"""add recurrence trigger modes

Revision ID: 0016_recurrence_trigger_modes
Revises: 0015_purge_operations
"""

import sqlalchemy as sa
from alembic import op

revision = "0016_recurrence_trigger_modes"
down_revision = "0015_purge_operations"
branch_labels = None
depends_on = None


def upgrade() -> None:
    with op.batch_alter_table("recurrence_templates") as batch_op:
        batch_op.alter_column("rrule", existing_type=sa.Text(), nullable=True)
        batch_op.add_column(
            sa.Column("trigger_mode", sa.String(length=32), nullable=False, server_default="scheduled")
        )
        batch_op.add_column(sa.Column("after_completion_days", sa.Integer(), nullable=True))
        batch_op.add_column(sa.Column("last_completed_at", sa.DateTime(timezone=True), nullable=True))
        batch_op.create_check_constraint(
            "ck_recurrence_trigger_configuration",
            "(trigger_mode = 'scheduled' AND rrule IS NOT NULL AND after_completion_days IS NULL) "
            "OR (trigger_mode = 'after_completion' AND rrule IS NULL "
            "AND after_completion_days BETWEEN 1 AND 3650)",
        )


def downgrade() -> None:
    with op.batch_alter_table("recurrence_templates") as batch_op:
        batch_op.drop_constraint("ck_recurrence_trigger_configuration", type_="check")
    # Legacy schema requires an RRULE. Completion-relative rows have none, so
    # preserve them as a compatible daily interval rule before restoring NOT NULL.
    op.execute(
        "UPDATE recurrence_templates "
        "SET rrule = 'FREQ=DAILY;INTERVAL=' || after_completion_days "
        "WHERE trigger_mode = 'after_completion' AND rrule IS NULL"
    )
    with op.batch_alter_table("recurrence_templates") as batch_op:
        batch_op.drop_column("last_completed_at")
        batch_op.drop_column("after_completion_days")
        batch_op.drop_column("trigger_mode")
        batch_op.alter_column("rrule", existing_type=sa.Text(), nullable=False)