-- Booking lifecycle milestones.
--
-- The status enum is reshaped to a lean "bucket": enquiry | reserved |
-- confirmed | ended | cancelled. The contract + deposit progression that
-- runs inside `reserved` (over ~1 year) is tracked as the columns below plus the
-- deposit row on the invoice table — NOT as extra statuses. A daily cron reads
-- these columns; nothing here runs a long-lived workflow.
ALTER TABLE booking ADD COLUMN contract_sent_at         TEXT;  -- ISO; day-0 anchor + R1 idempotency guard
ALTER TABLE booking ADD COLUMN contract_response        TEXT CHECK (contract_response IN ('approved', 'declined'));  -- null = pending
ALTER TABLE booking ADD COLUMN contract_response_at     TEXT;  -- ISO
ALTER TABLE booking ADD COLUMN deposit_reminder_sent_at TEXT;  -- ISO; R2 idempotency guard
ALTER TABLE booking ADD COLUMN flagged_at               TEXT;  -- ISO; set when admin review is needed
ALTER TABLE booking ADD COLUMN flag_reason              TEXT CHECK (flag_reason IN ('deposit_overdue', 'short_window', 'contract_declined'));

-- Collapse the two retired statuses onto the new bucket (for any non-reset DB).
UPDATE booking SET status = 'reserved'  WHERE status = 'form_received';
UPDATE booking SET status = 'confirmed' WHERE status = 'deposit_paid';