from __future__ import annotations

import logging
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles
from starlette.types import Scope

import config
from process_manager import ProcessManager
from ros_bridge import ROSBridge

logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(name)s: %(message)s")
logger = logging.getLogger("scan_web.app")

FRONTEND_DIR = Path(__file__).resolve().parent.parent / "frontend"


class SessionState:
    def __init__(self):
        self.camera_count = config.DEFAULT_CAMERA_COUNT
        self.recording = False
        self.recording_path: str | None = None
        self.recording_started_at: float | None = None
        self.camera_values: dict = {}  # cam_id -> camera_params.CameraParamValues


@asynccontextmanager
async def lifespan(app: FastAPI):
    app.state.pm = ProcessManager()
    app.state.session = SessionState()
    app.state.ros = ROSBridge(camera_count=app.state.session.camera_count)
    app.state.ros.start()
    logger.info("scan_web backend started (camera_count=%s)", app.state.session.camera_count)
    try:
        yield
    finally:
        logger.info("shutting down — stopping all managed processes")
        app.state.pm.stop_all()
        app.state.ros.stop()


app = FastAPI(title="scan_web", lifespan=lifespan)

from routers import system, camera, recording, telemetry  # noqa: E402  (needs app.state types defined above)

app.include_router(system.router, prefix="/api")
app.include_router(camera.router)
app.include_router(recording.router, prefix="/api")
app.include_router(telemetry.router)

class NoCacheStaticFiles(StaticFiles):
    """Frontend is actively edited during field testing — a browser caching a
    stale index.html/app.js/style.css (no Cache-Control was set before) led
    to confusing "it's not applying" reports that were actually just the
    prior version still running. Static assets here are small and local, so
    the no-caching cost is negligible."""

    async def get_response(self, path: str, scope: Scope):
        response = await super().get_response(path, scope)
        response.headers["Cache-Control"] = "no-store"
        return response


app.mount("/", NoCacheStaticFiles(directory=str(FRONTEND_DIR), html=True), name="frontend")