using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.InputSystem;
using BaseGames.Core.Events;

namespace BaseGames.Input
{
    [CreateAssetMenu(menuName = "BaseGames/Input/InputReader")]
    public class InputReaderSO : ScriptableObject
    {
        [SerializeField] private InputActionAsset _inputActions;
        [SerializeField] private VoidEventChannelSO _onPauseRequested;

        // ── Gameplay Events ───────────────────────────────────────────────────
        public event Action<Vector2> MoveEvent;
        public event Action JumpStartedEvent;
        public event Action JumpCancelledEvent;
        public event Action AttackEvent;
        public event Action ParryEvent;
        public event Action DashEvent;
        public event Action UseSpringEvent;
        public event Action SwitchSkyFormEvent;
        public event Action SwitchEarthFormEvent;
        public event Action SwitchDeathFormEvent;
        public event Action SoulSkillEvent;
        public event Action SpiritSkill1StartedEvent;
        public event Action SpiritSkill1CancelledEvent;
        public event Action SpiritSkill2StartedEvent;
        public event Action SpiritSkill2CancelledEvent;
        public event Action SpellCastEvent;
        public event Action InteractEvent;
        public event Action InteractCancelledEvent;

        // ── UI Events ─────────────────────────────────────────────────────────
        public event Action PauseEvent;
        public event Action<Vector2> NavigateEvent;
        public event Action SubmitEvent;
        public event Action CancelEvent;
        public event Action<Vector2> PointEvent;

        /// <summary>小地图视野档位切换（默认绑定：Tab 键 / 手柄右肩键）。</summary>
        public event Action CycleMinimapZoomEvent;

        /// <summary>全屏地图"居中到玩家"（默认绑定：F 键 / 手柄右摇杆按下）。</summary>
        public event Action MapCenterEvent;

        // ── Polling ───────────────────────────────────────────────────────────
        public Vector2 MoveInput { get; private set; }
        /// <summary>跳跃键当前是否处于按下状态。供 JumpState 在进入时检测短按是否已松开。</summary>
        public bool IsJumpHeld => _jumpAction != null && _jumpAction.IsPressed();

        // ── Runtime state ─────────────────────────────────────────────────────
        private InputActionMap _gameplay;
        private InputActionMap _ui;
        private bool _isBound;
        private InputAction _jumpAction;

        private void EnsureInitialized()
        {
            if (_inputActions == null)
            {
                Debug.LogError("[InputReaderSO] _inputActions is NULL! Asset not assigned in inspector?");
                return;
            }

            // Always disable first so the Input System tears down stale state,
            // then re-enable to create a fresh state for this Play session.
            _inputActions.Disable();
            _inputActions.Enable();

            _gameplay = _inputActions.FindActionMap("Gameplay", throwIfNotFound: false);
            if (_gameplay == null)
                Debug.LogError("[InputReaderSO] Could not find 'Gameplay' action map in asset!");

            _ui = _inputActions.FindActionMap("UI", throwIfNotFound: false);
            if (_ui == null)
                Debug.LogWarning("[InputReaderSO] Could not find 'UI' action map in asset!");

            if (_gameplay != null && !_isBound)
            {
                
                BindActions();
                
            }
        }

        private void OnEnable()
        {
            Debug.Assert(_onPauseRequested != null,
                "[InputReaderSO] _onPauseRequested 未赋值，请在 Inspector 中指定 EVT_PauseRequested。", this);
            // Reset private state on every OnEnable so stale ScriptableObject
            // references from a previous Play session don't cause
            // 'Map must be contained in state' errors.
            _gameplay = null;
            _ui = null;
            _isBound = false;
            _jumpAction = null;
            EnsureInitialized();
        }

        private void OnDisable()
        {
            _gameplay?.Disable();
            _ui?.Disable();
            _isBound = false;
        }

        // ── Action Map Switching ──────────────────────────────────────────────
        public void EnableGameplayInput()
        {
            // Disable UI map if it's active
            if (_ui != null && _ui.enabled)
            {
                
                _ui.Disable();
            }
            
            // Ensure gameplay map is enabled
            if (_gameplay != null && !_gameplay.enabled)
            {
               
                _gameplay.Enable();
            }
            else if (_gameplay == null)
            {
                Debug.LogError("[InputReaderSO.EnableGameplayInput] _gameplay is NULL!");
            }
        }

        public void EnableUIInput()
        {
            // Disable gameplay map if it's active
            if (_gameplay != null && _gameplay.enabled)
            {
                
                _gameplay.Disable();
            }
            
            // Ensure UI map is enabled
            if (_ui != null && !_ui.enabled)
            {
               
                _ui.Enable();
            }
            else if (_ui == null)
            {
                Debug.LogWarning("[InputReaderSO.EnableUIInput] _ui is NULL!");
            }
        }

        public void DisableAllInput()     { _gameplay?.Disable(); _ui?.Disable(); }

        // ── Binding ───────────────────────────────────────────────────────────
        private void BindActions()
        {
            if (_gameplay == null)
            {
                Debug.LogWarning("[InputReaderSO.BindActions] Skipped: _gameplay is NULL");
                return;
            }

            

            BindPerformed(_gameplay, "Move", ctx =>
            {
                MoveInput = ctx.ReadValue<Vector2>();
                MoveEvent?.Invoke(MoveInput);
            });
            BindCanceled(_gameplay, "Move", _ =>
            {
                MoveInput = Vector2.zero;
                MoveEvent?.Invoke(Vector2.zero);
            });

            BindStarted(_gameplay, "Jump",        () => JumpStartedEvent?.Invoke());
            BindCanceled(_gameplay, "Jump",       () => JumpCancelledEvent?.Invoke());
            _jumpAction = _gameplay.FindAction("Jump", throwIfNotFound: false);
            BindStarted(_gameplay, "Attack",      () => AttackEvent?.Invoke());
            BindStarted(_gameplay, "Parry",       () => ParryEvent?.Invoke());
            BindStarted(_gameplay, "Dash",        () => DashEvent?.Invoke());
            BindStarted(_gameplay, "UseSpring",        () => UseSpringEvent?.Invoke());
            BindStarted(_gameplay, "SwitchSkyForm",    () => SwitchSkyFormEvent?.Invoke());
            BindStarted(_gameplay, "SwitchEarthForm",  () => SwitchEarthFormEvent?.Invoke());
            BindStarted(_gameplay, "SwitchDeathForm",  () => SwitchDeathFormEvent?.Invoke());
            BindStarted(_gameplay, "SoulSkill",        () => SoulSkillEvent?.Invoke());
            BindStarted(_gameplay, "SpiritSkill1",     () => SpiritSkill1StartedEvent?.Invoke());
            BindCanceled(_gameplay, "SpiritSkill1",    () => SpiritSkill1CancelledEvent?.Invoke());
            BindStarted(_gameplay, "SpiritSkill2",     () => SpiritSkill2StartedEvent?.Invoke());
            BindCanceled(_gameplay, "SpiritSkill2",    () => SpiritSkill2CancelledEvent?.Invoke());
            BindStarted(_gameplay, "Spell",            () => SpellCastEvent?.Invoke());
            BindStarted(_gameplay,  "Interact", () => InteractEvent?.Invoke());
            BindCanceled(_gameplay, "Interact", () => InteractCancelledEvent?.Invoke());
            
            
            BindStarted(_gameplay, "Pause",       HandlePause);

            if (_ui != null)
            {
                BindPerformed(_ui, "Navigate", ctx => NavigateEvent?.Invoke(ctx.ReadValue<Vector2>()));
                BindCanceled(_ui,  "Navigate", _ => NavigateEvent?.Invoke(Vector2.zero));
                BindStarted(_ui,   "Submit",   () => SubmitEvent?.Invoke());
                BindStarted(_ui,   "Cancel",   () => CancelEvent?.Invoke());
                BindStarted(_ui,   "Pause",    HandlePause);
                BindPerformed(_ui, "Point",    ctx => PointEvent?.Invoke(ctx.ReadValue<Vector2>()));
                // R13-N3 小地图缩放档位切换；Action 名称需在 InputActionAsset UI Map 中添加（可选）
                BindStarted(_ui,   "CycleMinimapZoom", () => CycleMinimapZoomEvent?.Invoke());
                // R13-N4 全屏地图居中；Action 名称需在 InputActionAsset UI Map 中添加（可选）
                BindStarted(_ui,   "MapCenter",        () => MapCenterEvent?.Invoke());
            }

            _isBound = true;
        }

        private void HandlePause()
        {
            PauseEvent?.Invoke();
            _onPauseRequested?.Raise();
        }

        private static void BindStarted(InputActionMap map, string name, Action callback)
        {
            var action = map.FindAction(name, throwIfNotFound: false);
            if (action != null)
            {
                action.started += _ => callback();
                
            }
            else
            {
                Debug.LogWarning($"[BindStarted] Action '{name}' not found in map");
            }
        }

        private static void BindPerformed(InputActionMap map, string name,
            Action<InputAction.CallbackContext> callback)
        {
            var action = map.FindAction(name, throwIfNotFound: false);
            if (action != null) action.performed += callback;
        }

        private static void BindCanceled(InputActionMap map, string name,
            Action<InputAction.CallbackContext> callback)
        {
            var action = map.FindAction(name, throwIfNotFound: false);
            if (action != null) action.canceled += callback;
        }

        private static void BindCanceled(InputActionMap map, string name, Action callback)
        {
            var action = map.FindAction(name, throwIfNotFound: false);
            if (action != null) action.canceled += _ => callback();
        }

        // ── Rebinding API (P4-3) ──────────────────────────────────────────────

        private const string PrefKey = "InputBindings";

        /// <summary>查找单个 Action（供 RebindActionRow 显示当前绑定路径）。</summary>
        public InputAction FindAction(string name)
            => _inputActions?.FindAction(name);

        /// <summary>返回 Gameplay Map 所有 Action（供 ConflictDetector 扫描冲突）。</summary>
        public IEnumerable<InputAction> GetAllActionMap()
        {
            var map = _inputActions?.FindActionMap("Gameplay");
            return map != null ? (IEnumerable<InputAction>)map.actions : Array.Empty<InputAction>();
        }

        /// <summary>
        /// 启动交互式重绑定（Unity InputSystem RebindingOperation）。
        /// 调用方无需持有返回值；完成或取消后自动 Dispose。
        /// </summary>
        public void StartRebinding(
            string actionName, int bindingIndex, Action onComplete, Action onCancel)
        {
            var action = _inputActions?.FindAction(actionName);
            if (action == null) { onCancel?.Invoke(); return; }

            action.Disable();
            action.PerformInteractiveRebinding(bindingIndex)
                .OnComplete(op => { op.Dispose(); action.Enable(); onComplete?.Invoke(); })
                .OnCancel(op =>  { op.Dispose(); action.Enable(); onCancel?.Invoke(); })
                .Start();
        }

        /// <summary>将当前绑定覆盖序列化为 JSON，存入 PlayerPrefs（key = "InputBindings"）。</summary>
        public void SaveBindingOverrides()
        {
            if (_inputActions == null) return;
            PlayerPrefs.SetString(PrefKey, _inputActions.SaveBindingOverridesAsJson());
            PlayerPrefs.Save();
        }

        /// <summary>从 PlayerPrefs 加载并应用绑定覆盖（首次启动时无操作）。</summary>
        public void LoadBindingOverrides()
        {
            if (_inputActions != null && PlayerPrefs.HasKey(PrefKey))
                _inputActions.LoadBindingOverridesFromJson(PlayerPrefs.GetString(PrefKey));
        }

        /// <summary>重置所有绑定为默认值并清除 PlayerPrefs 记录。</summary>
        public void ResetBindings()
        {
            _inputActions?.RemoveAllBindingOverrides();
            PlayerPrefs.DeleteKey(PrefKey);
        }
    }
}