first commit

backend/internal/service/ops_histograms.go

@@ -0,0 +1,26 @@
+package service
+
+import (
+	"context"
+
+	infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
+)
+
+func (s *OpsService) GetLatencyHistogram(ctx context.Context, filter *OpsDashboardFilter) (*OpsLatencyHistogramResponse, error) {
+	if err := s.RequireMonitoringEnabled(ctx); err != nil {
+		return nil, err
+	}
+	if s.opsRepo == nil {
+		return nil, infraerrors.ServiceUnavailable("OPS_REPO_UNAVAILABLE", "Ops repository not available")
+	}
+	if filter == nil {
+		return nil, infraerrors.BadRequest("OPS_FILTER_REQUIRED", "filter is required")
+	}
+	if filter.StartTime.IsZero() || filter.EndTime.IsZero() {
+		return nil, infraerrors.BadRequest("OPS_TIME_RANGE_REQUIRED", "start_time/end_time are required")
+	}
+	if filter.StartTime.After(filter.EndTime) {
+		return nil, infraerrors.BadRequest("OPS_TIME_RANGE_INVALID", "start_time must be <= end_time")
+	}
+	return s.opsRepo.GetLatencyHistogram(ctx, filter)
+}