"""Simple JSON/general syntax highlighter for QTextEdit."""
import re
from PyQt6.QtGui import QSyntaxHighlighter, QTextCharFormat, QColor, QFont


class JsonHighlighter(QSyntaxHighlighter):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._rules = []

        def fmt(color, bold=False):
            f = QTextCharFormat()
            f.setForeground(QColor(color))
            if bold:
                f.setFontWeight(QFont.Weight.Bold)
            return f

        # Keys
        self._rules.append((re.compile(r'"([^"\\]|\\.)*"\s*(?=:)'), fmt("#9CDCFE")))
        # String values
        self._rules.append((re.compile(r'(?<!:)\s*"([^"\\]|\\.)*"'), fmt("#CE9178")))
        # Numbers
        self._rules.append((re.compile(r'\b-?\d+(\.\d+)?([eE][+-]?\d+)?\b'), fmt("#B5CEA8")))
        # Booleans & null
        self._rules.append((re.compile(r'\b(true|false|null)\b'), fmt("#569CD6", bold=True)))
        # Braces/brackets
        self._rules.append((re.compile(r'[{}\[\]]'), fmt("#FFD700")))

    def highlightBlock(self, text):
        for pattern, fmt in self._rules:
            for m in pattern.finditer(text):
                self.setFormat(m.start(), m.end() - m.start(), fmt)