// From from clause
type From struct {
	Tables []Table
	Joins  []Join
}

// Name from clause name
func (from From) Name() string {
	return "FROM"
}

// Build build from clause
func (from From) Build(builder Builder) {
	if len(from.Tables) > 0 {
		for idx, table := range from.Tables {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(table)
		}
	} else {

			if results[1] != "" {
				tx.Statement.Table = results[1]
			} else {
				tx.Statement.Table = results[2]
			}
		}
	} else if tables := strings.Split(name, "."); len(tables) == 2 {
		tx.Statement.TableExpr = &clause.Expr{SQL: tx.Statement.Quote(name)}
		tx.Statement.Table = tables[1]
	} else if name != "" {
		tx.Statement.TableExpr = &clause.Expr{SQL: tx.Statement.Quote(name)}

	}

	iv := DB.Table(`table_invoices`).Select(`seller, SUM(total) as total, SUM(paid) as paid, SUM(balance) as balance`).Group(`seller`)
	stmt = dryDB.Table(`table_employees`).Select(`id, name, iv.total, iv.paid, iv.balance`).Joins(`LEFT JOIN (?) AS iv ON iv.seller = table_employees.id`, iv).Scan(&user).Statement

	ScanType() reflect.Type
	Comment() (value string, ok bool)
	DefaultValue() (value string, ok bool)
}

type Index interface {
	Table() string
	Name() string
	Columns() []string
	PrimaryKey() (isPrimaryKey bool, ok bool)
	Unique() (unique bool, ok bool)
	Option() string
}

// TableType table type interface
type TableType interface {
	Schema() string
	Name() string
	Type() string
	Comment() (comment string, ok bool)

		},
		{
			[]clause.Interface{
				clause.Select{}, clause.From{
					Tables: []clause.Table{{Name: "users"}},
					Joins: []clause.Join{
						{
							Type:  clause.RightJoin,
							Table: clause.Table{Name: "profiles"},
							ON: clause.Where{
								[]clause.Expression{clause.Eq{clause.Column{Table: "profiles", Name: "email"}, clause.Column{Table: clause.CurrentTable, Name: "email"}}},
							},
						},
					},

)

// Namer namer interface
type Namer interface {
	TableName(table string) string
	SchemaName(table string) string
	ColumnName(table, column string) string
	JoinTableName(joinTable string) string
	RelationshipFKName(Relationship) string
	CheckerName(table, column string) string
	IndexName(table, column string) string
	UniqueName(table, column string) string
}

// Replacer replacer interface like strings.Replacer

		currentDatabase := m.DB.Migrator().CurrentDatabase()
		return m.DB.Raw("SELECT count(*) FROM information_schema.tables WHERE table_schema = ? AND table_name = ? AND table_type = ?", currentDatabase, stmt.Table, "BASE TABLE").Row().Scan(&count)
	})

	return count > 0
}

// RenameTable rename table from oldName to newName
func (m Migrator) RenameTable(oldName, newName interface{}) error {
	var oldTable, newTable interface{}

			if err := DB.Migrator().DropTable(table); err != nil {
				t.Fatalf("failed to drop table, got error: %v", err)
			}
			if err := DB.Table(table).AutoMigrate(test.from); err != nil {
				t.Fatalf("failed to migrate table, got error: %v", err)
			}
			if err := DB.Table(table).AutoMigrate(test.to); err != nil {
				t.Fatalf("failed to migrate table, got error: %v", err)
			}
			test.checkFunc(t)
		})

	} else {
		builder.WriteQuoted(insert.Table)
	}
}

// MergeClause merge insert clause
func (insert Insert) MergeClause(clause *Clause) {
	if v, ok := clause.Expression.(Insert); ok {
		if insert.Modifier == "" {
			insert.Modifier = v.Modifier
		}
		if insert.Table.Name == "" {
			insert.Table = v.Table
		}
	}
	clause.Expression = insert

	}

	// case 3: create from []map[string]interface{}
	records := []map[string]interface{}{
		{"name": "create_from_map_with_table_2", "age": 19},
		{"name": "create_from_map_with_table_3", "age": 20},
	}

	tableDB = DB.Table("users")
	if err := tableDB.Create(&records).Error; err != nil {
		t.Fatalf("failed to create data from slice of map, got error: %v", err)
	}