"""Add version field to tasks for optimistic locking

Revision ID: 015
Revises: 014
Create Date: 2026-01-10

Add version integer field to tasks table for optimistic locking.
This prevents concurrent update conflicts by tracking version numbers.
"""
from typing import Sequence, Union
from alembic import op
import sqlalchemy as sa

revision: str = '015'
down_revision: Union[str, None] = '014'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # Add version column to pjctrl_tasks table for optimistic locking
    op.add_column(
        'pjctrl_tasks',
        sa.Column('version', sa.Integer(), nullable=False, server_default='1')
    )


def downgrade() -> None:
    op.drop_column('pjctrl_tasks', 'version')