using AcDream.UI.Abstractions.Input;

namespace AcDream.App.Input;

internal interface IMovementInputSource
{
    MovementInput Capture();
}

/// <summary>
/// Owns held movement sampling and the retail autorun latch. The input
/// dispatcher remains the only keyboard/mouse-button state source.
/// </summary>
internal sealed class DispatcherMovementInputSource : IMovementInputSource
{
    private readonly IInputCaptureSource? _capture;
    private InputDispatcher? _dispatcher;

    public DispatcherMovementInputSource(IInputCaptureSource? capture = null) =>
        _capture = capture;

    public bool AutoRunActive { get; private set; }

    public void Bind(InputDispatcher dispatcher)
    {
        ArgumentNullException.ThrowIfNull(dispatcher);
        if (_dispatcher is not null && !ReferenceEquals(_dispatcher, dispatcher))
            throw new InvalidOperationException(
                "The movement input source is already bound to another dispatcher.");
        _dispatcher = dispatcher;
    }

    public MovementInput Capture()
    {
        // Devtools owns the whole gameplay keyboard while active, including
        // a latched autorun. Retained chat owns physical key state only;
        // retail's autorun latch continues until an explicit cancel action.
        if (_capture?.DevToolsWantCaptureKeyboard == true)
            return default;

        if (_dispatcher is not { } dispatcher)
            return default;

        bool walking = dispatcher.IsActionHeld(InputAction.MovementWalkMode);
        bool forward = dispatcher.IsActionHeld(InputAction.MovementForward);
        return new MovementInput(
            Forward: forward || AutoRunActive,
            Backward: dispatcher.IsActionHeld(InputAction.MovementBackup),
            StrafeLeft: dispatcher.IsActionHeld(InputAction.MovementStrafeLeft),
            StrafeRight: dispatcher.IsActionHeld(InputAction.MovementStrafeRight),
            TurnLeft: dispatcher.IsActionHeld(InputAction.MovementTurnLeft),
            TurnRight: dispatcher.IsActionHeld(InputAction.MovementTurnRight),
            Run: !walking,
            Jump: dispatcher.IsActionHeld(InputAction.MovementJump));
    }

    /// <summary>
    /// Applies the press-only autorun policy at the same point in the semantic
    /// action pipeline as the former GameWindow body.
    /// </summary>
    /// <returns>True when the action is fully consumed.</returns>
    public bool HandlePressedAction(InputAction action)
    {
        if (action == InputAction.MovementRunLock)
        {
            AutoRunActive = !AutoRunActive;
            return true;
        }

        if (AutoRunActive && action is (
            InputAction.MovementBackup
            or InputAction.MovementStop
            or InputAction.MovementStrafeLeft
            or InputAction.MovementStrafeRight))
        {
            AutoRunActive = false;
        }

        return false;
    }

    public void ResetSession() => AutoRunActive = false;
}