"""phase33 — contract_notification_recipients table

Per-contract additional notification recipients (users or free-form emails)
with a per-recipient event_types subscription list. Notified in addition to
the global NotificationMatrix routing, scoped to the contract's facilities.

Uses INFORMATION_SCHEMA table-existence check — safe to re-run.
"""

revision      = 'phase33_contract_recipients'
down_revision = 'phase32_device_token_columns'
branch_labels = None
depends_on    = None

from alembic import op
import sqlalchemy as sa


def _table_exists(conn, table):
    result = conn.execute(sa.text(
        "SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES "
        "WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = :t"
    ), {"t": table})
    return result.scalar() > 0


def upgrade():
    bind = op.get_bind()
    if _table_exists(bind, 'contract_notification_recipients'):
        return

    op.create_table(
        'contract_notification_recipients',
        sa.Column('id', sa.Integer, primary_key=True),
        sa.Column('project_id', sa.Integer,
                  sa.ForeignKey('projects.id', ondelete='CASCADE'), nullable=False),
        sa.Column('user_id', sa.Integer,
                  sa.ForeignKey('users.id', ondelete='CASCADE'), nullable=True),
        sa.Column('email', sa.String(200), nullable=True),
        sa.Column('event_types', sa.Text, nullable=True),
        sa.Column('created_at', sa.DateTime, nullable=False),
    )
    op.create_index('ix_cnr_project_id',
                    'contract_notification_recipients', ['project_id'])
    op.create_index('ix_cnr_user_id',
                    'contract_notification_recipients', ['user_id'])


def downgrade():
    bind = op.get_bind()
    if _table_exists(bind, 'contract_notification_recipients'):
        op.drop_table('contract_notification_recipients')