using System;

namespace MathInterpreter.Core;

public abstract class ExpressionException : Exception
{
    /// <summary>
    /// Initializes <see cref="ExpressionException"/> with the specified error <paramref name="message"/> and the optional <paramref name="innerException"/>
    /// </summary>
    /// <param name="message">The error message</param>
    /// <param name="innerException">The optional exception</param>
    protected ExpressionException(string message, Exception? innerException = null)
        : base(message, innerException) { }
}

public sealed class ExpressionFormatException : ExpressionException
{
    /// <summary>
    /// Initializes <see cref="ExpressionFormatException"/> with the specified error <paramref name="message" /> and the optional <paramref name="innerException"/>
    /// </summary>
    /// <param name="message">The error message</param>
    /// <param name="innerException">The innerException</param>
    public ExpressionFormatException(string message, Exception? innerException = null)
        : base(message, innerException) { }
}

public sealed class OperatorException : ExpressionException
{
    /// <summary>
    /// Initializes <see cref="OperatorException"/> with the specified error <paramref name="message"/>
    /// </summary>
    /// <param name="message">The error message</param>
    public OperatorException(string message) : base(message) { }
}

public sealed class NumberFormatException : ExpressionException
{
    /// <summary>
    /// Initializes <see cref="NumberFormatException"/> with the <paramref name="expression"/> and the optional <paramref name="reason"/>
    /// </summary>
    /// <param name="expression">The expression</param>
    /// <param name="reason">The optional reason</param>
    public NumberFormatException(ReadOnlySpan<char> expression, string? reason = null)
        : base(FormatMessage(expression, reason)) { }
    
    private static string FormatMessage(ReadOnlySpan<char> expression, string? reason = null)
    {
        reason = string.IsNullOrWhiteSpace(reason) ? string.Empty : $" ({reason})";
        return $"Unable to read number from beginning of '{expression}'{reason}";
    }
}

public sealed class NumberValueException : ExpressionException
{
    /// <summary>
    /// Initializes <see cref="NumberValueException"/> with the specified error <paramref name="message"/>
    /// </summary>
    /// <param name="message">The error message</param>
    public NumberValueException(string message) : base(message) { }
}