"""FastAPI application factory."""

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
import logging
import config
import os
from core.logging import setup_logger


def create_app() -> FastAPI:
    """Create and configure FastAPI application."""
    # Setup logging
    logger = setup_logger()
    logger.info("Creating FastAPI application")

    # Create app
    app = FastAPI(
        title="Syllabus",
        description="Media downloader for Dropout, YouTube, and more",
        version="1.0.0"
    )

    # Mount static files
    app.mount("/data", StaticFiles(directory=str(config.DATA_DIR)), name="data")

    # Setup templates
    app.templates = Jinja2Templates(directory=str(config.TEMPLATES_DIR))

    # Setup startup event to load series data
    @app.on_event("startup")
    async def startup_event():
        """Load series data from cache on startup."""
        logger.info("Running startup initialization")
        
        # Load existing dropout.json if it exists
        if os.path.exists(config.DROPOUT_JSON):
            try:
                from core.cache import series_cache
                series_cache.load_from_file(str(config.DROPOUT_JSON))
                logger.info("Series data loaded from cache")
            except Exception as e:
                logger.error(f"Failed to load series cache: {e}")
        else:
            logger.info("dropout.json not found - users must manually trigger /api/dropout/update or use HTML upload")

    # Setup middleware
    @app.middleware("http")
    async def log_requests(request, call_next):
        """Log all incoming HTTP requests."""
        try:
            response = await call_next(request)
        except Exception as e:
            logger.exception(f"EXCEPTION: {request.method} {request.url} - {str(e)}")
            from fastapi.responses import JSONResponse
            return JSONResponse(
                status_code=500,
                content={"detail": "Internal Server Error"},
            )

        logger.info(
            f"request_client={request.client.host}:{request.client.port}, "
            f"request_method={request.method}, request_url={request.url}, "
            f"status_code={response.status_code}"
        )
        return response

    return app