feat: add diagnostic interview loop

internal/interview/store.go

@@ -0,0 +1,62 @@
+package interview
+
+import (
+	"errors"
+	"sync"
+)
+
+var ErrSessionNotFound = errors.New("diagnostic session not found")
+
+type Store interface {
+	Create(Session) (Session, error)
+	Get(string) (Session, error)
+	Update(Session) (Session, error)
+}
+
+type MemoryStore struct {
+	mu       sync.RWMutex
+	sessions map[string]Session
+}
+
+func NewMemoryStore() *MemoryStore {
+	return &MemoryStore{
+		sessions: make(map[string]Session),
+	}
+}
+
+func (s *MemoryStore) Create(session Session) (Session, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.sessions[session.ID] = cloneSession(session)
+	return session, nil
+}
+
+func (s *MemoryStore) Get(id string) (Session, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	session, ok := s.sessions[id]
+	if !ok {
+		return Session{}, ErrSessionNotFound
+	}
+	return cloneSession(session), nil
+}
+
+func (s *MemoryStore) Update(session Session) (Session, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, ok := s.sessions[session.ID]; !ok {
+		return Session{}, ErrSessionNotFound
+	}
+	s.sessions[session.ID] = cloneSession(session)
+	return session, nil
+}
+
+func cloneSession(session Session) Session {
+	session.Stack = append([]string(nil), session.Stack...)
+	session.Questions = append([]Question(nil), session.Questions...)
+	session.Answers = append([]Answer(nil), session.Answers...)
+	return session
+}