#!/usr/bin/env python3
"""Fetch comments for a Reddit or YouTube URL and print them as JSON.

Usage:
    python fetch_comments.py <url>

Credentials are read from the environment (see .env.example); a .env file is
loaded automatically if present.
"""
import json
import logging
import os
import sys
from datetime import datetime, timezone
from urllib.parse import urlparse

from dotenv import load_dotenv

from chorus.api.reddit import RedditClient
from chorus.api.youtube import YouTubeClient
from chorus.logging_config import configure_logging

log = logging.getLogger("chorus.fetch_comments")


def client_for(uri: str):
    """Return the right API client for the given URL based on its host."""
    host = (urlparse(uri).hostname or "").lower()
    log.debug("Selecting client for host %r", host)

    if host.endswith("reddit.com") or host.endswith("redd.it"):
        return RedditClient(
            client_id=os.environ["REDDIT_CLIENT_ID"],
            client_secret=os.environ["REDDIT_CLIENT_SECRET"],
            user_agent=os.environ["REDDIT_USER_AGENT"],
        )

    if host.endswith("youtube.com") or host.endswith("youtu.be"):
        return YouTubeClient(api_key=os.environ["YOUTUBE_API_KEY"])

    raise ValueError(f"Unsupported URL host: {host!r}")


def main(argv):
    if len(argv) != 2:
        print(f"Usage: {argv[0]} <url>", file=sys.stderr)
        return 1

    configure_logging()
    load_dotenv()

    uri = argv[1]
    log.info("Fetching comments for %s", uri)
    try:
        client = client_for(uri)
        metadata = client.get_metadata_by_uri(uri)
        comments = client.get_comments_by_uri(uri)
    except Exception:
        log.exception("Failed to fetch comments for %s", uri)
        raise
    log.info("Fetched %d comment(s) for %s", len(comments), uri)

    output = {
        **metadata,
        "created_at": datetime.now(timezone.utc).isoformat(),
        "comments": comments
    }

    print(json.dumps(output, indent=2, ensure_ascii=False))
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv))