billing

backend/migrations/003_mailbox_billing_events.sql

@@ -0,0 +1,59 @@
+-- ============================================================
+-- 003_mailbox_billing_events.sql
+-- Append-only event log for inbox billing.
+--
+-- Each row records that a mailbox was created or deleted at a
+-- specific point in time. The aggregation per month is computed
+-- on the fly from these events.
+-- ============================================================
+
+CREATE TABLE IF NOT EXISTS mailbox_billing_events (
+  id           BIGSERIAL PRIMARY KEY,
+  occurred_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
+  domain       TEXT NOT NULL,
+  email        TEXT NOT NULL,
+  action       TEXT NOT NULL CHECK (action IN ('created', 'deleted')),
+  actor_email  TEXT,
+  notes        TEXT
+);
+
+CREATE INDEX IF NOT EXISTS idx_billing_events_domain_time
+  ON mailbox_billing_events(domain, occurred_at);
+
+CREATE INDEX IF NOT EXISTS idx_billing_events_email
+  ON mailbox_billing_events(email);
+
+-- ------------------------------------------------------------
+-- Backfill: synthesize 'created' events for every mailbox that
+-- already exists when this migration runs, so we have correct
+-- historical data right from the first deploy.
+--
+-- We use the mailbox's created_at as the event timestamp.
+-- For mailboxes that are already soft-deleted, also synthesize
+-- the matching 'deleted' event using deleted_at.
+--
+-- The WHERE NOT EXISTS guards make this migration idempotent
+-- in case it is re-run.
+-- ------------------------------------------------------------
+
+INSERT INTO mailbox_billing_events (occurred_at, domain, email, action, actor_email, notes)
+SELECT m.created_at, m.domain, m.email_address, 'created', NULL, 'backfill from migration 003'
+FROM mailboxes m
+WHERE NOT EXISTS (
+  SELECT 1 FROM mailbox_billing_events b
+  WHERE b.email = m.email_address
+    AND b.action = 'created'
+    AND b.occurred_at = m.created_at
+);
+
+INSERT INTO mailbox_billing_events (occurred_at, domain, email, action, actor_email, notes)
+SELECT m.deleted_at, m.domain, m.email_address, 'deleted', NULL, 'backfill from migration 003'
+FROM mailboxes m
+WHERE m.status = 'deleted'
+  AND m.deleted_at IS NOT NULL
+  AND NOT EXISTS (
+    SELECT 1 FROM mailbox_billing_events b
+    WHERE b.email = m.email_address
+      AND b.action = 'deleted'
+      AND b.occurred_at = m.deleted_at
+  );