// XODB is the common interface for database operations that can be used with
// types from schema '{{ schema .Schema }}'.
//
// This should work with database/sql.DB and database/sql.Tx.
type XODB interface {
	Exec(string, ...interface{}) (sql.Result, error)
	Query(string, ...interface{}) (*sql.Rows, error)
	QueryRow(string, ...interface{}) *sql.Row
}

// XOLog provides the log func used by generated queries.
var XOLog = func(string, ...interface{}) { }

// ScannerValuer is the common interface for types that implement both the
// database/sql.Scanner and sql/driver.Valuer interfaces.
type ScannerValuer interface {
	sql.Scanner
	driver.Valuer
}

// StringSlice is a slice of strings.
type StringSlice []string

// quoteEscapeRegex is the regex to match escaped characters in a string.
var quoteEscapeRegex = regexp.MustCompile(`([^\\]([\\]{2})*)\\"`)

// Scan satisfies the sql.Scanner interface for StringSlice.
func (ss *StringSlice) Scan(src interface{}) error {
	buf, ok := src.([]byte)
	if !ok {
		return errors.New("invalid StringSlice")
	}

	// change quote escapes for csv parser
	str := quoteEscapeRegex.ReplaceAllString(string(buf), `$1""`)
	str = strings.Replace(str, `\\`, `\`, -1)

	// remove braces
	str = str[1:len(str)-1]

	// bail if only one
	if len(str) == 0 {
		*ss = StringSlice([]string{})
		return nil
	}

	// parse with csv reader
	cr := csv.NewReader(strings.NewReader(str))
	slice, err := cr.Read()
	if err != nil {
		fmt.Printf("exiting!: %v\n", err)
		return err
	}

	*ss = StringSlice(slice)

	return nil
}

// Value satisfies the driver.Valuer interface for StringSlice.
func (ss StringSlice) Value() (driver.Value, error) {
	v := make([]string, len(ss))
	for i, s := range ss {
		v[i] = `"` + strings.Replace(strings.Replace(s, `\`, `\\\`, -1), `"`, `\"`, -1) + `"`
	}
	return "{" + strings.Join(v, ",") + "}", nil
}

// Slice is a slice of ScannerValuers.
type Slice []ScannerValuer