"""Regeln: Art (kind) je Regel + Unique inkl. kind.

Erlaubt, dasselbe Schlagwort einmal für eine Ausgabe- UND einmal für eine
Einnahme-Kategorie (bzw. als Transfer) zu verwenden. ``kind`` wird aus der
zugehörigen Kategorie bzw. ``is_transfer`` zurückgefüllt.

Revision ID: 0009
Revises: 0008
Create Date: 2026-08-20
"""
from alembic import op
import sqlalchemy as sa

revision = "0009"
down_revision = "0008"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column(
        "categorization_rules",
        sa.Column("kind", sa.String(length=16), nullable=False, server_default="expense"),
    )
    # Backfill: Transfer-Regeln -> "transfer", sonst die Art der Kategorie.
    op.execute("UPDATE categorization_rules SET kind = 'transfer' WHERE is_transfer = 1")
    op.execute(
        "UPDATE categorization_rules SET kind = ("
        "  SELECT c.type FROM categories c WHERE c.id = categorization_rules.category_id"
        ") WHERE is_transfer = 0 AND category_id IS NOT NULL"
    )
    # Unique-Constraint um kind erweitern (SQLite: über batch neu aufbauen).
    with op.batch_alter_table("categorization_rules") as batch:
        batch.drop_constraint("uq_rule_owner_field_pattern", type_="unique")
        batch.create_unique_constraint(
            "uq_rule_owner_field_pattern_kind",
            ["owner_id", "match_field", "pattern", "kind"],
        )


def downgrade() -> None:
    with op.batch_alter_table("categorization_rules") as batch:
        batch.drop_constraint("uq_rule_owner_field_pattern_kind", type_="unique")
        batch.create_unique_constraint(
            "uq_rule_owner_field_pattern",
            ["owner_id", "match_field", "pattern"],
        )
        batch.drop_column("kind")