+        var teacher1 = new Teacher("Teacher1")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE02
+        };
+        var teacher2 = new Teacher("Teacher2")
+        {
+            ConsultingHourWeekDay = DayOfWeek.Monday, 
+            ConsultingHourUnit = SchoolUnit.UE01
+        };
+
+        int result = comparer.Compare(teacher1, teacher2);
+
+        result.Should().Be(-1);
+    }
+}
--- a/MeetTheTeacher.Test/Model/Comparison/ByNameComparerTests.cs
+++ b/MeetTheTeacher.Test/Model/Comparison/ByNameComparerTests.cs
@ -0,0 +1,70 @@
+using MeetTheTeacher.Model;
+using MeetTheTeacher.Model.Comparison;
+
+namespace MeetTheTeacher.Test.Model.Comparison;
+
+public sealed class ByNameComparerTests
+{
+    [Fact]
+    public void Compare_Ascending_BothNull()
+    {
+        var comparer = new ByNameComparer(true);
+        comparer.Compare(null, null).Should().Be(0);
+    }
+
+    [Fact]
+    public void Compare_Ascending_FirstNull()
+    {
+        var teacher2 = new Teacher("Teacher2");
+        var comparer = new ByNameComparer(true);
+        
+        comparer.Compare(null, teacher2).Should().Be(1);
+    }
+
+    [Fact]
+    public void Compare_Ascending_SecondNull()
+    {
+        var teacher1 = new Teacher("Teacher1");
+        var comparer = new ByNameComparer(true);
+        
+        comparer.Compare(teacher1, null).Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_Ascending_DifferentNames()
+    {
+        var teacher1 = new Teacher("Teacher1");
+        var teacher2 = new Teacher("Teacher2");
+        var comparer = new ByNameComparer(true);
+        
+        comparer.Compare(teacher1, teacher2).Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_Descending_FirstNull()
+    {
+        var teacher2 = new Teacher("Teacher2");
+        var comparer = new ByNameComparer(false);
+        
+        comparer.Compare(null, teacher2).Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_Descending_SecondNull()
+    {
+        var teacher1 = new Teacher("Teacher1");
+        var comparer = new ByNameComparer(false);
+        
+        comparer.Compare(teacher1, null).Should().Be(1);
+    }
+
+    [Fact]
+    public void Compare_Descending_DifferentNames()
+    {
+        var teacher1 = new Teacher("Teacher1");
+        var teacher2 = new Teacher("Teacher2");
+        var comparer = new ByNameComparer(false);
+        
+        comparer.Compare(teacher1, teacher2).Should().Be(1);
+    }
+}
--- a/MeetTheTeacher.Test/Model/Comparison/ByRoomComparerTests.cs
+++ b/MeetTheTeacher.Test/Model/Comparison/ByRoomComparerTests.cs
@ -0,0 +1,64 @@
+using MeetTheTeacher.Model;
+using MeetTheTeacher.Model.Comparison;
+
+namespace MeetTheTeacher.Test.Model.Comparison;
+
+public sealed class ByRoomComparerTests
+{
+    private readonly IComparer<Teacher> _comparer;
+    
+    public ByRoomComparerTests()
+    {
+        _comparer = new ByRoomComparer();
+    }
+
+    [Fact]
+    public void Compare_BothNull()
+    {
+        _comparer.Compare(null, null).Should().Be(0);
+    }
+
+    [Fact]
+    public void Compare_FirstNull()
+    {
+        _comparer.Compare(null, new Teacher("Teacher2") { Room = "B" })
+                 .Should().Be(1);
+    }
+
+    [Fact]
+    public void Compare_SecondNull()
+    {
+        _comparer.Compare(new Teacher("Teacher1") { Room = "A" }, null)
+                 .Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_SameRoom()
+    {
+        var teacher1 = new Teacher("Teacher1") { Room = "A" };
+        var teacher2 = new Teacher("Teacher2") { Room = "A" };
+
+        _comparer.Compare(teacher1, teacher2)
+                 .Should().Be(0);
+    }
+
+    [Fact]
+    public void Compare_FirstIsLess()
+    {
+        var teacher1 = new Teacher("Teacher1") { Room = "A" };
+        var teacher2 = new Teacher("Teacher2") { Room = "B" };
+
+        _comparer.Compare(teacher1, teacher2)
+                 .Should().Be(-1);
+    }
+
+    [Fact]
+    public void Compare_FirstIsGreater()
+    {
+        var teacher1 = new Teacher("Teacher1") { Room = "B" };
+        var teacher2 = new Teacher("Teacher2") { Room = "A" };
+
+        _comparer.Compare(teacher1, teacher2)
+                 .Should().Be(1);
+    }
+}
--- a/MeetTheTeacher.Test/Model/CsvDataTests.cs
+++ b/MeetTheTeacher.Test/Model/CsvDataTests.cs
@ -0,0 +1,62 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Model;
+
+public sealed class CsvDataTests
+{
+    [Fact]
+    public void GetHeader_Valid()
+    {
+        var headerNames = new List<string> { "Name", "Day", "ConsultingHour", "Room" };
+        var data = new List<string> { "Teacher1", "Monday", "10:00-12:00", "A1" };
+        
+        var csvData = new CsvData(headerNames, data);
+
+        csvData.GetHeader().Should().Be("Name;Day;ConsultingHour;Room");
+    }
+
+    [Fact]
+    public void GetData_Valid()
+    {
+        var headerNames = new List<string> { "Name", "Day", "ConsultingHour", "Room" };
+        var data = new List<string> { "Teacher1", "Monday", "10:00-12:00", "A1" };
+        
+        var csvData = new CsvData(headerNames, data);
+
+        csvData.GetData().Should().Be("Teacher1;Monday;10:00-12:00;A1");
+    }
+
+    [Fact]
+    public void Deconstruct_Valid()
+    {
+        var headerNames = new List<string> { "Name", "Day", "ConsultingHour", "Room" };
+        var data = new List<string> { "Teacher1", "Monday", "10:00-12:00", "A1" };
+        
+        var csvData = new CsvData(headerNames, data);
+
+        var (deconstructedHeaderNames, deconstructedData) = csvData;
+
+        deconstructedHeaderNames.Should().BeEquivalentTo(headerNames);
+        deconstructedData.Should().BeEquivalentTo(data);
+    }
+    
+    [Theory]
+    [MemberData(nameof(EmptyInputData))]
+    public void GetHeaderAndData_EmptyInputData_ReturnsEmptyString(string[] headerNames, string[] data)
+    {
+        var csvData = new CsvData(headerNames, data);
+
+        string header = csvData.GetHeader();
+        string rowData = csvData.GetData();
+
+        header.Should().Be(string.Join(CsvData.Separator, headerNames));
+        rowData.Should().Be(string.Join(CsvData.Separator, data));
+    }
+    
+    public static TheoryData<string[], string[]> EmptyInputData => new()
+    {
+        { Array.Empty<string>(), new[] { "Teacher1", "Monday", "10:00-12:00", "A1" } },
+        { new[] { "Name", "Day", "ConsultingHour", "Room" }, Array.Empty<string>() },
+        { Array.Empty<string>(), Array.Empty<string>() }
+    };
+}
--- a/MeetTheTeacher.Test/Model/TeacherTests.cs
+++ b/MeetTheTeacher.Test/Model/TeacherTests.cs
@ -0,0 +1,41 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Model;
+
+public sealed class TeacherTests
+{
+     [Fact]
+        public void ToCsvData_Valid()
+        {
+            var teacher = new Teacher("John Doe")
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(10, 0), 
+                                               new TimeOnly(12, 0)),
+                ConsultingHourUnit = SchoolUnit.UE01,
+                ConsultingHourWeekDay = DayOfWeek.Monday,
+                Room = "A1"
+            };
+
+            var csvData = teacher.ToCsvData();
+
+            csvData.HeaderNames.Should().Equal("Name", "Day", "ConsultingHour", "Room");
+            csvData.Data.Should().ContainInOrder("John Doe", "Monday", "10:00-12:00 (UE01)", "A1");
+        }
+
+        [Fact]
+        public void ToCsvData_OptionalPropertiesNull()
+        {
+            var teacher = new Teacher("Jane Doe")
+            {
+                ConsultingHour = null,
+                ConsultingHourUnit = null,
+                ConsultingHourWeekDay = null,
+                Room = null
+            };
+
+            var csvData = teacher.ToCsvData();
+
+            csvData.HeaderNames.Should().Equal("Name", "Day", "ConsultingHour", "Room");
+            csvData.Data.Should().ContainInOrder("Jane Doe", string.Empty, string.Empty, string.Empty);
+        }
+}
--- a/MeetTheTeacher.Test/Model/TeacherWithBusinessCardTests.cs
+++ b/MeetTheTeacher.Test/Model/TeacherWithBusinessCardTests.cs
@ -0,0 +1,43 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Model;
+
+public sealed class TeacherWithBusinessCardTests
+{
+    [Fact]
+    public void ToCsvData_Valid()
+    {
+        var teacher = new TeacherWithBusinessCard("John Doe", 1)
+        {
+            ConsultingHour = new TimeFrame(new TimeOnly(10, 0), 
+                                           new TimeOnly(12, 0)),
+            ConsultingHourUnit = SchoolUnit.UE07,
+            ConsultingHourWeekDay = DayOfWeek.Monday,
+            Room = "A1"
+        };
+
+        var csvData = teacher.ToCsvData();
+
+        csvData.HeaderNames.Should().Equal("Name", "Day", "ConsultingHour", "Room", "Image");
+        csvData.Data.Should().Equal("John Doe", "Monday", "10:00-12:00 (UE07)", "A1", 
+                                    "https://www.htl-leonding.at/media/teacher-avatar/1");
+    }
+
+    [Fact]
+    public void ToCsvData_OptionalPropertiesNull()
+    {
+        var teacher = new TeacherWithBusinessCard("Jane Doe", 2)
+        {
+            ConsultingHour = null,
+            ConsultingHourUnit = null,
+            ConsultingHourWeekDay = null,
+            Room = null
+        };
+
+        var csvData = teacher.ToCsvData();
+
+        csvData.HeaderNames.Should().Equal("Name", "Day", "ConsultingHour", "Room", "Image");
+        csvData.Data.Should().Equal("Jane Doe", string.Empty, string.Empty, string.Empty, 
+                                    "https://www.htl-leonding.at/media/teacher-avatar/2");
+    }
+}
--- a/MeetTheTeacher.Test/Model/TimeFrameTests.cs
+++ b/MeetTheTeacher.Test/Model/TimeFrameTests.cs
@ -0,0 +1,67 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Test.Model;
+
+public sealed class TimeFrameTests
+{
+    [Fact]
+    public void Construction_Simple()
+    {
+        var start = new TimeOnly(14, 51);
+        var end = new TimeOnly(17, 28);
+        
+        var tf = new TimeFrame(start, end);
+
+        tf.Start.Should().Be(start);
+        tf.End.Should().Be(end);
+    }
+
+    [Theory]
+    [InlineData("10:00-12:00", "10:00", "12:00")]
+    [InlineData("14:30-15:00", "14:30", "15:00")]
+    [InlineData("09:15-09:45", "09:15", "09:45")]
+    public void TryParse_Valid(string input, string expectedStart, string expectedEnd)
+    {
+        TimeFrame.TryParse(input, out TimeFrame? result).Should().BeTrue();
+
+        result.Should().NotBeNull();
+        result?.Start.Should().Be(TimeOnly.Parse(expectedStart));
+        result?.End.Should().Be(TimeOnly.Parse(expectedEnd));
+    }
+
+    [Theory]
+    [InlineData("12:00-10:00", "10:00", "12:00")]
+    [InlineData("15:00-14:30", "14:30", "15:00")]
+    public void TryParse_StartEndSwapped(string input, string expectedStart, string expectedEnd)
+    {
+        TimeFrame.TryParse(input, out TimeFrame? result).Should().BeTrue();
+
+        result.Should().NotBeNull();
+        result?.Start.Should().Be(TimeOnly.Parse(expectedStart));
+        result?.End.Should().Be(TimeOnly.Parse(expectedEnd));
+    }
+
+    [Theory]
+    [InlineData("invalid-12:00")]
+    [InlineData("10:00-invalid")]
+    [InlineData("25:00-12:00")]
+    [InlineData("10:00-28:00")]
+    [InlineData("10:62-22:00")]
+    [InlineData("10:a2-22:00")]
+    [InlineData("  ")]
+    [InlineData("")]
+    public void TryParse_InvalidInputs_ReturnsFalse(string input)
+    {
+        TimeFrame.TryParse(input, out TimeFrame? result).Should().BeFalse();
+
+        result.Should().BeNull();
+    }
+
+    [Fact]
+    public void StringRepresentation()
+    {
+        var timeFrame = new TimeFrame(new TimeOnly(10, 0), new TimeOnly(12, 0));
+
+        timeFrame.ToString().Should().Be("10:00-12:00");
+    }
+}
--- a/MeetTheTeacher.sln
+++ b/MeetTheTeacher.sln
@ -0,0 +1,31 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.4.33103.184
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MeetTheTeacher", "MeetTheTeacher\MeetTheTeacher.csproj", "{7F30E637-BAFE-42FA-A173-F42B3902ED3B}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MeetTheTeacher.Test", "MeetTheTeacher.Test\MeetTheTeacher.Test.csproj", "{161D9B2A-4E8B-43B6-A77E-40BED559521F}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{7F30E637-BAFE-42FA-A173-F42B3902ED3B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7F30E637-BAFE-42FA-A173-F42B3902ED3B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7F30E637-BAFE-42FA-A173-F42B3902ED3B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7F30E637-BAFE-42FA-A173-F42B3902ED3B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{161D9B2A-4E8B-43B6-A77E-40BED559521F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{161D9B2A-4E8B-43B6-A77E-40BED559521F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{161D9B2A-4E8B-43B6-A77E-40BED559521F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{161D9B2A-4E8B-43B6-A77E-40BED559521F}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {D322E690-379C-4802-8F7E-1AC6AD090D59}
+	EndGlobalSection
+EndGlobal
--- a/MeetTheTeacher/Export/CsvDataExporter.cs
+++ b/MeetTheTeacher/Export/CsvDataExporter.cs
@ -0,0 +1,18 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Allows to export data of <see cref="ICsvRepresentable"/> type to a CSV file
+/// </summary>
+/// <inheritdoc cref="FileExporterBase" />
+/// <inheritdoc cref="IDataExporter" />
+public sealed class CsvDataExporter : FileExporterBase, IDataExporter
+{
+    public void Export(IEnumerable<ICsvRepresentable> items, string? fileName)
+    {
+        // TODO
+    }
+
+    protected override string FileExtension => ".csv";
+}
--- a/MeetTheTeacher/Export/DefaultExporterProvider.cs
+++ b/MeetTheTeacher/Export/DefaultExporterProvider.cs
@ -0,0 +1,12 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Default implementation of <see cref="IExporterProvider"/> which returns the following exporters:
+///     <see cref="CsvDataExporter"/> and <see cref="HtmlDataExporter"/>
+/// </summary>
+public sealed class DefaultExporterProvider : IExporterProvider
+{
+    public IDataExporter GetExporter(ExportFormat exportFormat) => null!; // TODO
+}
--- a/MeetTheTeacher/Export/Exporter.cs
+++ b/MeetTheTeacher/Export/Exporter.cs
@ -0,0 +1,37 @@
+using MeetTheTeacher.Model;
+using MeetTheTeacher.Model.Comparison;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     A utility class which allows to export data in a given format and order
+/// </summary>
+public sealed class Exporter
+{
+    // TODO
+    //private readonly IComparer<Teacher> _comparer;
+    private readonly IDataExporter _exporter;
+
+    /// <summary>
+    ///     Creates a new instance of <see cref="Exporter" /> initialized with the provided export options
+    /// </summary>
+    /// <param name="sortOrder">Order in which data should be sorted before export</param>
+    /// <param name="exportFormat">Desired export format</param>
+    /// <param name="exporterProvider">Export provider which supports exporting in the desired format</param>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown if you manage to pass an unexpected <see cref="SortOrder" /> value</exception>
+    public Exporter(SortOrder sortOrder, ExportFormat exportFormat, IExporterProvider exporterProvider)
+    {
+        _exporter = exporterProvider.GetExporter(exportFormat);
+        //_comparer = ... // TODO
+    }
+
+    /// <summary>
+    ///     First sorts the provided data based on the previous settings, then performs the actual export to a file
+    /// </summary>
+    /// <param name="fileName">Name of the file to export to; without extension</param>
+    /// <param name="teachers">Data to export - has to be list due to multiple enumeration</param>
+    public void Export(string fileName, List<Teacher> teachers)
+    {
+        // TODO
+    }
+}
--- a/MeetTheTeacher/Export/FileExporterBase.cs
+++ b/MeetTheTeacher/Export/FileExporterBase.cs
@ -0,0 +1,36 @@
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Base class for exporters which write data to a file
+/// </summary>
+public abstract class FileExporterBase
+{
+    /// <summary>
+    ///     File extension of the exported file including the dot
+    /// </summary>
+    protected abstract string FileExtension { get; }
+    
+    /// <summary>
+    ///     Exports the given content to a file with the given name.
+    ///     If the file already exists, it will be overwritten.
+    /// </summary>
+    /// <param name="fileName">Name of the file to export without the extension</param>
+    /// <param name="content">Content to write into the file</param>
+    protected void Export(string fileName, string content)
+    {
+        // TODO (don't forget to delete)
+    }
+    
+    /// <summary>
+    ///     Joins several lines into one text, separated by line breaks
+    /// </summary>
+    /// <param name="lines">Lines to merge</param>
+    /// <returns>A text containing all lines</returns>
+    protected static string LinesToText(IEnumerable<string> lines) => null!; // TODO (remember to use proper line break)
+
+    private string GetFilePath(string fileName)
+    {
+        // TODO (remember to use the current directory)
+        return null!;
+    }
+}
--- a/MeetTheTeacher/Export/HtmlDataExporter.cs
+++ b/MeetTheTeacher/Export/HtmlDataExporter.cs
@ -0,0 +1,27 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Allows to export data of <see cref="ICsvRepresentable"/> type to a file in HTML table syntax.
+///     Be careful: does not create valid HTML page, just a fragment!
+/// </summary>
+/// <inheritdoc cref="FileExporterBase" />
+/// <inheritdoc cref="IDataExporter" />
+public sealed class HtmlDataExporter : FileExporterBase, IDataExporter
+{
+    public void Export(IEnumerable<ICsvRepresentable> items, string? fileName)
+    {
+        // TODO (use a raw string literal with interpolation!)
+    }
+
+    private static string CreateTableRow(IEnumerable<string> values, bool isHeader = false)
+    {
+        // TODO
+        return null!;
+    }
+    
+    private static string WrapInTag(string content, string tag) => $"<{tag}>{content}</{tag}>";
+
+    protected override string FileExtension => ".html";
+}
--- a/MeetTheTeacher/Export/IDataExporter.cs
+++ b/MeetTheTeacher/Export/IDataExporter.cs
@ -0,0 +1,17 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Allows to export data of <see cref="ICsvRepresentable"/> type
+/// </summary>
+public interface IDataExporter
+{
+    /// <summary>
+    ///     Exports the given data.
+    ///     File based exporters will use the provided file name as the name of the file they export.
+    /// </summary>
+    /// <param name="data">Data to export</param>
+    /// <param name="fileName">File name to be used; without the extension</param>
+    void Export(IEnumerable<ICsvRepresentable> data, string? fileName);
+}
--- a/MeetTheTeacher/Export/IExporterProvider.cs
+++ b/MeetTheTeacher/Export/IExporterProvider.cs
@ -0,0 +1,16 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Provides an <see cref="IDataExporter"/> for the given <see cref="ExportFormat"/>
+/// </summary>
+public interface IExporterProvider
+{
+    /// <summary>
+    ///     Returns an <see cref="IDataExporter"/> for the given <see cref="ExportFormat"/>
+    /// </summary>
+    /// <param name="exportFormat">Requested export format</param>
+    /// <returns><see cref="IDataExporter"/> which supports exporting in the desired format</returns>
+    IDataExporter GetExporter(ExportFormat exportFormat);
+}
--- a/MeetTheTeacher/Export/SpectreTableExporter.cs
+++ b/MeetTheTeacher/Export/SpectreTableExporter.cs
@ -0,0 +1,51 @@
+using MeetTheTeacher.Model;
+using Spectre.Console;
+
+namespace MeetTheTeacher.Export;
+
+/// <summary>
+///     Allows to export data of <see cref="ICsvRepresentable" /> type to a <see cref="Table" /> in-memory data structure
+/// </summary>
+/// <inheritdoc cref="IDataExporter" />
+public sealed class SpectreTableExporter : IDataExporter
+{
+    /// <summary>
+    ///     Creates a new instance of the exporter with an empty <see cref="Table" />
+    /// </summary>
+    public SpectreTableExporter()
+    {
+        Table = new Table();
+    }
+
+    /// <summary>
+    ///     Gets the table containing the exported data
+    /// </summary>
+    public Table Table { get; private set; }
+
+    /// <summary>
+    ///     Exports the given data to a <see cref="Table" />.
+    ///     Does not write a file.
+    /// </summary>
+    /// <param name="data">Data to export</param>
+    /// <param name="fileName">Unused</param>
+    public void Export(IEnumerable<ICsvRepresentable> data, string? fileName)
+    {
+        var dataRows = new List<CsvData>();
+        foreach (var csvRepresentable in data)
+        {
+            dataRows.Add(csvRepresentable.ToCsvData());
+        }
+
+        var table = new Table();
+
+        // TODO
+
+        Table = table;
+    }
+
+    private static IEnumerable<string> FindMaxHeaderColumns(IEnumerable<CsvData> rows)
+    {
+        // TODO
+        return null!;
+    }
+}
--- a/MeetTheTeacher/Import/ITeacherDataImporter.cs
+++ b/MeetTheTeacher/Import/ITeacherDataImporter.cs
@ -0,0 +1,16 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Import;
+
+/// <summary>
+///     Allows to import data of <see cref="Teacher" /> type
+/// </summary>
+public interface ITeacherDataImporter
+{
+    /// <summary>
+    ///     Loads the data from various sources.
+    ///     Mind that instances of <see cref="Teacher"/> and <see cref="TeacherWithBusinessCard"/> can be returned.
+    /// </summary>
+    /// <returns>A collection of <see cref="Teacher"/> data</returns>
+    IEnumerable<Teacher> LoadTeacherData();
+}
--- a/MeetTheTeacher/Import/TeacherDataCsvImporter.cs
+++ b/MeetTheTeacher/Import/TeacherDataCsvImporter.cs
@ -0,0 +1,54 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Import;
+
+/// <summary>
+///     Imports <see cref="Teacher" /> data from CSV files
+/// </summary>
+/// <inheritdoc cref="ITeacherDataImporter" />
+public sealed class TeacherDataCsvImporter : ITeacherDataImporter
+{
+    private readonly string _businessCardDataFilePath;
+    private readonly string _generalDataFilePath;
+
+    /// <summary>
+    ///     Creates a new instance of <see cref="TeacherDataCsvImporter" /> configured to read from the given files
+    /// </summary>
+    /// <param name="generalDataFilePath">Path to file containing general <see cref="Teacher" /> data for all teachers</param>
+    /// <param name="businessCardDataFilePath">
+    ///     Path to file containing additional data for <see cref="TeacherWithBusinessCard" /> teachers
+    /// </param>
+    public TeacherDataCsvImporter(string generalDataFilePath, string businessCardDataFilePath)
+    {
+        _generalDataFilePath = generalDataFilePath;
+        _businessCardDataFilePath = businessCardDataFilePath;
+    }
+
+    public IEnumerable<Teacher> LoadTeacherData()
+    {
+        // TODO
+        return null!;
+    }
+
+    private static Dictionary<string, Teacher> CombineData(Dictionary<string, Teacher> generalData,
+                                                           IEnumerable<(string name, int id)> businessCardData)
+    {
+        // Note: this method is designed specifically to force you to deal with the dictionary and 
+        // different teacher classes as value. It could be done in different ways as well, of course.
+
+        // TODO
+        return null!;
+    }
+
+    private IEnumerable<(string name, int id)>? ReadTeacherBusinessCardData()
+    {
+        // TODO - CSV import (mind the return type: ValueTuple!)
+        return null!;
+    }
+
+    private Dictionary<string, Teacher>? ReadTeacherData()
+    {
+        // TODO - CSV import
+        return null!;
+    }
+}
--- a/MeetTheTeacher/Import/TeacherDataFakeImporter.cs
+++ b/MeetTheTeacher/Import/TeacherDataFakeImporter.cs
@ -0,0 +1,57 @@
+using MeetTheTeacher.Model;
+
+namespace MeetTheTeacher.Import;
+
+/// <summary>
+///     Fake implementation of <see cref="ITeacherDataImporter" /> which returns a fixed set of data.
+/// </summary>
+/// <inheritdoc cref="ITeacherDataImporter" />
+public sealed class TeacherDataFakeImporter : ITeacherDataImporter
+{
+    public IEnumerable<Teacher> LoadTeacherData() =>
+        new List<Teacher>
+        {
+            new("John Doe")
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(8, 0), new TimeOnly(8, 50)),
+                ConsultingHourUnit = SchoolUnit.UE01,
+                ConsultingHourWeekDay = DayOfWeek.Monday,
+                Room = "A101"
+            },
+            new("Jane Smith")
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(14, 35), new TimeOnly(15, 25)),
+                ConsultingHourUnit = SchoolUnit.UE08,
+                ConsultingHourWeekDay = DayOfWeek.Tuesday,
+                Room = "A102"
+            },
+            new("Alice Johnson")
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(10, 0), new TimeOnly(10, 50)),
+                ConsultingHourUnit = SchoolUnit.UE03,
+                ConsultingHourWeekDay = DayOfWeek.Wednesday,
+                Room = "A102"
+            },
+            new("Bob Brown")
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(10, 55), new TimeOnly(11, 45)),
+                ConsultingHourUnit = SchoolUnit.UE04,
+                ConsultingHourWeekDay = DayOfWeek.Friday,
+                Room = "A104"
+            },
+            new TeacherWithBusinessCard("Emily Davis", 1001)
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(12, 40), new TimeOnly(13, 35)),
+                ConsultingHourUnit = SchoolUnit.UE06,
+                ConsultingHourWeekDay = DayOfWeek.Thursday,
+                Room = "A101"
+            },
+            new TeacherWithBusinessCard("Tom Wilson", 1002)
+            {
+                ConsultingHour = new TimeFrame(new TimeOnly(8, 50), new TimeOnly(9, 45)),
+                ConsultingHourUnit = SchoolUnit.UE02,
+                ConsultingHourWeekDay = DayOfWeek.Monday,
+                Room = "A102"
+            }
+        };
+}
--- a/MeetTheTeacher/MeetTheTeacher.csproj
+++ b/MeetTheTeacher/MeetTheTeacher.csproj
@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+	<PropertyGroup>
+		<OutputType>Exe</OutputType>
+		<TargetFramework>net9.0</TargetFramework>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<Nullable>enable</Nullable>
+		<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+	</PropertyGroup>
+
+	<ItemGroup>
+	  <PackageReference Include="Spectre.Console" Version="0.49.2-preview.0.77" />
+	  <PackageReference Include="Spectre.Console.ImageSharp" Version="0.49.2-preview.0.77" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<Content Include="..\Data\*.csv" Link="Data\%(Filename)%(Extension)">
+			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+		</Content>
+	</ItemGroup>
+
+	<ItemGroup>
+	  <None Update="happy-dog.png">
+	    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+	  </None>
+	</ItemGroup>
+
+</Project>
--- a/MeetTheTeacher/Model/Comparison/ByHourComparer.cs
+++ b/MeetTheTeacher/Model/Comparison/ByHourComparer.cs
@ -0,0 +1,22 @@
+namespace MeetTheTeacher.Model.Comparison;
+
+/// <summary>
+///     Compares <see cref="Teacher" /> instances by their consulting hour, sorting in ascending order.
+///     First compares by <see cref="DayOfWeek" />, then by <see cref="SchoolUnit" />.
+/// </summary>
+/// <inheritdoc cref="ComparerBase" />
+/// <inheritdoc cref="IComparer{Teacher}" />
+public sealed class ByHourComparer : ComparerBase, IComparer<Teacher>
+{
+    /// <summary>
+    ///     Creates a new instance of <see cref="ByHourComparer" /> configured to sort in ascending or descending order
+    /// </summary>
+    /// <param name="ascending">Flag indicating if items should be sorted in ascending order; descending if false</param>
+    public ByHourComparer(bool ascending) : base(ascending) { }
+
+    public int Compare(Teacher? x, Teacher? y)
+    {
+        // TODO
+        return -1;
+    }
+}
--- a/MeetTheTeacher/Model/Comparison/ByNameComparer.cs
+++ b/MeetTheTeacher/Model/Comparison/ByNameComparer.cs
@ -0,0 +1,22 @@
+namespace MeetTheTeacher.Model.Comparison;
+
+/// <summary>
+///     A comparer which allows sorting <see cref="Teacher" /> instances by their name in either ascending or descending
+///     order
+/// </summary>
+/// <inheritdoc cref="ComparerBase" />
+/// <inheritdoc cref="IComparer{Teacher}"/>
+public sealed class ByNameComparer : ComparerBase, IComparer<Teacher>
+{
+    /// <summary>
+    ///     Creates a new instance of <see cref="ByNameComparer" /> configured to sort in ascending or descending order
+    /// </summary>
+    /// <param name="ascending">Flag indicating if items should be sorted in ascending order; descending if false</param>
+    public ByNameComparer(bool ascending) : base(ascending) { }
+
+    public int Compare(Teacher? x, Teacher? y)
+    {
+        // TODO
+        return -1;
+    }
+}
--- a/MeetTheTeacher/Model/Comparison/ByRoomComparer.cs
+++ b/MeetTheTeacher/Model/Comparison/ByRoomComparer.cs
@ -0,0 +1,14 @@
+namespace MeetTheTeacher.Model.Comparison;
+
+/// <summary>
+///     Compares <see cref="Teacher"/> instances by their room, sorting in ascending order
+/// </summary>
+/// <inheritdoc cref="IComparer{Teacher}"/>
+public sealed class ByRoomComparer : IComparer<Teacher>
+{
+    public int Compare(Teacher? x, Teacher? y)
+    {
+        // TODO
+        return -1;
+    }
+}
--- a/MeetTheTeacher/Model/Comparison/ComparerBase.cs
+++ b/MeetTheTeacher/Model/Comparison/ComparerBase.cs
@ -0,0 +1,24 @@
+namespace MeetTheTeacher.Model.Comparison;
+
+/// <summary>
+///     Base class for comparers which allow switching between ascending and descending mode
+/// </summary>
+public abstract class ComparerBase
+{
+    /// <summary>
+    ///     Creates a new instance of <see cref="ComparerBase" /> configured to sort in ascending or descending order
+    /// </summary>
+    /// <param name="ascending">Flag indicating if items should be sorted in ascending order; descending if false</param>
+    protected ComparerBase(bool ascending)
+    {
+        Ascending = ascending;
+    }
+
+    /// <summary>
+    ///     Gets if the comparer is configured to sort in ascending order; descending if false
+    /// </summary>
+    protected bool Ascending { get; }
+	
+	// TODO: consider moving the basic RefEquals code of CompareTo from the subclasses here
+	// maybe also rename this to SortOrderComparerBase or something and introduce another, common base class for all three?
+}
--- a/MeetTheTeacher/Model/CsvData.cs
+++ b/MeetTheTeacher/Model/CsvData.cs
@ -0,0 +1,57 @@
+namespace MeetTheTeacher.Model;
+
+/// <summary>
+///     Represents a single entity as a CSV processable object.
+/// </summary>
+public sealed class CsvData
+{
+    /// <summary>
+    ///     Separator used in CSV files
+    /// </summary>
+    public const char Separator = ';';
+
+    /// <summary>
+    ///     Creates a new instance of <see cref="CsvData" />
+    /// </summary>
+    /// <param name="headerNames">Header column names for the entity which has its data represented by this object</param>
+    /// <param name="data">Data column values for the entity which has its data represented by this object; stringly typed</param>
+    public CsvData(IReadOnlyList<string> headerNames, IReadOnlyList<string> data)
+    {
+        HeaderNames = headerNames;
+        Data = data;
+    }
+
+    /// <summary>
+    ///     Gets the header column names for the entity which has its data represented by this object
+    /// </summary>
+    public IReadOnlyList<string> HeaderNames { get; }
+
+    /// <summary>
+    ///     Gets the data column values for the entity which has its data represented by this object; stringly typed
+    /// </summary>
+    public IReadOnlyList<string> Data { get; }
+
+    /// <summary>
+    ///     Gets a CSV header based on <see cref="HeaderNames" />
+    /// </summary>
+    /// <returns>A CSV header line</returns>
+    public string GetHeader() => null!; // TODO
+
+    /// <summary>
+    ///     Gets a CSV data line based on <see cref="Data" />
+    /// </summary>
+    /// <returns>A CSV data line</returns>
+    public string GetData() => null!; // TODO
+
+    /// <summary>
+    ///     Allows to deconstruct the object into its header and data parts
+    /// </summary>
+    /// <param name="headerNames">Set to <see cref="HeaderNames" /></param>
+    /// <param name="data">Set to <see cref="Data" /></param>
+    public void Deconstruct(out IReadOnlyList<string> headerNames, out IReadOnlyList<string> data)
+    {
+        // TODO
+        headerNames = null!;
+        data = null!;
+    }
+}
--- a/MeetTheTeacher/Model/ICsvRepresentable.cs
+++ b/MeetTheTeacher/Model/ICsvRepresentable.cs
@ -0,0 +1,13 @@
+namespace MeetTheTeacher.Model;
+
+/// <summary>
+///     Allows to represent the entity in a CSV compatible way
+/// </summary>
+public interface ICsvRepresentable
+{
+    /// <summary>
+    ///     Converts the entity to a <see cref="CsvData" /> instance
+    /// </summary>
+    /// <returns>A <see cref="CsvData" /> instance representing this entity</returns>
+    CsvData ToCsvData();
+}
--- a/MeetTheTeacher/Model/Teacher.cs
+++ b/MeetTheTeacher/Model/Teacher.cs
@ -0,0 +1,54 @@
+namespace MeetTheTeacher.Model;
+
+/// <summary>
+///     Represents a teacher at a vocational college
+/// </summary>
+/// <inheritdoc cref="ICsvRepresentable" />
+public class Teacher : ICsvRepresentable
+{
+    /// <summary>
+    ///     Creates a new instance of <see cref="Teacher" />.
+    ///     The name is the only required property.
+    /// </summary>
+    /// <param name="name">Name of the teacher</param>
+    public Teacher(string name)
+    {
+        Name = name;
+    }
+
+    /// <summary>
+    ///     Gets the name of the teacher
+    /// </summary>
+    public string Name { get; }
+
+    /// <summary>
+    ///     Gets the time frame in which the teacher is available for consulting
+    /// </summary>
+    public TimeFrame? ConsultingHour { get; init; }
+
+    /// <summary>
+    ///     Gets the school unit in which the teacher is available for consulting
+    /// </summary>
+    public SchoolUnit? ConsultingHourUnit { get; init; }
+
+    /// <summary>
+    ///     Gets the day of the week the teacher is available for consulting
+    /// </summary>
+    public DayOfWeek? ConsultingHourWeekDay { get; init; }
+
+    /// <summary>
+    ///     Gets the room in which the teacher is available for consulting
+    /// </summary>
+    public string? Room { get; init; }
+
+    private string? ConsultingHourTime
+    {
+        get
+        {
+            // TODO
+            return null!;
+        }
+    }
+
+    public virtual CsvData ToCsvData() => null!; // TODO
+}
--- a/MeetTheTeacher/Model/TeacherWithBusinessCard.cs
+++ b/MeetTheTeacher/Model/TeacherWithBusinessCard.cs
@ -0,0 +1,32 @@
+namespace MeetTheTeacher.Model;
+
+/// <summary>
+///     Represents a teacher with a business card which means they have an id for their picture available as well
+/// </summary>
+/// <inheritdoc cref="Teacher" />
+public sealed class TeacherWithBusinessCard : Teacher
+{
+    private const string BaseUrl = "https://www.htl-leonding.at/media/teacher-avatar";
+
+    /// <summary>
+    ///     Creates a new instance of <see cref="TeacherWithBusinessCard" />.
+    ///     In addition to the name, the id of the picture is required as well.
+    /// </summary>
+    /// <param name="name">Name of the teacher</param>
+    /// <param name="id">Id of the teacher's picture</param>
+    public TeacherWithBusinessCard(string name, int id) : base(name)
+    {
+        Id = id;
+    }
+
+    /// <summary>
+    ///     Gets the picture id of the teacher
+    /// </summary>
+    public int Id { get; }
+
+    public override CsvData ToCsvData()
+    {
+        // TODO (remember to maybe use the base implementation...)
+        return null!;
+    }
+}
--- a/MeetTheTeacher/Model/TimeFrame.cs
+++ b/MeetTheTeacher/Model/TimeFrame.cs
@ -0,0 +1,38 @@
+using System.Globalization;
+
+namespace MeetTheTeacher.Model;
+
+/// <summary>
+///     Represents a time frame between a start and end time.
+///     Start time is always before end time.
+/// </summary>
+/// <param name="Start">Start time</param>
+/// <param name="End">End time</param>
+public readonly record struct TimeFrame(TimeOnly Start, TimeOnly End)
+{
+    private static readonly CultureInfo culture = new ("de-AT");
+    
+    /// <summary>
+    ///     Tries to parse a time frame from a string in format HH:MM-HH:MM.
+    ///     Additional whitespace is trimmed and ignored.
+    /// </summary>
+    /// <param name="timeFrame">Timeframe string to parse</param>
+    /// <param name="result">Set to the parsed time frame if possible</param>
+    /// <returns>True if time frame could be parsed successfully; false otherwise</returns>
+    public static bool TryParse(string timeFrame, out TimeFrame? result)
+    {
+        // TODO
+        result = null;
+        return false;
+    }
+
+    /// <summary>
+    ///     Returns a string representation of the time frame in format HH:MM-HH:MM
+    /// </summary>
+    /// <returns></returns>
+    public override string ToString()
+    {
+        // TODO
+        return null!; 
+    }
+}
--- a/MeetTheTeacher/Model/Various.cs
+++ b/MeetTheTeacher/Model/Various.cs
@ -0,0 +1,39 @@
+namespace MeetTheTeacher.Model;
+
+/// <summary>
+///     Represents school units, each taking 50 minutes
+/// </summary>
+public enum SchoolUnit
+{
+    UE01 = 01,
+    UE02 = 02,
+    UE03 = 03,
+    UE04 = 04,
+    UE05 = 05,
+    UE06 = 06,
+    UE07 = 07,
+    UE08 = 08,
+    UE09 = 09,
+    UE10 = 10
+}
+
+/// <summary>
+///     Represents possible data export formats
+/// </summary>
+public enum ExportFormat
+{
+    Csv,
+    Html
+}
+
+/// <summary>
+///     Represents possible sort orders for the teacher data
+/// </summary>
+public enum SortOrder
+{
+    ByNameAsc,
+    ByNameDesc,
+    ByHourAsc,
+    ByHourDesc,
+    Room
+}
--- a/MeetTheTeacher/Program.cs
+++ b/MeetTheTeacher/Program.cs
@ -0,0 +1,154 @@
+using System.Text;
+using MeetTheTeacher.Export;
+using MeetTheTeacher.Import;
+using MeetTheTeacher.Model;
+using Spectre.Console;
+
+Console.OutputEncoding = Encoding.UTF8;
+
+Clear();
+AnsiConsole.Markup("[orange3]Press any key to load HTL-Leonding teacher data[/] ");
+Console.ReadKey();
+
+// data loading
+bool loadRealData = AskForDataToUse();
+// wrapping IEnumerable in List, because we will iterate multiple times
+var data = new List<Teacher>(LoadData(loadRealData));
+var tableGenerator = new SpectreTableExporter();
+tableGenerator.Export(data, string.Empty);
+
+// fake loading
+Clear();
+await DisplayFakeProgress();
+Clear();
+AnsiConsole.Write(tableGenerator.Table);
+PrintStatistics(data);
+
+// user input
+WriteRule("Sort Order");
+var order = AskForSortOrder();
+WriteRule("Export Format");
+var format = AskForExportFormat();
+WriteRule("File Name");
+string fileName = AnsiConsole.Ask<string>("Which [blue]file name[/] should be used?");
+
+// export
+var exporter = new Exporter(order, format, new DefaultExporterProvider());
+exporter.Export(fileName, data);
+
+// done
+WriteRule(string.Empty);
+AnsiConsole.Write(new FigletText("All Done!").Centered().Color(Color.Green));
+DrawDog();
+
+return;
+
+static void Clear()
+{
+    Console.Clear();
+    AnsiConsole.Write(new FigletText("Teacher Data").Centered().Color(Color.Blue));
+}
+
+static void WriteRule(string text)
+{
+    AnsiConsole.Write(new Rule($"[blue]{text}[/]").LeftJustified());
+}
+
+static IEnumerable<Teacher> LoadData(bool realData)
+{
+    // TODO
+    // ITeacherDataImporter importer ...
+    // files: "Data/teachers.csv" & "Data/teachers-with-business-card.csv"
+    return null!;
+}
+
+static Task DisplayFakeProgress()
+{
+    const double Increase = 4.5;
+    const double ReducedIncrease = Increase * 0.8D;
+
+    return AnsiConsole.Progress()
+                      .StartAsync(async ctx =>
+                      {
+                          // we are actually already done, but want to fake some complex operation
+                          // to have the user appreciate the hard work our application is doing :)
+                          var task1 = ctx.AddTask("[green]Loading Data[/]");
+                          var task2 = ctx.AddTask("[green]Processing Data[/]");
+
+                          while (!ctx.IsFinished)
+                          {
+                              task1.Increment(Increase);
+                              task2.Increment(ReducedIncrease);
+                              await Task.Delay(TimeSpan.FromMilliseconds(125));
+                          }
+                      });
+}
+
+static void PrintStatistics(IReadOnlyCollection<Teacher> teachers)
+{
+    var hasConsultingHours = 0;
+    var hasBusinessCard = 0;
+    foreach (var teacher in teachers)
+    {
+        // TODO
+    }
+
+    double total = teachers.Count;
+    var cPercentage = (int) (hasConsultingHours / total * 100);
+    int ncPercentage = 100 - cPercentage;
+    var bPercentage = (int) (hasBusinessCard / total * 100);
+
+    AnsiConsole.Write(new BarChart()
+                      .Width(60)
+                      .Label($"[blue underline]Statistics ({total:F0} teachers)[/]")
+                      .CenterLabel()
+                      .AddItem("Has consulting hour", cPercentage, Color.Green)
+                      .AddItem("Has no consulting hour", ncPercentage, Color.Red)
+                      .AddItem("Has business card", bPercentage, Color.Purple));
+}
+
+static SortOrder AskForSortOrder()
+{
+    var options = new Dictionary<string, SortOrder>
+    {
+        ["Name Asc."] = SortOrder.ByNameAsc,
+        ["Name Desc."] = SortOrder.ByNameDesc,
+        ["Hour Asc."] = SortOrder.ByHourAsc,
+        ["Hour Desc."] = SortOrder.ByHourDesc,
+        ["Room"] = SortOrder.Room
+    };
+    string order = AnsiConsole.Prompt(new SelectionPrompt<string>()
+                                      .Title("How do you wish to [blue]sort[/] the data?")
+                                      .PageSize(3)
+                                      .MoreChoicesText("[grey](Move up and down to reveal more options)[/]")
+                                      .AddChoices(options.Keys));
+
+    AnsiConsole.MarkupLine($"Selected: [green]{order}[/]");
+
+    return options[order];
+}
+
+static ExportFormat AskForExportFormat()
+{
+    // TODO (similar to AskForDataToUse)
+    return default;
+}
+
+static bool AskForDataToUse()
+{
+    const string Real = "Real";
+    string dataToUse = AnsiConsole.Prompt(new SelectionPrompt<string>()
+                                          .Title("Do you want to load [blue]real[/] or [blue]sample[/] data?")
+                                          .AddChoices(Real, "Sample"));
+
+    AnsiConsole.MarkupLine($"Selected: [green]{dataToUse}[/]");
+
+    return dataToUse == Real;
+}
+
+static void DrawDog()
+{
+    var image = new CanvasImage("happy-dog.png");
+    image.MaxWidth(36);
+    AnsiConsole.Write(image);
+}
--- a/MeetTheTeacher/happy-dog.png
+++ b/MeetTheTeacher/happy-dog.png
--- a/pics/sample_run.mp4
+++ b/pics/sample_run.mp4
--- a/pics/spectre_examples.png
+++ b/pics/spectre_examples.png
--- a/readme.adoc
+++ b/readme.adoc
@ -0,0 +1,381 @@
+:sectnums:
+:nofooter:
+:toc: left
+:icons: font
+:data-uri:
+:source-highlighter: highlightjs
+:stem: latexmath
+
+= Int.02 -- Meet the Teacher
+
+This is an *extensive* assignment with the goal of processing the consultation hours of teachers (real data from a few years ago).
+
+== Introduction
+
+The application is split into several parts:
+
+. Importing Data
+** From multiple files and different sources
+. Performing Sort Operations
+** With a multitude of options
+. Exporting Data
+** In two different formats
+. User Interaction
+** A _modern_ console application
+
+NOTE: You _really_ should not wait to the last minute before starting to work on this assignment! It _will_ take you some time to understand the relations between the multitude of components.
+
+=== Sample Run [[sec:sample]]
+
+Before reading more about the individual parts and their requirements watch a sample run of the application to get a feeling for what you are going to implement.
+
+video::pics/sample_run.mp4[Sample Run,width=1000]
+
+=== Tests
+
+* Basic coverage with unit tests has been provided for you
+** But _not_ complete, especially for edge cases => do not rely only on the tests
+*** You are allowed to add tests, if you want to, of course
+* Take a look at how we can make use of interfaces when writing unit tests
+** Especially for _mocking_
+** => you will write such tests _yourself_ in the future!
+
+== Data Model
+
+[plantuml]
+----
+@startuml
+hide empty fields
+hide empty methods
+
+interface ICsvRepresentable {
+    +CsvData ToCsvData()
+}
+class CsvData <<sealed>> {
+    +char Separator [const]
+    +IReadOnlyList<string> HeaderNames [readonly]
+    +IReadOnlyList<string> Data [readonly]
+
+    +CsvData(IReadOnlyList<string> headerNames, IReadOnlyList<string> data)
+    +string GetHeader()
+    +string GetData()
+    +void Deconstruct(out IReadOnlyList<string> headerNames, out IReadOnlyList<string> data)
+}
+class Teacher {
+    +string Name [readonly]
+    +TimeFrame? ConsultingHour [init only]
+    +SchoolUnit? ConsultingHourUnit [init only]
+    +DayOfWeek? ConsultingHourWeekDay [init only]
+    +string? Room [init only]
+    -string? ConsultingHourTime [readonly]
+
+    +Teacher(string name)
+    +CsvData ToCsvData() [virtual]
+}
+class TeacherWithBusinessCard <<sealed>> {
+    -string BaseUrl [const]
+    +int Id [readonly]
+
+    +TeacherWithBusinessCard(string name, int id)
+    +CsvData ToCsvData() [override]
+}
+struct TimeFrame {
+    +TimeOnly Start [readonly]
+    +TimeOnly End [readonly]
+
+    +TimeFrame(TimeOnly start, TimeOnly end)
+    {static} +bool TryParse(string timeFrame, out TimeFrame? result)
+    +string ToString() [override]
+}
+enum SchoolUnit {
+    UE01
+    UE02
+    UE03
+    UE04
+    UE05
+    UE06
+    UE07
+    UE08
+    UE09
+    UE10
+}
+
+Teacher <|-- TeacherWithBusinessCard
+Teacher o-- TimeFrame
+Teacher o-- SchoolUnit
+ICsvRepresentable <|.. Teacher
+
+@enduml
+----
+
+The data model combines inheritance with interface implementation as it is common in modern applications.
+
+* `ICsvRepresentable`
+** Defines the _capability_ of a class to provide its own data in a format which can be easily processed to create a CSV file
+* `CsvData`
+** Contains data of a _single_ object in addition to the headers which define this data
+** Some properties are of type `IReadOnlyList` -- *that's something new* => https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.ireadonlylist-1?view=net-8.0[learn about it]
+*** We'll need it quite often from now on
+** We implement a `Deconstruct` method
+*** That allows the compiler to perform a https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/functional/deconstruct[_deconstruct_ operation]
+**** We can write things like `var (a, b) = objectWithAAndB`
+*** *This is _not_ the same as a _destructor_! Do _not_ use destructors!*
+* `Teacher`
+** _All_ teachers are of type `Teacher`
+** The name is required
+*** Other properties are _optional_ (some colleagues do not offer a consulting hour)
+** `DayOfWeek` is an `enum` defined in the framework -- https://learn.microsoft.com/en-us/dotnet/api/system.dayofweek?view=net-8.0[read, if you don't know it]
+** `ConsultingHourTime` combines information from `ConsultingHour` & `ConsultingHourUnit`
+*** Has to return `null` if components are `null`
+*** Otherwise, returns format `HH:MM-HH:MM (UEXX)`
+**** Example: `12:40-13:35 (UE06)`
+* `TeacherWithBusinessCard`
+** _Some_ teachers also want to display a business card, which requires a portrait picture, in addition to the regular information
+** This picture is stored on a webserver, so we only have to deal with the id
+** Such an image URI could look like this: `https://www.htl-leonding.at/media/teacher-avatar/1234`
+*** _Fictional address, doesn't work!_
+* `TimeFrame`
+** Defines a time frame with a start and end time
+*** Start time has to be before end time
+** Implemented as a https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/struct[struct]
+*** It's been some time since we last talked about structs.
+Do you still remember the guidelines when to use one and when better to use a class?
+If not, ask me to explain it again!
+
+TIP: If you find the class diagrams hard to read (due to size) remember that you don't have images but those are gnerated from PlantUML code => you can look at individual parts, zoom in, use different editors or even simply look at the diagram source code
+
+== Import
+
+[plantuml]
+----
+@startuml
+hide empty fields
+hide empty methods
+
+interface ITeacherDataImporter {
+    +IEnumerable<Teacher> LoadTeacherData()
+}
+class TeacherDataCsvImporter <<sealed>> {
+    -string _businessCardDataFilePath [readonly]
+    -string _generalDataFilePath [readonly]
+
+    +TeacherDataCsvImporter(string generalDataFilePath, string businessCardDataFilePath)
+    {static} -Dictionary<string, Teacher> CombineData(Dictionary<string, Teacher> generalData, IEnumerable<(string name, int id)> businessCardData)
+    -IEnumerable<(string name, int id)>? ReadTeacherBusinessCardData()
+    -Dictionary<string, Teacher>? ReadTeacherData()
+}
+class TeacherDataFakeImporter <<sealed>> {
+
+}
+
+ITeacherDataImporter <|.. TeacherDataCsvImporter
+ITeacherDataImporter <|.. TeacherDataFakeImporter
+
+@enduml
+----
+
+Data can be imported from various, different sources.
+In the main part of the application we are only interested in getting the data, not how or from where.
+To showcase this abstraction (and separation of concerns) we implement two 'data sources': one will read data from two CSV files and combine it to build the required format, while the other will simply fake importing and return sample data.
+
+* `ITeacherDataImporter`
+** Defines the capability to load `Teacher` data from a source
+* `TeacherDataCsvImporter`
+** Reads data from two CSV files
+... One file contains general `Teacher` information
+... The second file contains data only for `TeacherWithBusinessCard` teachers
+** Reading data from a CSV file is easy for you by now, but be aware that some properties are _optional_
+** The data from the two files has to be intelligently combined to create the required output
+*** Hint: a collection which holds `Teacher` objects can _at the same time_ contain instances of _subclasses_
+** Here you'll deal with `Dictionary` again -- we haven't used this collection extensively so far, maybe https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2?view=net-8.0[you want to refresh your memory]
+* `TeacherDataFakeImporter`
+** This is just an example how different import providers could be used in this application, thanks to the interfaces
+** Implementation has already been provided for you -- make sure you understand what's going on!
+
+== Sorting
+
+[plantuml]
+----
+@startuml
+hide empty methods
+hide empty fields
+
+enum SortOrder
+{
+    ByNameAsc
+    ByNameDesc
+    ByHourAsc
+    ByHourDesc
+    Room
+}
+abstract class ComparerBase {
+    #ComparerBase(bool ascending)
+    #bool Ascending [readonly]
+}
+interface IComparer<Teacher>
+class ByHourComparer <<sealed>> {
+    +int Compare(Teacher? x, Teacher? y)
+}
+class ByNameComparer <<sealed>> {
+    +int Compare(Teacher? x, Teacher? y)
+}
+class ByRoomComparer <<sealed>> {
+    +int Compare(Teacher? x, Teacher? y)
+}
+
+IComparer <|.. ByHourComparer
+IComparer <|.. ByNameComparer
+IComparer <|.. ByRoomComparer
+ComparerBase <|-- ByHourComparer
+ComparerBase <|-- ByNameComparer
+
+@enduml
+----
+
+Our application offers various sorting options.
+These are implemented by different `Comparer` implementation.
+
+TIP: Do you still remember the difference between https://learn.microsoft.com/en-us/dotnet/api/system.icomparable?view=net-8.0[`IComparable`] and https://learn.microsoft.com/en-us/dotnet/api/system.collections.icomparer?view=net-8.0[`IComparer`]?
+
+* `ComparerBase`
+** Base class for those comparers which support changing the sorting order from ascending to descending
+* `ByHourComparer`
+** Allows sorting of the teacher data by time of the consulting hour
+** Sorting order can be ascending or descending
+** _First_ the day of the week, and _then_ the unit is compared
+** Hint: some properties are optional, remember how to deal with `null` values when sorting/comparing
+* `ByNameComparer`
+** Allows sorting of the teacher data by name
+** Sorting order can be ascending or descending
+* `ByRoomComparer`
+** Allows sorting of the teacher data by room
+** Sorting order is _always_ ascending
+** Hint: `Room` can be `null`
+
+== Export
+
+CAUTION: The interactions between the individual components and the number of those is much more _complex_ than anything we did before -- do not hesitate to ask if you have trouble understanding!
+
+[plantuml]
+----
+@startuml
+hide empty methods
+hide empty fields
+
+enum ExportFormat
+{
+    Csv
+    Html
+}
+class CsvDataExporter <<sealed>> {}
+class DefaultExporterProvider <<sealed>> {}
+class Exporter <<sealed>> {
+    -IComparer<Teacher> _comparer [readonly]
+    -IDataExporter _exporter [readonly]
+
+    +Exporter(SortOrder sortOrder, ExportFormat exportFormat, IExporterProvider exporterProvider)
+    +void Export(string fileName, List<Teacher> teachers)
+}
+abstract class FileExporterBase {
+    {abstract} #string FileExtension [readonly]
+    #void Export(string fileName, string content)
+    {static} #string LinesToText(IEnumerable<string> lines)
+    -string GetFilePath(string fileName)
+}
+class HtmlDataExporter <<sealed>> {
+    {static} -string CreateTableRow(IEnumerable<string> values, bool isHeader = false)
+    {static} -string WrapInTag(string content, string tag)
+}
+interface IDataExporter {
+    +void Export(IEnumerable<ICsvRepresentable> data, string? fileName)
+}
+interface IExporterProvider {
+    +IDataExporter GetExporter(ExportFormat exportFormat)
+}
+class SpectreTableExporter <<sealed>> {
+    +Table Table [private set]
+
+    +public SpectreTableExporter()
+    {static} -IEnumerable<string> FindMaxHeaderColumns(IEnumerable<CsvData> rows)
+}
+
+IDataExporter <|.. SpectreTableExporter
+IDataExporter <|.. HtmlDataExporter
+IDataExporter <|.. CsvDataExporter
+FileExporterBase <|-- CsvDataExporter
+FileExporterBase <|-- HtmlDataExporter
+IExporterProvider <|.. DefaultExporterProvider
+Exporter *-- IDataExporter
+
+@enduml
+----
+
+Our application has a very _flexible_ export system.
+Not only are two different file exports (CSV & HTML) supported, but an export to a specific in-memory data structure as well.
+This requires a very sophisticated _decoupling_ of components => _many_ classes and interfaces.
+Some parts also improve the _testability_ of the export functionality.
+
+* `CsvDataExporter`
+** Exports data to a CSV file
+** This is very easy, because we are receiving `ICsvRepresentable` objects to export
+** Several features of the base class help as well
+* `DefaultExporterProvider`
+** The default provider for exporters used in the application
+* `Exporter`
+** Can be configured to export data in a specific format and with a specific sorting order
+** Before (finally) exporting, the data is sorted accordingly
+*** For this task use the https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.sort?view=net-8.0[`Sort`] method of `List<T>`
+* `FileExporterBase`
+** Base class for those exporters which write data to a file
+* `HtmlDataExporter`
+** Exports data _encoded_ as an HTML table
+*** Does _not_ create a full, valid HTML document -- only the data as HTML table
+*** We use `.html` as file extension anyway
+*** You know how to create such a table from WMC 😉
+** You _have to_ use a https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-11.0/raw-string-literal[raw string literal]
+*** This is useful when defining semi-structured data like JSON or HTML
+*** You can (and should) even use indentation
+** `CreateTableRow` will create either a `<tr><th>...</tr>` or `<tr><td>...</tr>` depending on the `isHeader` flag
+* `IDataExporter`
+** Defines the capability to export data of type `ICsvRepresentable`
+* `IExporterProvider`
+** Defines the capability to provide an exporter based on a specific, requested export format
+** Primarily used for testing here -- could be used at runtime as well if the application expanded
+* `SpectreTableExporter`
+** Exports data to a `Table` as used by `Spectre.Console`
+** We need this for our user interface
+** To make it easier for you, these two methods have to be used:
+... `table.AddColumn`
+... `table.AddRow`
+** In addition, you are _allowed_ (this time only, for now) to use the `ToArray` of `IReadOnlyList<string>`
+** `FindMaxHeaderColumns`
+*** Remember that the data to export can contain `Teacher` & `TeacherWithBusinessCard` objects at the same time
+*** The table has to be set to the _max._ number of columns
+**** `TeacherWithBusinessCard` has one more, which will simply stay empty for `Teacher` objects
+*** We don't know if there are `TeacherWithBusinessCard` contained, so we have to _check_ to find the max. set of headers
+
+TIP: Consider the provided, detailed XMLDoc as well, it offers additional insights
+
+== User Interaction
+
+To conclude this extensive assignment we want to give it the exciting user interface it deserves.
+After all, the interface is what customers will see of your product, so we cannot ignore the importance of making a good impression altogether (despite concentrating on clean and *correct* code primarily).
+So far, you are limited to console applications.
+But those don't have to be boring!
+
+This time we will be using the cross-platform, free & open-source https://www.nuget.org/packages/Spectre.Console[`Spectre.Console`] NuGet package.
+It has a https://spectreconsole.net/[good documentation] which I implore you to check out.
+There are many features, such as structure (tables, grids, rules,...), interactivity (prompts, loading indicators,...) and design (colors, fonts,...) -- see the examples below (taken from the package website).
+
+.`Spectre.Console` Examples
+[%collapsible]
+====
+image::pics/spectre_examples.png[Spectre.Console Examples]
+====
+
+Since this is the first time you have to work with this package, and because some features require callbacks -- which you know from WMC, but we haven't discussed in POSE so far -- most of the implementation has already been provided for you.
+Still, some things need to be implemented -- look for the `TODO`.
+
+A <<sec:sample,sample run>> has already been shown at the beginning of the document.
+
+🎉 Congratulations -- you completed the assignment, learnt new things and had a lot of programming exercise 🎉