using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using ToolboxApp.Models;

namespace ToolboxApp.Services;

public sealed class HotkeyService : IDisposable
{
    private const int WmHotkey = 0x0312;
    private readonly Dictionary<int, string> _registeredHotkeys = new();
    private HwndSource? _source;
    private Func<string, Task>? _onTriggered;
    private Action<LogMessage>? _log;
    private int _nextId = 1000;
    private nint _handle;

    public void RegisterAll(
        Window window,
        IEnumerable<ToolItem> tools,
        bool enabled,
        Func<string, Task> onTriggered,
        Action<LogMessage> log)
    {
        UnregisterAll();

        _onTriggered = onTriggered;
        _log = log;

        var helper = new WindowInteropHelper(window);
        _handle = helper.Handle;
        if (_handle == 0)
        {
            return;
        }

        _source ??= HwndSource.FromHwnd(_handle);
        _source?.RemoveHook(WndProc);
        _source?.AddHook(WndProc);

        foreach (var tool in tools)
        {
            tool.HotkeyStatus = string.IsNullOrWhiteSpace(tool.Hotkey) ? "未设置" : "等待注册";
        }

        if (!enabled)
        {
            foreach (var tool in tools.Where(tool => !string.IsNullOrWhiteSpace(tool.Hotkey)))
            {
                tool.HotkeyStatus = "已禁用";
            }

            return;
        }

        var activeTools = tools
            .Where(tool => !tool.IsDeleted && !string.IsNullOrWhiteSpace(tool.Hotkey))
            .ToList();
        var conflicts = activeTools
            .GroupBy(tool => HotkeyParser.Normalize(tool.Hotkey!))
            .Where(group => group.Count() > 1)
            .SelectMany(group => group)
            .ToHashSet();

        foreach (var conflict in conflicts)
        {
            conflict.HotkeyStatus = "内部冲突";
            log(CreateLog(LogLevel.Warning, $"快捷键内部冲突：{conflict.Hotkey}，{conflict.Name}"));
        }

        foreach (var tool in activeTools.Where(tool => !conflicts.Contains(tool)))
        {
            if (!HotkeyParser.TryParse(tool.Hotkey, out var modifiers, out var key))
            {
                tool.HotkeyStatus = "格式无效";
                log(CreateLog(LogLevel.Warning, $"快捷键格式无效：{tool.Name}，{tool.Hotkey}"));
                continue;
            }

            var id = _nextId++;
            if (RegisterHotKey(_handle, id, modifiers, key))
            {
                _registeredHotkeys[id] = tool.Id;
                tool.HotkeyStatus = "正常";
            }
            else
            {
                tool.HotkeyStatus = "系统注册失败";
                log(CreateLog(LogLevel.Warning, $"快捷键注册失败：{tool.Name}，{tool.Hotkey}"));
            }
        }
    }

    public void UnregisterAll()
    {
        if (_handle != 0)
        {
            foreach (var id in _registeredHotkeys.Keys.ToList())
            {
                UnregisterHotKey(_handle, id);
            }
        }

        _registeredHotkeys.Clear();
    }

    public void Dispose()
    {
        UnregisterAll();
        _source?.RemoveHook(WndProc);
    }

    private nint WndProc(nint hwnd, int msg, nint wParam, nint lParam, ref bool handled)
    {
        if (msg == WmHotkey && _registeredHotkeys.TryGetValue(wParam.ToInt32(), out var toolId))
        {
            handled = true;
            _ = TriggerAsync(toolId);
        }

        return 0;
    }

    private async Task TriggerAsync(string toolId)
    {
        if (_onTriggered is null)
        {
            return;
        }

        try
        {
            await _onTriggered(toolId);
        }
        catch (Exception ex)
        {
            _log?.Invoke(CreateLog(LogLevel.Error, $"快捷键触发失败：{ex.Message}"));
        }
    }

    private static LogMessage CreateLog(LogLevel level, string message)
    {
        return new LogMessage
        {
            Level = level,
            Message = message
        };
    }

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool RegisterHotKey(nint hWnd, int id, uint fsModifiers, uint vk);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool UnregisterHotKey(nint hWnd, int id);
}

public static class HotkeyParser
{
    private const uint ModAlt = 0x0001;
    private const uint ModControl = 0x0002;
    private const uint ModShift = 0x0004;
    private const uint ModWin = 0x0008;

    public static string Normalize(string hotkey)
    {
        return string.Join("+", hotkey.Split('+', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
            .Select(NormalizePart)
            .Where(part => part.Length > 0)
            .OrderBy(GetPartOrder)
            .ThenBy(part => part)
            .ToArray());
    }

    public static bool TryParse(string? hotkey, out uint modifiers, out uint key)
    {
        modifiers = 0;
        key = 0;

        if (string.IsNullOrWhiteSpace(hotkey))
        {
            return false;
        }

        var keyPart = "";
        foreach (var rawPart in hotkey.Split('+', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
        {
            var part = NormalizePart(rawPart);
            switch (part)
            {
                case "Ctrl":
                    modifiers |= ModControl;
                    break;
                case "Alt":
                    modifiers |= ModAlt;
                    break;
                case "Shift":
                    modifiers |= ModShift;
                    break;
                case "Win":
                    modifiers |= ModWin;
                    break;
                default:
                    keyPart = part;
                    break;
            }
        }

        if (modifiers == 0 || string.IsNullOrWhiteSpace(keyPart))
        {
            return false;
        }

        key = KeyToVirtualKey(keyPart);
        return key != 0;
    }

    private static string NormalizePart(string value)
    {
        var part = value.Trim();
        return part.ToLowerInvariant() switch
        {
            "control" or "ctrl" => "Ctrl",
            "menu" or "alt" => "Alt",
            "shift" => "Shift",
            "windows" or "win" => "Win",
            _ => part.Length == 1 ? part.ToUpperInvariant() : part.ToUpperInvariant().StartsWith("F", StringComparison.Ordinal) ? part.ToUpperInvariant() : part
        };
    }

    private static int GetPartOrder(string part)
    {
        return part switch
        {
            "Ctrl" => 0,
            "Alt" => 1,
            "Shift" => 2,
            "Win" => 3,
            _ => 4
        };
    }

    private static uint KeyToVirtualKey(string keyPart)
    {
        if (keyPart.Length == 1)
        {
            var character = keyPart[0];
            if (character is >= 'A' and <= 'Z')
            {
                return character;
            }

            if (character is >= '0' and <= '9')
            {
                return character;
            }
        }

        if (keyPart.StartsWith("F", StringComparison.OrdinalIgnoreCase)
            && int.TryParse(keyPart[1..], out var functionKey)
            && functionKey is >= 1 and <= 24)
        {
            return (uint)(0x70 + functionKey - 1);
        }

        return keyPart.ToLowerInvariant() switch
        {
            "escape" or "esc" => 0x1B,
            "tab" => 0x09,
            "space" => 0x20,
            "enter" => 0x0D,
            "backspace" => 0x08,
            "delete" => 0x2E,
            "insert" => 0x2D,
            "home" => 0x24,
            "end" => 0x23,
            "pageup" => 0x21,
            "pagedown" => 0x22,
            "left" => 0x25,
            "up" => 0x26,
            "right" => 0x27,
            "down" => 0x28,
            _ => 0
        };
    }
}