"""
Core - Structured Logging

JSON structured logging with correlation IDs.
"""
import logging
import sys
from contextvars import ContextVar
from datetime import datetime
from typing import Any, Dict

import structlog

# Correlation ID context variable
correlation_id_var: ContextVar[str] = ContextVar("correlation_id", default="")


def get_correlation_id() -> str:
    """Get current correlation ID"""
    return correlation_id_var.get()


def set_correlation_id(correlation_id: str) -> None:
    """Set correlation ID for current context"""
    correlation_id_var.set(correlation_id)


def add_correlation_id(logger: Any, method_name: str, event_dict: Dict) -> Dict:
    """Add correlation ID to log event"""
    event_dict["correlation_id"] = get_correlation_id()
    return event_dict


def add_service_info(logger: Any, method_name: str, event_dict: Dict) -> Dict:
    """Add service information to log event"""
    event_dict["service"] = "rag-onboarding-backend"
    event_dict["version"] = "1.0.0"
    return event_dict


def setup_logging(log_level: str = "INFO") -> None:
    """Setup structured logging"""

    # Configure structlog
    structlog.configure(
        processors=[
            structlog.contextvars.merge_contextvars,
            structlog.stdlib.filter_by_level,
            structlog.processors.TimeStamper(fmt="iso"),
            structlog.stdlib.add_logger_name,
            structlog.stdlib.add_log_level,
            structlog.processors.StackInfoRenderer(),
            add_correlation_id,
            add_service_info,
            structlog.processors.format_exc_info,
            structlog.processors.UnicodeDecoder(),
            structlog.processors.JSONRenderer(),
        ],
        wrapper_class=structlog.stdlib.BoundLogger,
        context_class=dict,
        logger_factory=structlog.stdlib.LoggerFactory(),
        cache_logger_on_first_use=True,
    )

    # Configure standard logging
    logging.basicConfig(
        format="%(message)s",
        stream=sys.stdout,
        level=getattr(logging, log_level.upper()),
    )


def get_logger(name: str) -> structlog.stdlib.BoundLogger:
    """Get logger instance"""
    return structlog.get_logger(name)