"""
Demo Session Middleware
Handles demo account restrictions and virtual tenant injection
"""

from fastapi import Request, HTTPException
from fastapi.responses import JSONResponse
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.responses import Response
from typing import Optional
import uuid
import httpx
import structlog
import json

logger = structlog.get_logger()

# Fixed Demo Tenant IDs (these are the template tenants that will be cloned)
# Professional demo (merged from San Pablo + La Espiga)
DEMO_TENANT_PROFESSIONAL = uuid.UUID("a1b2c3d4-e5f6-47a8-b9c0-d1e2f3a4b5c6")

# Enterprise chain demo (parent + 3 children)
DEMO_TENANT_ENTERPRISE_CHAIN = uuid.UUID("c3d4e5f6-a7b8-49c0-d1e2-f3a4b5c6d7e8")
DEMO_TENANT_CHILD_1 = uuid.UUID("d4e5f6a7-b8c9-40d1-e2f3-a4b5c6d7e8f9")
DEMO_TENANT_CHILD_2 = uuid.UUID("e5f6a7b8-c9d0-41e2-f3a4-b5c6d7e8f9a0")
DEMO_TENANT_CHILD_3 = uuid.UUID("f6a7b8c9-d0e1-42f3-a4b5-c6d7e8f9a0b1")

# Demo tenant IDs (base templates)
DEMO_TENANT_IDS = {
    str(DEMO_TENANT_PROFESSIONAL),  # Professional demo tenant
    str(DEMO_TENANT_ENTERPRISE_CHAIN),  # Enterprise chain parent
    str(DEMO_TENANT_CHILD_1),  # Enterprise chain child 1
    str(DEMO_TENANT_CHILD_2),  # Enterprise chain child 2
    str(DEMO_TENANT_CHILD_3),  # Enterprise chain child 3
}

# Allowed operations for demo accounts (limited write)
DEMO_ALLOWED_OPERATIONS = {
    # Read operations - all allowed
    "GET": ["*"],

    # Limited write operations for realistic testing
    "POST": [
        "/api/v1/pos/sales",
        "/api/v1/pos/sessions",
        "/api/v1/orders",
        "/api/v1/inventory/adjustments",
        "/api/v1/sales",
        "/api/v1/production/batches",
        "/api/v1/tenants/batch/sales-summary",
        "/api/v1/tenants/batch/production-summary",
        "/api/v1/auth/me/onboarding/complete",  # Allow completing onboarding (no-op for demos)
        # Note: Forecast generation is explicitly blocked (see DEMO_BLOCKED_PATHS)
    ],

    "PUT": [
        "/api/v1/pos/sales/*",
        "/api/v1/orders/*",
        "/api/v1/inventory/stock/*",
        "/api/v1/auth/me/onboarding/step",  # Allow onboarding step updates (no-op for demos)
    ],

    # Blocked operations
    "DELETE": [],  # No deletes allowed
    "PATCH": [],   # No patches allowed
}

# Explicitly blocked paths for demo accounts (even if method would be allowed)
# These require trained AI models which demo tenants don't have
DEMO_BLOCKED_PATHS = [
    "/api/v1/forecasts/single",
    "/api/v1/forecasts/multi-day",
    "/api/v1/forecasts/batch",
]

DEMO_BLOCKED_PATH_MESSAGE = {
    "forecasts": {
        "message": "La generación de pronósticos no está disponible para cuentas demo. "
                  "Las cuentas demo no tienen modelos de IA entrenados.",
        "message_en": "Forecast generation is not available for demo accounts. "
                     "Demo accounts do not have trained AI models.",
    }
}


class DemoMiddleware(BaseHTTPMiddleware):
    """Middleware to handle demo session logic with Redis caching"""

    def __init__(self, app, demo_session_url: str = "http://demo-session-service:8000"):
        super().__init__(app)
        self.demo_session_url = demo_session_url
        self._redis_client = None

    async def _get_redis_client(self):
        """Get or lazily initialize Redis client"""
        if self._redis_client is None:
            try:
                from shared.redis_utils import get_redis_client
                self._redis_client = await get_redis_client()
                logger.debug("Demo middleware: Redis client initialized")
            except Exception as e:
                logger.warning(f"Demo middleware: Failed to get Redis client: {e}. Caching disabled.")
                self._redis_client = False  # Sentinel value to avoid retrying

        return self._redis_client if self._redis_client is not False else None

    async def _get_cached_session(self, session_id: str) -> Optional[dict]:
        """Get session info from Redis cache"""
        try:
            redis_client = await self._get_redis_client()
            if not redis_client:
                return None

            cache_key = f"demo_session:{session_id}"
            cached_data = await redis_client.get(cache_key)

            if cached_data:
                logger.debug("Demo middleware: Cache HIT", session_id=session_id)
                return json.loads(cached_data)
            else:
                logger.debug("Demo middleware: Cache MISS", session_id=session_id)
                return None
        except Exception as e:
            logger.warning(f"Demo middleware: Redis cache read error: {e}")
            return None

    async def _cache_session(self, session_id: str, session_info: dict, ttl: int = 30):
        """Cache session info in Redis with TTL"""
        try:
            redis_client = await self._get_redis_client()
            if not redis_client:
                return

            cache_key = f"demo_session:{session_id}"
            serialized = json.dumps(session_info)
            await redis_client.setex(cache_key, ttl, serialized)
            logger.debug(f"Demo middleware: Cached session {session_id} (TTL: {ttl}s)")
        except Exception as e:
            logger.warning(f"Demo middleware: Redis cache write error: {e}")

    async def dispatch(self, request: Request, call_next) -> Response:
        """Process request through demo middleware"""

        # Skip demo middleware for demo service endpoints
        demo_service_paths = [
            "/api/v1/demo/accounts",
            "/api/v1/demo/sessions",
            "/api/v1/demo/stats",
            "/api/v1/demo/operations",
        ]

        if any(request.url.path.startswith(path) or request.url.path == path for path in demo_service_paths):
            return await call_next(request)

        # Extract session ID from header or cookie
        session_id = (
            request.headers.get("X-Demo-Session-Id") or
            request.cookies.get("demo_session_id")
        )

        logger.info(f"🎭 DemoMiddleware - path: {request.url.path}, session_id: {session_id}")

        # Extract tenant ID from request
        tenant_id = request.headers.get("X-Tenant-Id")

        # Check if this is a demo session request
        if session_id:
            try:
                # PERFORMANCE OPTIMIZATION: Check Redis cache first before HTTP call
                session_info = await self._get_cached_session(session_id)

                if not session_info:
                    # Cache miss - fetch from demo service
                    logger.debug("Demo middleware: Fetching from demo service", session_id=session_id)
                    session_info = await self._get_session_info(session_id)

                    # Cache the result if successful (30s TTL to balance freshness vs performance)
                    if session_info:
                        await self._cache_session(session_id, session_info, ttl=30)

                # Accept pending, ready, partial, failed (if data exists), and active (deprecated) statuses
                # Even "failed" sessions can be usable if some services succeeded
                valid_statuses = ["pending", "ready", "partial", "failed", "active"]
                current_status = session_info.get("status") if session_info else None

                if session_info and current_status in valid_statuses:
                    # Inject virtual tenant ID
                    request.state.tenant_id = session_info["virtual_tenant_id"]
                    request.state.is_demo_session = True
                    request.state.demo_account_type = session_info["demo_account_type"]
                    request.state.demo_session_status = current_status  # Track status for monitoring

                    # Inject demo user context for auth middleware
                    # Map demo account type to the actual demo user IDs from fixture files
                    # These IDs are the owner IDs from the respective 01-tenant.json files
                    DEMO_USER_IDS = {
                        "professional": "c1a2b3c4-d5e6-47a8-b9c0-d1e2f3a4b5c6",  # María García López (professional/01-tenant.json -> owner.id)
                        "enterprise": "d2e3f4a5-b6c7-48d9-e0f1-a2b3c4d5e6f7"      # Director (enterprise/parent/01-tenant.json -> owner.id)
                    }
                    demo_user_id = DEMO_USER_IDS.get(
                        session_info.get("demo_account_type", "professional"),
                        DEMO_USER_IDS["professional"]
                    )

                    # This allows the request to pass through AuthMiddleware
                    request.state.user = {
                        "user_id": demo_user_id,  # Use actual demo user UUID
                        "email": f"demo-{session_id}@demo.local",
                        "tenant_id": session_info["virtual_tenant_id"],
                        "role": "owner",  # Demo users have owner role
                        "is_demo": True,
                        "demo_session_id": session_id,
                        "demo_account_type": session_info.get("demo_account_type", "professional"),
                        "demo_session_status": current_status
                    }

                    # Update activity
                    await self._update_session_activity(session_id)

                    # Check if path is explicitly blocked
                    blocked_reason = self._check_blocked_path(request.url.path)
                    if blocked_reason:
                        return JSONResponse(
                            status_code=403,
                            content={
                                "error": "demo_restriction",
                                **blocked_reason,
                                "upgrade_url": "/pricing",
                                "session_expires_at": session_info.get("expires_at")
                            }
                        )

                    # Check if operation is allowed
                    if not self._is_operation_allowed(request.method, request.url.path):
                        return JSONResponse(
                            status_code=403,
                            content={
                                "error": "demo_restriction",
                                "message": "Esta operación no está permitida en cuentas demo. "
                                          "Las sesiones demo se eliminan automáticamente después de 30 minutos. "
                                          "Suscríbete para obtener acceso completo.",
                                "message_en": "This operation is not allowed in demo accounts. "
                                             "Demo sessions are automatically deleted after 30 minutes. "
                                             "Subscribe for full access.",
                                "upgrade_url": "/pricing",
                                "session_expires_at": session_info.get("expires_at")
                            }
                        )
                else:
                    # Session expired, invalid, or in failed/destroyed state
                    logger.warning(f"Invalid demo session state", session_id=session_id, status=current_status)
                    return JSONResponse(
                        status_code=401,
                        content={
                            "error": "session_expired",
                            "message": "Tu sesión demo ha expirado. Crea una nueva sesión para continuar.",
                            "message_en": "Your demo session has expired. Create a new session to continue.",
                            "session_status": current_status
                        }
                    )

            except Exception as e:
                logger.error("Demo middleware error", error=str(e), session_id=session_id, path=request.url.path)
                # On error, return 401 instead of continuing
                return JSONResponse(
                    status_code=401,
                    content={
                        "error": "session_error",
                        "message": "Error validando sesión demo. Por favor, inténtalo de nuevo.",
                        "message_en": "Error validating demo session. Please try again."
                    }
                )

        # Check if this is a demo tenant (base template)
        elif tenant_id in DEMO_TENANT_IDS:
            # Direct access to demo tenant without session - block writes
            request.state.is_demo_session = True
            request.state.tenant_id = tenant_id

            if request.method not in ["GET", "HEAD", "OPTIONS"]:
                return JSONResponse(
                    status_code=403,
                    content={
                        "error": "demo_restriction",
                        "message": "Acceso directo al tenant demo no permitido. Crea una sesión demo.",
                        "message_en": "Direct access to demo tenant not allowed. Create a demo session."
                    }
                )

        # Proceed with request
        response = await call_next(request)

        # Add demo session header to response if demo session
        if hasattr(request.state, "is_demo_session") and request.state.is_demo_session:
            response.headers["X-Demo-Session"] = "true"

        return response

    async def _get_session_info(self, session_id: str) -> Optional[dict]:
        """Get session information from demo service"""
        try:
            async with httpx.AsyncClient(timeout=5.0) as client:
                response = await client.get(
                    f"{self.demo_session_url}/api/v1/demo/sessions/{session_id}"
                )
                if response.status_code == 200:
                    return response.json()
                return None
        except Exception as e:
            logger.error("Failed to get session info", session_id=session_id, error=str(e))
            return None

    async def _update_session_activity(self, session_id: str):
        """Update session activity timestamp"""
        # Note: Activity tracking is handled by the demo service internally
        # No explicit endpoint needed - activity is updated on session access
        pass

    def _check_blocked_path(self, path: str) -> Optional[dict]:
        """Check if path is explicitly blocked for demo accounts"""
        for blocked_path in DEMO_BLOCKED_PATHS:
            if blocked_path in path:
                # Determine which category of blocked path
                if "forecast" in blocked_path:
                    return DEMO_BLOCKED_PATH_MESSAGE["forecasts"]
                # Can add more categories here in the future
                return {
                    "message": "Esta funcionalidad no está disponible para cuentas demo.",
                    "message_en": "This functionality is not available for demo accounts."
                }
        return None

    def _is_operation_allowed(self, method: str, path: str) -> bool:
        """Check if method + path combination is allowed for demo"""

        allowed_paths = DEMO_ALLOWED_OPERATIONS.get(method, [])

        # Check for wildcard
        if "*" in allowed_paths:
            return True

        # Check for exact match or pattern match
        for allowed_path in allowed_paths:
            if allowed_path.endswith("*"):
                # Pattern match: /api/orders/* matches /api/orders/123
                if path.startswith(allowed_path[:-1]):
                    return True
            elif path == allowed_path:
                # Exact match
                return True

        return False