declare type presetId = string;

declare interface Preset {
  // translation source's id, only accpet en words
  // and "_" as separator
  readonly id: presetId;
  // extends a full preset, by source's id
  // must be set in children preset
  readonly extends?: presetId;

  [index: string]: any;
}

declare type sourceId = presetId;

declare interface SourcePreset extends Preset {
  readonly id: sourceId;

  readonly extends?: sourceId;

  // display name
  readonly name?: string;

  // query.<type>.url can override this
  url: string;

  // request method
  method?: 'get' | 'post' | string;

  // translation request
  // if false, use xhr or fetch by "url" and
  // parser's selectors as Dom selector
  query: {
    text: TextQuery;
    audio?: AudioQuery;
  } | false;

  // parse response result
  // must be set in parent preset, optional in children
  // preset which has extends
  parser: { [name: string]: selector; };

  // test parser's item whether got vaild result or not
  // use string as RegExp param: '\\w\\W+'  
  // use custom placeholder repeat default: ['.+', 'Not Existed']
  test?: { [name: string]: string | [string, string]; };

  // support ['auto:>AUTO', 'zh-cn:>zh-CHS', ...]
  // or [['auto', 'AUTO'], ['zh-cn', 'zh-CHS'], ...]
  // or [[{ code: 'auto' }, { code: 'AUTO' }], ...]
  modify?: string[] |
    Array<Language['code'][]> |
    Array<[
      { code: Language['code'], name?: Language['name'], locale?: Language['locale'] },
      { code?: Language['code'], name?: Language['name'], locale?: Language['locale'] }
    ]>;

  // initial translating direction
  fromto: [Language['code'], Language['code']];

  // just include necessary languages
  // if not exist, load all of languages
  include?: Array<Language['code']>;

  // invalid when "include" is set
  // if exist, exclude from all languages
  exclude?: Array<Language['code']>;

  // custom all languages that your preset needs
  languages?: Array<Language>;
}

declare interface Language {
  readonly code: string; // standard language code
  readonly name: string; // show when has not "locale"
  readonly locale?: string; // for i18n translation
}

declare type queryParams = string | { [param: string]: string | string[]; } | string[][];
declare interface TextQuery {
  method: 'get' | 'post' | string;
  url: string;
  params?: queryParams;
  unsupport?: Language['code'][];
}

declare interface AudioQuery extends TextQuery {
  // Feature: not implement
  tune?: {
    volume: number; // float number, minimum: 0 ~ maximum: 1
  };
}

// object index such as "a.b.c" or Dom selecotr
declare type selector = string | string[] | undefined;

declare type templateId = presetId;

declare interface LayoutPreset extends Preset {
  id: templateId;
  extends?: templateId;

  // layout
  rows: string[][];

  // check has or not existed "keys" in result. such as
  // expect ['phonetic', 'translation'] in result { phonetic: '...', translation: '...' } is true
  expect?: string[],

  // replace string while result's item got unexpect things
  // string: as placeholder if no content
  // string[]: [regexp string for test, regexp string as replace rule, replaceing string]
  // undefined: ignore this one
  replace?: (string | string[] | undefined)[];

  title?: string;
  description?: string;
}