type MessageKey =
  | "colIndex"
  | "colTitle"
  | "colChannel"
  | "colDuration"
  | "colViews"
  | "colPublished"
  | "colCategory"
  | "colAddedBy"
  | "colVotes"
  | "filterTitle"
  | "filterChannel"
  | "filterAddedBy"
  | "filterCategory"
  | "badgeLive"
  | "headerVideos"
  | "headerLoading"
  | "fetchViews"
  | "fetchViewsProgress"
  | "fetchViewsDone"
  | "colSettings"
  | "colSettingsReset"
  | "statsDuration"
  | "statsChannels"
  | "statsPlayable"
  | "statsTotalViews"
  | "statsDetail"
  | "statsDetailChannelRank"
  | "statsDetailAddedByRank"
  | "statsDetailCategoryBreak"
  | "statsDetailDurationAvg"
  | "statsDetailDurationMedian"
  | "statsDetailVideos";

const messages: Record<string, Record<MessageKey, string>> = {
  ja: {
    colIndex: "#",
    colTitle: "タイトル",
    colChannel: "チャンネル",
    colDuration: "長さ",
    colViews: "再生数",
    colPublished: "公開日",
    colCategory: "カテゴリ",
    colAddedBy: "追加者",
    colVotes: "投票",
    filterTitle: "タイトル検索...",
    filterChannel: "チャンネル...",
    filterAddedBy: "追加者...",
    filterCategory: "カテゴリ...",
    badgeLive: "ライブ",
    headerVideos: "本の動画",
    headerLoading: "読み込み中…",
    fetchViews: "全件詳細を取得",
    fetchViewsProgress: "取得中…",
    fetchViewsDone: "取得完了",
    colSettings: "表示",
    colSettingsReset: "リセット",
    statsDuration: "合計時間",
    statsChannels: "チャンネル",
    statsPlayable: "再生可能",
    statsTotalViews: "総再生数",
    statsDetail: "詳細",
    statsDetailChannelRank: "チャンネル別",
    statsDetailAddedByRank: "追加者別",
    statsDetailCategoryBreak: "カテゴリ別",
    statsDetailDurationAvg: "平均再生時間",
    statsDetailDurationMedian: "中央値",
    statsDetailVideos: "本",
  },
  en: {
    colIndex: "#",
    colTitle: "Title",
    colChannel: "Channel",
    colDuration: "Duration",
    colViews: "Views",
    colPublished: "Published",
    colCategory: "Category",
    colAddedBy: "Added by",
    colVotes: "Votes",
    filterTitle: "Search title...",
    filterChannel: "Channel...",
    filterAddedBy: "Added by...",
    filterCategory: "Category...",
    badgeLive: "LIVE",
    headerVideos: "videos",
    headerLoading: "loading…",
    fetchViews: "Fetch all details",
    fetchViewsProgress: "Fetching…",
    fetchViewsDone: "Done",
    colSettings: "View",
    colSettingsReset: "Reset",
    statsDuration: "Total",
    statsChannels: "Channels",
    statsPlayable: "Playable",
    statsTotalViews: "Total views",
    statsDetail: "Details",
    statsDetailChannelRank: "By channel",
    statsDetailAddedByRank: "By contributor",
    statsDetailCategoryBreak: "By category",
    statsDetailDurationAvg: "Avg. duration",
    statsDetailDurationMedian: "Median",
    statsDetailVideos: "videos",
  },
};

function detectLang(): string {
  const htmlLang = document.documentElement.lang;
  if (htmlLang?.startsWith("ja")) return "ja";
  return "en";
}

export function t(key: MessageKey): string {
  const lang = detectLang();
  return (messages[lang] ?? messages.en)[key];
}