feat: add teaching asset prompts

internal/teachingassets/service.go

@@ -0,0 +1,96 @@
+package teachingassets
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"tutor/internal/ontology"
+	"tutor/internal/workflows"
+)
+
+type Service struct {
+	store         Store
+	ontology      *ontology.Service
+	imageModelKey string
+	ids           atomic.Uint64
+}
+
+func NewService(store Store, ontology *ontology.Service, imageModelKey string) *Service {
+	return &Service{
+		store:         store,
+		ontology:      ontology,
+		imageModelKey: imageModelKey,
+	}
+}
+
+func (s *Service) GeneratePrompt(input GenerateInput) (PromptCandidate, error) {
+	if strings.TrimSpace(input.ConceptID) == "" {
+		return PromptCandidate{}, errors.New("concept_id is required")
+	}
+	assetType := input.AssetType
+	if assetType == "" {
+		assetType = workflows.AssetDiagram
+	}
+
+	concept, err := s.findConcept(input.ConceptID)
+	if err != nil {
+		return PromptCandidate{}, err
+	}
+	if len(concept.Evidence) == 0 {
+		return PromptCandidate{}, errors.New("concept has no source evidence")
+	}
+
+	prompt := PromptCandidate{
+		ID:                          s.nextID("asset-prompt"),
+		Concept:                     concept.Concept,
+		AssetType:                   assetType,
+		Prompt:                      buildPrompt(concept.Concept, assetType),
+		SourceEvidence:              append([]workflows.EvidenceRef(nil), concept.Evidence...),
+		ModelKey:                    s.imageModelKey,
+		RequiresModelIDVerification: true,
+		ReviewState:                 ReviewCandidate,
+		CreatedAt:                   time.Now().UTC(),
+	}
+	return s.store.SavePrompt(prompt)
+}
+
+func (s *Service) Snapshot() Snapshot {
+	return s.store.Snapshot()
+}
+
+func (s *Service) findConcept(id string) (ontology.ConceptCandidate, error) {
+	if s.ontology == nil {
+		return ontology.ConceptCandidate{}, errors.New("ontology not configured")
+	}
+	snapshot := s.ontology.Snapshot()
+	for _, concept := range snapshot.Concepts {
+		if concept.Concept.ID == id {
+			return concept, nil
+		}
+	}
+	return ontology.ConceptCandidate{}, errors.New("concept not found")
+}
+
+func buildPrompt(concept workflows.ConceptRef, assetType workflows.AssetType) string {
+	switch assetType {
+	case workflows.AssetLessonSlice:
+		return "Create a concise slide-like lesson slice explaining " + concept.Label +
+			" for a backend developer interview, with one example and one pitfall."
+	case workflows.AssetWorksheet:
+		return "Create a worksheet for practicing " + concept.Label +
+			" with short prompts, answer space, and a rubric."
+	case workflows.AssetInterviewCard:
+		return "Create an interview explanation card for " + concept.Label +
+			" with definition, production tradeoff, and follow-up question."
+	default:
+		return "Create a clear technical diagram explaining " + concept.Label +
+			" for a backend developer interview, grounded in the provided source evidence."
+	}
+}
+
+func (s *Service) nextID(prefix string) string {
+	return fmt.Sprintf("%s-%d", prefix, s.ids.Add(1))
+}