using System;
using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.U2D;


[Serializable]
public sealed class GlyphEntry
{
    public Sprite Sprite;
    public InputAction action;
}

[Serializable]
public sealed class DeviceGlyphTable
{
    public string deviceName;

    public Texture2D spriteSheetTexture;

    public Sprite platformIcons;

    public List<GlyphEntry> entries = new List<GlyphEntry>();
}

[CreateAssetMenu(fileName = "InputGlyphDatabase", menuName = "InputGlyphs/InputGlyphDatabase", order = 400)]
public sealed class InputGlyphDatabase : ScriptableObject
{
    private const string DEVICE_KEYBOARD = "Keyboard";
    private const string DEVICE_XBOX = "Xbox";
    private const string DEVICE_PLAYSTATION = "PlayStation";

    public List<DeviceGlyphTable> tables = new List<DeviceGlyphTable>();

    // 当 FindEntryByControlPath 传空 path 时返回的占位 sprite
    public Sprite placeholderSprite;

    // 用于更快查找的缓存
    private Dictionary<string, DeviceGlyphTable> _tableCache;
    private Dictionary<(string path, InputDeviceWatcher.InputDeviceCategory device), Sprite> _spriteCache;

    /// <summary>
    /// 启用时构建缓存
    /// </summary>
    private void OnEnable()
    {
        BuildCache();
    }

    /// <summary>
    /// 构建表和精灵的查找缓存
    /// </summary>
    private void BuildCache()
    {
        if (_tableCache == null)
        {
            _tableCache = new Dictionary<string, DeviceGlyphTable>(tables.Count);
        }
        else
        {
            _tableCache.Clear();
        }

        if (_spriteCache == null)
        {
            _spriteCache = new Dictionary<(string, InputDeviceWatcher.InputDeviceCategory), Sprite>();
        }
        else
        {
            _spriteCache.Clear();
        }

        for (int i = 0; i < tables.Count; i++)
        {
            var table = tables[i];
            if (table != null && !string.IsNullOrEmpty(table.deviceName))
            {
                _tableCache[table.deviceName.ToLowerInvariant()] = table;
            }
        }
    }

    /// <summary>
    /// 根据设备名称获取设备图标表
    /// </summary>
    /// <param name="deviceName">设备名称</param>
    /// <returns>设备图标表</returns>
    public DeviceGlyphTable GetTable(string deviceName)
    {
        if (string.IsNullOrEmpty(deviceName)) return null;
        if (tables == null) return null;

        // 确保缓存已构建
        if (_tableCache == null || _tableCache.Count == 0)
        {
            BuildCache();
        }

        // 使用缓存进行 O(1) 查找
        if (_tableCache.TryGetValue(deviceName.ToLowerInvariant(), out var table))
        {
            return table;
        }

        return null;
    }

    /// <summary>
    /// 获取平台图标
    /// </summary>
    /// <param name="device">设备类型</param>
    /// <returns>平台图标 Sprite</returns>
    public Sprite GetPlatformIcon(InputDeviceWatcher.InputDeviceCategory device)
    {
        var table = GetTable(device);
        if (table == null) return null;
        return table.platformIcons;
    }

    /// <summary>
    /// 根据设备类型获取设备图标表
    /// </summary>
    /// <param name="device">设备类型</param>
    /// <returns>设备图标表</returns>
    public DeviceGlyphTable GetTable(InputDeviceWatcher.InputDeviceCategory device)
    {
        // 使用常量避免字符串分配
        string name;
        switch (device)
        {
            case InputDeviceWatcher.InputDeviceCategory.Keyboard:
                name = DEVICE_KEYBOARD;
                break;
            case InputDeviceWatcher.InputDeviceCategory.Xbox:
                name = DEVICE_XBOX;
                break;
            case InputDeviceWatcher.InputDeviceCategory.PlayStation:
                name = DEVICE_PLAYSTATION;
                break;
            default:
                name = DEVICE_XBOX;
                break;
        }

        return GetTable(name);
    }

    /// <summary>
    /// 根据控制路径和设备类型查找 Sprite
    /// </summary>
    /// <param name="controlPath">控制路径</param>
    /// <param name="device">设备类型</param>
    /// <returns>找到的 Sprite，未找到则返回占位 Sprite</returns>
    public Sprite FindSprite(string controlPath, InputDeviceWatcher.InputDeviceCategory device)
    {
        if (string.IsNullOrEmpty(controlPath))
        {
            return placeholderSprite;
        }

        // 首先检查缓存
        var cacheKey = (controlPath, device);
        if (_spriteCache != null && _spriteCache.TryGetValue(cacheKey, out var cachedSprite))
        {
            return cachedSprite ?? placeholderSprite;
        }

        var entry = FindEntryByControlPath(controlPath, device);
        var sprite = entry?.Sprite ?? placeholderSprite;

        // 缓存结果（包括 null 结果以避免重复查找）
        if (_spriteCache != null)
        {
            _spriteCache[cacheKey] = sprite;
        }

        return sprite;
    }

    /// <summary>
    /// 根据控制路径和设备类型查找图标条目
    /// </summary>
    /// <param name="controlPath">控制路径</param>
    /// <param name="device">设备类型</param>
    /// <returns>找到的图标条目，未找到则返回 null</returns>
    public GlyphEntry FindEntryByControlPath(string controlPath, InputDeviceWatcher.InputDeviceCategory device)
    {
        var t = GetTable(device);
        if (t != null && t.entries != null)
        {
            for (int i = 0; i < t.entries.Count; ++i)
            {
                var e = t.entries[i];
                if (e == null) continue;
                if (e.action == null) continue;

                var bindings = e.action.bindings;
                int bindingCount = bindings.Count;
                if (bindingCount <= 0) continue;

                for (int j = 0; j < bindingCount; j++)
                {
                    var b = bindings[j];
                    if (!string.IsNullOrEmpty(b.path) && string.Equals(b.path, controlPath, StringComparison.OrdinalIgnoreCase))
                    {
                        return e;
                    }

                    if (!string.IsNullOrEmpty(b.effectivePath) && string.Equals(b.effectivePath, controlPath, StringComparison.OrdinalIgnoreCase))
                    {
                        return e;
                    }
                }
            }
        }

        return null;
    }
}