const crypto = require('crypto');

function createPlayerPlaylistService(options) {
  const pool = options && options.pool ? options.pool : null;
  const common = options && options.common ? options.common : null;

  if (!pool) {
    throw new Error('pool is required');
  }
  if (!common) {
    throw new Error('common is required');
  }

  async function buildScreenPlaylist(slug) {
    const [screenRows] = await pool.query('SELECT id, name, slug, playlist_id, created_at, modified_at, created_by, modified_by FROM screens WHERE slug = ?', [slug]);
    if (!screenRows.length) {
      return { screen: null, playlist: null, slides: [] };
    }

    const screen = screenRows[0];
    if (!screen.playlist_id) {
      return {
        screen: screen,
        playlist: null,
        slides: [],
        revision: getPlaylistRevision(screen, null, [], [], [])
      };
    }

    const [playlistRows] = await pool.query('SELECT id, name, fade_between_slides, created_at, modified_at, created_by, modified_by FROM playlists WHERE id = ?', [screen.playlist_id]);
    const playlist = playlistRows[0] || null;
    const [slideRows] = await pool.query(`
      SELECT sl.id, sl.title, sl.body, sl.template_id, sl.content_json, sl.media_path, sl.media_type, sl.created_at, sl.modified_at,
             ps.position, ps.duration_seconds AS duration_seconds, ps.schedule_mode, ps.schedule_start_datetime, ps.schedule_end_datetime, ps.schedule_start_time, ps.schedule_end_time, ps.schedule_days_json,
             st.name AS template_name, cs.name AS canvas_size_name, cs.width AS canvas_size_width, cs.height AS canvas_size_height, cs.width AS canvas_width, cs.height AS canvas_height
      FROM playlist_slides ps
      JOIN slides sl ON sl.id = ps.slide_id
      LEFT JOIN slide_templates st ON st.id = sl.template_id
      LEFT JOIN canvas_sizes cs ON cs.id = st.canvas_size_id
      WHERE ps.playlist_id = ?
      ORDER BY ps.position ASC, ps.id ASC
    `, [screen.playlist_id]);

    const templateIds = slideRows
      .filter(function (slide) { return slide.template_id; })
      .map(function (slide) { return slide.template_id; });
    const templatesById = {};
    let templateRows = [];
    let regionRows = [];
    if (templateIds.length) {
      [templateRows] = await pool.query(`
              SELECT st.id, st.name, st.canvas_size_id, st.background_image_path, st.background_color, st.created_at, st.modified_at,
               cs.name AS canvas_size_name, cs.width AS canvas_size_width, cs.height AS canvas_size_height, cs.width AS canvas_width, cs.height AS canvas_height
        FROM slide_templates st
        LEFT JOIN canvas_sizes cs ON cs.id = st.canvas_size_id
        WHERE st.id IN (?)
      `, [templateIds]);
      [regionRows] = await pool.query('SELECT id, template_id, region_key, region_type, label, font_family, x, y, width, height, z_index, created_at, modified_at, created_by, modified_by FROM slide_template_regions WHERE template_id IN (?) ORDER BY template_id ASC, z_index ASC, id ASC', [templateIds]);
      templateRows.forEach(function (template) {
        template.regions = regionRows.filter(function (region) { return region.template_id === template.id; });
        templatesById[template.id] = template;
      });
    }

    const slides = slideRows.map(function (slide) {
      return {
        id: slide.id,
        title: slide.title,
        body: slide.body,
        duration_seconds: slide.duration_seconds,
        schedule_mode: slide.schedule_mode,
        schedule_start_datetime: slide.schedule_start_datetime,
        schedule_end_datetime: slide.schedule_end_datetime,
        schedule_start_time: slide.schedule_start_time,
        schedule_end_time: slide.schedule_end_time,
        schedule_days_json: slide.schedule_days_json,
        media_url: slide.media_path,
        media_type: slide.media_type,
        kind: common.mediaKind(slide.media_path),
        template_id: slide.template_id,
        template: slide.template_id ? templatesById[slide.template_id] || null : null,
        content: common.parseJsonSafe(slide.content_json) || {}
      };
    });

    const revision = getPlaylistRevision(screen, playlist, slideRows, templateRows, regionRows);

    return { screen: screen, playlist: playlist, slides: slides, revision: revision };
  }

  function updatePlaylistRevisionHash(hash, value) {
    hash.update(String(value === null || value === undefined ? '' : value));
    hash.update('\0');
  }

  function getPlaylistRevision(screen, playlist, slideRows, templateRows, regionRows) {
    const hash = crypto.createHash('sha1');

    updatePlaylistRevisionHash(hash, screen && screen.id);
    updatePlaylistRevisionHash(hash, screen && screen.playlist_id);
    updatePlaylistRevisionHash(hash, screen && screen.modified_at);

    updatePlaylistRevisionHash(hash, playlist && playlist.id);
    updatePlaylistRevisionHash(hash, playlist && playlist.modified_at);
    updatePlaylistRevisionHash(hash, playlist && playlist.fade_between_slides);

    (Array.isArray(slideRows) ? slideRows : []).forEach(function (slide) {
      updatePlaylistRevisionHash(hash, slide.id);
      updatePlaylistRevisionHash(hash, slide.title);
      updatePlaylistRevisionHash(hash, slide.body);
      updatePlaylistRevisionHash(hash, slide.template_id);
      updatePlaylistRevisionHash(hash, slide.content_json);
      updatePlaylistRevisionHash(hash, slide.media_path);
      updatePlaylistRevisionHash(hash, slide.media_type);
      updatePlaylistRevisionHash(hash, slide.modified_at);
      updatePlaylistRevisionHash(hash, slide.position);
      updatePlaylistRevisionHash(hash, slide.duration_seconds);
      updatePlaylistRevisionHash(hash, slide.schedule_mode);
      updatePlaylistRevisionHash(hash, slide.schedule_start_datetime);
      updatePlaylistRevisionHash(hash, slide.schedule_end_datetime);
      updatePlaylistRevisionHash(hash, slide.schedule_start_time);
      updatePlaylistRevisionHash(hash, slide.schedule_end_time);
      updatePlaylistRevisionHash(hash, slide.schedule_days_json);
    });

    (Array.isArray(templateRows) ? templateRows : []).forEach(function (template) {
      updatePlaylistRevisionHash(hash, template.id);
      updatePlaylistRevisionHash(hash, template.name);
      updatePlaylistRevisionHash(hash, template.canvas_size_id);
      updatePlaylistRevisionHash(hash, template.canvas_size_width);
      updatePlaylistRevisionHash(hash, template.canvas_size_height);
      updatePlaylistRevisionHash(hash, template.background_image_path);
      updatePlaylistRevisionHash(hash, template.background_color);
      updatePlaylistRevisionHash(hash, template.modified_at);
    });

    (Array.isArray(regionRows) ? regionRows : []).forEach(function (region) {
      updatePlaylistRevisionHash(hash, region.id);
      updatePlaylistRevisionHash(hash, region.template_id);
      updatePlaylistRevisionHash(hash, region.region_key);
      updatePlaylistRevisionHash(hash, region.region_type);
      updatePlaylistRevisionHash(hash, region.label);
      updatePlaylistRevisionHash(hash, region.font_family);
      updatePlaylistRevisionHash(hash, region.x);
      updatePlaylistRevisionHash(hash, region.y);
      updatePlaylistRevisionHash(hash, region.width);
      updatePlaylistRevisionHash(hash, region.height);
      updatePlaylistRevisionHash(hash, region.z_index);
      updatePlaylistRevisionHash(hash, region.modified_at);
    });

    return hash.digest('hex');
  }

  return {
    buildScreenPlaylist: buildScreenPlaylist
  };
}

module.exports = {
  createPlayerPlaylistService: createPlayerPlaylistService
};