Implement source-oriented briefing modules

internal/briefing/modules.go

@@ -4,10 +4,22 @@ import (
 	"fmt"
 	"reflect"
 
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/facts"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 )
 
+type ModuleContext struct {
+	Resolved  report.Resolved
+	Collected facts.CollectedFacts
+	Derived   facts.DerivedFacts
+	Units     string
+	Timezone  string
+	Location  *LocationContext
+}
+
+type ModuleBuilder func(ModuleContext, any) (*module.Output, error)
+
 type ModuleDefinition struct {
 	ID                module.ID
 	StanzaName        string
@@ -17,6 +29,7 @@ type ModuleDefinition struct {
 	SupportedReports  []report.ID
 	MissingData       module.MissingDataBehavior
 	AllowDuplicate    bool
+	Builder           ModuleBuilder
 }
 
 type ModuleRegistry struct {
@@ -65,6 +78,40 @@ func (r ModuleRegistry) Lookup(id module.ID) (ModuleDefinition, error) {
 	return definition, nil
 }
 
+func (r ModuleRegistry) BuildModule(ctx ModuleContext, item module.ConfigItem) (*module.Output, error) {
+	definition, err := r.Lookup(item.ID)
+	if err != nil {
+		return nil, err
+	}
+	if !definition.SupportsReport(ctx.Resolved.Definition.ID) {
+		return nil, fmt.Errorf("module %q is not compatible with report %q", item.ID, ctx.Resolved.Definition.ID)
+	}
+	if err := definition.ValidateOptions(item.Options); err != nil {
+		return nil, err
+	}
+	if definition.Builder == nil {
+		return nil, fmt.Errorf("module %q has no builder", item.ID)
+	}
+	options := item.Options
+	if options == nil {
+		options = definition.DefaultOptions
+	}
+	output, err := definition.Builder(ctx, options)
+	if err != nil {
+		return nil, err
+	}
+	if output == nil {
+		return nil, nil
+	}
+	if output.ID != definition.ID {
+		return nil, fmt.Errorf("module %q produced output id %q", definition.ID, output.ID)
+	}
+	if output.StanzaName != definition.StanzaName {
+		return nil, fmt.Errorf("module %q produced stanza %q, want %q", definition.ID, output.StanzaName, definition.StanzaName)
+	}
+	return output, nil
+}
+
 func (r ModuleRegistry) ValidateComposition(reportID report.ID, items []module.ConfigItem) error {
 	seenModules := map[module.ID]struct{}{}
 	seenStanzas := map[string]module.ID{}
@@ -132,6 +179,7 @@ func defaultModuleDefinitions() []ModuleDefinition {
 			RequiredCollected: []module.FactRequirement{module.CollectedSourceMetadata},
 			SupportedReports:  allReports,
 			MissingData:       module.MissingDataEmpty,
+			Builder:           buildMetadataModule,
 		},
 		{
 			ID:                module.CurrentConditions,
@@ -140,6 +188,7 @@ func defaultModuleDefinitions() []ModuleDefinition {
 			RequiredCollected: []module.FactRequirement{module.CollectedCurrentConditions},
 			SupportedReports:  allReports,
 			MissingData:       module.MissingDataOmit,
+			Builder:           buildCurrentConditionsModule,
 		},
 		{
 			ID:               module.DerivedDailySummary,
@@ -181,6 +230,7 @@ func defaultModuleDefinitions() []ModuleDefinition {
 			RequiredDerived:   []module.FactRequirement{module.RequiresDerivedAlertOverlaps},
 			SupportedReports:  allReports,
 			MissingData:       module.MissingDataEmpty,
+			Builder:           buildAlertDigestModule,
 		},
 		{
 			ID:                module.AreaForecastDiscussion,
@@ -189,6 +239,7 @@ func defaultModuleDefinitions() []ModuleDefinition {
 			RequiredCollected: []module.FactRequirement{module.CollectedDiscussion},
 			SupportedReports:  allReports,
 			MissingData:       module.MissingDataOmit,
+			Builder:           buildAreaForecastDiscussionModule,
 		},
 		{
 			ID:                module.WeatherStory,
@@ -197,6 +248,7 @@ func defaultModuleDefinitions() []ModuleDefinition {
 			RequiredCollected: []module.FactRequirement{module.CollectedWeatherStory},
 			SupportedReports:  allReports,
 			MissingData:       module.MissingDataOmit,
+			Builder:           buildWeatherStoryModule,
 		},
 		{
 			ID:               module.ForecastDelta,