"""Starlette application factory for ollama-web."""

from __future__ import annotations

import logging
from collections.abc import AsyncIterator
from contextlib import asynccontextmanager
from pathlib import Path
from typing import Any

from starlette.applications import Starlette
from starlette.middleware import Middleware
from starlette.middleware.cors import CORSMiddleware
from starlette.responses import Response
from starlette.routing import Mount, Route
from starlette.staticfiles import StaticFiles

from .auth import AuthMiddleware
from .config import settings
from .middleware import SecurityHeadersMiddleware
from .routes import auth as auth_route
from .routes import chat as chat_route
from .routes import mcp as mcp_route
from .routes import models as models_route
from .routes import pages as pages_route
from .routes import sessions as sessions_route
from .routes import settings_route
from .sessions import SessionStore


class NoCacheStaticFiles(StaticFiles):
    """StaticFiles variant that disables browser caching for local development.

    This ensures language changes and JS updates are reflected immediately after
    a server restart, without requiring users to clear the browser cache.
    """

    async def get_response(self, path: str, scope: Any) -> Response:
        response = await super().get_response(path, scope)
        response.headers["Cache-Control"] = "no-store, no-cache, must-revalidate, max-age=0"
        return response


_STATIC_DIR = Path(__file__).resolve().parent / "static"


@asynccontextmanager
async def _lifespan(app: Starlette) -> AsyncIterator[None]:
    """Keep the application log handler scoped to the ASGI lifespan."""
    log_dir = Path(app.state.settings.data_dir).resolve()
    log_dir.mkdir(parents=True, exist_ok=True)
    handler = logging.FileHandler(str(log_dir / "server.log"), encoding="utf-8")
    handler.setFormatter(
        logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
    )
    logger = logging.getLogger("ollama_web")
    previous_level = logger.level
    logger.setLevel(logging.INFO)
    logger.addHandler(handler)
    try:
        yield
    finally:
        logger.removeHandler(handler)
        handler.close()
        logger.setLevel(previous_level)


def create_app() -> Starlette:
    """Build and return the configured Starlette application."""
    routes = [
        Route("/login", pages_route.login, name="login_page"),
        Route("/api/auth/login", auth_route.login, methods=["POST"], name="auth_login"),
        Route("/api/auth/logout", auth_route.logout, methods=["POST"], name="auth_logout"),
        Route("/api/auth/status", auth_route.status, methods=["GET"], name="auth_status"),
        Route("/", pages_route.index, name="index"),
        Route("/api/chat", chat_route.chat, methods=["POST"], name="chat"),
        Route("/api/models", models_route.get_models, methods=["GET"], name="models"),
        Route(
            "/api/models/{model:path}/capabilities",
            models_route.get_model_capabilities,
            methods=["GET"],
            name="model_capabilities",
        ),
        Route("/api/health", models_route.health, methods=["GET"], name="health"),
        Route(
            "/api/settings",
            settings_route.get_settings,
            methods=["GET"],
            name="settings",
        ),
        Route(
            "/api/settings",
            settings_route.put_settings,
            methods=["PUT"],
            name="settings_update",
        ),
        Route("/api/sessions", sessions_route.list_sessions, methods=["GET"], name="list_sessions"),
        Route(
            "/api/sessions",
            sessions_route.create_session,
            methods=["POST"],
            name="create_session",
        ),
        Route(
            "/api/sessions/{session_id}",
            sessions_route.get_session,
            methods=["GET"],
            name="get_session",
        ),
        Route(
            "/api/sessions/{session_id}",
            sessions_route.delete_session,
            methods=["DELETE"],
            name="delete_session",
        ),
        Route(
            "/api/sessions/{session_id}/files",
            sessions_route.upload_file,
            methods=["POST"],
            name="upload_file",
        ),
        Route(
            "/api/sessions/{session_id}/files/{file_id}",
            sessions_route.delete_file,
            methods=["DELETE"],
            name="delete_file",
        ),
        Route(
            "/api/sessions/{session_id}/files/{file_id}/content",
            sessions_route.get_file_content,
            methods=["GET", "HEAD"],
            name="get_file_content",
        ),
        Route(
            "/api/sessions/{session_id}/messages",
            sessions_route.clear_messages,
            methods=["DELETE"],
            name="clear_messages",
        ),
        Route("/api/mcp/servers", mcp_route.get_servers, methods=["GET"], name="mcp_servers"),
        Route(
            "/api/mcp/servers",
            mcp_route.put_servers,
            methods=["PUT"],
            name="mcp_servers_update",
        ),
        Mount("/static", app=NoCacheStaticFiles(directory=str(_STATIC_DIR)), name="static"),
    ]

    middleware = [Middleware(SecurityHeadersMiddleware), Middleware(AuthMiddleware)]
    if settings.allowed_origins:
        middleware.append(
            Middleware(
                CORSMiddleware,
                allow_origins=settings.allowed_origins,
                allow_methods=["GET", "POST", "PUT", "DELETE"],
                allow_headers=["Content-Type", "X-CSRF-Token"],
                allow_credentials=True,
            )
        )

    app = Starlette(routes=routes, middleware=middleware, lifespan=_lifespan)
    app.state.settings = settings
    app.state.session_store = SessionStore(settings.data_dir)
    app.state.tool_names = ["web_search", "scrape_url", "search_and_fetch", "pdf_to_text"]
    return app


app = create_app()