"""Indeks pod sortowanie scen po dlugosci (najdluzsze / najkrotsze).

Jeden indeks (duration_sec, created_at, id) WHERE duration_sec IS NOT NULL obsluguje
oba kierunki: skan w przod daje najkrotsze, w tyl najdluzsze. Sceny bez dlugosci sa
odfiltrowane w zapytaniu, wiec kolejnosc NULL-i nie gra roli i wystarczy jeden indeks.

CONCURRENTLY w autocommit_block, jak w 0027: zwykly CREATE INDEX blokowalby zapisy
ingestu na czas budowy (4,1 mln wierszy). Nieudany CONCURRENTLY zostawia indeks
INVALID; wtedy DROP INDEX i ponownie.

Revision ID: 0035_scenes_duration_idx
Revises: 0034_favorite_sites
Create Date: 2026-09-14
"""
from __future__ import annotations

from alembic import op

revision = "0035_scenes_duration_idx"
down_revision: str | None = "0034_favorite_sites"
branch_labels = None
depends_on = None


def upgrade() -> None:
    with op.get_context().autocommit_block():
        op.execute(
            "CREATE INDEX CONCURRENTLY IF NOT EXISTS ix_scenes_duration "
            "ON scenes (duration_sec, created_at, id) WHERE duration_sec IS NOT NULL"
        )


def downgrade() -> None:
    with op.get_context().autocommit_block():
        op.execute("DROP INDEX CONCURRENTLY IF EXISTS ix_scenes_duration")