'use strict';
const { volumeKey } = require('../../chapter-identity');
const { batchFlags } = require('../../chapter-dates');

// First-party, pure parsing functions. This module never fetches remote content.
const decode = value => value.replace(/&amp;/g, '&').replace(/&#39;/g, "'").replace(/&quot;/g, '"').replace(/<[^>]+>/g, '').trim();
const absolute = (base, value) => new URL(value, base).href;

function series({ html, url }) {
  const title = decode(html.match(/<h1\b[^>]*>([\s\S]*?)<\/h1>/i)?.[1] || 'Untitled');
  const listUrl = html.match(/hx-get="([^"]+\/full-chapter-list)"/i)?.[1];
  return { title, listUrl: listUrl ? absolute(url, listUrl) : null };
}

function catalog({ html, url }) {
  const found = [];
  const re = /<a\b[^>]*href="([^"]*\/chapters\/([A-Z0-9]+)[^"]*)"[^>]*>([\s\S]*?)<\/a>/gi;
  for (const match of html.matchAll(re)) {
    const text = decode(match[3]).replace(/\s+/g, ' ');
    const season = Number(text.match(/^S(\d+)\s*-/i)?.[1] || 0) || null;
    const regular = text.match(/\b(?:Chapter|Rating|Episode|Night|Log|Act|Scene|Kapitel|File|Battle)\s*[.:]?\s*([0-9]+(?:\.[0-9]+)?)/i)?.[1];
    const volume = !regular ? text.match(/^Volume\s+([0-9]+(?:\.[0-9]+)?)(?!\d)/i)?.[1] : null;
    const prologue = text.match(/Prologue(?:\s+([0-9]+))?/i)?.[1];
    const number = regular || (prologue ? `0.${prologue.padStart(2, '0')}` : /Prologue/i.test(text) ? '0' : null);
    // The full chapter list carries each upload time; the chapter page itself has none.
    const uploaded = match[3].match(/datetime="([^"]+)"/i)?.[1];
    const uploadedAt = uploaded && Number.isFinite(Date.parse(uploaded)) ? uploaded : undefined;
    if (number) found.push({
      id: match[2], number, title: regular ? '' : `Prologue ${prologue || ''}`.trim(),
      ...(season ? { book: { number: season, title: `Season ${season}` } } : {}),
      url: absolute(url, match[1]), raw: text, ...(uploadedAt ? { uploadedAt } : {}),
    });
    else if (volume) found.push({
      id: match[2], number: volumeKey(match[2]), title: '', special: true,
      label: `Volume ${volume}`, releaseKind: 'volume', volume,
      book: { number: Number(volume), title: `Volume ${volume}` },
      url: absolute(url, match[1]), raw: text, ...(uploadedAt ? { uploadedAt } : {}),
    });
  }
  const chapters = [...new Map(found.map(chapter => [chapter.id, chapter])).values()];
  // Back-catalog chapters were imported together; their upload time is not a release date.
  batchFlags(chapters.map(chapter => chapter.uploadedAt)).forEach((batch, index) => {
    if (batch !== null) chapters[index].uploadBatch = batch;
  });
  const chapterLinks = [...html.matchAll(/<a\b[^>]*href="[^"]*\/chapters\/[A-Z0-9]+[^"]*"/gi)].length;
  return { chapters, chapterLinks };
}

function chapter({ html, url }) {
  return {
    manifestUrl: html.match(/['"](https?:\/\/weebcentral\.com\/chapters\/[^'"]+\/images\?is_prev=[^'"]+)['"]/i)?.[1]
      || `${url}/images?is_prev=False`,
  };
}

function pages({ html, url }) {
  const urls = [];
  for (const match of html.matchAll(/<img\b[^>]*(?:src|data-src)="([^"]+)"/gi)) {
    const pageUrl = absolute(url, match[1].replace(/&amp;/g, '&'));
    if (!pageUrl.startsWith('data:')) urls.push(pageUrl);
  }
  return { pages: [...new Set(urls)] };
}

module.exports = { series, catalog, chapter, pages };