nws: add `GetForecastGridData`

2 files changed, 103 insertions, 0 deletions

diff --git a/nws/nws.go b/nws/nws.go
index 67b351c..4fcc15b 100644
--- a/nws/nws.go
+++ b/nws/nws.go
@@ -30,6 +30,7 @@ type PointProperties struct {
 	GridY            int
 	Forecast         string
 	ForecastHourly   string
+	ForecastGridData string
 	RelativeLocation PointLocation
 }
 
@@ -77,6 +78,24 @@ type FeatureCollection struct {
 	Features []Feature
 }
 
+type ForecastGrid struct {
+	Properties GridProperties
+}
+
+type GridProperties struct {
+	RelativeHumidity GridHumidity
+}
+
+type GridHumidity struct {
+	Uom    string
+	Values []GridHumidityValue
+}
+
+type GridHumidityValue struct {
+	ValidTime string
+	Value     int
+}
+
 type Error struct {
 	Title  string
 	Type   string
@@ -95,6 +114,7 @@ type ForecastBundle struct {
 var pCache *cache.Cache
 var fCache *cache.Cache
 var fhCache *cache.Cache
+var fgCache *cache.Cache
 var aCache *cache.Cache
 var baseUrl *url.URL
 
@@ -104,6 +124,7 @@ func init() {
 	pCache = cache.NewCache()
 	fCache = cache.NewCache()
 	fhCache = cache.NewCache()
+	fgCache = cache.NewCache()
 	aCache = cache.NewCache()
 
 	// Parse NWS base url.
@@ -326,6 +347,53 @@ func GetForecastHourly(point *Point) (*Forecast, *Error) {
 	return forecast, nil
 }
 
+// NWS forecast grid data endpoint.
+func GetForecastGridData(point *Point) (*ForecastGrid, *Error) {
+	var nwsErr *Error
+	var expires time.Time
+	var body []byte
+
+	if point == nil {
+		return nil, &Error{
+			Title:  "point is nil",
+			Type:   "griddata-points-invalid",
+			Status: 500,
+			Detail: "point is nil",
+		}
+	}
+	if len(point.Properties.ForecastGridData) == 0 {
+		return nil, &Error{
+			Title:  "forecast grid data link is empty",
+			Type:   "forecast-griddata-link-invalid",
+			Status: 500,
+			Detail: "forecast grid data link is empty",
+		}
+	}
+
+	if body = fgCache.Get(point.Properties.ForecastGridData); len(body) == 0 {
+		// Get the forecast grid data
+		body, expires, nwsErr = get(point.Properties.ForecastGridData)
+		if nwsErr != nil {
+			return nil, nwsErr
+		}
+		// Cache it.
+		fgCache.Set(point.Properties.ForecastGridData, body, expires)
+	}
+
+	// Unmarshal.
+	grid := new(ForecastGrid)
+	err := json.Unmarshal(body, grid)
+	if err != nil {
+		return nil, &Error{
+			Title:  "forecast grid data json unmarshal failed",
+			Type:   "forecast-griddata-json-error",
+			Status: 500,
+			Detail: "forecast grid data json unmarshal failed",
+		}
+	}
+	return grid, nil
+}
+
 // NWS active alerts endpoint.
 func GetAlerts(lat, lng float32) (fc *FeatureCollection, err *Error) {
 	// Alerts endpoint.
diff --git a/nws/nws_test.go b/nws/nws_test.go
index 88f1c2b..7ddd97f 100644
--- a/nws/nws_test.go
+++ b/nws/nws_test.go
@@ -151,6 +151,41 @@ func TestGetForecastHourly(t *testing.T) {
 	}
 }
 
+func TestGetForecastGridData(t *testing.T) {
+	// Get point.
+	np, nwsErr := Points(41.115, -83.177)
+	if nwsErr != nil {
+		t.Errorf("error: %v", nwsErr)
+		return
+	}
+
+	// Get forecast grid data
+	grid, nwsErr := GetForecastGridData(np)
+	if nwsErr != nil {
+		t.Errorf("error: %v", nwsErr)
+		return
+	}
+
+	if len(grid.Properties.RelativeHumidity.Values) < 1 {
+		t.Error("error: humidity values empty")
+		return
+	}
+
+	// Verify humidity values.
+	for i, value := range grid.Properties.RelativeHumidity.Values {
+		if len(value.ValidTime) < 1 {
+			t.Errorf("humidity: %d: valid time invalid: %v", i,
+				value.ValidTime)
+			return
+		}
+		if value.Value < 1 {
+			t.Errorf("humidity: %d: value invalid: %v", i,
+				value.Value)
+			return
+		}
+	}
+}
+
 func TestNWSGetWrapper(t *testing.T) {
 	// Initialize test NWS server.
 	fails := 0