from fastapi import FastAPI, Request, BackgroundTasks, Depends
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
from fastapi.responses import HTMLResponse
import os
import asyncio
import logging
from datetime import datetime

from app.api.api_v1.api import api_router
from app.core.config import get_settings
from app.core.security import require_admin_auth, generate_api_key, add_api_key
from app.middleware.security import SecurityHeadersMiddleware
from app.services.imap_client import IMAPClient
from app.services.report_store import ReportStore

# Set up logging
logger = logging.getLogger(__name__)

settings = get_settings()

# Global variables for background task management
background_task = None
last_check_time = None


async def scheduled_imap_polling():
    """Background task for periodically checking IMAP for new DMARC reports"""
    global last_check_time
    
    try:
        # How often to check for emails (in seconds)
        check_interval = 3600  # Default: 1 hour
        
        while True:
            logger.info("Starting scheduled IMAP polling for DMARC reports")
            
            try:
                # Create IMAP client and fetch reports
                imap_client = IMAPClient(delete_emails=False)
                results = imap_client.fetch_reports(days=9999)
                
                # Update last check time
                last_check_time = datetime.now()
                
                if results["success"]:
                    logger.info(f"IMAP polling completed: {results['processed']} emails processed, "
                                f"{results['reports_found']} reports found")
                    
                    # If new domains were found, log them
                    if results["new_domains"]:
                        logger.info(f"New domains found: {', '.join(results['new_domains'])}")
                    
                else:
                    logger.error(f"IMAP polling failed: {results.get('error', 'Unknown error')}")
                
            except Exception as e:
                logger.error(f"Error in IMAP polling task: {str(e)}")
            
            # Wait for the next check interval
            await asyncio.sleep(check_interval)
            
    except asyncio.CancelledError:
        logger.info("IMAP polling task cancelled")


def create_app() -> FastAPI:
    """Create and configure the FastAPI application"""
    app = FastAPI(
        title=settings.PROJECT_NAME,
        openapi_url=f"{settings.API_V1_STR}/openapi.json",
        version="0.1.0",
    )
    
    # Add security headers middleware
    # Determine environment from settings or environment variable
    environment = os.getenv("ENVIRONMENT", "development")
    app.add_middleware(SecurityHeadersMiddleware, environment=environment)

    # Improved CORS configuration - restrict to specific methods and headers
    if settings.BACKEND_CORS_ORIGINS:
        app.add_middleware(
            CORSMiddleware,
            allow_origins=[str(origin) for origin in settings.BACKEND_CORS_ORIGINS],
            allow_credentials=True,
            # Security: Restrict to only necessary HTTP methods
            allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
            # Security: Specify allowed headers instead of wildcard
            allow_headers=[
                "Content-Type", 
                "Authorization", 
                "X-API-Key",
                "Accept",
                "Origin",
                "X-Requested-With"
            ],
            # Security: Limit exposed headers
            expose_headers=["Content-Length", "X-RateLimit-Limit"],
            max_age=600,  # Cache preflight requests for 10 minutes
        )

    # Include API router
    app.include_router(api_router, prefix=settings.API_V1_STR)
    
    # Mount static files directory
    app.mount("/static", StaticFiles(directory=os.path.join(os.path.dirname(__file__), "static")), name="static")
    
    # Set up event handlers for startup and shutdown
    @app.on_event("startup")
    async def startup_event():
        """Initialize background tasks and security on application startup"""
        global background_task
        
        # Generate and log initial API key for admin access
        api_key = generate_api_key()
        add_api_key(api_key)
        logger.warning(
            "=" * 80 + "\n"
            "IMPORTANT: Admin API Key Generated\n"
            f"API Key: {api_key}\n"
            "Save this key securely - it will not be shown again.\n"
            "Use this key in the X-API-Key header for admin endpoints.\n"
            "=" * 80
        )
        
        # Check if IMAP credentials are configured
        if all([settings.IMAP_SERVER, settings.IMAP_USERNAME, settings.IMAP_PASSWORD]):
            logger.info("Starting IMAP polling background task")
            background_task = asyncio.create_task(scheduled_imap_polling())
        else:
            logger.warning("IMAP credentials not fully configured, polling disabled")
    
    @app.on_event("shutdown")
    async def shutdown_event():
        """Clean up background tasks on application shutdown"""
        global background_task
        if background_task:
            logger.info("Cancelling IMAP polling background task")
            background_task.cancel()
            try:
                await background_task
            except asyncio.CancelledError:
                pass
    
    return app


app = create_app()

# Initialize Jinja2 templates
templates_dir = os.path.join(os.path.dirname(__file__), "templates")
templates = Jinja2Templates(directory=templates_dir)


@app.get("/", response_class=HTMLResponse)
async def dashboard(request: Request):
    return templates.TemplateResponse("index.html", {"request": request})


# Individual page routes
@app.get("/dashboard", response_class=HTMLResponse)
async def dashboard(request: Request):
    return templates.TemplateResponse(
        "dashboard.html", {"request": request, "app_name": settings.PROJECT_NAME}
    )

@app.get("/login", response_class=HTMLResponse)
async def login(request: Request):
    return templates.TemplateResponse(
        "login.html", {"request": request, "app_name": settings.PROJECT_NAME}
    )

@app.get("/setup", response_class=HTMLResponse)
async def setup(request: Request):
    return templates.TemplateResponse(
        "setup.html", {"request": request, "app_name": settings.PROJECT_NAME}
    )

@app.get("/domains", response_class=HTMLResponse)
async def domains(request: Request):
    return templates.TemplateResponse("domains.html", {"request": request})

@app.get("/domain/{domain_id}", response_class=HTMLResponse)
async def domain_details(request: Request, domain_id: str):
    """View detailed reports for a specific domain"""
    store = ReportStore.get_instance()
    domains = store.get_domains()
    
    if domain_id not in domains:
        # Domain not found, redirect to domains list
        return templates.TemplateResponse(
            "domains.html", 
            {"request": request, "error": f"Domain {domain_id} not found"}
        )
    
    domain_summary = store.get_domain_summary(domain_id)
    
    return templates.TemplateResponse(
        "domain_details.html", 
        {
            "request": request,
            "domain_id": domain_id,
            "domain": {
                "name": domain_id,
                "description": "",  # Add description if available
                "policy": domain_summary.get("policy", "unknown")
            }
        }
    )

@app.get("/reports", response_class=HTMLResponse)
async def reports(request: Request):
    return templates.TemplateResponse("reports.html", {"request": request})

@app.get("/settings", response_class=HTMLResponse)
async def settings_page(request: Request):
    return templates.TemplateResponse("settings.html", {"request": request})

@app.get("/upload", response_class=HTMLResponse)
async def upload_page(request: Request):
    return templates.TemplateResponse("upload.html", {"request": request})


# API endpoint to manually trigger IMAP polling
@app.post("/api/v1/admin/trigger-poll")
async def trigger_imap_poll(
    background_tasks: BackgroundTasks,
    auth: dict = Depends(require_admin_auth)
):
    """
    Manually trigger IMAP polling (admin only - requires authentication)
    
    Security: Requires either X-API-Key header or Bearer token
    """
    global last_check_time
    
    try:
        # Create IMAP client and fetch reports
        imap_client = IMAPClient(delete_emails=False)
        results = imap_client.fetch_reports(days=7)
        
        # Update last check time
        last_check_time = datetime.now()
        
        return {
            "success": results["success"],
            "timestamp": last_check_time.isoformat(),
            "processed": results["processed"],
            "reports_found": results["reports_found"],
            "new_domains": results["new_domains"],
            "authenticated_by": auth.get("auth_type")
        }
    except Exception as e:
        logger.error(f"Error triggering IMAP poll: {str(e)}")
        return {
            "success": False,
            "error": "Failed to trigger IMAP poll. Check server logs for details."
        }


# API endpoint to check status of IMAP polling
@app.get("/api/v1/admin/poll-status")
async def get_poll_status(auth: dict = Depends(require_admin_auth)):
    """
    Get the status of IMAP polling (admin only - requires authentication)
    
    Security: Requires either X-API-Key header or Bearer token
    """
    global last_check_time
    
    return {
        "is_running": background_task is not None and not background_task.done(),
        "last_check": last_check_time.isoformat() if last_check_time else None,
        "authenticated_by": auth.get("auth_type")
    }