feat: add ability to regenerate summaries

fix: database cascade settings
chore: debug log mode for gorm queries is back

migrations/common/custom_pre.go

@@ -30,6 +30,71 @@ func init() {
 			},
 			name: "rename language mappings table",
 		},
+		{
+			f: func(db *gorm.DB, cfg *config.Config) error {
+				// drop all already existing foreign key constraints
+				// afterwards let them be re-created by auto migrate with the newly introduced cascade settings,
+
+				migrator := db.Migrator()
+				const lookupKey = "20201106-migration_cascade_constraints"
+
+				if cfg.Db.Dialect == "sqlite3" {
+					// https://stackoverflow.com/a/1884893/3112139
+					// unfortunately, we can't migrate existing sqlite databases to the newly introduced cascade settings
+					// things like deleting all summaries won't work in those cases unless an entirely new db is created
+					log.Println("not attempting to drop and regenerate constraints on sqlite")
+					return nil
+				}
+
+				if !migrator.HasTable(&models.KeyStringValue{}) {
+					log.Println("key-value table not yet existing")
+					return nil
+				}
+
+				condition := "key = ?"
+				if cfg.Db.Dialect == "mysql" {
+					condition = "`key` = ?"
+				}
+				lookupResult := db.Where(condition, lookupKey).First(&models.KeyStringValue{})
+				if lookupResult.Error == nil && lookupResult.RowsAffected > 0 {
+					log.Println("no need to migrate cascade constraints")
+					return nil
+				}
+
+				// SELECT * FROM INFORMATION_SCHEMA.table_constraints;
+				constraints := map[string]interface{}{
+					"fk_summaries_editors":           &models.SummaryItem{},
+					"fk_summaries_languages":         &models.SummaryItem{},
+					"fk_summaries_machines":          &models.SummaryItem{},
+					"fk_summaries_operating_systems": &models.SummaryItem{},
+					"fk_summaries_projects":          &models.SummaryItem{},
+					"fk_summary_items_summary":       &models.SummaryItem{},
+					"fk_summaries_user":              &models.Summary{},
+					"fk_language_mappings_user":      &models.LanguageMapping{},
+					"fk_heartbeats_user":             &models.Heartbeat{},
+					"fk_aliases_user":                &models.Alias{},
+				}
+
+				for name, table := range constraints {
+					if migrator.HasConstraint(table, name) {
+						log.Printf("dropping constraint '%s'", name)
+						if err := migrator.DropConstraint(table, name); err != nil {
+							return err
+						}
+					}
+				}
+
+				if err := db.Create(&models.KeyStringValue{
+					Key:   lookupKey,
+					Value: "done",
+				}).Error; err != nil {
+					return err
+				}
+
+				return nil
+			},
+			name: "add cascade constraints",
+		},
 	}
 }