"""API Middleware Components.

This module provides middleware for request processing including
authentication, logging, rate limiting, and error handling.

Author: Lisa Park
Created: February 2024

Middleware Execution Order:
1. RequestLoggingMiddleware - Log incoming requests
2. RateLimitMiddleware - Check rate limits
3. AuthenticationMiddleware - Verify JWT tokens
4. ErrorHandlerMiddleware - Catch and format errors
"""

import logging
from datetime import datetime
from typing import Any

logger = logging.getLogger(__name__)


class RequestLoggingMiddleware:
    """Logs all incoming HTTP requests.

    Log Format: [timestamp] method path status duration_ms

    Example: [2024-03-15 10:30:45] GET /api/users 200 45ms
    """

    def __init__(self, app: Any):
        self.app = app

    async def __call__(self, request: Any) -> Any:
        start_time = datetime.now()
        response = await self.app(request)
        duration = (datetime.now() - start_time).total_seconds() * 1000
        logger.info(
            f"[{datetime.now()}] {request.method} {request.path} "
            f"{response.status_code} {duration:.0f}ms"
        )
        return response


class RateLimitMiddleware:
    """Implements sliding window rate limiting.

    Uses Redis sorted sets for distributed rate limiting.
    Configurable per-endpoint and per-user limits.

    Headers added to response:
    - X-RateLimit-Limit: Maximum requests allowed
    - X-RateLimit-Remaining: Requests remaining in window
    - X-RateLimit-Reset: Timestamp when limit resets
    """

    def __init__(self, app: Any, redis_client: Any):
        self.app = app
        self.redis_client = redis_client
        self.window_seconds = 60

    async def __call__(self, request: Any) -> Any:
        # Check rate limit before processing
        pass


class AuthenticationMiddleware:
    """Validates JWT tokens and attaches user context.

    Public endpoints (no auth required):
    - GET /api/health
    - POST /api/auth/login
    - POST /api/auth/register
    - GET /api/docs

    All other endpoints require valid JWT in Authorization header.
    """

    PUBLIC_ENDPOINTS = [
        "/api/health",
        "/api/auth/login",
        "/api/auth/register",
        "/api/docs",
    ]

    def __init__(self, app: Any, jwt_secret: str):
        self.app = app
        self.jwt_secret = jwt_secret

    async def __call__(self, request: Any) -> Any:
        if request.path in self.PUBLIC_ENDPOINTS:
            return await self.app(request)
        # Validate JWT token
        pass


class ErrorHandlerMiddleware:
    """Catches exceptions and returns formatted error responses.

    Provides consistent error response format:
    {
        "success": false,
        "error": "Human readable message",
        "error_code": 500,
        "request_id": "uuid"
    }

    Logs full stack traces for 5xx errors.
    Sanitizes error messages to prevent information leakage.
    """

    def __init__(self, app: Any):
        self.app = app

    async def __call__(self, request: Any) -> Any:
        try:
            return await self.app(request)
        except Exception as e:
            logger.exception(f"Unhandled exception: {e}")
            # Return sanitized error response
            pass
