from PyQt6.QtGui import QTextCharFormat, QFont, QTextCursor
from PyQt6.QtCore import QRegularExpression

class HeaderFormatter:
    def __init__(self):
        self.regex_h1 = QRegularExpression(r'^#\s(.+)$')
        self.regex_h2 = QRegularExpression(r'^##\s(.+)$')
        self.regex_h3 = QRegularExpression(r'^###\s(.+)$')
        self.regex_h4 = QRegularExpression(r'^####\s(.+)$')
        self.regex_h5 = QRegularExpression(r'^#####\s(.+)$')
        self.regex_h6 = QRegularExpression(r'^######\s(.+)$')

    def apply_header_format(self, block, font_size, font_weight):
        cursor = QTextCursor(block)
        char_format = QTextCharFormat()
        char_format.setFontWeight(font_weight)
        char_format.setFontPointSize(font_size * 16)
        cursor.select(QTextCursor.SelectionType.BlockUnderCursor)
        cursor.setCharFormat(char_format)

    def clear_header_format(self, block):
        cursor = QTextCursor(block)
        char_format = QTextCharFormat()
        cursor.select(QTextCursor.SelectionType.BlockUnderCursor)
        cursor.setCharFormat(char_format)

    def process_headers(self, text_edit):
        block = text_edit.document().firstBlock()
        while block.isValid():
            text = block.text()
            if self.regex_h1.match(text).hasMatch():
                self.apply_header_format(block, 2.0, QFont.Weight.Bold)
            elif self.regex_h2.match(text).hasMatch():
                self.apply_header_format(block, 1.5, QFont.Weight.Bold)
            elif self.regex_h3.match(text).hasMatch():
                self.apply_header_format(block, 1.25, QFont.Weight.Bold)
            elif self.regex_h4.match(text).hasMatch():
                self.apply_header_format(block, 1.0, QFont.Weight.Bold)
            elif self.regex_h5.match(text).hasMatch():
                self.apply_header_format(block, 0.875, QFont.Weight.Bold)
            elif self.regex_h6.match(text).hasMatch():
                self.apply_header_format(block, 0.85, QFont.Weight.Bold)
            else:
                self.clear_header_format(block)
            block = block.next()