using System.Text.RegularExpressions;
using anjianjingling.Native;

namespace anjianjingling.Forms
{
    /// <summary>
    /// Lua 脚本编辑器：行号栏 + 语法着色（关键字/字符串/注释/数字）。
    /// 纯 WinForms，无第三方依赖。
    /// </summary>
    public sealed class LuaEditor : UserControl
    {
        private readonly RichTextBox _rtb = new();
        private readonly Panel _gutter = new();
        private readonly System.Windows.Forms.Timer _hlTimer = new();
        private bool _highlighting;

        private const int WM_SETREDRAW = 0x000B;
        private const int WM_USER = 0x0400;
        private const int EM_GETFIRSTVISIBLELINE = WM_USER + 206;

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        public LuaEditor()
        {
            _gutter.Dock = DockStyle.Left;
            _gutter.Width = 46;
            _gutter.BackColor = Color.FromArgb(240, 243, 248);
            _gutter.Paint += GutterPaint;

            _rtb.Dock = DockStyle.Fill;
            _rtb.BorderStyle = BorderStyle.None;
            _rtb.Font = new Font("Consolas", 11F);
            _rtb.BackColor = Color.FromArgb(252, 253, 255);
            _rtb.ForeColor = Color.FromArgb(30, 34, 42);
            _rtb.WordWrap = false;
            _rtb.AcceptsTab = true;
            _rtb.ScrollBars = RichTextBoxScrollBars.Both;
            _rtb.DetectUrls = false;
            _rtb.HideSelection = false;
            _rtb.VScroll += (s, e) => _gutter.Invalidate();
            _rtb.HScroll += (s, e) => _gutter.Invalidate();
            _rtb.TextChanged += (s, e) =>
            {
                _hlTimer.Stop();
                _hlTimer.Start();
                ScriptChanged?.Invoke(this, EventArgs.Empty);
                _gutter.Invalidate();
            };
            _rtb.SelectionChanged += (s, e) => CaretMoved?.Invoke(LineOf(_rtb.SelectionStart), ColumnOf(_rtb.SelectionStart));
            _rtb.KeyDown += (s, e) =>
            {
                if (e.Control && e.KeyCode == Keys.A)
                {
                    _rtb.SelectAll();
                    e.SuppressKeyPress = true;
                }
                // Tab 插入 4 空格而不是制表符
                if (e.KeyCode == Keys.Tab && !e.Shift && !e.Control)
                {
                    _rtb.SelectedText = "    ";
                    e.SuppressKeyPress = true;
                }
            };

            _hlTimer.Interval = 180;
            _hlTimer.Tick += (s, e) => { _hlTimer.Stop(); Highlight(); };

            Controls.Add(_rtb);
            Controls.Add(_gutter);
        }

        /// <summary>脚本文本（不用基类 Text，避免与控件标题混淆）。</summary>
        [System.ComponentModel.Browsable(false)]
        [System.ComponentModel.DesignerSerializationVisibility(System.ComponentModel.DesignerSerializationVisibility.Hidden)]
        public string Script
        {
            get => _rtb.Text;
            set { _rtb.Text = value; Highlight(); }
        }

        public RichTextBox Inner => _rtb;
        public event EventHandler? ScriptChanged;
        public event Action<int, int>? CaretMoved;

        public void FocusEditor() => _rtb.Focus();

        public int CurrentLine => LineOf(_rtb.SelectionStart);

        public void GotoLine(int line)
        {
            var lines = _rtb.Lines;
            if (line < 0 || line >= lines.Length) return;
            int idx = 0;
            for (int i = 0; i < line; i++) idx += lines[i].Length + 1;
            _rtb.SelectionStart = idx;
            _rtb.SelectionLength = 0;
            _rtb.ScrollToCaret();
            _rtb.Focus();
        }

        private int LineOf(int charIndex)
        {
            int line = _rtb.GetLineFromCharIndex(charIndex);
            return line + 1;
        }

        private int ColumnOf(int charIndex)
        {
            int first = _rtb.GetFirstCharIndexFromLine(_rtb.GetLineFromCharIndex(charIndex));
            return charIndex - first + 1;
        }

        // ===================== 行号 =====================

        private void GutterPaint(object? sender, PaintEventArgs e)
        {
            var g = e.Graphics;
            g.Clear(_gutter.BackColor);
            using var font = new Font("Consolas", 9.5F);
            using var brush = new SolidBrush(Color.FromArgb(130, 142, 162));
            using var curBrush = new SolidBrush(Color.FromArgb(37, 99, 235));

            int firstVisible = (int)SendMessage(_rtb.Handle, EM_GETFIRSTVISIBLELINE, IntPtr.Zero, IntPtr.Zero);
            int lineCount = _rtb.Lines.Length;
            int lineHeight = _rtb.Font.Height;

            int curLine = _rtb.GetLineFromCharIndex(_rtb.SelectionStart);
            for (int i = 0; i < 200; i++)
            {
                int lineIdx = firstVisible + i;
                if (lineIdx >= lineCount) break;
                int y = i * lineHeight + 2;
                if (y > _gutter.Height) break;
                string num = (lineIdx + 1).ToString();
                var sz = g.MeasureString(num, font);
                var b = lineIdx == curLine ? curBrush : brush;
                g.DrawString(num, font, b, _gutter.Width - sz.Width - 8, y);
            }
        }

        // ===================== 语法着色 =====================

        private static readonly Regex RxComment = new(@"--\[\[.*?\]\]|--[^\n]*", RegexOptions.Compiled | RegexOptions.Singleline);
        private static readonly Regex RxString = new("\"(?:\\\\.|[^\"\\\\])*\"|'(?:\\\\.|[^'\\\\])*'", RegexOptions.Compiled);
        private static readonly Regex RxNumber = new(@"\b0x[0-9a-fA-F]+\b|\b\d+(\.\d+)?\b", RegexOptions.Compiled);
        private static readonly Regex RxKeyword = new(
            @"\b(and|break|do|else|elseif|end|false|for|function|goto|if|in|local|nil|not|or|repeat|return|then|true|until|while)\b",
            RegexOptions.Compiled);
        private static readonly Regex RxApi = new(
            @"\b(delay|delayRandom|moveTo|moveR|leftClick|rightClick|middleClick|doubleClick|wheel|drag|keyPress|keyDown|keyUp|hotkey|typeText|sayText|findImage|findColor|waitImage|exists|screenshot|colorAt|clipGet|clipSet|run|activate|log|stop|random|now|sleep|mouse|key|screen|win|sys|clip|browser)\b",
            RegexOptions.Compiled);

        private static readonly Color CKeyword = Color.FromArgb(175, 45, 130);
        private static readonly Color CString = Color.FromArgb(20, 130, 80);
        private static readonly Color CComment = Color.FromArgb(140, 150, 165);
        private static readonly Color CNumber = Color.FromArgb(198, 106, 22);
        private static readonly Color CApi = Color.FromArgb(30, 90, 200);
        private static readonly Color CPlain = Color.FromArgb(30, 34, 42);

        public void Highlight()
        {
            if (_highlighting || _rtb.TextLength == 0) return;
            _highlighting = true;
            try
            {
                string text = _rtb.Text;
                int selStart = _rtb.SelectionStart;
                int selLen = _rtb.SelectionLength;

                SendMessage(_rtb.Handle, WM_SETREDRAW, IntPtr.Zero, IntPtr.Zero);

                _rtb.SelectAll();
                _rtb.SelectionColor = CPlain;

                void Paint(Regex rx, Color color)
                {
                    foreach (Match m in rx.Matches(text))
                    {
                        if (m.Length == 0) continue;
                        _rtb.Select(m.Index, m.Length);
                        _rtb.SelectionColor = color;
                    }
                }

                Paint(RxNumber, CNumber);
                Paint(RxKeyword, CKeyword);
                Paint(RxApi, CApi);
                Paint(RxString, CString);
                Paint(RxComment, CComment);

                _rtb.Select(selStart, selLen);
                _rtb.SelectionColor = CPlain;

                SendMessage(_rtb.Handle, WM_SETREDRAW, (IntPtr)1, IntPtr.Zero);
                _rtb.Invalidate();
            }
            catch { }
            finally { _highlighting = false; }
        }
    }
}