package models

import (
	"fmt"
	"io"
)

// ChapterCommentMode represents the kind of tags.
type ChapterCommentMode string

const (
	// ChapterCommentModeDisabled is a chapter comment mode, see GraphQL documentation.
	ChapterCommentModeDisabled ChapterCommentMode = "Disabled"

	// ChapterCommentModeArticle is a chapter comment mode, see GraphQL documentation.
	ChapterCommentModeArticle ChapterCommentMode = "Article"

	// ChapterCommentModeChat is a chapter comment mode, see GraphQL documentation.
	ChapterCommentModeChat ChapterCommentMode = "Chat"

	// ChapterCommentModeMessage is a chapter comment mode, see GraphQL documentation.
	ChapterCommentModeMessage ChapterCommentMode = "Message"
)

// UnmarshalGQL unmarshals
func (e *ChapterCommentMode) UnmarshalGQL(v interface{}) error {
	str, ok := v.(string)
	if !ok {
		return fmt.Errorf("enums must be strings")
	}

	*e = ChapterCommentMode(str)
	switch *e {
	case ChapterCommentModeDisabled, ChapterCommentModeArticle, ChapterCommentModeChat, ChapterCommentModeMessage:
		return nil
	default:
		return fmt.Errorf("%s is not a valid ChapterCommentMode", str)
	}
}

// IsEnabled returns true if comments are enabled.
func (e ChapterCommentMode) IsEnabled() bool {
	return e != ChapterCommentModeDisabled && len(e) != 0
}

// MarshalGQL turns it into a JSON string
func (e ChapterCommentMode) MarshalGQL(w io.Writer) {
	// Backwards compatibility: Empty value means disabled.
	if len(e) == 0 {
		w.Write(disabledChapterCommentModeBytes)
		return
	}

	fmt.Fprint(w, "\""+string(e)+"\"")
}

var disabledChapterCommentModeBytes = []byte(`"Disabled"`)