namespace GermanApp.Domain.Entities;

/// <summary>
/// Represents a CEFR level in the DeutschLernen system (A1, A2, B1, B2, C1).
/// </summary>
public class Level
{
    public int Id { get; private set; }
    public string Name { get; private set; } = string.Empty;
    public string Code { get; private set; } = string.Empty;
    public int Order { get; private set; }

    /// <summary>
    /// Constructor for EF Core deserialization.
    /// </summary>
    private Level() { }

    /// <summary>
    /// Factory method to create a new level.
    /// </summary>
    /// <param name="name">Display name of the level (e.g., "Beginner A1")</param>
    /// <param name="code">Short code for the level (e.g., "A1")</param>
    /// <param name="order">Sort order of the level</param>
    public static Level Create(string name, string code, int order)
    {
        return new Level
        {
            Name = name,
            Code = code.ToUpperInvariant(),
            Order = order
        };
    }

    /// <summary>
    /// Updates the level's display name.
    /// </summary>
    public void UpdateName(string newName)
    {
        Name = newName;
    }

    /// <summary>
    /// Updates the level's code.
    /// </summary>
    public void UpdateCode(string newCode)
    {
        Code = newCode.ToUpperInvariant();
    }

    /// <summary>
    /// Updates the level's sort order.
    /// </summary>
    public void UpdateOrder(int newOrder)
    {
        Order = newOrder;
    }

    // Navigation properties
    public virtual ICollection<Lesson> Lessons { get; private set; } = new List<Lesson>();
    public virtual ICollection<StorySegment> StorySegments { get; private set; } = new List<StorySegment>();
}