import json
import re
from datetime import datetime
from typing import Any, Optional

from loglens.parsers.base import BaseParser, LogFormat, ParsedEntry


class JSONParser(BaseParser):
    """Parser for JSON log formats."""

    def get_format(self) -> LogFormat:
        return LogFormat.JSON

    def parse(self, line: str) -> Optional[ParsedEntry]:
        """Parse a JSON log line."""
        try:
            data = json.loads(line.strip())
        except json.JSONDecodeError:
            return None

        if isinstance(data, list):
            return None

        if not isinstance(data, dict):
            return None

        timestamp = self._extract_timestamp(data)
        level = self._extract_level(data)
        message = self._extract_message(data)

        return ParsedEntry(
            raw_line=line.strip(),
            format=self.get_format(),
            timestamp=timestamp,
            level=level,
            message=message,
            metadata=data,
        )

    def _extract_timestamp(self, data: dict[str, Any]) -> Optional[str]:
        timestamp_fields = ["timestamp", "time", "@timestamp", "date", "created_at"]
        for field in timestamp_fields:
            if field in data:
                value = data[field]
                if isinstance(value, str):
                    return value
                elif isinstance(value, (int, float)):
                    return datetime.fromtimestamp(value).isoformat()
        return None

    def _extract_level(self, data: dict[str, Any]) -> Optional[str]:
        level_fields = ["level", "severity", "log_level", "levelname", "status"]
        for field in level_fields:
            if field in data:
                value = data[field]
                if isinstance(value, str):
                    return value.lower()
        return None

    def _extract_message(self, data: dict[str, Any]) -> str:
        message_fields = ["message", "msg", "text", "content", "error", "reason"]
        for field in message_fields:
            if field in data:
                value = data[field]
                if isinstance(value, str):
                    return value
                elif isinstance(value, dict):
                    return json.dumps(value)
        return str(data)