using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using Gma.System.MouseKeyHook;

namespace ShortcutsHelper.Services
{
    public class KeyCaptureService : IDisposable
    {
        private IKeyboardMouseEvents? _globalHook;
        private bool _isCapturing = false;
        private List<string> _capturedKeys = new();

        public event EventHandler<string>? KeyCaptured;
        public event EventHandler? CaptureCancelled;

        public bool IsCapturing => _isCapturing;

        public void StartCapturing()
        {
            if (_isCapturing) return;

            _isCapturing = true;
            _capturedKeys.Clear();
            
            _globalHook = Hook.GlobalEvents();
            _globalHook.KeyDown += OnKeyDown;
            _globalHook.KeyUp += OnKeyUp;
        }

        public void StopCapturing()
        {
            _isCapturing = false;
            if (_globalHook != null)
            {
                _globalHook.KeyDown -= OnKeyDown;
                _globalHook.KeyUp -= OnKeyUp;
                _globalHook.Dispose();
                _globalHook = null;
            }
        }

        private void OnKeyDown(object? sender, KeyEventArgs e)
        {
            if (!_isCapturing) return;

            if (e.KeyCode == Keys.Escape)
            {
                StopCapturing();
                CaptureCancelled?.Invoke(this, EventArgs.Empty);
                return;
            }

            var keyString = BuildKeyString(e);
            if (!string.IsNullOrEmpty(keyString))
            {
                _capturedKeys.Clear();
                _capturedKeys.Add(keyString);
            }
        }

        private void OnKeyUp(object? sender, KeyEventArgs e)
        {
            if (!_isCapturing || _capturedKeys.Count == 0) return;

            StopCapturing();
            KeyCaptured?.Invoke(this, _capturedKeys.First().Replace(" ", ""));
        }

        private string BuildKeyString(KeyEventArgs e)
        {
            var parts = new List<string>();
            
            if ((Control.ModifierKeys & Keys.Control) != 0) parts.Add("Ctrl");
            if ((Control.ModifierKeys & Keys.Alt) != 0) parts.Add("Alt");
            if ((Control.ModifierKeys & Keys.Shift) != 0) parts.Add("Shift");
            if ((Control.ModifierKeys & Keys.LWin) != 0 || (Control.ModifierKeys & Keys.RWin) != 0) parts.Add("Win");
            
            if (e.KeyCode != Keys.ControlKey && e.KeyCode != Keys.LControlKey && e.KeyCode != Keys.RControlKey &&
                e.KeyCode != Keys.Menu && e.KeyCode != Keys.LMenu && e.KeyCode != Keys.RMenu &&
                e.KeyCode != Keys.ShiftKey && e.KeyCode != Keys.LShiftKey && e.KeyCode != Keys.RShiftKey &&
                e.KeyCode != Keys.LWin && e.KeyCode != Keys.RWin)
            {
                parts.Add(GetKeyName(e.KeyCode));
            }
            
            return string.Join("+", parts);
        }

        private string GetKeyName(Keys key)
        {
            return key switch
            {
                Keys.Space => "Space",
                Keys.Enter => "Enter",
                Keys.Tab => "Tab",
                Keys.Back => "Backspace",
                Keys.Delete => "Delete",
                Keys.Insert => "Insert",
                Keys.Home => "Home",
                Keys.End => "End",
                Keys.PageUp => "PageUp",
                Keys.PageDown => "PageDown",
                Keys.Up => "↑",
                Keys.Down => "↓",
                Keys.Left => "←",
                Keys.Right => "→",
                Keys.F1 => "F1",
                Keys.F2 => "F2",
                Keys.F3 => "F3",
                Keys.F4 => "F4",
                Keys.F5 => "F5",
                Keys.F6 => "F6",
                Keys.F7 => "F7",
                Keys.F8 => "F8",
                Keys.F9 => "F9",
                Keys.F10 => "F10",
                Keys.F11 => "F11",
                Keys.F12 => "F12",
                _ => key.ToString()
            };
        }

        public void Dispose()
        {
            StopCapturing();
        }
    }
}