"""Migration 0112's data step, DB-lane: a user who already has two Watch later lists keeps the oldest,
with the other's videos moved in after its own (one it already held is not added twice), and the
one-per-user index then refuses a second list.

The schema half is checked by test_migrations.py; a video lost on the way is invisible there.
"""

from datetime import datetime, timezone

import pytest
from alembic import command
from alembic.config import Config
from sqlalchemy import text
from sqlalchemy.exc import IntegrityError

from app.catalog.models import Channel, Video
from app.db import engine


def test_a_second_watch_later_is_folded_into_the_first(db, make_user):
    user, other = make_user(), make_user()
    db.add(Channel(id="UCm", title="M"))
    now = datetime.now(timezone.utc)
    for v in ("v1", "v2", "v3"):
        db.add(Video(id=v, channel_id="UCm", published_at=now, duration_seconds=60))
    db.commit()
    cfg = Config("alembic.ini")
    command.downgrade(cfg, "0111_audit_request_id")
    try:
        with engine.begin() as conn:
            ids = conn.execute(
                text(
                    "INSERT INTO playlists (user_id, name, kind, position) VALUES"
                    " (:u, 'Watch later', 'watch_later', 0), (:u, 'Watch later', 'watch_later', 1),"
                    " (:o, 'Watch later', 'watch_later', 0) RETURNING id"
                ),
                {"u": user.id, "o": other.id},
            ).scalars()
            first, second, theirs = list(ids)
            conn.execute(
                text(
                    "INSERT INTO playlist_items (playlist_id, video_id, position) VALUES"
                    " (:a, 'v1', 0), (:b, 'v2', 0), (:b, 'v1', 1), (:c, 'v3', 0)"
                ),
                {"a": first, "b": second, "c": theirs},
            )
    finally:
        command.upgrade(cfg, "head")

    with engine.connect() as conn:
        lists = conn.execute(
            text("SELECT id, user_id FROM playlists WHERE kind = 'watch_later' ORDER BY id")
        ).all()
        assert [tuple(r) for r in lists] == [(first, user.id), (theirs, other.id)]
        items = conn.execute(
            text(
                "SELECT playlist_id, video_id, position FROM playlist_items ORDER BY playlist_id, position"
            )
        ).all()
        assert [tuple(r) for r in items] == [(first, "v1", 0), (first, "v2", 1), (theirs, "v3", 0)]
    with pytest.raises(IntegrityError), engine.begin() as conn:
        conn.execute(
            text(
                "INSERT INTO playlists (user_id, name, kind, position)"
                " VALUES (:u, 'Watch later', 'watch_later', 2)"
            ),
            {"u": user.id},
        )