"""
代码编辑器控件
带语法高亮的代码编辑器
"""
from PyQt5.QtWidgets import QPlainTextEdit, QWidget, QVBoxLayout
from PyQt5.QtCore import Qt, QRect
from PyQt5.QtGui import (
    QColor, QTextFormat, QPainter, QFont,
    QSyntaxHighlighter, QTextCharFormat
)
import re


class LineNumberArea(QWidget):
    """行号区域"""

    def __init__(self, editor):
        super().__init__(editor)
        self.editor = editor

    def sizeHint(self):
        return self.editor.lineNumberAreaWidth()

    def paintEvent(self, event):
        self.editor.lineNumberAreaPaintEvent(event)


class CppHighlighter(QSyntaxHighlighter):
    """C++语法高亮器"""

    def __init__(self, document):
        super().__init__(document)

        # 定义高亮规则
        self.highlighting_rules = []

        # 关键字
        keyword_format = QTextCharFormat()
        keyword_format.setForeground(QColor(86, 156, 214))
        keyword_format.setFontWeight(QFont.Bold)

        keywords = [
            'class', 'struct', 'enum', 'namespace', 'public', 'private', 'protected',
            'virtual', 'override', 'const', 'static', 'inline', 'explicit',
            'if', 'else', 'for', 'while', 'do', 'switch', 'case', 'default',
            'return', 'break', 'continue', 'goto',
            'int', 'float', 'double', 'char', 'bool', 'void', 'auto',
            'true', 'false', 'nullptr', 'this',
            'include', 'define', 'ifdef', 'ifndef', 'endif'
        ]

        for keyword in keywords:
            pattern = f'\\b{keyword}\\b'
            self.highlighting_rules.append((re.compile(pattern), keyword_format))

        # 字符串
        string_format = QTextCharFormat()
        string_format.setForeground(QColor(206, 145, 120))
        self.highlighting_rules.append((re.compile(r'"[^"\\]*(\\.[^"\\]*)*"'), string_format))

        # 注释
        comment_format = QTextCharFormat()
        comment_format.setForeground(QColor(106, 153, 85))
        self.highlighting_rules.append((re.compile(r'//[^\n]*'), comment_format))

        # 数字
        number_format = QTextCharFormat()
        number_format.setForeground(QColor(181, 206, 168))
        self.highlighting_rules.append((re.compile(r'\b\d+\.?\d*\b'), number_format))

    def highlightBlock(self, text):
        """高亮文本块"""
        for pattern, format in self.highlighting_rules:
            for match in pattern.finditer(text):
                start = match.start()
                length = match.end() - start
                self.setFormat(start, length, format)


class CodeEditorWidget(QPlainTextEdit):
    """代码编辑器控件"""

    def __init__(self, language='cpp'):
        super().__init__()

        self.language = language

        # 设置字体
        font = QFont("Consolas", 10)
        font.setFixedPitch(True)
        self.setFont(font)

        # 创建行号区域
        self.line_number_area = LineNumberArea(self)

        # 连接信号
        self.blockCountChanged.connect(self.updateLineNumberAreaWidth)
        self.updateRequest.connect(self.updateLineNumberArea)

        # 初始化行号宽度
        self.updateLineNumberAreaWidth(0)

        # 设置语法高亮
        if language == 'cpp':
            self.highlighter = CppHighlighter(self.document())

    def lineNumberAreaWidth(self):
        """计算行号区域宽度"""
        digits = len(str(max(1, self.blockCount())))
        space = 3 + self.fontMetrics().horizontalAdvance('9') * digits
        return space

    def updateLineNumberAreaWidth(self, _):
        """更新行号区域宽度"""
        self.setViewportMargins(self.lineNumberAreaWidth(), 0, 0, 0)

    def updateLineNumberArea(self, rect, dy):
        """更新行号区域"""
        if dy:
            self.line_number_area.scroll(0, dy)
        else:
            self.line_number_area.update(0, rect.y(),
                                         self.line_number_area.width(), rect.height())

        if rect.contains(self.viewport().rect()):
            self.updateLineNumberAreaWidth(0)

    def resizeEvent(self, event):
        """窗口大小改变事件"""
        super().resizeEvent(event)

        cr = self.contentsRect()
        self.line_number_area.setGeometry(
            QRect(cr.left(), cr.top(), self.lineNumberAreaWidth(), cr.height())
        )

    def lineNumberAreaPaintEvent(self, event):
        """绘制行号"""
        painter = QPainter(self.line_number_area)
        painter.fillRect(event.rect(), QColor(240, 240, 240))

        block = self.firstVisibleBlock()
        block_number = block.blockNumber()
        top = self.blockBoundingGeometry(block).translated(self.contentOffset()).top()
        bottom = top + self.blockBoundingRect(block).height()

        while block.isValid() and top <= event.rect().bottom():
            if block.isVisible() and bottom >= event.rect().top():
                number = str(block_number + 1)
                painter.setPen(QColor(100, 100, 100))
                painter.drawText(0, int(top), self.line_number_area.width() - 3,
                                 self.fontMetrics().height(),
                                 Qt.AlignRight, number)

            block = block.next()
            top = bottom
            bottom = top + self.blockBoundingRect(block).height()
            block_number += 1