package handlers

import (
	"net/http"
	"strings"
)

// SQL fragment: nine i18n text columns on resources.
const resourceI18nColsSQL = `
	COALESCE(r.title_zh_tw,''), COALESCE(r.title_zh_cn,''), COALESCE(r.title_en,''),
	COALESCE(r.description_zh_tw,''), COALESCE(r.description_zh_cn,''), COALESCE(r.description_en,''),
	COALESCE(r.body_text_zh_tw,''), COALESCE(r.body_text_zh_cn,''), COALESCE(r.body_text_en,'')`

type resourceTextI18n struct {
	TitleZhTw, TitleZhCn, TitleEn string
	DescZhTw, DescZhCn, DescEn    string
	BodyZhTw, BodyZhCn, BodyEn    string
}

func pickLangField(r *http.Request, zhTW, zhCN, en string) string {
	lang := strings.TrimSpace(r.URL.Query().Get("lang"))
	if lang == "" {
		lang = r.Header.Get("Accept-Language")
	}
	lang = strings.ToLower(strings.TrimSpace(strings.Split(lang, ",")[0]))
	switch {
	case strings.HasPrefix(lang, "zh-cn"), lang == "zh-hans":
		if zhCN != "" {
			return zhCN
		}
	case strings.HasPrefix(lang, "en"):
		if en != "" {
			return en
		}
	}
	if zhTW != "" {
		return zhTW
	}
	if zhCN != "" {
		return zhCN
	}
	return en
}

func (t resourceTextI18n) pick(r *http.Request) (title, description, body string) {
	return pickLangField(r, t.TitleZhTw, t.TitleZhCn, t.TitleEn),
		pickLangField(r, t.DescZhTw, t.DescZhCn, t.DescEn),
		pickLangField(r, t.BodyZhTw, t.BodyZhCn, t.BodyEn)
}