/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

import {
  AddonManagerListenerHandler,
  DiscoveryAPI,
} from "../aboutaddons-utils.mjs";

const { AddonManager } = ChromeUtils.importESModule(
  "resource://gre/modules/AddonManager.sys.mjs"
);

class RecommendedAddonList extends HTMLElement {
  connectedCallback() {
    if (this.isConnected) {
      this.loadCardsIfNeeded();
      this.updateCardsWithAddonManager();
    }
    AddonManagerListenerHandler.addListener(this);
  }

  disconnectedCallback() {
    AddonManagerListenerHandler.removeListener(this);
  }

  get type() {
    return this.getAttribute("type");
  }

  /**
   * Set the add-on type for this list. This will be used to filter the add-ons
   * that are displayed.
   *
   * Must be set prior to the first render.
   *
   * @param {string} val The type to filter on.
   */
  set type(val) {
    this.setAttribute("type", val);
  }

  get hideInstalled() {
    return this.hasAttribute("hide-installed");
  }

  /**
   * Set whether installed add-ons should be hidden from the list. If false,
   * installed add-ons will be shown with a "Manage" button, otherwise they
   * will be hidden.
   *
   * Must be set prior to the first render.
   *
   * @param {boolean} val Whether to show installed add-ons.
   */
  set hideInstalled(val) {
    this.toggleAttribute("hide-installed", val);
  }

  getCardById(addonId) {
    for (let card of this.children) {
      if (card.addonId === addonId) {
        return card;
      }
    }
    return null;
  }

  setAddonForCard(card, addon) {
    card.setAddon(addon);

    let wasHidden = card.hidden;
    card.hidden = this.hideInstalled && addon;

    if (wasHidden != card.hidden) {
      let eventName = card.hidden ? "card-hidden" : "card-shown";
      this.dispatchEvent(new CustomEvent(eventName, { detail: { card } }));
    }
  }

  /**
   * Whether the client ID should be preferred. This is disabled for themes
   * since they don't use the telemetry data and don't show the TAAR notice.
   */
  get preferClientId() {
    return !this.type || this.type == "extension";
  }

  async updateCardsWithAddonManager() {
    let cards = Array.from(this.children);
    let addonIds = cards.map(card => card.addonId);
    let addons = await AddonManager.getAddonsByIDs(addonIds);
    for (let [i, card] of cards.entries()) {
      let addon = addons[i];
      this.setAddonForCard(card, addon);
      if (addon) {
        // Already installed, move card to end.
        this.append(card);
      }
    }
  }

  async loadCardsIfNeeded() {
    // Use promise as guard. Also used by tests to detect when load completes.
    if (!this.cardsReady) {
      this.cardsReady = this._loadCards();
    }
    return this.cardsReady;
  }

  async _loadCards() {
    let recommendedAddons;
    try {
      recommendedAddons = await DiscoveryAPI.getResults(this.preferClientId);
    } catch (e) {
      return;
    }

    let frag = document.createDocumentFragment();
    for (let addon of recommendedAddons) {
      if (this.type && addon.type != this.type) {
        continue;
      }
      let card = document.createElement("recommended-addon-card");
      card.setDiscoAddon(addon);
      frag.append(card);
    }
    this.append(frag);
    await this.updateCardsWithAddonManager();
  }

  /**
   * AddonManager listener events.
   */

  onInstalled(addon) {
    let card = this.getCardById(addon.id);
    if (card) {
      this.setAddonForCard(card, addon);
    }
  }

  onUninstalled(addon) {
    let card = this.getCardById(addon.id);
    if (card) {
      this.setAddonForCard(card, null);
    }
  }
}
customElements.define("recommended-addon-list", RecommendedAddonList);