-- Durable customer-machine links; no changes to existing sessions during migration.
CREATE TABLE IF NOT EXISTS anydesk_machine_links (
    anydesk_id VARCHAR(64) PRIMARY KEY CHECK (anydesk_id ~ '^[0-9]+$'),
    customer_id INTEGER NOT NULL REFERENCES customers(id) ON DELETE CASCADE,
    contact_id INTEGER REFERENCES contacts(id) ON DELETE SET NULL,
    source_session_id INTEGER REFERENCES anydesk_sessions(id) ON DELETE SET NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);
CREATE INDEX IF NOT EXISTS idx_anydesk_machine_links_customer ON anydesk_machine_links(customer_id);