feat: Authors feature backend (and upgraded deprecated mods)

internal/infrastructure/useCases/DeleteAuthor.go

@@ -0,0 +1,76 @@
+package useCases
+
+import (
+	"RenewCMS/internal/domain/audit"
+	"RenewCMS/internal/domain/author"
+	"context"
+)
+
+type ReassignMode int
+
+const (
+	ReassignAbsent ReassignMode = iota
+	ReassignNone
+	ReassignToAuthor
+	ReassignMalformed
+)
+
+type Reassignment struct {
+	Mode        ReassignMode
+	Destination uint32
+}
+
+type DeleteAuthorUseCase struct {
+	authors  author.Repository
+	recorder audit.Recorder
+}
+
+func NewDeleteAuthorUseCase(authors author.Repository, recorder audit.Recorder) *DeleteAuthorUseCase {
+	return &DeleteAuthorUseCase{authors: authors, recorder: recorder}
+}
+
+func (u *DeleteAuthorUseCase) Delete(ctx context.Context, id uint32, reassignment Reassignment) error {
+	target, err := u.authors.Get(id)
+	if err != nil {
+		return err
+	}
+
+	event := audit.NewEvent(audit.ActionAuthorDelete, audit.CategoryAuthors)
+	event.Target = authorTarget(target)
+	if err := u.delete(target, reassignment); err != nil {
+		recordFailure(ctx, u.recorder, event, err)
+		return err
+	}
+	u.recorder.Record(ctx, event)
+	return nil
+}
+
+func (u *DeleteAuthorUseCase) delete(target author.Author, reassignment Reassignment) error {
+	if reassignment.Mode == ReassignNone {
+		return u.authors.DeleteUncrediting(target.ID)
+	}
+	if target.ArticleCount == 0 {
+		return u.authors.DeleteMovingCredits(target.ID, nil)
+	}
+	destination, err := u.destination(target, reassignment)
+	if err != nil {
+		return err
+	}
+	return u.authors.DeleteMovingCredits(target.ID, &destination)
+}
+
+func (u *DeleteAuthorUseCase) destination(target author.Author, reassignment Reassignment) (uint32, error) {
+	switch reassignment.Mode {
+	case ReassignAbsent:
+		return 0, author.ErrAuthorHasArticles
+	case ReassignMalformed:
+		return 0, author.ErrInvalidReassign
+	}
+	if reassignment.Destination == 0 || reassignment.Destination == target.ID {
+		return 0, author.ErrInvalidReassign
+	}
+	if _, err := u.authors.Get(reassignment.Destination); err != nil {
+		return 0, err
+	}
+	return reassignment.Destination, nil
+}