text: // Copyright 2020 The Gitea Authors. All rights reserved.
  // Use of this source code is governed by a MIT-style
  // license that can be found in the LICENSE file.
  
  package migrations
  
  import (
  	"fmt"
  	"strings"
  
  	"code.gitea.io/gitea/modules/log"
  	"code.gitea.io/gitea/modules/setting"
  
  	"xorm.io/xorm"
  	"xorm.io/xorm/schemas"
  )
  
  func setDefaultPasswordToArgon2(x *xorm.Engine) error {
  	switch {
  	case setting.Database.UseMySQL:
  		_, err := x.Exec("ALTER TABLE `user` ALTER passwd_hash_algo SET DEFAULT 'argon2';")
  		return err
  	case setting.Database.UsePostgreSQL:
  		_, err := x.Exec("ALTER TABLE `user` ALTER COLUMN passwd_hash_algo SET DEFAULT 'argon2';")
  		return err
  	case setting.Database.UseMSSQL:
  		// need to find the constraint and drop it, then recreate it.
  		sess := x.NewSession()
  		defer sess.Close()
  		if err := sess.Begin(); err != nil {
  			return err
  		}
  		res, err := sess.QueryString("SELECT [name] FROM sys.default_constraints WHERE parent_object_id=OBJECT_ID(?) AND COL_NAME(parent_object_id, parent_column_id)=?;", "user", "passwd_hash_algo")
  		if err != nil {
  			return err
  		}
  		if len(res) > 0 {
  			constraintName := res[0]["name"]
  			log.Error("Results of select constraint: %s", constraintName)
  			_, err := sess.Exec("ALTER TABLE [user] DROP CONSTRAINT " + constraintName)
  			if err != nil {
  				return err
  			}
  			_, err = sess.Exec("ALTER TABLE [user] ADD CONSTRAINT " + constraintName + " DEFAULT 'argon2' FOR passwd_hash_algo")
  			if err != nil {
  				return err
  			}
  		} else {
  			_, err := sess.Exec("ALTER TABLE [user] ADD DEFAULT('argon2') FOR passwd_hash_algo")
  			if err != nil {
  				return err
  			}
  		}
  		return sess.Commit()
  
  	case setting.Database.UseSQLite3:
  		// drop through
  	default:
  		log.Fatal("Unrecognized DB")
  	}
  
  	tables, err := x.DBMetas()
  	if err != nil {
  		return err
  	}
  
  	// Now for SQLite we have to recreate the table
  	var table *schemas.Table
  	tableName := "user"
  
  	for _, table = range tables {
  		if table.Name == tableName {
  			break
  		}
  	}
  	if table == nil || table.Name != tableName {
  		type User struct {
  			PasswdHashAlgo string `xorm:"NOT NULL DEFAULT 'argon2'"`
  		}
  		return x.Sync2(new(User))
  	}
  	column := table.GetColumn("passwd_hash_algo")
  	if column == nil {
  		type User struct {
  			PasswdHashAlgo string `xorm:"NOT NULL DEFAULT 'argon2'"`
  		}
  		return x.Sync2(new(User))
  	}
  	sess := x.NewSession()
  	defer sess.Close()
  	if err := sess.Begin(); err != nil {
  		return err
  	}
  
  	tempTableName := "tmp_recreate__user"
  	column.Default = "'argon2'"
  
  	createTableSQL, _ := x.Dialect().CreateTableSQL(table, tempTableName)
  	for _, sql := range createTableSQL {
  		if _, err := sess.Exec(sql); err != nil {
  			log.Error("Unable to create table %s. Error: %v\n", tempTableName, err, createTableSQL)
  			return err
  		}
  	}
  	for _, index := range table.Indexes {
  		if _, err := sess.Exec(x.Dialect().CreateIndexSQL(tempTableName, index)); err != nil {
  			log.Error("Unable to create indexes on temporary table %s. Error: %v", tempTableName, err)
  			return err
  		}
  	}
  
  	newTableColumns := table.Columns()
  	if len(newTableColumns) == 0 {
  		return fmt.Errorf("no columns in new table")
  	}
  	hasID := false
  	for _, column := range newTableColumns {
  		hasID = hasID || (column.IsPrimaryKey && column.IsAutoIncrement)
  	}
  
  	sqlStringBuilder := &strings.Builder{}
  	_, _ = sqlStringBuilder.WriteString("INSERT INTO `")
  	_, _ = sqlStringBuilder.WriteString(tempTableName)
  	_, _ = sqlStringBuilder.WriteString("` (`")
  	_, _ = sqlStringBuilder.WriteString(newTableColumns[0].Name)
  	_, _ = sqlStringBuilder.WriteString("`")
  	for _, column := range newTableColumns[1:] {
  		_, _ = sqlStringBuilder.WriteString(", `")
  		_, _ = sqlStringBuilder.WriteString(column.Name)
  		_, _ = sqlStringBuilder.WriteString("`")
  	}
  	_, _ = sqlStringBuilder.WriteString(")")
  	_, _ = sqlStringBuilder.WriteString(" SELECT ")
  	if newTableColumns[0].Default != "" {
  		_, _ = sqlStringBuilder.WriteString("COALESCE(`")
  		_, _ = sqlStringBuilder.WriteString(newTableColumns[0].Name)
  		_, _ = sqlStringBuilder.WriteString("`, ")
  		_, _ = sqlStringBuilder.WriteString(newTableColumns[0].Default)
  		_, _ = sqlStringBuilder.WriteString(")")
  	} else {
  		_, _ = sqlStringBuilder.WriteString("`")
  		_, _ = sqlStringBuilder.WriteString(newTableColumns[0].Name)
  		_, _ = sqlStringBuilder.WriteString("`")
  	}
  
  	for _, column := range newTableColumns[1:] {
  		if column.Default != "" {
  			_, _ = sqlStringBuilder.WriteString(", COALESCE(`")
  			_, _ = sqlStringBuilder.WriteString(column.Name)
  			_, _ = sqlStringBuilder.WriteString("`, ")
  			_, _ = sqlStringBuilder.WriteString(column.Default)
  			_, _ = sqlStringBuilder.WriteString(")")
  		} else {
  			_, _ = sqlStringBuilder.WriteString(", `")
  			_, _ = sqlStringBuilder.WriteString(column.Name)
  			_, _ = sqlStringBuilder.WriteString("`")
  		}
  	}
  	_, _ = sqlStringBuilder.WriteString(" FROM `")
  	_, _ = sqlStringBuilder.WriteString(tableName)
  	_, _ = sqlStringBuilder.WriteString("`")
  
  	if _, err := sess.Exec(sqlStringBuilder.String()); err != nil {
  		log.Error("Unable to set copy data in to temp table %s. Error: %v", tempTableName, err)
  		return err
  	}
  
  	// SQLite will drop all the constraints on the old table
  	if _, err := sess.Exec(fmt.Sprintf("DROP TABLE `%s`", tableName)); err != nil {
  		log.Error("Unable to drop old table %s. Error: %v", tableName, err)
  		return err
  	}
  
  	for _, index := range table.Indexes {
  		if _, err := sess.Exec(x.Dialect().DropIndexSQL(tempTableName, index)); err != nil {
  			log.Error("Unable to drop indexes on temporary table %s. Error: %v", tempTableName, err)
  			return err
  		}
  	}
  
  	if _, err := sess.Exec(fmt.Sprintf("ALTER TABLE `%s` RENAME TO `%s`", tempTableName, tableName)); err != nil {
  		log.Error("Unable to rename %s to %s. Error: %v", tempTableName, tableName, err)
  		return err
  	}
  
  	for _, index := range table.Indexes {
  		if _, err := sess.Exec(x.Dialect().CreateIndexSQL(tableName, index)); err != nil {
  			log.Error("Unable to recreate indexes on table %s. Error: %v", tableName, err)
  			return err
  		}
  	}
  
  	return sess.Commit()
  }
  