Implemented NWS weather stories support

internal/sources/nws/weatherstories.go

@@ -0,0 +1,118 @@
+package nws
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"time"
+
+	"gitea.maximumdirect.net/ejr/feedkit/config"
+	"gitea.maximumdirect.net/ejr/feedkit/event"
+	fksources "gitea.maximumdirect.net/ejr/feedkit/sources"
+	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
+	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
+)
+
+// WeatherStoriesSource polls an NWS weatherstories endpoint and emits a RAW weather story Event.
+//
+// Output schema:
+//   - standards.SchemaRawNWSWeatherStoriesV1
+type WeatherStoriesSource struct {
+	http *fksources.HTTPSource
+}
+
+func NewWeatherStoriesSource(cfg config.SourceConfig) (*WeatherStoriesSource, error) {
+	const driver = "nws_weatherstories"
+
+	hs, err := fksources.NewHTTPSource(driver, cfg, "application/geo+json, application/json")
+	if err != nil {
+		return nil, err
+	}
+
+	return &WeatherStoriesSource{http: hs}, nil
+}
+
+func (s *WeatherStoriesSource) Name() string { return s.http.Name }
+
+func (s *WeatherStoriesSource) Kinds() []event.Kind {
+	return []event.Kind{event.Kind("weather_story")}
+}
+
+func (s *WeatherStoriesSource) Poll(ctx context.Context) ([]event.Event, error) {
+	raw, meta, changed, err := s.fetchRaw(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if !changed {
+		return nil, nil
+	}
+
+	var effectiveAt *time.Time
+	switch {
+	case !meta.ParsedLatestUpdateTime.IsZero():
+		t := meta.ParsedLatestUpdateTime.UTC()
+		effectiveAt = &t
+	case !meta.ParsedLatestStartTime.IsZero():
+		t := meta.ParsedLatestStartTime.UTC()
+		effectiveAt = &t
+	}
+
+	emittedAt := time.Now().UTC()
+	eventID := fksources.DefaultEventID("", s.http.Name, effectiveAt, emittedAt)
+
+	return fksources.SingleEvent(
+		event.Kind("weather_story"),
+		s.http.Name,
+		standards.SchemaRawNWSWeatherStoriesV1,
+		eventID,
+		emittedAt,
+		effectiveAt,
+		raw,
+	)
+}
+
+type weatherStoriesMeta struct {
+	Stories []struct {
+		StartTime  string `json:"startTime"`
+		UpdateTime string `json:"updateTime"`
+	} `json:"stories"`
+
+	ParsedLatestUpdateTime time.Time `json:"-"`
+	ParsedLatestStartTime  time.Time `json:"-"`
+}
+
+func (s *WeatherStoriesSource) fetchRaw(ctx context.Context) (json.RawMessage, weatherStoriesMeta, bool, error) {
+	raw, changed, err := s.http.FetchJSONIfChanged(ctx)
+	if err != nil {
+		return nil, weatherStoriesMeta{}, false, err
+	}
+	if !changed {
+		return nil, weatherStoriesMeta{}, false, nil
+	}
+
+	var meta weatherStoriesMeta
+	if err := json.Unmarshal(raw, &meta); err != nil {
+		return raw, weatherStoriesMeta{}, true, nil
+	}
+
+	for _, story := range meta.Stories {
+		if ts := strings.TrimSpace(story.UpdateTime); ts != "" {
+			if t, err := nwscommon.ParseTime(ts); err == nil {
+				t = t.UTC()
+				if meta.ParsedLatestUpdateTime.IsZero() || t.After(meta.ParsedLatestUpdateTime) {
+					meta.ParsedLatestUpdateTime = t
+				}
+			}
+		}
+		if ts := strings.TrimSpace(story.StartTime); ts != "" {
+			if t, err := nwscommon.ParseTime(ts); err == nil {
+				t = t.UTC()
+				if meta.ParsedLatestStartTime.IsZero() || t.After(meta.ParsedLatestStartTime) {
+					meta.ParsedLatestStartTime = t
+				}
+			}
+		}
+	}
+
+	return raw, meta, true, nil
+}