using AcDream.Core.Combat;

namespace AcDream.Core.Net;

/// <summary>
/// Routes the local player's server-owned combat-mode quality into
/// <see cref="CombatState"/>. Retail
/// <c>ClientCombatSystem::OnQualityChanged @ 0x0056C1B0</c> reads
/// PropertyInt 40 and calls <c>SetCombatMode</c> on every change.
/// </summary>
public static class CombatStateWiring
{
    public const uint CombatModePropertyId = 40u;

    public static IDisposable Wire(
        WorldSession session,
        CombatState combat,
        Func<bool>? accepting = null)
    {
        ArgumentNullException.ThrowIfNull(session);
        ArgumentNullException.ThrowIfNull(combat);

        Action<WorldSession.PlayerIntPropertyUpdate> handler = update =>
        {
            if (accepting?.Invoke() == false) return;
            ApplyPlayerIntProperty(combat, update.Property, update.Value);
        };
        session.PlayerIntPropertyUpdated += handler;
        return new EventSubscription(session, handler);
    }

    /// <summary>
    /// Pure event adapter exposed for conformance tests. Composite or unknown
    /// values are ignored: retail's quality contains one concrete mode.
    /// </summary>
    public static bool ApplyPlayerIntProperty(
        CombatState combat,
        uint property,
        int value)
    {
        ArgumentNullException.ThrowIfNull(combat);
        if (property != CombatModePropertyId)
            return false;

        CombatMode mode = (CombatMode)value;
        if (mode is not (CombatMode.NonCombat
            or CombatMode.Melee
            or CombatMode.Missile
            or CombatMode.Magic))
            return false;

        combat.SetCombatMode(mode);
        return true;
    }

    private sealed class EventSubscription(
        WorldSession session,
        Action<WorldSession.PlayerIntPropertyUpdate> handler) : IDisposable
    {
        private Action? _unsubscribe =
            () => session.PlayerIntPropertyUpdated -= handler;

        public void Dispose() =>
            Interlocked.Exchange(ref _unsubscribe, null)?.Invoke();
    }
}