"""
Correlation ID Middleware - ServiceManagerWeb

Middleware para rastrear requests con correlation ID
"""

from fastapi import Request
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.responses import Response
import uuid
import structlog

logger = structlog.get_logger(__name__)


class CorrelationIDMiddleware(BaseHTTPMiddleware):
    """
    Middleware para manejar correlation IDs.
    
    Extrae el correlation ID del header X-Correlation-ID o genera uno nuevo.
    Lo almacena en el estado de la request para uso en logs y responses.
    """
    
    async def dispatch(self, request: Request, call_next) -> Response:
        """Process request and add correlation ID."""
        
        # Extract or generate correlation ID
        correlation_id = request.headers.get("X-Correlation-ID")
        if not correlation_id:
            correlation_id = str(uuid.uuid4())
        
        # Store in request state
        request.state.correlation_id = correlation_id
        
        # Add to structlog context
        with structlog.contextvars.bound_contextvars(
            correlation_id=correlation_id,
            path=request.url.path,
            method=request.method
        ):
            response = await call_next(request)
        
        # Add correlation ID to response headers
        response.headers["X-Correlation-ID"] = correlation_id
        
        return response