using System;
using System.Runtime.InteropServices;

namespace ClipForge
{
    public class TrayIconService : IDisposable
    {
        [DllImport("shell32.dll", CharSet = CharSet.Unicode)]
        private static extern bool Shell_NotifyIcon(uint dwMessage, ref NOTIFYICONDATA lpdata);

        [DllImport("user32.dll")]
        private static extern bool DestroyMenu(IntPtr hMenu);

        [DllImport("user32.dll")]
        private static extern IntPtr CreatePopupMenu();

        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        private static extern bool AppendMenu(IntPtr hMenu, uint uFlags, uint uIDNewItem, string lpNewItem);

        [DllImport("user32.dll")]
        private static extern int TrackPopupMenu(IntPtr hMenu, uint uFlags, int x, int y, int nReserved, IntPtr hWnd, IntPtr prcRect);

        [DllImport("user32.dll")]
        private static extern bool GetCursorPos(out POINT lpPoint);

        [DllImport("user32.dll")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);

        // This overload loads from a file path
        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        private static extern IntPtr LoadImage(IntPtr hInst, string lpszName,
            uint uType, int cxDesired, int cyDesired, uint fuLoad);

        // This overload loads a system icon by ID
        [DllImport("user32.dll")]
        private static extern IntPtr LoadImage(IntPtr hInst, IntPtr lpszName,
            uint uType, int cxDesired, int cyDesired, uint fuLoad);

        [DllImport("user32.dll")]
        private static extern IntPtr SetWindowLongPtr(IntPtr hWnd, int nIndex, WndProcDelegate newProc);

        [DllImport("user32.dll")]
        private static extern IntPtr CallWindowProc(IntPtr lpPrevWndFunc, IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll")]
        private static extern IntPtr GetModuleHandle(string? lpModuleName);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        private struct NOTIFYICONDATA
        {
            public uint cbSize;
            public IntPtr hWnd;
            public uint uID;
            public uint uFlags;
            public uint uCallbackMessage;
            public IntPtr hIcon;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
            public string szTip;
            public uint dwState;
            public uint dwStateMask;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string szInfo;
            public uint uTimeoutOrVersion;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)]
            public string szInfoTitle;
            public uint dwInfoFlags;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct POINT { public int x; public int y; }

        private delegate IntPtr WndProcDelegate(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);

        private const uint NIM_ADD = 0x00000000;
        private const uint NIM_MODIFY = 0x00000001;
        private const uint NIM_DELETE = 0x00000002;
        private const uint NIF_MESSAGE = 0x00000001;
        private const uint NIF_ICON = 0x00000002;
        private const uint NIF_TIP = 0x00000004;
        private const uint WM_APP = 0x8000;
        private const uint WM_TRAYICON = WM_APP + 1;
        private const uint WM_RBUTTONUP = 0x0205;
        private const uint WM_LBUTTONDBLCLK = 0x0203;
        private const uint MF_STRING = 0x00000000;
        private const uint MF_SEPARATOR = 0x00000800;
        private const uint TPM_RETURNCMD = 0x0100;
        private const int IDI_APPLICATION = 32512;
        private const uint IMAGE_ICON = 1;
        private const uint LR_SHARED = 0x00008000;
        private const uint LR_LOADFROMFILE = 0x00000010;
        private const int GWLP_WNDPROC = -4;

        private const uint CMD_OPEN = 1001;
        private const uint CMD_EXIT = 1002;

        private NOTIFYICONDATA _iconData;
        private IntPtr _hwnd;
        private bool _added;
        private WndProcDelegate? _wndProc;
        private IntPtr _oldWndProc;

        private Action? _showWindow;
        private Action? _exitApp;

        public void Initialize(IntPtr hwnd, Action showWindow, Action exitApp)
        {
            _hwnd = hwnd;
            _showWindow = showWindow;
            _exitApp = exitApp;

            _wndProc = TrayWndProc;
            _oldWndProc = SetWindowLongPtr(_hwnd, GWLP_WNDPROC, _wndProc);

            // Try to load our custom icon from the app directory
            var iconPath = System.IO.Path.Combine(
                AppContext.BaseDirectory, "clipforge.ico");

            IntPtr hIcon;
            if (System.IO.File.Exists(iconPath))
            {
                hIcon = LoadImage(IntPtr.Zero, iconPath,
                    IMAGE_ICON, 16, 16, LR_LOADFROMFILE);
            }
            else
            {
                // Fallback to generic Windows icon
                hIcon = LoadImage(IntPtr.Zero, new IntPtr(IDI_APPLICATION),
                    IMAGE_ICON, 16, 16, LR_SHARED);
            }

            _iconData = new NOTIFYICONDATA
            {
                cbSize = (uint)Marshal.SizeOf<NOTIFYICONDATA>(),
                hWnd = _hwnd,
                uID = 1,
                uFlags = NIF_ICON | NIF_TIP | NIF_MESSAGE,
                uCallbackMessage = WM_TRAYICON,
                hIcon = hIcon,
                szTip = "ClipForge — Recording"
            };

            Shell_NotifyIcon(NIM_ADD, ref _iconData);
            _added = true;
        }

        private IntPtr TrayWndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
        {
            if (msg == WM_TRAYICON)
            {
                uint mouseEvent = (uint)lParam & 0xFFFF;

                if (mouseEvent == WM_LBUTTONDBLCLK)
                    _showWindow?.Invoke();

                if (mouseEvent == WM_RBUTTONUP)
                    ShowContextMenu();
            }

            return CallWindowProc(_oldWndProc, hWnd, msg, wParam, lParam);
        }

        private void ShowContextMenu()
        {
            var hMenu = CreatePopupMenu();
            AppendMenu(hMenu, MF_STRING, CMD_OPEN, "Open ClipForge");
            AppendMenu(hMenu, MF_SEPARATOR, 0, "");
            AppendMenu(hMenu, MF_STRING, CMD_EXIT, "Exit");

            GetCursorPos(out POINT pt);
            SetForegroundWindow(_hwnd);

            int cmd = TrackPopupMenu(hMenu, TPM_RETURNCMD,
                pt.x, pt.y, 0, _hwnd, IntPtr.Zero);

            DestroyMenu(hMenu);

            if (cmd == CMD_OPEN) _showWindow?.Invoke();
            if (cmd == CMD_EXIT) _exitApp?.Invoke();
        }

        public void SetStatus(string status)
        {
            if (!_added) return;
            _iconData.szTip = $"ClipForge — {status}";
            Shell_NotifyIcon(NIM_MODIFY, ref _iconData);
        }

        public void Dispose()
        {
            if (_added)
            {
                Shell_NotifyIcon(NIM_DELETE, ref _iconData);
                _added = false;
            }
        }
    }
}