import asyncio
import csv
import sys
import time

import aiohttp


def get_urls(filename: str, limit: int | None = None) -> list[str]:
    """Get a list of URLs from FILENAME.

    FILENAME should be that of a CSV file with a field 'Domain',
    denoting the site URL.

    The 'https://' schema is prefixed to each URL.

    If LIMIT is not None, then stop after LIMIT URLs have been read.

    Return the list of URLs.

    """

    urls: list[str] = []

    with open(filename) as f:
        reader = csv.DictReader(f)
        for i, row in enumerate(reader):
            if limit is not None and i == limit:
                break

            urls.append(f"https://{row['Domain']}")

        return urls


async def fetch(session: aiohttp.ClientSession, url: str, semaphore: asyncio.Semaphore) -> str:
    try:
        async with semaphore, session.get(url) as response:
            print(".", end="", flush=True)
            if response.ok:
                return "😁"
            else:
                return "😓"
    except aiohttp.ClientError:
        return "🤮"
    except TimeoutError:
        return "😴"


async def ping(urls: list[str], max_concurrency: int = 1) -> list[str]:
    """Make a GET request to members of URLS.

    If MAX_CONCURRENCY is None, browse every site at once.

    Else, only browse MAX_CONCURRENCY number of sites at a time.

    Print the sites as they get browsed; don't return anything.

    """

    async with (
        aiohttp.ClientSession(max_field_size=8190 * 2, timeout=aiohttp.ClientTimeout(5)) as session,
        asyncio.TaskGroup() as tg,
    ):
        semaphore = asyncio.Semaphore(max_concurrency)
        tasks = [tg.create_task(fetch(session, url, semaphore)) for url in urls]

    return [t.result() for t in tasks]


def main():
    limit: int | None = None

    if len(sys.argv) > 1:
        limit = int(sys.argv[1])

    urls = get_urls("majestic_million.csv", limit)

    start_time = time.perf_counter()
    results = asyncio.run(ping(urls))
    print()
    print(results)
    end_time = time.perf_counter()

    elapsed_time = end_time - start_time
    print(f"Execution time: {elapsed_time:.6f} seconds")


if __name__ == "__main__":
    main()