"""Drop AI chat tables (migrated to comm conversations)

Revision ID: 0137
Revises: 0136
Create Date: 2026-08-21

AI chat functionality is now handled by the kommunikation plugin's
comm_conversations and comm_messages tables. The old AI-specific tables
(ai_chat_sessions, ai_chat_messages, ai_chat_attachments, ai_conversations,
ai_messages) are no longer needed and are dropped.
"""

from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision = "0137"
down_revision = "0136"
branch_labels = None
depends_on = None


def upgrade() -> None:
    # Use IF EXISTS to avoid errors if tables are already gone
    op.execute("DROP TABLE IF EXISTS ai_chat_attachments CASCADE")
    op.execute("DROP TABLE IF EXISTS ai_chat_messages CASCADE")
    op.execute("DROP TABLE IF EXISTS ai_chat_sessions CASCADE")
    op.execute("DROP TABLE IF EXISTS ai_messages CASCADE")
    op.execute("DROP TABLE IF EXISTS ai_conversations CASCADE")


def downgrade() -> None:
    # Tables cannot be restored — data was migrated or was empty.
    pass