package metrics

// Global histograms for the relay's hot paths. Single-threaded per
// domain so direct globals are race-free under the moxie cooperative
// scheduler. Code on the hot path observes via these references; the
// /metrics endpoint snapshots via SnapshotAll.
//
// To add a new metric: declare a *Histogram global, initialize in init,
// and append to allHistograms below.

var (
	// IngestPipelineNs measures end-to-end pipeline.Ingest cost from
	// envelope-parsed event in to Result emitted out. Includes signature
	// verify, ACL, expiration check, replaceable resolution, and store.
	IngestPipelineNs = NewHistogram("ingest_pipeline_ns")

	// SigVerifyNs measures BIP340 Schnorr verification time per event.
	SigVerifyNs = NewHistogram("sig_verify_ns")

	// ACLAllowWriteNs measures the ACL.AllowWrite call duration. Open
	// mode is sub-µs; social/grapevine modes can spike under cold cache.
	ACLAllowWriteNs = NewHistogram("acl_allowwrite_ns")

	// WALAppendNs measures WAL.Append wall time, including the optional
	// fsync at the configured cadence (default every 100 writes).
	WALAppendNs = NewHistogram("wal_append_ns")

	// WALFsyncNs measures the explicit fsync syscall when triggered.
	WALFsyncNs = NewHistogram("wal_fsync_ns")

	// AcceptLoopHandleNs measures wall time of one EpollWait → handler
	// dispatch cycle (excluding the EpollWait blocking wait itself).
	AcceptLoopHandleNs = NewHistogram("accept_handle_ns")

	// AcceptLoopWaitNs measures EpollWait blocking wait.
	AcceptLoopWaitNs = NewHistogram("accept_wait_ns")
)

var allHistograms = []*Histogram{
	IngestPipelineNs,
	SigVerifyNs,
	ACLAllowWriteNs,
	WALAppendNs,
	WALFsyncNs,
	AcceptLoopHandleNs,
	AcceptLoopWaitNs,
}

// SnapshotAll emits a JSON object of all registered histograms.
func SnapshotAll(buf []byte) []byte {
	buf = append(buf, '{')
	for i, h := range allHistograms {
		if i > 0 {
			buf = append(buf, ',')
		}
		buf = h.AppendJSON(buf)
	}
	buf = append(buf, '}')
	return buf
}

// ResetAll clears all histograms. Used between benchmark phases.
func ResetAll() {
	for _, h := range allHistograms {
		h.Reset()
	}
}