package state

import "fmt"

// LineParity indicates whether odd or even lines are indented.
type LineParity uint8

const (
	// OddLines indicates that odd lines - 1, 3, 5... - are indented by 1/2 cell.
	OddLines LineParity = 1
	// EvenLines indicates that even lines - 0, 2, 4... - are indented by 1/2 cell.
	EvenLines LineParity = 2
)

// UnmarshalText unmarshals from the equivalent Javascript constant name.
func (o *LineParity) UnmarshalText(text []byte) error {
	switch string(text) {
	case "ODD":
		*o = OddLines
		return nil
	case "EVEN":
		*o = EvenLines
		return nil
	default:
		return fmt.Errorf("can't unmarshal unknown LineParity %s", text)
	}
}

// MarshalText marshals into the equivalent JavaScript constant name.
func (o LineParity) MarshalText() (text []byte, err error) {
	switch o {
	case OddLines, EvenLines:
		return []byte(o.String()), nil
	default:
		return nil, fmt.Errorf("can't marshal unknown LineParity %d", o)
	}
}

// String returns the equivalent JavaScript constant name.
func (o LineParity) String() string {
	switch o {
	case OddLines:
		return "ODD_LINES"
	case EvenLines:
		return "EVEN_LINES"
	default:
		return fmt.Sprintf("[unknown LineParity %d]", o)
	}
}