"""project collab prep: indexes, task version, comment user_id

Revision ID: 057
Revises: 056
Create Date: 2025-01-01 00:00:00.000000

"""
from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision = "057"
down_revision = "056"
branch_labels = None
depends_on = None


def upgrade() -> None:
    # 1a. Performance indexes for project_tasks
    # Use IF NOT EXISTS to handle indexes that may already exist on the DB
    op.execute("CREATE INDEX IF NOT EXISTS ix_project_tasks_project_id ON project_tasks (project_id)")
    op.execute("CREATE INDEX IF NOT EXISTS ix_project_tasks_parent_task_id ON project_tasks (parent_task_id) WHERE parent_task_id IS NOT NULL")
    op.execute("CREATE INDEX IF NOT EXISTS ix_project_tasks_project_updated ON project_tasks (project_id, updated_at DESC)")
    op.execute("CREATE INDEX IF NOT EXISTS ix_projects_user_updated ON projects (user_id, updated_at DESC)")

    # 1b. Add user_id to task_comments for multi-user attribution
    op.add_column(
        "task_comments",
        sa.Column("user_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="SET NULL"), nullable=True),
    )

    # 1c. Add version column to project_tasks for optimistic locking
    op.add_column(
        "project_tasks",
        sa.Column("version", sa.Integer(), server_default="1", nullable=False),
    )

    # Calendar delta polling index (Phase 4 prep)
    op.execute("CREATE INDEX IF NOT EXISTS ix_events_calendar_updated ON calendar_events (calendar_id, updated_at DESC)")


def downgrade() -> None:
    op.drop_index("ix_events_calendar_updated", table_name="calendar_events")
    op.drop_column("project_tasks", "version")
    op.drop_column("task_comments", "user_id")
    op.drop_index("ix_projects_user_updated", table_name="projects")
    op.drop_index("ix_project_tasks_project_updated", table_name="project_tasks")
    op.drop_index("ix_project_tasks_parent_task_id", table_name="project_tasks")
    op.drop_index("ix_project_tasks_project_id", table_name="project_tasks")