import { parseViews } from './numbers.js';
import { parseVideoLink } from './video-id.js';
import { readVidiqData } from './vidiq.js';

export const LINK_SELECTOR = 'a[href*="/watch?v="], a[href*="/shorts/"]';
export const CARD_SELECTOR = [
  'ytd-rich-item-renderer',
  'ytd-video-renderer',
  'ytd-compact-video-renderer',
  'ytd-grid-video-renderer',
  'yt-lockup-view-model',
  'ytm-shorts-lockup-view-model',
  'ytd-reel-item-renderer',
].join(',');

// Spans that hold the channel name, the view count and the age in the new and old card layouts.
const METADATA_TEXT = '.ytContentMetadataViewModelMetadataText, .inline-metadata-item, #metadata-line span';
const CHANNEL_LINK = 'a[href^="/@"], a[href^="/channel/"], a[href^="/c/"], a[href^="/user/"]';
const RELATIVE_TIME = /назад|(^|\s)ago(\s|$)/i;

// VidIQ puts its own text (subscribers, VPH, score) inside `.vidiq-scope`; it must not be read as YouTube's.
const outsideVidiq = (element) => !element.closest('.vidiq-scope');

function readTitle(card) {
  const heading = card.querySelector('h3[title]')?.getAttribute('title')?.trim();
  if (heading) return heading;
  const oldTitle = card.querySelector('#video-title');
  const oldText = (oldTitle?.getAttribute('title') || oldTitle?.textContent || '').trim();
  if (oldText) return oldText;
  return card.querySelector('.ytLockupMetadataViewModelTitle')?.textContent.trim() || null;
}

function readThumbnail(card, videoId) {
  const image = card.querySelector('img[src^="https://i.ytimg.com/vi/"], img[src^="https://i.ytimg.com/vi_webp/"]');
  return image ? image.src : `https://i.ytimg.com/vi/${videoId}/mqdefault.jpg`;
}

function readViews(card) {
  for (const element of card.querySelectorAll(METADATA_TEXT)) {
    if (!outsideVidiq(element)) continue;
    const views = parseViews(element.textContent) ?? parseViews(element.getAttribute('aria-label'));
    if (views !== null) return views;
  }
  return null;
}

function absoluteChannelUrl(href) {
  try {
    const url = new URL(href, 'https://www.youtube.com');
    return url.origin + url.pathname;
  } catch {
    return null;
  }
}

function readChannel(card, context) {
  const link = [...card.querySelectorAll(CHANNEL_LINK)].find((a) => outsideVidiq(a) && a.textContent.trim());
  if (link) return { channelTitle: link.textContent.trim(), channelUrl: absoluteChannelUrl(link.getAttribute('href')) };

  // New layouts show the channel name as plain text: the first metadata text that is neither a count nor an age.
  for (const element of card.querySelectorAll(METADATA_TEXT)) {
    const text = element.textContent.trim();
    if (outsideVidiq(element) && text && parseViews(text) === null && !RELATIVE_TIME.test(text)) {
      return { channelTitle: text, channelUrl: context?.channelUrl ?? null };
    }
  }
  return { channelTitle: context?.channelTitle ?? null, channelUrl: context?.channelUrl ?? null };
}

// Reads one video card. `context` supplies the channel on channel pages, where cards do not name it.
export function scrapeCard(card, link, context = null) {
  const parsed = parseVideoLink(link.getAttribute('href'));
  if (!parsed) return null;
  const { outlierScore, subscribers } = readVidiqData(card);
  const { channelTitle, channelUrl } = readChannel(card, context);
  return {
    videoId: parsed.videoId,
    isShort: parsed.isShort,
    title: readTitle(card),
    thumbnailUrl: readThumbnail(card, parsed.videoId),
    channelTitle,
    channelUrl,
    subscribers,
    views: readViews(card),
    outlierScore,
  };
}