/* global View, Sanitizer, LazyLoader */
'use strict';

var HomeView = View.extend(function HomeView() {
  View.call(this); // super();

  this.thumbnailCache = {};

  this.tiles = document.getElementById('tiles');

  this.tiles.addEventListener('click', (evt) => {
    var link = evt.target.closest('a[data-file-path]');
    if (link) {
      this.queueAlbum(link.dataset.filePath);
    }
  });

  this.onScroll = debounce(this.loadVisibleImages.bind(this), 500);
  window.addEventListener('scroll', () => this.onScroll());
  this.client.on('databaseChange', () => this.update());

  // Two phase setup prevents non-critical
  // work blocking getting content on the screen
  this.update()
    .then(() => this.lazyLoadScripts());
});

/**
 * List of scripts that can be
 * lazy-loaded after the critical
 * path has completed.
 *
 * @type {Array}
 */
HomeView.prototype.nonCriticalScripts = [
  '/components/dom-scheduler/lib/dom-scheduler.js',
  '/components/fast-list/fast-list.js',
  '/components/poplar/poplar.js',
  '/components/gaia-component/gaia-component.js',
  '/components/gaia-text-input/gaia-text-input.js',
  '/components/gaia-fast-list/gaia-fast-list.js',
  '/components/gaia-sub-header/gaia-sub-header.js',
  '/elements/music-search-box.js',
  '/elements/music-search-results.js'
];

/**
 * Setup everything that is not
 * critical for first-paint.
 *
 * @return {Promise}
 */
HomeView.prototype.lazyLoadScripts = function() {
  return new Promise((resolve) => {
    setTimeout(() => {
      LazyLoader.load(this.nonCriticalScripts).then(() => {
        this.setupSearch();
        resolve();
      });
    }, 500);
  });
};

HomeView.prototype.setupSearch = function() {
  this.searchBox = document.getElementById('search-box');
  this.searchResults = document.getElementById('search-results');
  this.searchBoxHeight = this.searchBox.HEIGHT + 11;// 10px padding + 1px border

  this.searchBox.addEventListener('search', (evt) => this.search(evt.detail));

  this.searchResults.addEventListener('open', () => {
    this.client.method('searchOpen');
    document.body.dataset.search = true;
    document.body.classList.add('search-open');
  });

  this.searchResults.addEventListener('close', () => {
    this.client.method('searchClose');
    document.body.dataset.search = false;
    document.body.classList.remove('search-open');
    window.scrollTo(0, this.searchBoxHeight);
  });

  this.searchResults.addEventListener('resultclick', (evt) => {
    var link = evt.detail;
    if (link) {
      if (link.dataset.section === 'songs') {
        this.queueSong(link.dataset.filePath);
      }

      this.client.method('navigate', link.getAttribute('href'));
    }
  });

  this.searchResults.getItemImageSrc = (item) => this.getThumbnail(item.name);
  this.searchBox.hidden = false;
  window.scrollTo(0, this.searchBoxHeight);
};

HomeView.prototype.update = function() {
  return this.getAlbums().then((albums) => {
    this.albums = albums;
    return this.render();
  });
};

HomeView.prototype.loadVisibleImages = function() {
  var scrollTop = window.scrollY;
  var scrollBottom = scrollTop + window.innerHeight;
  var promises = [];

  var tiles = this.tiles.querySelectorAll('.tile');
  var lastTileVisible = false;
  var tile, tileOffset;

  for (var i = 0, length = tiles.length; i < length; i++) {
    tile = tiles[i];
    tileOffset = tile.offsetTop;

    if (scrollTop <= tileOffset && tileOffset <= scrollBottom) {
      lastTileVisible = true;
      promises.push(this.loadTile(tile));
    }

    else if (lastTileVisible) {
      break;
    }
  }

  return Promise.all(promises);
};

HomeView.prototype.loadTile = function(tile) {
  return new Promise((resolve) => {
    if (tile.dataset.loaded) {
      return;
    }

    this.getThumbnail(tile.dataset.filePath).then((url) => {
      var img = tile.querySelector('img');
      img.src = url;
      tile.dataset.loaded = true;
      img.onload = () => {
        setTimeout(() => {
          requestAnimationFrame(() => {
            tile.classList.add('loaded');
            resolve();
          });
        });
      };
    });
  });
};

HomeView.prototype.destroy = function() {
  this.client.destroy();

  View.prototype.destroy.call(this); // super(); // Always call *last*
};

HomeView.prototype.render = function() {
  return document.l10n.formatValues(
    'unknownArtist', 'unknownAlbum'
  ).then(([unknownArtist, unknownAlbum]) => {
    var html = [];

    this.albums.forEach((album) => {
      var template =
Sanitizer.createSafeHTML `
<a class="${album.metadata.picture ? 'tile' : 'tile show-title'}" dir="auto"
   href="/player"
   data-artist="${album.metadata.artist || unknownArtist}"
   data-album="${album.metadata.album || unknownAlbum}"
   data-file-path="${album.name}">
  <img>
</a>`;

      html.push(template);
    });

    this.tiles.innerHTML = Sanitizer.unwrapSafeHTML(...html);
    return Promise.all([
      this.loadVisibleImages(),
      document.l10n.ready
    ]);
  }).then(this.onRenderDone);
};

HomeView.prototype.getAlbums = function() {
  return this.fetch('/api/albums/list').then(response => response.json());
};

HomeView.prototype.getThumbnail = function(filePath) {
  if (!filePath) return;

  if (this.thumbnailCache[filePath]) {
    return Promise.resolve(this.thumbnailCache[filePath]);
  }

  return this.fetch('/api/artwork/url/thumbnail/' + filePath)
    .then((response) => response.json())
    .then((url) => {
      this.thumbnailCache[filePath] = url;
      return url;
    });
};

HomeView.prototype.queueAlbum = function(filePath) {
  this.fetch('/api/queue/album/' + filePath);
};

HomeView.prototype.queueSong = function(filePath) {
  this.fetch('/api/queue/song/' + filePath);
};

HomeView.prototype.search = function(query) {
  if (!query) {
    return Promise.resolve(this.searchResults.clearResults());
  }

  var results = [];

  return document.l10n.formatValues(
    'unknownTitle', 'unknownArtist', 'unknownAlbum'
  ).then(([unknownTitle, unknownArtist, unknownAlbum]) => {
    var albumResults = this.fetch('/api/search/album/' + query)
      .then(response => response.json())
      .then((albums) => {
        var albumResults = albums.map((album) => {
          return {
            name:     album.name,
            title:    album.metadata.album  || unknownAlbum,
            subtitle: album.metadata.artist || unknownArtist,
            section:  'albums',
            url:      '/album-detail?id=' + encodeURIComponent(album.name)
          };
        });

        results = results.concat(albumResults);

        this.searchResults.setResults(results);
        return albumResults;
      });

    var artistResults = this.fetch('/api/search/artist/' + query)
      .then(response => response.json())
      .then((artists) => {
        var artistResults = artists.map((artist) => {
          return {
            name:     artist.name,
            title:    artist.metadata.artist || unknownArtist,
            subtitle: '',
            section:  'artists',
            url:      '/artist-detail?id=' + encodeURIComponent(artist.name)
          };
        });

        results = results.concat(artistResults);

        this.searchResults.setResults(results);
        return artistResults;
      });

    var songResults = this.fetch('/api/search/title/' + query)
      .then(response => response.json())
      .then((songs) => {
        var songResults = songs.map((song) => {
          return {
            name:     song.name,
            title:    song.metadata.title  || unknownTitle,
            subtitle: song.metadata.artist || unknownArtist,
            section:  'songs',
            url:      '/player'
          };
        });

        results = results.concat(songResults);

        this.searchResults.setResults(results);
        return songResults;
      });

    return Promise.all([albumResults, artistResults, songResults]).then(() => {
      return results;
    });
  });
};

function debounce(fn, ms) {
  var timeout;
  return (...args) => {
    clearTimeout(timeout);
    timeout = setTimeout(() => fn.apply(this, args), ms);
  };
}

window.view = new HomeView();