"""Drop unused sync columns from lab tables (server-only module).

Revision ID: lab_drop_sync_columns
Revises: lab_animal_profile_milk_yield
Create Date: 2026-06-09
"""

from __future__ import annotations

import sqlalchemy as sa
from alembic import op

revision = "lab_drop_sync_columns"
down_revision = "lab_animal_profile_milk_yield"
branch_labels = None
depends_on = None

_LAB_TABLES = (
    "lab_animal_profile",
    "lab_recipe_ration",
    "lab_ration_line",
)

_CUSTOMER_DROP_TABLES = ("lab_customer_address", "lab_customer")
_CUSTOMER_ID_COLUMNS = (("lab_recipe_ration", "customer_id"),)

_SYNC_COLS = ("sync_timestamp", "sync_status", "content_hash")


def _drop_customer_layer(insp: sa.Inspector) -> None:
    for table, column in _CUSTOMER_ID_COLUMNS:
        idx = f"ix_{table}_{column}"
        if table in insp.get_table_names():
            op.execute(sa.text(f'DROP INDEX IF EXISTS "{idx}"'))
    for table, column in _CUSTOMER_ID_COLUMNS:
        if table not in insp.get_table_names():
            continue
        cols = {c["name"] for c in insp.get_columns(table)}
        if column in cols:
            with op.batch_alter_table(table) as batch:
                batch.drop_column(column)
    for table in _CUSTOMER_DROP_TABLES:
        if table in insp.get_table_names():
            op.drop_table(table)


def upgrade(**kw) -> None:
    if kw.get("tag") == "reports":
        return
    bind = op.get_bind()
    insp = sa.inspect(bind)
    _drop_customer_layer(insp)
    insp = sa.inspect(bind)
    for table in _LAB_TABLES:
        if table not in insp.get_table_names():
            continue
        cols = {c["name"] for c in insp.get_columns(table)}
        drop = [c for c in _SYNC_COLS if c in cols]
        if not drop:
            continue
        with op.batch_alter_table(table) as batch:
            for col in drop:
                batch.drop_column(col)


def downgrade(**kw) -> None:
    if kw.get("tag") == "reports":
        return
    bind = op.get_bind()
    insp = sa.inspect(bind)
    for table in _LAB_TABLES:
        if table not in insp.get_table_names():
            continue
        cols = {c["name"] for c in insp.get_columns(table)}
        with op.batch_alter_table(table) as batch:
            if "sync_timestamp" not in cols:
                batch.add_column(sa.Column("sync_timestamp", sa.DateTime(), nullable=True))
            if "sync_status" not in cols:
                batch.add_column(
                    sa.Column("sync_status", sa.String(length=20), nullable=False, server_default="pending")
                )
            if "content_hash" not in cols:
                batch.add_column(
                    sa.Column("content_hash", sa.String(length=64), nullable=False, server_default="")
                )