feat: editor write path

internal/infrastructure/persistence/database/articleStoryBackfill.go

@@ -2,6 +2,7 @@ package database
 
 import (
 	entity "RenewCMS/internal/infrastructure/persistence/models"
+	"fmt"
 
 	"gorm.io/gorm"
 )
@@ -9,7 +10,9 @@ import (
 const (
 	articleStoriesMarker         = "article_stories"
 	articleStoryLanguageIndex    = "idx_articles_story_lang"
-	articleStoryLanguageIndexSQL = "CREATE UNIQUE INDEX idx_articles_story_lang ON articles (story_id, lang)"
+	articleStoryLanguageIndexSQL = "CREATE UNIQUE INDEX idx_articles_story_lang ON articles (story_id, lang, retired_id)"
+	articleStoryRetiredMarker    = "article_story_language_retired"
+	articleRetiredIDsMarker      = "article_retired_ids"
 )
 
 func BackfillArticleStories(db *gorm.DB) error {
@@ -35,9 +38,64 @@ func BackfillArticleStories(db *gorm.DB) error {
 	})
 }
 
+func BackfillRetiredArticles(db *gorm.DB) error {
+	return db.Transaction(func(tx *gorm.DB) error {
+		applied, err := markerApplied(tx, articleRetiredIDsMarker)
+		if err != nil || applied {
+			return err
+		}
+		if err := tx.Unscoped().Model(&entity.Article{}).Where("deleted_at IS NOT NULL AND retired_id = ?", 0).UpdateColumn("retired_id", gorm.Expr("id")).Error; err != nil {
+			return err
+		}
+		return applyMarker(tx, articleRetiredIDsMarker)
+	})
+}
+
+type duplicateStoryLanguage struct {
+	StoryID   uint32
+	Lang      string
+	RetiredID uint32
+	Versions  int
+}
+
+func checkStoryLanguagesUnique(db *gorm.DB) error {
+	var duplicates []duplicateStoryLanguage
+	err := db.Unscoped().Model(&entity.Article{}).
+		Select("story_id, lang, retired_id, COUNT(*) AS versions").
+		Group("story_id, lang, retired_id").
+		Having("COUNT(*) > 1").
+		Order("story_id ASC, lang ASC").
+		Limit(1).
+		Scan(&duplicates).Error
+	if err != nil || len(duplicates) == 0 {
+		return err
+	}
+	first := duplicates[0]
+	return fmt.Errorf("cannot create the unique index %s: story %d holds %d versions in language %q; merge or delete the extra versions, then start again", articleStoryLanguageIndex, first.StoryID, first.Versions, first.Lang)
+}
+
 func ensureArticleStoryLanguageIndex(db *gorm.DB) error {
-	if db.Migrator().HasIndex(&entity.Article{}, articleStoryLanguageIndex) {
+	replaced, err := markerApplied(db, articleStoryRetiredMarker)
+	if err != nil {
+		return err
+	}
+	indexed := db.Migrator().HasIndex(&entity.Article{}, articleStoryLanguageIndex)
+	if replaced && indexed {
 		return nil
 	}
-	return db.Exec(articleStoryLanguageIndexSQL).Error
+	if indexed {
+		if err := db.Migrator().DropIndex(&entity.Article{}, articleStoryLanguageIndex); err != nil {
+			return err
+		}
+	}
+	if err := checkStoryLanguagesUnique(db); err != nil {
+		return err
+	}
+	if err := db.Exec(articleStoryLanguageIndexSQL).Error; err != nil {
+		return err
+	}
+	if replaced {
+		return nil
+	}
+	return applyMarker(db, articleStoryRetiredMarker)
 }

internal/infrastructure/persistence/database/migrate.go

@@ -41,6 +41,9 @@ func Migrate(db *gorm.DB, publicURL string) error {
 	if err := SeedSiteLanguageSuggestions(db); err != nil {
 		return err
 	}
+	if err := BackfillRetiredArticles(db); err != nil {
+		return err
+	}
 	if err := ensureArticleStoryLanguageIndex(db); err != nil {
 		return err
 	}

internal/infrastructure/persistence/database/mysql.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"slices"
 	"strings"
 	"time"
 
@@ -25,6 +26,8 @@ const (
 	redactedPassword     = "***"
 	mysqlLockNowait      = 3572
 	mysqlLockWaitTimeout = 1205
+	mysqlDeadlock        = 1213
+	mysqlSnapshotChanged = 1020
 )
 
 type mysqlDriver struct{}
@@ -88,7 +91,9 @@ func tableOptionsFor(db *gorm.DB) *gorm.DB {
 	return db
 }
 
+var mysqlContentionCodes = []uint16{mysqlLockNowait, mysqlLockWaitTimeout, mysqlDeadlock, mysqlSnapshotChanged}
+
 func (mysqlDriver) IsLockContention(err error) bool {
 	var failure *mysqldriver.MySQLError
-	return errors.As(err, &failure) && (failure.Number == mysqlLockNowait || failure.Number == mysqlLockWaitTimeout)
+	return errors.As(err, &failure) && slices.Contains(mysqlContentionCodes, failure.Number)
 }

internal/infrastructure/persistence/database/postgres.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"net/url"
 	"reflect"
+	"slices"
 	"time"
 
 	"github.com/jackc/pgx/v5/pgconn"
@@ -23,6 +24,8 @@ const (
 	postgresUTCCallback           = "renewcms:postgres_utc"
 	gormQueryCallback             = "gorm:query"
 	postgresLockNotAvailable      = "55P03"
+	postgresDeadlockDetected      = "40P01"
+	postgresSerializationFailure  = "40001"
 )
 
 var timeType = reflect.TypeOf(time.Time{})
@@ -109,7 +112,9 @@ func (postgresDriver) NewBackup(db *gorm.DB, directory string, now func() time.T
 	return NewPostgresBackup(db, directory, now)
 }
 
+var postgresContentionCodes = []string{postgresLockNotAvailable, postgresDeadlockDetected, postgresSerializationFailure}
+
 func (postgresDriver) IsLockContention(err error) bool {
 	var failure *pgconn.PgError
-	return errors.As(err, &failure) && failure.Code == postgresLockNotAvailable
+	return errors.As(err, &failure) && slices.Contains(postgresContentionCodes, failure.Code)
 }

internal/infrastructure/persistence/mappers/articleMapper.go

@@ -55,6 +55,9 @@ func ArticleToDomain(m models.Article) article.Article {
 		Lang:              m.Lang,
 		StoryID:           m.StoryID,
 		ContentRevision:   m.ContentRevision,
+		EditRevision:      m.EditRevision,
+		SourceArticleID:   m.SourceArticleID,
+		SourceRevision:    m.SourceRevision,
 	}
 }
 
@@ -82,5 +85,8 @@ func ArticleToModel(a article.Article) models.Article {
 		Lang:              a.Lang,
 		StoryID:           a.StoryID,
 		ContentRevision:   a.ContentRevision,
+		EditRevision:      a.EditRevision,
+		SourceArticleID:   a.SourceArticleID,
+		SourceRevision:    a.SourceRevision,
 	}
 }

internal/infrastructure/persistence/models/articleModel.go

@@ -31,4 +31,8 @@ type Article struct {
 	Lang              string    `gorm:"size:35;not null;default:''"`
 	StoryID           uint32    `gorm:"not null;default:0"`
 	ContentRevision   uint32    `gorm:"not null;default:1"`
+	EditRevision      uint32    `gorm:"not null;default:1"`
+	SourceArticleID   *uint32
+	SourceRevision    uint32 `gorm:"not null;default:0"`
+	RetiredID         uint32 `gorm:"column:retired_id;not null;default:0"`
 }

internal/infrastructure/persistence/repositories/articleRepository.go

@@ -4,18 +4,23 @@ import (
 	domain "RenewCMS/internal/domain/article"
 	authordomain "RenewCMS/internal/domain/author"
 	"RenewCMS/internal/domain/language"
+	"RenewCMS/internal/domain/transaction"
+	"RenewCMS/internal/infrastructure/persistence/database"
 	"RenewCMS/internal/infrastructure/persistence/mappers"
 	entity "RenewCMS/internal/infrastructure/persistence/models"
 	"errors"
+	"slices"
 	"sort"
 
 	"strings"
+	"time"
 	"unicode"
 
 	"golang.org/x/text/runes"
 	"golang.org/x/text/transform"
 	"golang.org/x/text/unicode/norm"
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 )
 
 type ArticleRepository struct {
@@ -217,11 +222,12 @@ func (a *ArticleRepository) withAuthorsOne(db *gorm.DB, article domain.Article)
 	return loaded[0], nil
 }
 
-var preservedArticleColumns = []string{"lang", "story_id", "content_revision"}
+var errArticleSiteChanged = errors.New("the article moved to another site while it was being locked")
 
 const (
-	idChunkSize            = 500
-	initialContentRevision = 1
+	idChunkSize       = 500
+	maxUpdateAttempts = 5
+	maxSiteLockRounds = 5
 )
 
 func chunkIDs(ids []uint32) [][]uint32 {
@@ -321,14 +327,16 @@ func (a *ArticleRepository) GetByName(name string) (domain.Article, error) {
 }
 
 func (a *ArticleRepository) Create(article domain.Article) (domain.Article, error) {
-	created := mappers.ArticleToModel(article)
-	created.ContentRevision = initialContentRevision
+	created := mappers.ArticleToModel(article.Opened())
 	err := a.db.Transaction(func(tx *gorm.DB) error {
 		if article.SiteID != 0 {
 			if _, err := lockSite(tx, article.SiteID); err != nil {
 				return err
 			}
 		}
+		if err := ensureStoryLanguageFree(tx, created.StoryID, created.Lang); err != nil {
+			return err
+		}
 		if err := ensureSlugFree(tx, created.SiteID, created.Lang, created.Slug, 0); err != nil {
 			return err
 		}
@@ -346,6 +354,27 @@ func (a *ArticleRepository) Create(article domain.Article) (domain.Article, erro
 	return a.withAuthorsOne(a.db, mappers.ArticleToDomain(created))
 }
 
+func ensureStoryLanguageFree(tx *gorm.DB, storyID uint32, lang string) error {
+	if storyID == 0 {
+		return nil
+	}
+	var stories int64
+	if err := tx.Model(&entity.Story{}).Where("id = ?", storyID).Count(&stories).Error; err != nil {
+		return err
+	}
+	if stories == 0 {
+		return domain.ErrArticleNotFound
+	}
+	var versions int64
+	if err := tx.Model(&entity.Article{}).Where("story_id = ? AND lang = ?", storyID, lang).Count(&versions).Error; err != nil {
+		return err
+	}
+	if versions > 0 {
+		return domain.ErrLanguageTaken
+	}
+	return nil
+}
+
 func openStory(tx *gorm.DB, created *entity.Article) error {
 	if created.StoryID != 0 {
 		return nil
@@ -408,44 +437,71 @@ func (a *ArticleRepository) GetAll() ([]domain.Article, error) {
 }
 
 func (a *ArticleRepository) UpdateBody(id uint32, body string) (domain.Article, error) {
-	var localArticle entity.Article
-	err := a.db.Model(&entity.Article{}).First(&localArticle, id).Error
-	if err != nil {
-		return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
-	}
+	return a.updateColumns(id, map[string]any{"body": body})
+}
 
-	localArticle.Body = body
-	err = a.db.Omit(preservedArticleColumns...).Save(&localArticle).Error
-	if err != nil {
+func (a *ArticleRepository) updateColumns(id uint32, columns map[string]any) (domain.Article, error) {
+	columns["updated_at"] = time.Now()
+	if err := a.db.Model(&entity.Article{}).Where("id = ?", id).Updates(columns).Error; err != nil {
 		return domain.Article{}, err
 	}
-
-	return a.withAuthorsOne(a.db, mappers.ArticleToDomain(localArticle))
+	return a.Get(id)
 }
 
 func (a *ArticleRepository) Update(id uint32, update domain.Update) (domain.Article, error) {
+	var updated domain.Article
+	var err error
+	for attempt := 0; attempt < maxUpdateAttempts; attempt++ {
+		updated, err = a.updateOnce(id, update)
+		if err == nil || !database.IsLockContention(a.db, err) {
+			break
+		}
+	}
+	return updated, err
+}
+
+func (a *ArticleRepository) updateOnce(id uint32, update domain.Update) (domain.Article, error) {
+	for round := 0; round < maxSiteLockRounds; round++ {
+		var probe entity.Article
+		if err := a.db.Model(&entity.Article{}).Select("id", "site_id").First(&probe, id).Error; err != nil {
+			return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
+		}
+		updated, err := a.updateAt(id, update, probe.SiteID)
+		if !errors.Is(err, errArticleSiteChanged) {
+			return updated, err
+		}
+	}
+	return domain.Article{}, transaction.ErrLockContention
+}
+
+func (a *ArticleRepository) updateAt(id uint32, update domain.Update, probedSiteID uint32) (domain.Article, error) {
 	var localArticle entity.Article
 	err := a.db.Transaction(func(tx *gorm.DB) error {
-		if update.SiteID != nil {
-			if _, err := lockSite(tx, *update.SiteID); err != nil {
-				return err
-			}
+		locked, err := lockArticleBehindSites(tx, id, update, probedSiteID)
+		if err != nil {
+			return err
 		}
-		if err := tx.Model(&entity.Article{}).First(&localArticle, id).Error; err != nil {
-			return mapNotFoundErr(err, domain.ErrArticleNotFound)
-		}
-		if update.SiteID == nil && update.Slug != nil {
-			if _, err := lockSite(tx, localArticle.SiteID); err != nil {
-				return err
-			}
+		localArticle = locked
+		if update.IfRevision != nil && localArticle.EditRevision != *update.IfRevision {
+			return &domain.RevisionConflictError{Current: localArticle.EditRevision}
 		}
+		before := localArticle
 		applyUpdate(&localArticle, update)
 		if update.Slug != nil || update.SiteID != nil {
 			if err := ensureSlugFree(tx, localArticle.SiteID, localArticle.Lang, localArticle.Slug, id); err != nil {
 				return err
 			}
 		}
-		if err := tx.Omit(preservedArticleColumns...).Save(&localArticle).Error; err != nil {
+		authorsChanged, err := authorsDiffer(tx, id, update.AuthorIDs)
+		if err != nil {
+			return err
+		}
+		impact := domain.ImpactOf(mappers.ArticleToDomain(before), mappers.ArticleToDomain(localArticle), authorsChanged)
+		revised := mappers.ArticleToDomain(localArticle).Revised(impact)
+		localArticle.EditRevision = revised.EditRevision
+		localArticle.ContentRevision = revised.ContentRevision
+		localArticle.UpdatedAt = time.Now()
+		if err := writeArticleColumns(tx, localArticle, before.EditRevision); err != nil {
 			return err
 		}
 		if update.AuthorIDs != nil {
@@ -453,13 +509,97 @@ func (a *ArticleRepository) Update(id uint32, update domain.Update) (domain.Arti
 		}
 		return nil
 	})
+	if errors.Is(err, domain.ErrRevisionConflict) || errors.Is(err, errArticleSiteChanged) {
+		return domain.Article{}, err
+	}
 	if err != nil {
 		return domain.Article{}, a.explainSlugFailure(localArticle.SiteID, localArticle.Lang, localArticle.Slug, id, err)
 	}
 	return a.withAuthorsOne(a.db, mappers.ArticleToDomain(localArticle))
 }
 
+func lockArticleBehindSites(tx *gorm.DB, id uint32, update domain.Update, probedSiteID uint32) (entity.Article, error) {
+	if update.SiteID != nil || update.Slug != nil {
+		if err := lockSitesInOrder(tx, probedSiteID, update.SiteID); err != nil {
+			return entity.Article{}, err
+		}
+	}
+	var locked entity.Article
+	if err := tx.Model(&entity.Article{}).Clauses(clause.Locking{Strength: "UPDATE"}).First(&locked, id).Error; err != nil {
+		return entity.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
+	}
+	if locked.SiteID != probedSiteID {
+		return entity.Article{}, errArticleSiteChanged
+	}
+	return locked, nil
+}
+
+func lockSitesInOrder(tx *gorm.DB, currentSiteID uint32, targetSiteID *uint32) error {
+	siteIDs := []uint32{currentSiteID}
+	if targetSiteID != nil {
+		siteIDs = append(siteIDs, *targetSiteID)
+	}
+	slices.Sort(siteIDs)
+	for _, siteID := range slices.Compact(siteIDs) {
+		if siteID == 0 && targetSiteID != nil {
+			continue
+		}
+		if _, err := lockSite(tx, siteID); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func authorsDiffer(tx *gorm.DB, articleID uint32, authorIDs *[]uint32) (bool, error) {
+	if authorIDs == nil {
+		return false, nil
+	}
+	var current []uint32
+	if err := tx.Model(&entity.ArticleAuthor{}).Where("article_id = ?", articleID).Order("position ASC, id ASC").Pluck("author_id", &current).Error; err != nil {
+		return false, err
+	}
+	return !slices.Equal(current, *authorIDs), nil
+}
+
+func writeArticleColumns(tx *gorm.DB, written entity.Article, expectedRevision uint32) error {
+	result := tx.Model(&entity.Article{}).Where("id = ? AND edit_revision = ?", written.ID, expectedRevision).Updates(map[string]any{
+		"title":              written.Title,
+		"body":               written.Body,
+		"site_id":            written.SiteID,
+		"slug":               written.Slug,
+		"excerpt":            written.Excerpt,
+		"seo_title":          written.SEOTitle,
+		"seo_description":    written.SEODescription,
+		"cover_image_id":     written.CoverImageID,
+		"cover_image_alt":    written.CoverImageAlt,
+		"social_title":       written.SocialTitle,
+		"social_description": written.SocialDescription,
+		"social_image_id":    written.SocialImageID,
+		"canonical_url":      written.CanonicalURL,
+		"noindex":            written.Noindex,
+		"seo_dismissed":      written.SEODismissed,
+		"edit_revision":      written.EditRevision,
+		"content_revision":   written.ContentRevision,
+		"updated_at":         written.UpdatedAt,
+	})
+	if result.Error != nil {
+		return result.Error
+	}
+	if result.RowsAffected == 0 {
+		return &domain.RevisionConflictError{Current: currentRevision(tx, written.ID)}
+	}
+	return nil
+}
+
+func currentRevision(tx *gorm.DB, id uint32) uint32 {
+	var revision uint32
+	_ = tx.Model(&entity.Article{}).Where("id = ?", id).Pluck("edit_revision", &revision).Error
+	return revision
+}
+
 func applyUpdate(target *entity.Article, update domain.Update) {
+	setString(&target.Title, update.Title)
 	setString(&target.Body, update.Body)
 	setString(&target.Slug, update.Slug)
 	setString(&target.Excerpt, update.Excerpt)
@@ -493,19 +633,7 @@ func setString(target *string, value *string) {
 }
 
 func (a *ArticleRepository) UpdateIsOnline(id uint32, isOnline bool) (domain.Article, error) {
-	var localArticle entity.Article
-	err := a.db.Model(&entity.Article{}).First(&localArticle, id).Error
-	if err != nil {
-		return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
-	}
-
-	localArticle.IsOnline = isOnline
-	err = a.db.Omit(preservedArticleColumns...).Save(&localArticle).Error
-	if err != nil {
-		return domain.Article{}, err
-	}
-
-	return a.withAuthorsOne(a.db, mappers.ArticleToDomain(localArticle))
+	return a.updateColumns(id, map[string]any{"is_online": isOnline})
 }
 
 func (a *ArticleRepository) Delete(id uint32) error {
@@ -514,14 +642,60 @@ func (a *ArticleRepository) Delete(id uint32) error {
 		if err := tx.First(&found, id).Error; err != nil {
 			return mapNotFoundErr(err, domain.ErrArticleNotFound)
 		}
-		tombstone := domain.Tombstone(id)
-		if err := tx.Model(&entity.Article{}).Where("id = ?", id).UpdateColumn("slug", tombstone).Error; err != nil {
+		if found.SiteID != 0 {
+			if _, err := lockSite(tx, found.SiteID); err != nil {
+				return err
+			}
+		}
+		retired := map[string]any{"slug": domain.Tombstone(id), "retired_id": id}
+		if err := tx.Model(&entity.Article{}).Where("id = ?", id).UpdateColumns(retired).Error; err != nil {
 			return err
 		}
 		if err := deleteOrNotFound(tx.Delete(&entity.Article{}, id), domain.ErrArticleNotFound); err != nil {
 			return err
 		}
-		return tx.Where("article_id = ?", id).Delete(&entity.ArticleAuthor{}).Error
+		if err := tx.Where("article_id = ?", id).Delete(&entity.ArticleAuthor{}).Error; err != nil {
+			return err
+		}
+		return closeEmptyStory(tx, found.StoryID)
+	})
+}
+
+func closeEmptyStory(tx *gorm.DB, storyID uint32) error {
+	if storyID == 0 {
+		return nil
+	}
+	var remaining int64
+	if err := tx.Model(&entity.Article{}).Where("story_id = ?", storyID).Count(&remaining).Error; err != nil || remaining > 0 {
+		return err
+	}
+	return tx.Delete(&entity.Story{}, storyID).Error
+}
+
+func (a *ArticleRepository) ListByStory(storyID uint32) ([]domain.Article, error) {
+	var found []entity.Article
+	if err := a.db.Model(&entity.Article{}).Where("story_id = ?", storyID).Order("id ASC").Find(&found).Error; err != nil {
+		return nil, err
+	}
+	return toDomainArticles(found), nil
+}
+
+func (a *ArticleRepository) MoveToSite(ids []uint32, siteID uint32) error {
+	return a.db.Transaction(func(tx *gorm.DB) error {
+		for _, id := range ids {
+			var moving entity.Article
+			if err := tx.First(&moving, id).Error; err != nil {
+				return mapNotFoundErr(err, domain.ErrArticleNotFound)
+			}
+			if err := ensureSlugFree(tx, siteID, moving.Lang, moving.Slug, id); err != nil {
+				return err
+			}
+			moved := map[string]any{"site_id": siteID, "edit_revision": gorm.Expr("edit_revision + 1")}
+			if err := tx.Model(&entity.Article{}).Where("id = ?", id).Updates(moved).Error; err != nil {
+				return err
+			}
+		}
+		return nil
 	})
 }