DeutschLernen/GermanApp/Domain/ValueObjects/GermanWord.cs

using GermanApp.Domain.Exceptions;

namespace GermanApp.Domain.ValueObjects;

/// <summary>
/// Represents a German word with its translation and metadata.
/// This is a value object - it has no identity and is defined by its attributes.
/// </summary>
public record GermanWord
{
    public string Value { get; }
    public string Translation { get; }
    public string? Article { get; } // der, die, das, or null for verbs/adjectives
    public string PartOfSpeech { get; }

    public GermanWord(string value, string translation, string? article, string partOfSpeech)
    {
        if (string.IsNullOrWhiteSpace(value))
            throw new DomainException("German word cannot be empty");
        
        if (string.IsNullOrWhiteSpace(translation))
            throw new DomainException("Translation cannot be empty");
        
        if (string.IsNullOrWhiteSpace(partOfSpeech))
            throw new DomainException("Part of speech is required");
        
        if (article != null && !IsValidArticle(article))
            throw new DomainException("Invalid article. Must be 'der', 'die', or 'das'");
        
        Value = value.Trim();
        Translation = translation.Trim();
        Article = article?.Trim();
        PartOfSpeech = partOfSpeech.Trim();
    }

    private static bool IsValidArticle(string article) =>
        article.Equals("der", StringComparison.OrdinalIgnoreCase) ||
        article.Equals("die", StringComparison.OrdinalIgnoreCase) ||
        article.Equals("das", StringComparison.OrdinalIgnoreCase);

    /// <summary>
    /// Check if this word has a definite article.
    /// </summary>
    public bool HasArticle() => Article != null;

    /// <summary>
    /// Get the word with its article (if applicable).
    /// </summary>
    public string GetWithArticle() => Article != null ? $"{Article} {Value}" : Value;
}