Add Daily recent changes comparison

internal/app/app_test.go

@@ -12,7 +12,9 @@ import (
 	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/adapters/scriptorium"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/state"
 )
@@ -222,6 +224,9 @@ func TestGenerateDailyReportWritesReportAndPreflight(t *testing.T) {
 	if result.Metadata.RenderedReportPath != result.ReportPath {
 		t.Fatalf("metadata rendered report path = %q, want %q", result.Metadata.RenderedReportPath, result.ReportPath)
 	}
+	if len(result.RecentChanges) != 0 {
+		t.Fatalf("RecentChanges = %#v, want none without prior snapshot", result.RecentChanges)
+	}
 	report, err := os.ReadFile(outputPath)
 	if err != nil {
 		t.Fatalf("read report output: %v", err)
@@ -337,6 +342,78 @@ func TestGenerateDailyReportReturnsRunErrorAfterPreflight(t *testing.T) {
 	}
 }
 
+func TestGenerateDailyReportIncludesRecentChangesFromPriorSnapshot(t *testing.T) {
+	server := dailyBundleServer(t)
+	cfg := config.Defaults()
+	cfg.WeatherAPI.BaseURL = server.URL + "/"
+	cfg.WeatherAPI.Timezone = "America/Chicago"
+	cfg.Workspace.Root = t.TempDir()
+	store, err := state.NewFilesystemStore(cfg.Workspace)
+	if err != nil {
+		t.Fatalf("NewFilesystemStore() error = %v", err)
+	}
+	priorResolved, err := ResolveGenerate(GenerateRequest{
+		Config: cfg,
+		Report: ReportDaily,
+		Date:   mustParse("2026-05-29T12:00:00-05:00"),
+	}, mustParse("2026-05-29T04:00:00-05:00"))
+	if err != nil {
+		t.Fatalf("ResolveGenerate(prior) error = %v", err)
+	}
+	priorBriefing := priorDailyBriefing(priorResolved)
+	priorBriefingPath, err := store.SaveBriefing(context.Background(), priorResolved, priorBriefing)
+	if err != nil {
+		t.Fatalf("SaveBriefing() error = %v", err)
+	}
+	priorPaths, err := store.Paths(priorResolved)
+	if err != nil {
+		t.Fatalf("Paths() error = %v", err)
+	}
+	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
+		Briefing:       priorBriefingPath,
+		DataPackage:    priorPaths.DataPackage,
+		Preflight:      priorPaths.Preflight,
+		RenderedReport: priorPaths.RenderedReport,
+	}))
+	if err != nil {
+		t.Fatalf("SaveMetadata() error = %v", err)
+	}
+
+	currentResolved, err := ResolveGenerate(GenerateRequest{
+		Config: cfg,
+		Report: ReportDaily,
+		Date:   mustParse("2026-05-29T12:00:00-05:00"),
+	}, mustParse("2026-05-29T05:00:00-05:00"))
+	if err != nil {
+		t.Fatalf("ResolveGenerate(current) error = %v", err)
+	}
+	renderer := &recordingRenderer{
+		renderResult: &scriptorium.RenderResult{ExitCode: 0},
+		runResult:    &scriptorium.RunResult{ExitCode: 0},
+		runBody:      "# Daily Report\n",
+	}
+
+	result, err := GenerateDailyReport(context.Background(), DailyReportRequest{
+		Config:   cfg,
+		Resolved: currentResolved,
+		Renderer: renderer,
+		Store:    store,
+	})
+	if err != nil {
+		t.Fatalf("GenerateDailyReport() error = %v", err)
+	}
+	if len(result.RecentChanges) == 0 {
+		t.Fatal("RecentChanges length = 0, want changes from prior snapshot")
+	}
+	data, err := os.ReadFile(result.DataPackagePath)
+	if err != nil {
+		t.Fatalf("read data package: %v", err)
+	}
+	if !strings.Contains(string(data), "alert_added") || !strings.Contains(string(data), "temperature_shift") {
+		t.Fatalf("data package missing recent changes:\n%s", string(data))
+	}
+}
+
 func TestResolveGenerateMapsCommandToReportDefinition(t *testing.T) {
 	cfg := config.Defaults()
 	cfg.WeatherAPI.Timezone = "America/Chicago"
@@ -435,6 +512,37 @@ func mustParse(value string) time.Time {
 	return parsed
 }
 
+func priorDailyBriefing(resolved report.Resolved) briefing.Package {
+	low := 50.0
+	high := 58.0
+	precip := 10.0
+	return briefing.Package{
+		Metadata: briefing.Metadata{
+			SchemaVersion: briefing.SchemaVersion,
+			RunID:         resolved.Metadata().RunID,
+			ReportID:      resolved.Definition.ID,
+			Variant:       "today",
+			PromptID:      resolved.Definition.PromptID,
+			GeneratedAt:   resolved.GeneratedAt,
+			Units:         "us",
+			Timezone:      resolved.Timezone,
+			ValidPeriod:   resolved.ValidPeriod,
+		},
+		Daily: &briefing.Daily{
+			BottomLine: briefing.BottomLine{
+				Temperature: forecast.Range{Min: &low, Max: &high},
+				MaxPrecipProbability: &forecast.TimedValue{
+					Value: precip,
+					Time:  resolved.ValidPeriod.Start.Add(6 * time.Hour),
+				},
+			},
+			Dayparts: []forecast.DaypartSummary{
+				{Name: "morning"},
+			},
+		},
+	}
+}
+
 type recordingRenderer struct {
 	renderCalls   int
 	runCalls      int