namespace NeonSprawl.Server.Game.Mastery;

/// <summary>Read model for one player's perk state (NEO-47).</summary>
public sealed class PerkStateSnapshot
{
    public static PerkStateSnapshot Empty { get; } = new(
        new Dictionary<string, IReadOnlyDictionary<int, string>>(StringComparer.Ordinal),
        new HashSet<string>(StringComparer.Ordinal));

    public PerkStateSnapshot(
        IReadOnlyDictionary<string, IReadOnlyDictionary<int, string>> branchPicksBySkillId,
        IReadOnlySet<string> unlockedPerkIds)
    {
        BranchPicksBySkillId = branchPicksBySkillId;
        UnlockedPerkIds = unlockedPerkIds;
    }

    /// <summary><c>skillId</c> → <c>tierIndex</c> → <c>branchId</c>.</summary>
    public IReadOnlyDictionary<string, IReadOnlyDictionary<int, string>> BranchPicksBySkillId { get; }

    public IReadOnlySet<string> UnlockedPerkIds { get; }

    public bool TryGetBranchPick(string skillId, int tierIndex, out string branchId)
    {
        branchId = string.Empty;
        if (!BranchPicksBySkillId.TryGetValue(skillId, out var tiers))
        {
            return false;
        }

        return tiers.TryGetValue(tierIndex, out branchId!);
    }
}