"""FastAPI application factory for SneakySwole.

Creates and configures the FastAPI app with routes, templates,
static files, and structured logging.
"""

import os
import secrets
from pathlib import Path

import structlog
from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
from sqlmodel import SQLModel, Session

from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
from starlette.requests import Request as StarletteRequest
from starlette.responses import Response
from fastapi.responses import RedirectResponse

from app.models.user import User
from app.config import get_settings
from app.database import get_engine, get_db_session
from app.logging_config import setup_logging
from app.routes.auth import router as auth_router
from app.routes.exercises import router as exercises_router
from app.routes.history import router as history_router
from app.routes.health import router as health_router
from app.routes.pages import router as pages_router
from app.routes.profiles import router as profiles_router
from app.routes.logging import router as logging_router
from app.routes.workouts import router as workouts_router
from app.routes.dashboard import router as dashboard_router
from app.routes.schedule import router as schedule_router
from app.services.seed_service import SeedService
from app.services.auth_service import AuthService
from app.services.user_service import UserService
from app.utils.auth import SESSION_COOKIE_NAME, NotAuthenticatedError

logger = structlog.get_logger(__name__)

# Template and static file directories
_BASE_DIR = Path(__file__).resolve().parent
TEMPLATES_DIR = _BASE_DIR / "templates"
STATIC_DIR = _BASE_DIR / "static"


class NavContextMiddleware(BaseHTTPMiddleware):
    """Injects admin, profiles, and active_profile into request.state for templates."""

    async def dispatch(self, request: StarletteRequest, call_next: RequestResponseEndpoint) -> Response:
        request.state.admin = None
        request.state.profiles = []
        request.state.active_profile = None

        token = request.cookies.get(SESSION_COOKIE_NAME)
        if token and hasattr(request.app.state, "engine"):
            try:
                with Session(request.app.state.engine) as session:
                    secret_key = getattr(request.app.state, "secret_key", "")
                    auth_service = AuthService(session, secret_key=secret_key)
                    user_id = auth_service.validate_session_token(token)
                    if user_id:
                        admin = session.get(User, user_id)
                        if admin and admin.is_admin:
                            request.state.admin = admin
                            user_service = UserService(session)
                            request.state.profiles = user_service.list_users(exclude_admin=True)

                            profile_id = request.cookies.get("active_profile_id")
                            if profile_id and profile_id.isdigit():
                                request.state.active_profile = user_service.get_user_by_id(int(profile_id))
            except Exception:
                pass

        return await call_next(request)


def create_app() -> FastAPI:
    """Create and configure the FastAPI application.

    Returns:
        A fully configured FastAPI application instance.
    """
    settings = get_settings()
    setup_logging(log_level=settings.app_log_level)

    app = FastAPI(
        title="SneakySwole",
        description="Open-source workout tracking and programming",
        version="0.1.0",
    )

    # Redirect unauthenticated requests to login
    @app.exception_handler(NotAuthenticatedError)
    async def _not_authenticated_handler(request, exc):
        return RedirectResponse(url="/login", status_code=302)

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

    # Jinja2 templates (available to routes via request.state or dependency)
    templates = Jinja2Templates(directory=str(TEMPLATES_DIR))
    app.state.templates = templates

    # Secret key for session signing
    app.state.secret_key = os.environ.get("SECRET_KEY", secrets.token_hex(32))

    # Nav context middleware — injects admin/profiles/active_profile into request.state
    app.add_middleware(NavContextMiddleware)

    # Register route modules
    app.include_router(auth_router)
    app.include_router(exercises_router)
    app.include_router(health_router)
    app.include_router(history_router)
    app.include_router(logging_router)
    app.include_router(pages_router)
    app.include_router(profiles_router)
    app.include_router(workouts_router)
    app.include_router(dashboard_router)
    app.include_router(schedule_router)

    # Database setup
    engine = get_engine(settings.database_url)
    SQLModel.metadata.create_all(engine)
    app.state.engine = engine

    # DB session dependency for routes
    def _get_session():
        yield from get_db_session(engine)

    app.dependency_overrides[get_db_session] = _get_session

    # Seed database on startup
    @app.on_event("startup")
    async def on_startup():
        with Session(engine) as session:
            seed_service = SeedService(session)
            seed_service.seed_all()

    logger.info("app_started", environment=settings.app_env)

    return app


# Uvicorn entry point
app = create_app()