"""plex HU-overlay item/show columns + guid (E5 S5a)

On plex_items and plex_shows: `guid` (canonical external id, the EN<->HU pairing key), the Hungarian
twin fields `title_hu`/`summary_hu`/`genres_hu`, and a STORED generated `search_vector_hu` mirroring
the EN vector (title_hu A / people_text B / left(summary_hu,1000) C) + a GIN index. people_text is
language-neutral, reused for both vectors.

Run BEFORE the first HU overlay sync: while the *_hu columns are all NULL the generated-column build
is trivial. ADD only (no drop/rebuild of the EN search_vector). NOTE: adding a STORED generated
column + its GIN takes an ACCESS EXCLUSIVE lock and rewrites the table — brief, but flag it on prod.
"""

from typing import Sequence, Union

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

revision: str = "0064_plex_hu_overlay_cols"
down_revision: Union[str, None] = "0063_plex_library_overlay"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None

_TABLES = ("plex_items", "plex_shows")

# Mirror of the EN search_vector (models.py) but over the HU twin columns; people_text is shared.
_VECTOR_HU = (
    "setweight(to_tsvector('public.unaccent_simple', coalesce(title_hu, '')), 'A') || "
    "setweight(to_tsvector('public.unaccent_simple', coalesce(people_text, '')), 'B') || "
    "setweight(to_tsvector('public.unaccent_simple', left(coalesce(summary_hu, ''), 1000)), 'C')"
)


def upgrade() -> None:
    for t in _TABLES:
        op.add_column(t, sa.Column("guid", sa.String(64), nullable=True))
        op.add_column(t, sa.Column("title_hu", sa.String(512), nullable=True))
        op.add_column(t, sa.Column("summary_hu", sa.Text(), nullable=True))
        op.add_column(t, sa.Column("genres_hu", postgresql.JSONB(), nullable=True))
        op.create_index(f"ix_{t}_guid", t, ["guid"])
        op.create_index(f"ix_{t}_genres_hu_gin", t, ["genres_hu"], postgresql_using="gin")
        # Generated column can't be expressed via add_column — raw DDL, matching the EN idiom (0044).
        op.execute(
            f"ALTER TABLE {t} ADD COLUMN search_vector_hu tsvector "
            f"GENERATED ALWAYS AS ({_VECTOR_HU}) STORED"
        )
        op.execute(f"CREATE INDEX ix_{t}_search_vector_hu ON {t} USING gin (search_vector_hu)")


def downgrade() -> None:
    for t in _TABLES:
        op.execute(f"DROP INDEX IF EXISTS ix_{t}_search_vector_hu")
        op.execute(f"ALTER TABLE {t} DROP COLUMN IF EXISTS search_vector_hu")
        op.drop_index(f"ix_{t}_genres_hu_gin", table_name=t)
        op.drop_index(f"ix_{t}_guid", table_name=t)
        op.drop_column(t, "genres_hu")
        op.drop_column(t, "summary_hu")
        op.drop_column(t, "title_hu")
        op.drop_column(t, "guid")