feat: storage, language rules and migration

internal/infrastructure/persistence/database/articleSlugBackfill.go

@@ -11,11 +11,13 @@ import (
 const (
 	articleSlugIndexName         = "idx_articles_site_slug"
 	articleSlugBackfillBatchSize = 500
-	articleSlugIndexStatement    = "CREATE UNIQUE INDEX idx_articles_site_slug ON articles (site_id, slug)"
+	articleSlugIndexStatement    = "CREATE UNIQUE INDEX idx_articles_site_slug ON articles (site_id, lang, slug)"
+	articleSlugLanguageMarker    = "article_slug_index_per_language"
 )
 
 type slugOwner struct {
 	siteID uint32
+	lang   string
 	slug   string
 }
 
@@ -26,7 +28,7 @@ type slugAssignment struct {
 
 func BackfillArticleSlugs(db *gorm.DB) error {
 	var rows []entity.Article
-	if err := db.Unscoped().Select("id", "site_id", "title", "slug", "deleted_at").Order("id ASC").Find(&rows).Error; err != nil {
+	if err := db.Unscoped().Select("id", "site_id", "lang", "title", "slug", "deleted_at").Order("id ASC").Find(&rows).Error; err != nil {
 		return err
 	}
 	assignments := planSlugAssignments(rows)
@@ -60,7 +62,7 @@ func planSlugAssignments(rows []entity.Article) []slugAssignment {
 			}
 			continue
 		}
-		owner := slugOwner{row.SiteID, row.Slug}
+		owner := slugOwner{row.SiteID, row.Lang, row.Slug}
 		if row.Slug == "" || claimed[owner] {
 			pending = append(pending, row)
 			continue
@@ -74,25 +76,41 @@ func planSlugAssignments(rows []entity.Article) []slugAssignment {
 			base = snapshotSlug(row.Title)
 			attempt = 1
 		}
-		slug := firstFreeSnapshotSlug(claimed, row.SiteID, base, attempt)
-		claimed[slugOwner{row.SiteID, slug}] = true
+		slug := firstFreeSnapshotSlug(claimed, row.SiteID, row.Lang, base, attempt)
+		claimed[slugOwner{row.SiteID, row.Lang, slug}] = true
 		assignments = append(assignments, slugAssignment{row.ID, slug})
 	}
 	return assignments
 }
 
-func firstFreeSnapshotSlug(claimed map[slugOwner]bool, siteID uint32, base string, attempt int) string {
+func firstFreeSnapshotSlug(claimed map[slugOwner]bool, siteID uint32, lang string, base string, attempt int) string {
 	for ; ; attempt++ {
 		candidate := snapshotSlugWithSuffix(base, attempt)
-		if !claimed[slugOwner{siteID, candidate}] {
+		if !claimed[slugOwner{siteID, lang, candidate}] {
 			return candidate
 		}
 	}
 }
 
 func ensureArticleSlugIndex(db *gorm.DB) error {
-	if db.Migrator().HasIndex(&entity.Article{}, articleSlugIndexName) {
+	replaced, err := markerApplied(db, articleSlugLanguageMarker)
+	if err != nil {
+		return err
+	}
+	indexed := db.Migrator().HasIndex(&entity.Article{}, articleSlugIndexName)
+	if replaced && indexed {
 		return nil
 	}
-	return db.Exec(articleSlugIndexStatement).Error
+	if indexed {
+		if err := db.Migrator().DropIndex(&entity.Article{}, articleSlugIndexName); err != nil {
+			return err
+		}
+	}
+	if err := db.Exec(articleSlugIndexStatement).Error; err != nil {
+		return err
+	}
+	if replaced {
+		return nil
+	}
+	return applyMarker(db, articleSlugLanguageMarker)
 }