import gc

from datetime import datetime, timedelta
from zoneinfo import ZoneInfo

from fastapi import FastAPI, BackgroundTasks
from fastapi.responses import JSONResponse
from fastapi.middleware import Middleware
from starlette.middleware.cors import CORSMiddleware
from fastapi_utils.tasks import repeat_every

from app.settings import *

from services.grib import Grib

service_grib = Grib()

# App
middleware = [
    Middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    ),
]
app = FastAPI(title="parser-gfs", middleware=middleware)


# API
# GET 'test'
@app.get("/test/")
async def get_test():
    # check source availability
    # fresh one might be missing and old ones get deleted, so check yesterday's
    yesterday_news = datetime.now(tz=ZoneInfo("US/Eastern")) - timedelta(days=1)
    url = service_grib.form_gfswave_link(target_time=yesterday_news)
    if not service_grib.is_reachable(url):  # just one should be fine
        print(url, " is not reachable at this time")
        # TODO: should we actually error out?
    return JSONResponse(content={"status": "success"})


@app.get("/download/")
async def download_grib(
    background_tasks: BackgroundTasks,
    target_time: str = None,
):
    """Download and process GRIB files into csv of requested parameters

    :param target_time: well formed ISO 8601 time string, we will try to download GRIB available just before it
    """
    background_tasks.add_task(service_grib.extract_useful_data, target_time)
    return JSONResponse(content={"status": "Background task started"})


# Tasks
# gc
@app.on_event("startup")
@repeat_every(seconds=(1 * 60))
async def task_gc() -> None:
    gc.collect()