using PkmnLib.Static.Utils;

namespace PkmnLib.Static.Species;

/// <summary>
/// The storage of the moves a Pokemon can learn.
/// </summary>
public interface ILearnableMoves
{
    /// <summary>
    /// Adds a new level move the Pokemon can learn.
    /// </summary>
    /// <param name="level">The level the Pokemon learns the move at.</param>
    /// <param name="move">The move the Pokemon learns.</param>
    /// <returns>Whether the move was added successfully.</returns>
    void AddLevelMove(LevelInt level, StringKey move);

    /// <summary>
    /// Gets all moves a Pokemon can learn when leveling up to a specific level.
    /// </summary>
    /// <param name="level">The level the Pokemon is learning moves at.</param>
    /// <returns>The moves the Pokemon learns at that level.</returns>
    IReadOnlyList<StringKey> GetLearnedByLevel(LevelInt level);

    /// <summary>
    /// Gets the distinct moves a Pokemon can learn through leveling up.
    /// </summary>
    /// <returns>The moves the Pokemon can learn through leveling up.</returns>
    IReadOnlyList<StringKey> GetDistinctLevelMoves();
}

public class LearnableMovesImpl : ILearnableMoves
{
    private readonly Dictionary<LevelInt, List<StringKey>> _learnedByLevel = new();
    private readonly HashSet<StringKey> _distinctLevelMoves = new();


    public void AddLevelMove(LevelInt level, StringKey move)
    {
        if (!_learnedByLevel.TryGetValue(level, out var value))
            _learnedByLevel[level] = [move];
        else
            value.Add(move);
        _distinctLevelMoves.Add(move);
    }

    public IReadOnlyList<StringKey> GetLearnedByLevel(LevelInt level)
    {
        if (!_learnedByLevel.TryGetValue(level, out var value))
            return Array.Empty<StringKey>();
        return value;
    }

    public IReadOnlyList<StringKey> GetDistinctLevelMoves()
    {
        return _distinctLevelMoves.ToList();
    }
}