"""
Enterprise Structured Logging with Correlation IDs

Features:
- Structured logging with structlog
- Correlation ID tracking across requests
- Request/response logging
- Performance timing
- JSON output for log aggregation (ELK, Datadog, etc.)
"""
import os
import sys
import uuid
import time
import logging
from typing import Optional
from contextvars import ContextVar
from aiohttp import web

import structlog

# Context variable for correlation ID
correlation_id_var: ContextVar[Optional[str]] = ContextVar('correlation_id', default=None)
request_start_time_var: ContextVar[Optional[float]] = ContextVar('request_start_time', default=None)


def get_correlation_id() -> str:
    """Get current correlation ID or generate new one"""
    corr_id = correlation_id_var.get()
    if not corr_id:
        corr_id = str(uuid.uuid4())
        correlation_id_var.set(corr_id)
    return corr_id


def set_correlation_id(corr_id: str):
    """Set correlation ID"""
    correlation_id_var.set(corr_id)


def add_correlation_id(logger, method_name, event_dict):
    """Add correlation ID to log context"""
    event_dict["correlation_id"] = get_correlation_id()
    return event_dict


def add_timestamp(logger, method_name, event_dict):
    """Add ISO timestamp to log"""
    event_dict["timestamp"] = time.strftime("%Y-%m-%dT%H:%M:%S")
    return event_dict


def add_service_info(logger, method_name, event_dict):
    """Add service information to log"""
    event_dict["service"] = os.getenv("SERVICE_NAME", "cx_ai_agent")
    event_dict["environment"] = os.getenv("ENVIRONMENT", "development")
    return event_dict


def configure_logging(
    level: str = "INFO",
    json_output: bool = False,
    service_name: str = "cx_ai_agent"
):
    """
    Configure structured logging

    Args:
        level: Log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
        json_output: Whether to output JSON format (for production)
        service_name: Service name for logging
    """
    os.environ["SERVICE_NAME"] = service_name

    # Configure structlog processors
    processors = [
        structlog.contextvars.merge_contextvars,
        structlog.stdlib.filter_by_level,
        add_correlation_id,
        add_timestamp,
        add_service_info,
        structlog.stdlib.add_logger_name,
        structlog.stdlib.add_log_level,
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.TimeStamper(fmt="iso"),
        structlog.processors.StackInfoRenderer(),
    ]

    if json_output:
        # JSON output for production (parseable by log aggregators)
        processors.append(structlog.processors.JSONRenderer())
    else:
        # Human-readable output for development
        processors.extend([
            structlog.processors.format_exc_info,
            structlog.dev.ConsoleRenderer(colors=True)
        ])

    structlog.configure(
        processors=processors,
        wrapper_class=structlog.stdlib.BoundLogger,
        context_class=dict,
        logger_factory=structlog.stdlib.LoggerFactory(),
        cache_logger_on_first_use=True,
    )

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

    logger = structlog.get_logger()
    logger.info("Structured logging configured", level=level, json_output=json_output)


def get_logger(name: str = None) -> structlog.stdlib.BoundLogger:
    """
    Get a structured logger

    Args:
        name: Logger name (optional)

    Returns:
        Structured logger instance
    """
    return structlog.get_logger(name)


class LoggingMiddleware:
    """aiohttp middleware for request/response logging"""

    def __init__(self, logger_name: str = "mcp.server"):
        self.logger = get_logger(logger_name)

    @web.middleware
    async def middleware(self, request: web.Request, handler):
        """Middleware handler"""

        # Extract or generate correlation ID
        corr_id = request.headers.get("X-Correlation-ID") or request.headers.get("X-Request-ID")
        if not corr_id:
            corr_id = str(uuid.uuid4())

        set_correlation_id(corr_id)

        # Record start time
        start_time = time.time()
        request_start_time_var.set(start_time)

        # Extract request info
        method = request.method
        path = request.path
        client_ip = request.remote or "unknown"
        user_agent = request.headers.get("User-Agent", "unknown")

        # Log request
        self.logger.info(
            "request_started",
            method=method,
            path=path,
            client_ip=client_ip,
            user_agent=user_agent,
            correlation_id=corr_id
        )

        try:
            # Process request
            response = await handler(request)

            # Calculate duration
            duration = time.time() - start_time

            # Log response
            self.logger.info(
                "request_completed",
                method=method,
                path=path,
                status=response.status,
                duration_ms=round(duration * 1000, 2),
                correlation_id=corr_id
            )

            # Add correlation ID to response headers
            response.headers["X-Correlation-ID"] = corr_id

            return response

        except Exception as e:
            # Calculate duration
            duration = time.time() - start_time

            # Log error
            self.logger.error(
                "request_failed",
                method=method,
                path=path,
                error=str(e),
                error_type=type(e).__name__,
                duration_ms=round(duration * 1000, 2),
                correlation_id=corr_id,
                exc_info=True
            )

            raise


class PerformanceLogger:
    """Context manager for performance logging"""

    def __init__(self, operation: str, logger: Optional[structlog.stdlib.BoundLogger] = None):
        self.operation = operation
        self.logger = logger or get_logger()
        self.start_time = None

    def __enter__(self):
        self.start_time = time.time()
        self.logger.debug(f"{self.operation}_started")
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        duration = time.time() - self.start_time
        duration_ms = round(duration * 1000, 2)

        if exc_type is None:
            self.logger.info(
                f"{self.operation}_completed",
                duration_ms=duration_ms
            )
        else:
            self.logger.error(
                f"{self.operation}_failed",
                duration_ms=duration_ms,
                error_type=exc_type.__name__,
                error=str(exc_val),
                exc_info=True
            )


def log_mcp_call(
    logger: structlog.stdlib.BoundLogger,
    server: str,
    method: str,
    params: dict,
    result: any = None,
    error: Exception = None,
    duration_ms: float = None
):
    """
    Log MCP call with structured data

    Args:
        logger: Structured logger
        server: MCP server name (search, email, store, etc.)
        method: MCP method name
        params: Method parameters
        result: Method result (optional)
        error: Error if call failed (optional)
        duration_ms: Call duration in milliseconds (optional)
    """
    log_data = {
        "mcp_server": server,
        "mcp_method": method,
        "mcp_params_keys": list(params.keys()) if params else [],
    }

    if duration_ms is not None:
        log_data["duration_ms"] = round(duration_ms, 2)

    if error:
        logger.error(
            "mcp_call_failed",
            **log_data,
            error=str(error),
            error_type=type(error).__name__
        )
    else:
        logger.info(
            "mcp_call_success",
            **log_data,
            result_type=type(result).__name__ if result else None
        )


# Example usage
if __name__ == "__main__":
    # Configure logging for development
    configure_logging(level="DEBUG", json_output=False)

    logger = get_logger(__name__)

    # Set correlation ID
    set_correlation_id("test-correlation-123")

    # Log some messages
    logger.info("Application started", version="1.0.0")
    logger.debug("Debug message", data={"key": "value"})
    logger.warning("Warning message")

    try:
        raise ValueError("Test error")
    except Exception as e:
        logger.error("Error occurred", exc_info=True)

    # Performance logging
    with PerformanceLogger("database_query", logger):
        time.sleep(0.1)  # Simulate work