from django.core.management.base import BaseCommand, CommandError

from apps.follows import sync
from apps.follows.models import FollowedPool
from apps.library import e621


class Command(BaseCommand):
    help = (
        "Fetch new posts for every followed pool: fills each feed, refreshes "
        "the card cover (latest image), pool name/count and unseen badges."
    )

    def add_arguments(self, parser):
        parser.add_argument(
            "--user",
            help="Only sync follows belonging to this username "
            "(default: every user's follows).",
        )
        parser.add_argument(
            "--limit",
            type=int,
            default=sync.FEED_LIMIT,
            help=f"Posts fetched per pool (default {sync.FEED_LIMIT}).",
        )

    def handle(self, *args, **options):
        username = options.get("user")
        if username and sync.preferred_fetch_user(username) is None:
            raise CommandError(f"No such user: {username}")
        fetch_user = sync.preferred_fetch_user(username)

        follows = FollowedPool.objects.select_related("user").order_by(
            "pool_id", "user_id"
        )
        if username:
            follows = follows.filter(user__username=username)
        follows = list(follows)
        grouped = {}
        for follow in follows:
            grouped.setdefault(follow.pool_id, []).append(follow)

        created = 0
        for pool_id, group in grouped.items():
            try:
                posts = sync.search_posts(
                    fetch_user, f"pool:{pool_id}", options["limit"]
                )
            except e621.E621Error as exc:
                raise CommandError(f"Aborted at pool #{pool_id}: {exc}")
            for follow in group:
                created += sync.sync_pool_follow(
                    follow, fetch_user, posts=posts
                )

        identity = getattr(fetch_user, "username", None) or "anonymous"
        self.stdout.write(
            self.style.SUCCESS(
                f"Synced {len(grouped)} pool(s) across {len(follows)} follow(s) "
                f"as {identity}: {created} new post(s)."
            )
        )