"""phash_backfill_queue: kolejka scen do policzenia phasha z zapisanej miniaturki

Uzasadnienie i liczby: `app/models/phash_backfill_queue.py`.

Revision ID: 0028_phash_backfill_queue
Revises: 0027_scenes_title_trgm
Create Date: 2026-08-13
"""
from __future__ import annotations

import sqlalchemy as sa
from alembic import op
from sqlalchemy.dialects import postgresql

revision: str = "0028_phash_backfill_queue"
down_revision: str | None = "0027_scenes_title_trgm"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.create_table(
        "phash_backfill_queue",
        sa.Column("scene_id", postgresql.UUID(as_uuid=True), nullable=False),
        sa.Column("thumbnail_url", sa.String(length=1024), nullable=False),
        sa.Column("referer", sa.String(length=255), nullable=True),
        sa.Column("attempts", sa.Integer(), nullable=False, server_default="0"),
        sa.Column("done_at", sa.DateTime(timezone=True), nullable=True),
        sa.Column(
            "created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False
        ),
        sa.ForeignKeyConstraint(["scene_id"], ["scenes.id"], ondelete="CASCADE"),
        sa.PrimaryKeyConstraint("scene_id"),
    )
    # Jedyne zapytanie ścieżki gorącej: „weź N nieprzetworzonych". Indeks częściowy,
    # bo przetworzone wiersze zostają w tabeli jako ślad, ale nigdy ich nie czytamy.
    op.create_index(
        "ix_phash_backfill_pending",
        "phash_backfill_queue",
        ["attempts"],
        postgresql_where=sa.text("done_at IS NULL"),
    )


def downgrade() -> None:
    op.drop_index("ix_phash_backfill_pending", table_name="phash_backfill_queue")
    op.drop_table("phash_backfill_queue")