-- Migration: Add refund/honest-accounting columns to jobs table
-- Users are refunded the overpayment (work invoice amount - actual cost) after job completion.

ALTER TABLE jobs
  ADD COLUMN IF NOT EXISTS actual_amount_sats  INTEGER,
  ADD COLUMN IF NOT EXISTS refund_amount_sats  INTEGER,
  ADD COLUMN IF NOT EXISTS refund_state        TEXT,
  ADD COLUMN IF NOT EXISTS refund_payment_hash TEXT;

COMMENT ON COLUMN jobs.actual_amount_sats   IS 'Actual charge in sats (raw token cost + DO infra + margin), computed post-execution using the locked BTC price';
COMMENT ON COLUMN jobs.refund_amount_sats   IS 'Overpayment in sats to return to the user (work_amount_sats - actual_amount_sats, clamped >= 0)';
COMMENT ON COLUMN jobs.refund_state         IS 'Refund lifecycle: not_applicable | pending | paid';
COMMENT ON COLUMN jobs.refund_payment_hash  IS 'Payment hash of the outgoing Lightning refund payment once sent';