import { XMLElement, XMLRootElement, XMLTagType, XMLText } from './xml';

class XMLElementWithRSSUtil extends XMLElement {
  protected replaceChildByTagName(tag: string) {
    const existingEl = this.findElementChild(v => v.tagName === tag);
    if (existingEl) {
      existingEl.children.length = 0;
      existingEl.attributes.clear();
    }
    const el = existingEl ?? new XMLElement(tag);
    if (!existingEl)
      this.child(el)
    return el
  }
}
export class RSSItemElement extends XMLElementWithRSSUtil {
  public constructor(title: string | null, description: string | null, link: string | URL | null) {
    super("item");
    if (title !== null)
      this.title(title);
    if (description !== null)
      this.description(description)
    if (link !== null)
      this.link(link)
  }
  /** Replaces the title of the item */
  public title(title: string) {
    this.replaceChildByTagName('title').child(new XMLText(title))
    return this;
  }
  /** Replaces the link to the item */
  public link(link: string | URL) {
    this.replaceChildByTagName('link').child(new XMLText(typeof link === 'string' ? link : link.href))
    return this;
  }
  /** Sets the description of the item, replacing it if it already exists */
  public description(description: string) {
    this.replaceChildByTagName('description').child(new XMLText(description))
    return this;
  }
  /** Sets the URL for the comment section of an item, replacing it if it already exists */
  public comments(comments: string | URL) {
    return this.child(new XMLElement('comments').child(new XMLText(typeof comments === 'string' ? comments : comments.href)));
  }
  /** Sets the timestamp where the most recent item in the channel was published, replacing it if it already exists */
  public pubDate(pubDate: Date) {
    this.replaceChildByTagName('pubDate').child(new XMLText(pubDate.toUTCString()))
    return this;
  }
  /** Specifies a third-party source for the item. */
  public source(sourceName: string, sourceUrl: string | URL) {
    return this.child(new XMLElement('source').attribute('url', typeof sourceUrl === 'string' ? sourceUrl : sourceUrl.href).child(new XMLText(sourceName)))
  }
  /** Adds a category to the post */
  public category(
    category: string,
  ) {
    return this.child(new XMLElement('category').child(new XMLText(category)));
  }
  /** Adds a author to the post */
  public author(
    author: string,
  ) {
    return this.child(new XMLElement('author').child(new XMLText(author)));
  }
  /** Adds a unique ID to the post. This ID must be globally unique, but has no format specifications. */
  public guid(
    id: string,
    /** If this is a permanent link to the post. If true, this must be a URL that permanently points to this item. */
    isPermaLink: boolean
  ) {
    return this.child(new XMLElement('guid').child(new XMLText(id)).attribute('isPermaLink', isPermaLink ? 'true' : 'false'));
  }
  /** Adds a media file to be included with an item */
  public enclosure(
    url: string,
    mimeType: string,
    /** in bytes */
    length: number
  ) {
    return this.child(
      new XMLElement('enclosure')
        .attribute('url', url)
        .attribute('length', length.toString())
        .attribute('type', mimeType)
    )
  }
}
export class RSSChannelElement extends XMLElementWithRSSUtil {
  public constructor(title: string | null, description: string | null, link: URL | string | null) {
    super("channel");
    if (title !== null)
      this.title(title);
    if (description !== null)
      this.description(description)
    if (link !== null)
      this.link(link)
  }
  /** Replaces the title of the channel */
  public title(title: string) {
    this.replaceChildByTagName('title').child(new XMLText(title))
    return this;
  }
  /** Replaces the link to the channel */
  public link(link: string | URL) {
    this.replaceChildByTagName('link').child(new XMLText(typeof link === 'string' ? link : link.href))
    return this;
  }
  /** Sets the description of the channel, replacing it if it already exists */
  public description(description: string) {
    this.replaceChildByTagName('description').child(new XMLText(description))
    return this;
  }
  /** Sets the timestamp where the most recent item in the channel was published, replacing it if it already exists */
  public pubDate(pubDate: Date) {
    this.replaceChildByTagName('pubDate').child(new XMLText(pubDate.toUTCString()))
    return this;
  }
  /** Sets the timestamp where the RSS file was last modified in any way, replacing it if it already exists */
  public lastBuildDate(lastBuildDate: Date) {
    this.replaceChildByTagName('lastBuildDate').child(new XMLText(lastBuildDate.toUTCString()))
    return this;
  }
  /** Sets the time to live for the channel - the maximum time until clients should re-fetch it, replacing it if it already exists */
  public ttl(ttl: number) {
    this.replaceChildByTagName('ttl').child(new XMLText(ttl.toString()))
    return this;
  }
  /** Adds the copyright information of the channel */
  public copyright(copyright: string) {
    return this.child(new XMLElement('copyright').child(new XMLText(copyright)))
  }
  /** Adds the generator used for this RSS feed - we recommend calling this and keeping it at .rsstrogen() - Can be called multiple times */
  public generator(generator: string = 'rsstrogen') {
    return this.child(new XMLElement('generator').child(new XMLText(generator)));
  }
  /** Adds the webmaster managing this feed's email address */
  public webmaster(webmaster: string) {
    return this.child(new XMLElement('webMaster').child(new XMLText(webmaster)))
  }
  /** Adds the managing editor managing this feed's email address */
  public managingEditor(managingEditor: string) {
    return this.child(new XMLElement('managingEditor').child(new XMLText(managingEditor)))
  }
  /**
   * Adds a URL of an image to be displayed when aggregators present a feed
   * 
   * **Note:** The image must be of type GIF, JPEG or PNG.
   */
  public image(image: {
    /** Defines the hyperlink to the website that offers the channel */
    link: string;
    /** Defines the text to display if the image could not be shown and/or for screen readers */
    alt: string;
    /** Specifies the URL to the image */
    url: URL | string;
    /** Specifies the text in the HTML title attribute of the link around the image. Defaults to the value of alt */
    description?: string | null;
    /** The resolution of the image. Per Spec: Default is 88x31, Max is 144x400. */
    resolution?: [width: number, height: number]
  }) {
    const img = new XMLElement('image').child(
      new XMLElement('link').child(new XMLText(image.link)),
      new XMLElement('title').child(new XMLText(image.alt)),
      new XMLElement('url').child(new XMLText(typeof image.url === 'string' ? image.url : image.url.href)),
    );
    if (image.description !== null)
      img.child(
        new XMLElement('description').child(new XMLText(image.description ?? image.alt)),
      );
    if (image.resolution)
      img.child(
        new XMLElement('width').child(new XMLText(image.resolution[0].toString())),
        new XMLElement('height').child(new XMLText(image.resolution[1].toString())),
      );
    return this.child(img);
  }
  /** Sets (or specifies an additional) language for the feed */
  public language(language: RSSLanguageCode) {
    return this.child(new XMLElement('language').child(new XMLText(language)));
  }
  /** Specifies a search engine/text input should be specified with the feed */
  public search(engine: {
    /** @default "Search" */
    title?: string,
    /** @example "Search Neobot Systems" */
    description: string,
    /** @example "https://search.example.com/search?" */
    link: string,
    /** @example "query" */
    param: string,
  }) {
    this.replaceChildByTagName('textInput').child(
      new XMLElement('title').child(new XMLText(engine.title ?? 'Search')),
      new XMLElement('description').child(new XMLText(engine.description)),
      new XMLElement('link').child(new XMLText(engine.link)),
      new XMLElement('name').child(new XMLText(engine.param)),
    );
    return this;
  }
  /** Adds a category to the feed */
  public category(
    category: string,
    /** Optional - A string or URL that identifies a categorization taxonomy. */
    domain?: string
  ) {
    const cat = new XMLElement('category');
    if (domain !== undefined) cat.attribute('domain', domain)
    this.child(cat.child(new XMLText(category)))
    return this;
  }
  // TODO: add more tags
  /** Adds items to the RSS feed */
  public items(...items: RSSItemElement[]) {
    return this.child(...items);
  }
}
export class RSSRootElement extends XMLRootElement {
  public constructor() {
    super("rss")
    this
      .attribute("version", "2.0")
      .xmlns("content", "http://purl.org/rss/1.0/modules/content/")
  }
  public channel(...channels: RSSChannelElement[]) {
    return this.child(...channels)
  }
}

/** @link https://www.rssboard.org/rss-language-codes */
export type RSSLanguageCode = 'af' | 'sq' | 'eu' | 'be' | 'bg' | 'ca' | 'zh-cn' | 'zh-tw' | 'hr' | 'cs' | 'da' | 'nl' | 'nl-be' | 'nl-nl' | 'en' | 'en-au' | 'en-bz' | 'en-ca' | 'en-ie' | 'en-jm' | 'en-nz' | 'en-ph' | 'en-za' | 'en-tt' | 'en-gb' | 'en-us' | 'en-zw' | ' et' | 'fo' | 'fi' | 'fr' | 'fr-be' | 'fr-ca' | 'fr-fr' | 'fr-lu' | 'fr-mc' | 'fr-ch' | 'gl' | 'gd' | 'de' | 'de-at' | 'de-de' | 'de-li' | 'de-lu' | 'de-ch' | 'el' | 'haw' | 'hu' | 'is' | 'in' | 'ga' | 'it' | 'it-it' | 'it-ch' | 'ja' | 'ko' | 'mk' | 'no' | 'pl' | 'pt' | 'pt-br' | 'pt-pt' | 'ro' | 'ro-mo' | 'ro-ro' | 'ru' | 'ru-mo' | 'ru-ru' | 'sr' | 'sk' | 'sl' | 'es' | 'es-ar' | 'es-bo' | 'es-cl' | 'es-co' | 'es-cr' | 'es-do' | 'es-ec' | 'es-sv' | 'es-gt' | 'es-hn' | 'es-mx' | 'es-ni' | 'es-pa' | 'es-py' | 'es-pe' | 'es-pr' | 'es-es' | 'es-uy' | 'es-ve' | 'sv' | 'sv-fi' | 'sv-se' | 'tr' | 'uk'