using System;
using System.Collections.Generic;
using DragonLi.Core;
using Knife.Effects.SimpleController;
using UnityEngine;

/// <summary>
/// 管理玩家手部武器：
/// - 拾取后加入可用列表并切换；
/// - 弹尽后自动移除、切回初始武器；
/// - 滚轮/摇杆循环切换。  
/// 已去除相机 FOV 同步（与瞄准放大无关），并优化了字典查找与数组长度缓存，减少循环与属性访问开销。
/// </summary>
public class PlayerHands : MonoBehaviour
{
    [Header("所有武器预置（含初始武器 + 可捡起武器），0号为初始武器")]
    public GameObject[] WeaponsObjects;
    
    public int[] Indices;                     // 可选：UI 圆环选择器索引
    public WeaponSelector weaponSelector;     // 可选：UI 武器选择器事件源
    [SerializeField] private Player player;   // 用于后坐力回调

    private IWeapon[] weapons;                // 缓存的 IWeapon 组件
    private List<int> idToIndex;   // weaponId -> WeaponsObjects 下标

    // “当前已拾取并可用”列表里存的是真实数组下标
    private List<int> availableWeaponIndices = new List<int>();
    private int currentAvailableListIndex = -1;

    void Start()
    {
        int weaponCount = WeaponsObjects.Length;
        weapons = new IWeapon[weaponCount];

        // 构建 weaponId→数组下标 的字典
        idToIndex = new List<int>(weaponCount);
        for (int i = 0; i < weaponCount; i++)
        {
            weapons[i] = WeaponsObjects[i].GetComponent<IWeapon>();
            // 只要实现 IWeapon，就取它的 weaponId（向下转型）
            var w = WeaponsObjects[i].GetComponent<Weapon>();
            w.weaponId = i+1;
            if (w != null && !idToIndex.Contains(w.weaponId))
                idToIndex.Add(w.weaponId);

            // 初始全部隐藏
            weapons[i].SetActive(false);
        }

        // ——————————————————————————————
        // 把索引 0 号初始武器加入可用列表并激活
        availableWeaponIndices.Clear();
        availableWeaponIndices.Add(0);
        currentAvailableListIndex = 0;
        weapons[0].SetActive(true);
        weapons[0].OnFire += OnFire;
        // ——————————————————————————————

        // 注册 WeaponSelector 回调（若不需要可留空）
        if (weaponSelector != null)
            weaponSelector.OnSelectedEvent += OnWeaponSelected;

        // 监听弹尽事件
        Weapon.OnAmmoDepleted += HandleAmmoDepleted;
    }

    void OnDestroy()
    {
        if (weaponSelector != null)
            weaponSelector.OnSelectedEvent -= OnWeaponSelected;

        Weapon.OnAmmoDepleted -= HandleAmmoDepleted;

        // 卸载所有 OnFire 监听
        foreach (var w in weapons)
        {
            if (w != null)
                w.OnFire -= OnFire;
        }
    }

    void Update()
    {
        // Editor 下用滚轮切换
#if UNITY_EDITOR
        float scroll = Input.GetAxis("Mouse ScrollWheel");
        if (scroll > 0f)
            SwitchToNextAvailable();
        else if (scroll < 0f)
            SwitchToPreviousAvailable();
#endif
        // VR（PICO）摇杆的切换由 Player 脚本里调用
    }

    /// <summary>
    /// UI 圆环选中时，传入 selectorIndex，映射到 WeaponsObjects 下标后切换
    /// </summary>
    public void OnWeaponSelected(int selectorIndex)
    {
        if (Indices == null || Indices.Length == 0) return;

        int foundIdx = -1;
        for (int i = 0, len = Indices.Length; i < len; i++)
        {
            if (Indices[i] == selectorIndex)
            {
                foundIdx = i;
                break;
            }
        }
        if (foundIdx < 0) return;

        int listPos = availableWeaponIndices.IndexOf(foundIdx);
        if (listPos >= 0)
            DeployByAvailableListIndex(listPos);
    }

    /// <summary>
    /// 切到下一个可用武器（循环）
    /// </summary>
    public void SwitchToNextAvailable()
    {
        int count = availableWeaponIndices.Count;
        if (count <= 1) return;

        int next = (currentAvailableListIndex + 1) % count;
        DeployByAvailableListIndex(next);
    }

    /// <summary>
    /// 切到上一个可用武器（循环）
    /// </summary>
    public void SwitchToPreviousAvailable()
    {
        int count = availableWeaponIndices.Count;
        if (count <= 1) return;

        int prev = (currentAvailableListIndex - 1 + count) % count;
        DeployByAvailableListIndex(prev);
    }

    /// <summary>
    /// 内部：切换到 availableWeaponIndices[listIdx] 对应的武器
    /// </summary>
    private void DeployByAvailableListIndex(int listIdx)
    {
        int availCount = availableWeaponIndices.Count;
        if (listIdx < 0 || listIdx >= availCount) return;
        int weaponArrayIndex = availableWeaponIndices[listIdx];

        // 如果已经就是这把，直接返回
        int oldArrayIndex = availableWeaponIndices[currentAvailableListIndex];
        if (weaponArrayIndex == oldArrayIndex) return;

        // 停掉旧武器
        weapons[oldArrayIndex].OnFire -= OnFire;
        weapons[oldArrayIndex].SetActive(false);

        // 激活新武器
        currentAvailableListIndex = listIdx;
        weapons[weaponArrayIndex].OnFire += OnFire;
        weapons[weaponArrayIndex].SetActive(true);
        Weapon curPlayerWeapon = WeaponsObjects[weaponArrayIndex].GetComponent<Weapon>();
        EventDispatcher.TriggerEvent("ChangeWeaponIcon",(PlayerWeaponType)weaponArrayIndex,curPlayerWeapon.bulletsLeft);
    }

    /// <summary>
    /// 玩家捡到武器道具时调用：
    /// 1. 将 weaponArrayIndex 加入可用列表（若尚未存在）；
    /// 2. 给它加 ammoCount 子弹；
    /// 3. 切到它。
    /// </summary>
    public void PickUpAndSwitchTo(int weaponArrayIndex, int ammoCount)
    {
        weaponArrayIndex -= 1;
        int maxIdx = WeaponsObjects.Length - 1;
        if (weaponArrayIndex < 0 || weaponArrayIndex > maxIdx) return;

        // 1. 加入可用列表（若没在里头）
        if (!availableWeaponIndices.Contains(weaponArrayIndex))
            availableWeaponIndices.Add(weaponArrayIndex);

        // 2. 给这一把上弹
        var w = WeaponsObjects[weaponArrayIndex].GetComponent<Weapon>();
        if (w != null)
            w.PickUpWeapon(w.weaponId, ammoCount);

        // 3. 切换到这一把
        int listPos = availableWeaponIndices.IndexOf(weaponArrayIndex);
        DeployByAvailableListIndex(listPos);
    }

    /// <summary>
    /// 监听 Weapon.OnAmmoDepleted(weaponId) 事件，移除对应武器并自动切回 0 号
    /// </summary>
    private void HandleAmmoDepleted(int weaponId)
    {
        int weaponArrayIndex = weaponId-1;
        if (!idToIndex.Contains(weaponArrayIndex)) return;

        int listPos = availableWeaponIndices.IndexOf(weaponArrayIndex);
        if (listPos < 0) return;

        availableWeaponIndices.RemoveAt(listPos);

        // 如果移除的正是当前持有的武器，切回 0 号
        if (listPos == currentAvailableListIndex)
        {
            weapons[weaponArrayIndex].OnFire -= OnFire;
            weapons[weaponArrayIndex].SetActive(false);

            // 确保 0 号在列表里
            if (!availableWeaponIndices.Contains(0))
                availableWeaponIndices.Insert(0, 0);

            currentAvailableListIndex = availableWeaponIndices.IndexOf(0);
            weapons[0].SetActive(true);
            weapons[0].OnFire += OnFire;
        }
        else if (listPos < currentAvailableListIndex)
        {
            // 若移除的索引小于当前索引要减 1
            currentAvailableListIndex--;
        }
    }

    /// <summary>
    /// 武器开火时的后坐力回调，将 recoilDelta 传给 Player
    /// </summary>
    private void OnFire(Vector2 recoilDelta)
    {
        if (player != null)
            player.ApplyRecoil(recoilDelta);
    }
}