using System.Collections.Generic;
using UnityEngine;
using Unity.Cinemachine;
#if ENABLE_INPUT_SYSTEM
using UnityEngine.InputSystem;
#endif

/// <summary>
/// Switches the game between high-level modes (Player Control, Paint, Free Cam). The switch
/// key (Tab) cycles to the next registered mode. Register additional modes in
/// <see cref="BuildModes"/>. Attach to a single, persistent scene GameObject.
/// </summary>
[DisallowMultipleComponent]
public class GameModeManager : MonoBehaviour
{
    [Header("Controlled Systems")]
    [Tooltip("Player movement controller. Empty = found automatically.")]
    public PlayerCharacterController player;

    [Tooltip("Third-person orbit camera input. Empty = found automatically.")]
    public ThirdPersonOrbitInput cameraInput;

    [Tooltip("Mesh painter. Empty = found automatically.")]
    public MeshPainter painter;

    [Tooltip("Free-fly spectator camera. Empty = found automatically. Absent = Free Cam is left out of the cycle.")]
    public FreeCamController freeCam;

    [Tooltip("First-person camera. Empty = found automatically. Absent = First Person is left out of the cycle.")]
    public FirstPersonController firstPerson;

    //[Tooltip("Insect / surface-walk controller. Empty = found automatically.")]
    //public InsectController insect;

    [Header("Switching")]
    [Tooltip("Key that cycles to the next mode.")]
#if ENABLE_INPUT_SYSTEM
    public Key switchKey = Key.Tab;
#else
    public KeyCode switchKey = KeyCode.Tab;
#endif

    [Tooltip("Mode active at startup (0 = Player Control).")]
    public int startModeIndex = 0;

    public PlayerCharacterController Player => player;
    public ThirdPersonOrbitInput CameraInput => cameraInput;
    public MeshPainter Painter => painter;
    public FreeCamController FreeCam => freeCam;
    public FirstPersonController FirstPerson => firstPerson;
    //public InsectController Insect => insect;

    /// <summary>Raised after a mode switch finishes (the new mode's Enter has already run).
    /// Argument = the now-active mode. Used by UI (e.g. the paint HUD) to follow the mode.</summary>
    public event System.Action<GameMode> ModeChanged;

    /// <summary>Raised when the painter the HUD should edit changes - i.e. when the local
    /// networked avatar spawns and <see cref="BindLocalPlayer"/> binds its per-avatar painter.
    /// With spawn-on-connect there is no painter at scene start, so the paint HUD follows this
    /// to (re)bind its widgets to the live painter once it exists.</summary>
    public event System.Action<MeshPainter> PainterChanged;

    private readonly List<GameMode> _modes = new List<GameMode>();
    private int _activeIndex = -1;

    /// <summary>The currently active mode (null before startup).</summary>
    public GameMode ActiveMode =>
        (_activeIndex >= 0 && _activeIndex < _modes.Count) ? _modes[_activeIndex] : null;

    private void Awake()
    {
        if (!player) player = FindFirstObjectByType<PlayerCharacterController>();
        if (!cameraInput) cameraInput = FindFirstObjectByType<ThirdPersonOrbitInput>();
        if (!painter) painter = FindFirstObjectByType<MeshPainter>();
        // Include inactive so a freecam rig that starts disabled is still found and wired.
        if (!freeCam) freeCam = FindFirstObjectByType<FreeCamController>(FindObjectsInactive.Include);
        if (!firstPerson) firstPerson = FindFirstObjectByType<FirstPersonController>(FindObjectsInactive.Include);
        //if (!insect) insect = FindFirstObjectByType<InsectController>();

        BuildModes();
    }

    private void Start()
    {
        if (_modes.Count > 0)
            SwitchTo(Mathf.Clamp(startModeIndex, 0, _modes.Count - 1));
    }

    /// <summary>Registers all available modes. Add new modes here.</summary>
    private void BuildModes()
    {
        _modes.Clear();

        // Player Control only joins the Tab cycle when a gravity player is present, so a scene
        // running only the insect walker doesn't trap input in a dead, player-freezing mode.
        if (player)
            _modes.Add(new PlayerControlMode());

        _modes.Add(new PaintMode());

        // Free Cam only joins the cycle when a freecam rig is present, so scenes without one are unchanged.
        if (freeCam)
            _modes.Add(new FreeCamMode());

        // First Person only joins the cycle when a first-person rig is present, so scenes without one are unchanged.
        if (firstPerson)
            _modes.Add(new FirstPersonMode());

        // Insect mode only joins the Tab cycle when a surface walker is present, so a scene
        // without one behaves exactly as before (no dead, player-freezing mode in the cycle).
        //if (insect)
        //    _modes.Add(new InsectMode());

        foreach (var m in _modes)
            m.Bind(this);
    }

    /// <summary>
    /// Binds the scene singletons (this manager, the orbit/first-person cameras, the painter) to the
    /// locally-owned networked player after it spawns, then enters Player Control. Called from
    /// <see cref="NetworkPlayerSetup"/> on the owning client. Before this runs the scene has no player,
    /// so the cycle sits in a player-less mode (Paint); this promotes it once the avatar exists.
    /// </summary>
    public void BindLocalPlayer(PlayerCharacterController localPlayer)
    {
        if (!localPlayer) return;
        player = localPlayer;

        // The painter lives on the player (per-avatar), so bind the local one.
        if (!painter) painter = localPlayer.GetComponentInChildren<MeshPainter>(true);
        PainterChanged?.Invoke(painter);

        Transform camTarget = localPlayer.transform.Find("CameraTarget");

        // Re-point the third-person orbit camera (Cinemachine Follow/LookAt) at the local avatar.
        if (cameraInput)
        {
            var vcam = cameraInput.GetComponent<CinemachineCamera>();
            if (vcam) { vcam.Follow = camTarget; vcam.LookAt = camTarget; }
        }

        if (firstPerson)
            firstPerson.SetPlayer(localPlayer);

        // Tear down the pre-spawn (player-less) mode and rebuild with Player Control available.
        ActiveMode?.Exit();
        _activeIndex = -1;
        BuildModes();

        int idx = _modes.FindIndex(m => m is PlayerControlMode);
        SwitchTo(idx >= 0 ? idx : Mathf.Clamp(startModeIndex, 0, _modes.Count - 1));
    }

    private void Update()
    {
        if (_modes.Count == 0) return;

        if (WasSwitchPressed())
            SwitchTo((_activeIndex + 1) % _modes.Count);

        ActiveMode?.Tick();
    }

    /// <summary>Activates the mode at <paramref name="index"/> (Exit old, Enter new).</summary>
    public void SwitchTo(int index)
    {
        if (index < 0 || index >= _modes.Count || index == _activeIndex) return;

        ActiveMode?.Exit();
        _activeIndex = index;
        ActiveMode.Enter();

        Debug.Log($"[GameModeManager] Mode -> {ActiveMode.DisplayName}", this);
        ModeChanged?.Invoke(ActiveMode);
    }

    private bool WasSwitchPressed()
    {
#if ENABLE_INPUT_SYSTEM
        return Keyboard.current != null && Keyboard.current[switchKey].wasPressedThisFrame;
#else
        return Input.GetKeyDown(switchKey);
#endif
    }
}