using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Windows.Media;

namespace WpfEditor
{
    public class SyntaxHighlighter
    {
        private Dictionary<string, Brush> _keywords = new Dictionary<string, Brush>();
        private List<Regex> _patterns = new List<Regex>();
        private Dictionary<Regex, Brush> _patternColors = new Dictionary<Regex, Brush>();
        private string _commentStart = "/*";
        private string _commentEnd = "*/";
        private string _lineComment = "//";

        public SyntaxHighlighter()
        {
            // 默认配置
            SetupCppHighlighting();
        }

        public void SetupCppHighlighting()
        {
            // C++ 关键字
            string[] keywords = new string[] {
                "auto", "break", "case", "catch", "class", "const", "continue", "default", "delete", "do", "else",
                "enum", "explicit", "export", "extern", "for", "friend", "goto", "if", "inline", "mutable", "namespace",
                "new", "operator", "private", "protected", "public", "register", "return", "sizeof", "static", "struct",
                "switch", "template", "this", "throw", "try", "typedef", "typeid", "typename", "union", "using",
                "virtual", "volatile", "while"
            };

            foreach (var keyword in keywords)
            {
                _keywords[keyword] = Brushes.Blue;
            }

            // 数字
            _patterns.Add(new Regex(@"\b\d+(\.\d+)?([eE][+-]?\d+)?\b"));
            _patternColors[_patterns[_patterns.Count - 1]] = Brushes.DarkOrange;

            // 字符串
            _patterns.Add(new Regex(@"""\.\*?""")); // 使用两个连续的双引号表示一个双引号字符
            _patternColors[_patterns[_patterns.Count - 1]] = Brushes.Brown;
            // 字符
            _patterns.Add(new Regex(@"'.'|'\\.'|'\\\\'"));
            _patternColors[_patterns[_patterns.Count - 1]] = Brushes.Brown;

            // 注释
            _commentStart = "/*";
            _commentEnd = "*/";
            _lineComment = "//";
        }

        public void Colorize(List<TextLine> lines)
        {
            bool inMultiLineComment = false;

            for (int i = 0; i < lines.Count; i++)
            {
                var line = lines[i];
                string lineText = string.Concat(line.Characters.Select(c => c.Character.ToString()));

                // 重置所有字符的颜色
                foreach (var c in line.Characters)
                {
                    c.IsComment = false;
                    c.IsKeyword = false;
                    c.IsString = false;
                    c.IsNumber = false;
                    c.Foreground = Brushes.Black;
                }

                // 处理多行注释
                if (inMultiLineComment)
                {
                    int endIndex = lineText.IndexOf(_commentEnd);
                    if (endIndex >= 0)
                    {
                        // 注释结束
                        for (int j = 0; j <= endIndex + _commentEnd.Length - 1 && j < line.Characters.Count; j++)
                        {
                            line.Characters[j].IsComment = true;
                            line.Characters[j].Foreground = Brushes.Green;
                        }
                        inMultiLineComment = false;

                        // 处理注释后的部分
                        if (endIndex + _commentEnd.Length < lineText.Length)
                        {
                            ColorizeLineSegment(line, endIndex + _commentEnd.Length, lineText.Length - (endIndex + _commentEnd.Length));
                        }
                    }
                    else
                    {
                        // 整行都是注释
                        for (int j = 0; j < line.Characters.Count; j++)
                        {
                            line.Characters[j].IsComment = true;
                            line.Characters[j].Foreground = Brushes.Green;
                        }
                    }
                }
                else
                {
                    // 处理单行注释和多行注释开始
                    int lineCommentIndex = lineText.IndexOf(_lineComment);
                    int multiLineCommentIndex = lineText.IndexOf(_commentStart);

                    if (lineCommentIndex >= 0 && (multiLineCommentIndex < 0 || lineCommentIndex < multiLineCommentIndex))
                    {
                        // 单行注释优先
                        if (lineCommentIndex > 0)
                        {
                            ColorizeLineSegment(line, 0, lineCommentIndex);
                        }

                        // 注释部分
                        for (int j = lineCommentIndex; j < line.Characters.Count; j++)
                        {
                            line.Characters[j].IsComment = true;
                            line.Characters[j].Foreground = Brushes.Green;
                        }
                    }
                    else if (multiLineCommentIndex >= 0)
                    {
                        // 多行注释开始
                        if (multiLineCommentIndex > 0)
                        {
                            ColorizeLineSegment(line, 0, multiLineCommentIndex);
                        }

                        int endIndex = lineText.IndexOf(_commentEnd, multiLineCommentIndex + _commentStart.Length);
                        if (endIndex >= 0)
                        {
                            // 同一行内结束
                            for (int j = multiLineCommentIndex; j <= endIndex + _commentEnd.Length - 1 && j < line.Characters.Count; j++)
                            {
                                line.Characters[j].IsComment = true;
                                line.Characters[j].Foreground = Brushes.Green;
                            }

                            // 处理注释后的部分
                            if (endIndex + _commentEnd.Length < lineText.Length)
                            {
                                ColorizeLineSegment(line, endIndex + _commentEnd.Length, lineText.Length - (endIndex + _commentEnd.Length));
                            }
                        }
                        else
                        {
                            // 注释延续到下一行
                            for (int j = multiLineCommentIndex; j < line.Characters.Count; j++)
                            {
                                line.Characters[j].IsComment = true;
                                line.Characters[j].Foreground = Brushes.Green;
                            }
                            inMultiLineComment = true;
                        }
                    }
                    else
                    {
                        // 没有注释，正常处理整行
                        ColorizeLineSegment(line, 0, lineText.Length);
                    }
                }
            }
        }

        private void ColorizeLineSegment(TextLine line, int startIndex, int length)
        {
            if (length <= 0 || startIndex >= line.Characters.Count)
                return;

            // 将Rune转换为字符串进行处理
            string text = string.Concat(line.Characters.GetRange(startIndex, Math.Min(length, line.Characters.Count - startIndex)).Select(c => c.Character.ToString()));
            
            // 处理关键字
            foreach (var keyword in _keywords.Keys)
            {
                int index = 0;
                while ((index = text.IndexOf(keyword, index)) >= 0)
                {
                    // 确保是完整的单词
                    bool isWordStart = index == 0 || !char.IsLetterOrDigit(text[index - 1]);
                    bool isWordEnd = index + keyword.Length == text.Length || !char.IsLetterOrDigit(text[index + keyword.Length]);

                    if (isWordStart && isWordEnd)
                    {
                        for (int i = 0; i < keyword.Length && i + index + startIndex < line.Characters.Count; i++)
                        {
                            line.Characters[i + index + startIndex].IsKeyword = true;
                            line.Characters[i + index + startIndex].Foreground = _keywords[keyword];
                        }
                    }
                    index += keyword.Length;
                }
            }

            // 处理正则表达式模式
            for (int i = 0; i < _patterns.Count; i++)
            {
                var regex = _patterns[i];
                var matches = regex.Matches(text);

                foreach (Match match in matches)
                {
                    for (int j = 0; j < match.Length && j + match.Index + startIndex < line.Characters.Count; j++)
                    {
                        if (regex.ToString().Contains("\\d"))
                        {
                            line.Characters[j + match.Index + startIndex].IsNumber = true;
                        }
                        else if (regex.ToString().Contains("\\\""))
                        {
                            line.Characters[j + match.Index + startIndex].IsString = true;
                        }
                        line.Characters[j + match.Index + startIndex].Foreground = _patternColors[regex];
                    }
                }
            }
        }
    }
}