package handlers

import (
	"net/http"
	"regexp"
	"strings"
)

const postI18nColsSQL = `
	COALESCE(p.text_zh,''), COALESCE(p.text_en,''), COALESCE(p.text_ja,''),
	COALESCE(p.text_ko,''), COALESCE(p.text_vi,''), COALESCE(p.text_id,''), COALESCE(p.text_ms,'')`

const maxPostTextLen = 32768
const maxPostAttachments = 20

var postLinkRe = regexp.MustCompile(`https?://`)

type postTextI18n struct {
	TextZh, TextEn, TextJa, TextKo, TextVi, TextId, TextMs string
}

type postLocalePayload struct {
	Text string `json:"text"`
}

// requestLangCode is the normalized locale from ?lang= or Accept-Language (zh, en, ja, …).
func requestLangCode(r *http.Request) string {
	raw := strings.TrimSpace(r.URL.Query().Get("lang"))
	if raw == "" {
		raw = r.Header.Get("Accept-Language")
	}
	raw = strings.TrimSpace(strings.Split(raw, ",")[0])
	if raw == "" {
		return "zh"
	}
	return translateNormalizePostLang(raw)
}

// textForLang returns body text stored for the post's source language only.
func (t postTextI18n) textForLang(lang string) string {
	switch translateNormalizePostLang(lang) {
	case "en":
		return strings.TrimSpace(t.TextEn)
	case "ja":
		return strings.TrimSpace(t.TextJa)
	case "ko":
		return strings.TrimSpace(t.TextKo)
	case "vi":
		return strings.TrimSpace(t.TextVi)
	case "id":
		return strings.TrimSpace(t.TextId)
	case "ms":
		return strings.TrimSpace(t.TextMs)
	default:
		return strings.TrimSpace(t.TextZh)
	}
}

func postTextI18nFromSingle(lang, text string) postTextI18n {
	lang = translateNormalizePostLang(lang)
	text = strings.TrimSpace(text)
	var t postTextI18n
	switch lang {
	case "en":
		t.TextEn = text
	case "ja":
		t.TextJa = text
	case "ko":
		t.TextKo = text
	case "vi":
		t.TextVi = text
	case "id":
		t.TextId = text
	case "ms":
		t.TextMs = text
	default:
		t.TextZh = text
	}
	return t
}

func normalizePostSourceLang(lang string) string {
	lang = translateNormalizePostLang(strings.TrimSpace(lang))
	switch lang {
	case "zh", "en", "ja", "ko", "vi", "id", "ms":
		return lang
	default:
		return "zh"
	}
}

func (t postTextI18n) anyNonEmpty() bool {
	return strings.TrimSpace(t.TextZh) != "" ||
		strings.TrimSpace(t.TextEn) != "" ||
		strings.TrimSpace(t.TextJa) != "" ||
		strings.TrimSpace(t.TextKo) != "" ||
		strings.TrimSpace(t.TextVi) != "" ||
		strings.TrimSpace(t.TextId) != "" ||
		strings.TrimSpace(t.TextMs) != ""
}

func (t postTextI18n) legacyPrimary() string {
	if strings.TrimSpace(t.TextZh) != "" {
		return strings.TrimSpace(t.TextZh)
	}
	if strings.TrimSpace(t.TextEn) != "" {
		return strings.TrimSpace(t.TextEn)
	}
	return ""
}

func scanPostTextI18n(zh, en, ja, ko, vi, id, ms string) postTextI18n {
	return postTextI18n{TextZh: zh, TextEn: en, TextJa: ja, TextKo: ko, TextVi: vi, TextId: id, TextMs: ms}
}

func (t postTextI18n) toLocalizations() map[string]postLocalePayload {
	return map[string]postLocalePayload{
		"zh": {Text: t.TextZh},
		"en": {Text: t.TextEn},
		"ja": {Text: t.TextJa},
		"ko": {Text: t.TextKo},
		"vi": {Text: t.TextVi},
		"id": {Text: t.TextId},
		"ms": {Text: t.TextMs},
	}
}

func postTextHasLink(text string) bool {
	return postLinkRe.MatchString(text)
}

func truncatePostTexts(t postTextI18n) postTextI18n {
	tr := func(s string) string {
		s = strings.TrimSpace(s)
		if len(s) > maxPostTextLen {
			return s[:maxPostTextLen]
		}
		return s
	}
	t.TextZh = tr(t.TextZh)
	t.TextEn = tr(t.TextEn)
	t.TextJa = tr(t.TextJa)
	t.TextKo = tr(t.TextKo)
	t.TextVi = tr(t.TextVi)
	t.TextId = tr(t.TextId)
	t.TextMs = tr(t.TextMs)
	return t
}