Phase F

docs/integrations/whmcs/usage-billing.md

@@ -0,0 +1,50 @@
+# WHMCS usage billing (Phase F)
+
+GameCloud aggregates immutable usage from `usage_records` and exposes WHMCS-compatible metrics.
+
+## Metrics
+
+| Key | Source |
+|-----|--------|
+| `runtime_minutes` | Sum of metered runtime |
+| `memory_gib_minutes` | RAM × runtime (GiB-minutes) |
+| `cpu_core_minutes` | Runtime × plan CPU cores |
+| `storage_gib_days` | Allocated disk × period days |
+| `backup_storage_gib_days` | Completed backup sizes |
+| `egress_gib` | Reserved (0 until metering) |
+| `extra_port_days` | Reserved (0) |
+| `priority_queue_minutes` | Queue priority weighted runtime |
+| `managed_service_units` | Reserved (0) |
+
+## API
+
+| Method | Path | Purpose |
+|--------|------|---------|
+| `GET` | `/integrations/whmcs/services/:id/usage` | Period metrics + UsageUpdate values |
+| `POST` | `/integrations/whmcs/services/:id/usage/adjustments` | Post-export corrections |
+
+Query parameters:
+
+- `periodStart` / `periodEnd` — ISO-8601 UTC (default: current UTC month)
+- `testMode=true` — draft export, no billing event
+
+Responses are idempotent per installation, service, period, and test mode. Each export stores a `contentHash` for audit.
+
+## Adjustments
+
+Corrections never mutate historical raw `usage_records`. Submit metric deltas via the adjustments endpoint; the export status becomes `ADJUSTED`.
+
+## PHP module
+
+- `hexagamecloud_MetricProvider()` — returns `metrics` for WHMCS usage metrics
+- `hexagamecloud_UsageUpdate()` — returns `diskusage` and `bandwidth` for classic billing
+
+Both call `GET .../usage` on GameCloud.
+
+## Test mode
+
+Set `testMode` in the API query or enable test mode in the product config. Test exports use status `DRAFT` and do not emit `usage_period_closed` events.
+
+## Pricing
+
+All prices remain in WHMCS. GameCloud only supplies measured quantities.