feat: expand vehicle data platform capabilities

go/vehicle-gateway/internal/stats/pure_hydrogen.go

@@ -0,0 +1,120 @@
+package stats
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+const (
+	gb32960FuelCellEngineWorkMode = 2
+	yutongFuelCellRunningMode     = 4
+	yutongFuelCellDrivingMode     = 11
+)
+
+// PureHydrogenModeFromEnvelope returns whether the reported vehicle is in a
+// fuel-cell-only work mode and whether the source value is understood.
+//
+// The 32960 fuel-cell extension reports engine_work_state; production frames
+// use mode 2 for normal fuel-cell operation. Yutong reports the equivalent
+// state through TRIANGLE_STATE; production frames use 1 for inactive and 4/11
+// for active fuel-cell operating modes.
+func PureHydrogenModeFromEnvelope(env envelope.FrameEnvelope) (active bool, known bool) {
+	value, exists := env.Fields[envelope.FieldFuelCellWorkMode]
+	if !exists {
+		return false, false
+	}
+	mode, ok := integerMode(value)
+	if !ok {
+		return false, false
+	}
+	switch env.Protocol {
+	case envelope.ProtocolGB32960:
+		switch mode {
+		case gb32960FuelCellEngineWorkMode:
+			return true, true
+		case 0, 1:
+			return false, true
+		default:
+			return false, false
+		}
+	case envelope.ProtocolYutongMQTT:
+		switch mode {
+		case yutongFuelCellRunningMode, yutongFuelCellDrivingMode:
+			return true, true
+		case 1:
+			return false, true
+		default:
+			return false, false
+		}
+	default:
+		return false, false
+	}
+}
+
+// PureHydrogenMileageDelta returns the odometer delta that can be attributed
+// to pure-hydrogen operation. Both endpoints must report a known active mode;
+// this deliberately leaves transitions and missing mode data unclassified.
+func PureHydrogenMileageDelta(
+	previousKM float64,
+	currentKM float64,
+	previousActive bool,
+	previousKnown bool,
+	currentActive bool,
+	currentKnown bool,
+) float64 {
+	delta := currentKM - previousKM
+	if !previousKnown || !previousActive || !currentKnown || !currentActive {
+		return 0
+	}
+	if delta < 0 || delta > maxSelectedDailyMileageKM {
+		return 0
+	}
+	return delta
+}
+
+func integerMode(value any) (int, bool) {
+	switch typed := value.(type) {
+	case json.Number:
+		parsed, err := strconv.Atoi(typed.String())
+		return parsed, err == nil
+	case string:
+		parsed, err := strconv.Atoi(strings.TrimSpace(typed))
+		return parsed, err == nil
+	case int:
+		return typed, true
+	case int8:
+		return int(typed), true
+	case int16:
+		return int(typed), true
+	case int32:
+		return int(typed), true
+	case int64:
+		return int(typed), true
+	case uint:
+		return int(typed), true
+	case uint8:
+		return int(typed), true
+	case uint16:
+		return int(typed), true
+	case uint32:
+		return int(typed), true
+	case uint64:
+		if typed > uint64(^uint(0)>>1) {
+			return 0, false
+		}
+		return int(typed), true
+	case float32:
+		parsed := int(typed)
+		return parsed, float32(parsed) == typed
+	case float64:
+		parsed := int(typed)
+		return parsed, float64(parsed) == typed
+	default:
+		parsed, err := strconv.Atoi(strings.TrimSpace(fmt.Sprint(value)))
+		return parsed, err == nil
+	}
+}