namespace VocabularyTrainer;

/// <summary>
///     Represents one word in the vocabulary
/// </summary>
public sealed class VocabularyItem
{
    private int _countCorrect;
    private int _countAsked;
    public readonly string NativeWord;
    public readonly string Translation;

    public VocabularyItem(string nativeWord, string translation)
    {
        NativeWord = nativeWord;
        Translation = translation;
    }
    
    /// <summary>
    ///     A translation attempt is checked for correctness.
    /// </summary>
    /// <param name="translationAttempt">The user provided translation</param>
    /// <returns>True if the translation was correct; false otherwise</returns>
    public bool TestTranslation(string translationAttempt)
    {
        _countAsked++;
        if (string.Equals(Translation, translationAttempt, StringComparison.CurrentCultureIgnoreCase))
        {
            _countCorrect++;
            return true;
        }

        return false;
    }
    
    /// <summary>
    ///     The vocabulary item is compared to another. First the number of correct answers is compared.
    ///     If it is equal the native words are compared ordinal.
    /// </summary>
    /// <param name="other">The <see cref="VocabularyItem"/> to compare with</param>
    /// <returns>0 if equal; less than 0 if this item is smaller; greater than 0 otherwise</returns>
    public int CompareTo(VocabularyItem other)
    {
        if (_countCorrect == other._countCorrect)
        {
            return CompareStrings(NativeWord, other.NativeWord);
        }
        else if (_countCorrect < other._countCorrect)
        {
            return 1;
        }
        else
        {
            return -1;
        }
    }
    
    /// <summary>
    ///     Overrides the default string representation to display the word and translation statistics.
    /// </summary>
    /// <returns>A string containing the word, its translation and the training statistics</returns>
    public override string ToString()
    {
        return $"{NativeWord,-10} {Translation,-10} {_countAsked,-5} {_countCorrect,-7}";;
    }
    
    /// <summary>
    ///     Compares two strings by ordinal value, ignoring case.
    /// </summary>
    /// <param name="a">First string</param>
    /// <param name="b">Second string</param>
    /// <returns>Less than 0 if a precedes b in the sorting order; greater than 0 if b precedes a; 0 otherwise</returns>

    private static int CompareStrings(string a, string b) => string.Compare(a, b, StringComparison.OrdinalIgnoreCase);
    
}