import { useLocale } from '../../i18n';
import type { LanguageCode } from '../../types/runtime';

type Primitive = string | number;
type MessageTree = {
  [key: string]: Primitive | MessageTree;
};
type InterpolationParams = Record<string, Primitive>;

export type KnowledgeTranslate = (path: string, params?: InterpolationParams, fallback?: string) => string;

function normalizeKnowledgePath(path: string): string {
  return path.startsWith('knowledge.') ? path.slice('knowledge.'.length) : path;
}

const EN_KNOWLEDGE_MESSAGES: MessageTree = {
  title: 'Knowledge Docs',
  subtitle: 'Upload, review, and delete local documentation files stored in the knowledge directory.',
  refresh: 'Refresh',
  upload: 'Upload document',
  uploadHint: 'This page fully replaces the previous Knowledge demo and now focuses on local docs only.',
  documentsLabel: 'Documents',
  storageLabel: 'Storage',
  emptyTitle: 'No documents yet',
  emptyDescription: 'Upload a file to start managing the local knowledge docs directory.',
  deleteConfirm: 'Delete this document?',
  table: {
    name: 'Name',
    size: 'Size',
    modifiedAt: 'Modified At',
    type: 'Type',
    actions: 'Actions',
    delete: 'Delete',
  },
  dialog: {
    title: 'Upload document',
    description: 'Choose a file and save it into the local knowledge docs directory.',
    fileLabel: 'File',
    fileHint: 'The uploaded file will be written with its file name and metadata preserved.',
    cancel: 'Cancel',
    confirm: 'Upload',
  },
  status: {
    loading: 'Loading documents...',
    uploading: 'Uploading...',
    deleting: 'Deleting...',
    uploadSuccess: 'Document uploaded successfully',
    deleteSuccess: 'Document deleted successfully',
    failed: 'Knowledge docs request failed: {error}',
  },
  common: {
    cancel: 'Cancel',
    confirm: 'Confirm',
  },
};

const ZH_KNOWLEDGE_MESSAGES: MessageTree = {
  title: '知识文档管理',
  subtitle: '上传、查看和删除保存在知识目录中的本地文档文件。',
  refresh: '刷新',
  upload: '上传文档',
  uploadHint: '此页面已完全替换旧 Knowledge demo，只保留本地文档管理能力。',
  documentsLabel: '文档数量',
  storageLabel: '占用空间',
  emptyTitle: '暂无文档',
  emptyDescription: '先上传一个文件，开始管理本地知识文档目录。',
  deleteConfirm: '确定要删除此文档吗？',
  table: {
    name: '名称',
    size: '大小',
    modifiedAt: '修改时间',
    type: '类型',
    actions: '操作',
    delete: '删除',
  },
  dialog: {
    title: '上传文档',
    description: '选择一个文件并保存到本地知识文档目录中。',
    fileLabel: '文件',
    fileHint: '上传后的文件会保留文件名和元信息。',
    cancel: '取消',
    confirm: '上传',
  },
  status: {
    loading: '正在加载文档...',
    uploading: '上传中...',
    deleting: '删除中...',
    uploadSuccess: '文档上传成功',
    deleteSuccess: '文档删除成功',
    failed: '知识文档请求失败：{error}',
  },
  common: {
    cancel: '取消',
    confirm: '确认',
  },
};

const JA_KNOWLEDGE_MESSAGES: MessageTree = {
  title: 'Knowledge Docs',
  subtitle: 'ローカルのナレッジ文書をアップロード、確認、削除できます。',
  refresh: '更新',
  upload: '文書をアップロード',
  uploadHint: 'このページは旧 Knowledge デモを置き換え、ローカル文書管理に専念します。',
  documentsLabel: 'Documents',
  storageLabel: 'Storage',
  emptyTitle: '文書がありません',
  emptyDescription: 'まずファイルをアップロードして、ローカルの knowledge docs を管理してください。',
  deleteConfirm: 'この文書を削除しますか？',
  table: {
    name: '名前',
    size: 'サイズ',
    modifiedAt: '更新日時',
    type: '種類',
    actions: '操作',
    delete: '削除',
  },
  dialog: {
    title: '文書をアップロード',
    description: 'ファイルを選んでローカルの knowledge docs ディレクトリに保存します。',
    fileLabel: 'ファイル',
    fileHint: 'アップロードしたファイルはファイル名とメタデータを保持します。',
    cancel: 'キャンセル',
    confirm: 'アップロード',
  },
  status: {
    loading: '文書を読み込み中...',
    uploading: 'アップロード中...',
    deleting: '削除中...',
    uploadSuccess: '文書をアップロードしました',
    deleteSuccess: '文書を削除しました',
    failed: 'Knowledge docs のリクエストに失敗しました: {error}',
  },
  common: {
    cancel: 'キャンセル',
    confirm: '確認',
  },
};

const KNOWLEDGE_MESSAGES: Record<LanguageCode, MessageTree> = {
  en: EN_KNOWLEDGE_MESSAGES,
  zh: ZH_KNOWLEDGE_MESSAGES,
  ja: JA_KNOWLEDGE_MESSAGES,
};

function lookupMessage(source: MessageTree, path: string): unknown {
  return path.split('.').reduce<unknown>((current, segment) => {
    if (!current || typeof current !== 'object') return undefined;
    return (current as Record<string, unknown>)[segment];
  }, source);
}

function interpolate(template: string, params?: InterpolationParams): string {
  if (!params) return template;

  return template.replace(/\{(\w+)\}/g, (_match, token) => {
    const value = params[token];
    return typeof value === 'undefined' ? `{${token}}` : String(value);
  });
}

function createKnowledgeTranslate(locale: LanguageCode): KnowledgeTranslate {
  return (path, params, fallback) => {
    const normalizedPath = normalizeKnowledgePath(path);
    const translated = lookupMessage(KNOWLEDGE_MESSAGES[locale] ?? KNOWLEDGE_MESSAGES.en, normalizedPath)
      ?? lookupMessage(KNOWLEDGE_MESSAGES.en, normalizedPath);

    if (typeof translated === 'string' || typeof translated === 'number') {
      return interpolate(String(translated), params);
    }

    return fallback ?? path;
  };
}

export function useKnowledgeCopy(): KnowledgeTranslate {
  const locale = useLocale();

  return createKnowledgeTranslate(locale);
}