/* global hexo */

'use strict';

const { resolve, basename } = require('path');
const { readFileSync } = require('fs');
const cheerio = require('cheerio');
const lunr = require('lunr');
const full_url_for = hexo.extend.helper.get('full_url_for').bind(hexo);

const localizedPath = ['tutorials', 'filters', 'tags', 'playground', 'api'];

hexo.extend.helper.register('page_nav', function() {
  const type = this.page.canonical_path.split('/')[0];
  const sidebar = this.site.data.sidebar[type];
  const path = basename(this.path);
  const list = {};
  const prefix = 'sidebar.' + type + '.';

  for (const i in sidebar) {
    if (typeof sidebar[i] === 'string') list[sidebar[i]] = i;
    else for (const j in sidebar[i]) list[sidebar[i][j]] = j;
  }

  const keys = Object.keys(list);
  const index = keys.indexOf(path);
  let result = '';

  if (index > 0) {
    result += `<a href="${keys[index - 1]}" class="article-footer-prev" title="${this.__(prefix + list[keys[index - 1]])}"><i class="icon-chevron-left"></i><span>${this.__('page.prev')}</span></a>`;
  }

  if (index < keys.length - 1) {
    result += `<a href="${keys[index + 1]}" class="article-footer-next" title="${this.__(prefix + list[keys[index + 1]])}"><span>${this.__('page.next')}</span><i class="icon-chevron-right"></i></a>`;
  }

  return result;
});

hexo.extend.helper.register('raw', function(filepath) {
  const content = readFileSync(resolve(this.view_dir, filepath));
  return content;
});

hexo.extend.helper.register('doc_sidebar', function(className) {
  const type = this.page.canonical_path.split('/')[0];
  const sidebar = this.site.data.sidebar[type];
  const path = basename(this.path);
  let result = '';
  const self = this;
  const prefix = 'sidebar.' + type + '.';

  if (typeof sidebar === 'undefined') {
    return '';
  }

  for (const [title, menu] of Object.entries(sidebar)) {
    if (typeof menu === 'string') renderLink(title, menu);
    else renderSection(title, menu);
  }

  return result;

  function renderLink(text, link) {
    let itemClass = className + '-link';
    if (link === path) itemClass += ' current';

    const localized = self.__(prefix + text) === prefix + text ? text : self.__(prefix + text);
    result += '<a href="' + link + '" class="' + itemClass + '">' + localized + '</a>';
  }

  function renderSection(title, menu) {
    result += '<strong class="' + className + '-title">' + self.__(prefix + title) + '</strong>';
    for (const [text, link] of Object.entries(menu)) renderLink(text, link);
  }
});

hexo.extend.helper.register('header_menu', function(className) {
  const menu = this.site.data.menu;
  let result = '';
  const self = this;
  const lang = this.page.lang;
  const isEnglish = lang === 'en';

  for (const [title, path] of Object.entries(menu)) {
    let langPath = path;
    if (!isEnglish && ~localizedPath.indexOf(title)) langPath = lang + path;
    const url = self.url_for(langPath);
    const active = ('/' + this.page.canonical_path).slice(0, path.length) === path ? ' active' : '';
    result += `<a href="${url}" class="${className}-link${active}">${self.__('menu.' + title)}</a>`;
  }

  return result;
});

hexo.extend.helper.register('canonical_url', function(lang) {
  let path = this.page.path;
  if (lang && lang !== 'en') path = lang + '/' + path;

  return full_url_for(path);
});

hexo.extend.helper.register('url_for_lang', function(path) {
  const lang = this.page.lang;
  let url = this.url_for(path);

  if (lang !== 'en' && path[0] === '/') url = '/' + lang + path;

  return url;
});

hexo.extend.helper.register('raw_link', path => `https://github.com/hexojs/site/edit/master/source/${path}`);

hexo.extend.helper.register('page_anchor', str => {
  const $ = cheerio.load(str, {decodeEntities: false});
  const headings = $('h1, h2, h3, h4, h5, h6');

  if (!headings.length) return str;

  headings.each(function() {
    const id = $(this).attr('id');

    $(this)
      .addClass('article-heading')
      .append(`<a class="article-anchor" href="#${id}" aria-hidden="true"></a>`);
  });

  return $.html();
});

// Will be replace with full_url_for after hexo v4 release
hexo.extend.helper.register('canonical_path_for_nav', function() {
  const path = this.page.canonical_path;
  for (const slug of localizedPath) if (path.startsWith(slug)) return path;
  return '';
});

hexo.extend.helper.register('lang_name', function(lang) {
  const data = this.site.data.languages[lang];
  return data.name || data;
});

hexo.extend.helper.register('hexo_version', function() {
  return this.env.version;
});