/*
 * This file is part of Adblock Plus <https://adblockplus.org/>,
 * Copyright (C) 2006-present eyeo GmbH
 *
 * Adblock Plus is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 *
 * Adblock Plus is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 */

"use strict";

const i18nAttributes = ["alt", "placeholder", "title", "value"];

function assignAction(elements, action)
{
  for (const element of elements)
  {
    switch (typeof action)
    {
      case "string":
        element.href = action;
        element.target = "_blank";
        break;
      case "function":
        element.href = "#";
        element.addEventListener("click", (ev) =>
        {
          ev.preventDefault();
          action();
        });
        break;
    }
  }
}

function* getRemainingLinks(parent)
{
  const links = parent.querySelectorAll("a:not([data-i18n-index])");
  for (const link of links)
  {
    yield link;
  }
}

function setElementLinks(idOrElement, ...actions)
{
  const element = typeof idOrElement === "string" ?
                  document.getElementById(idOrElement) :
                  idOrElement;

  const remainingLinks = getRemainingLinks(element);

  for (let i = 0; i < actions.length; i++)
  {
    // Assign action to links with matching index
    const links = element.querySelectorAll(`a[data-i18n-index='${i}']`);
    if (links.length)
    {
      assignAction(links, actions[i]);
      continue;
    }

    // Assign action to non-indexed link in the order they appear
    // Note that this behavior is deprecated and only exists
    // for backwards compatibility
    // https://issues.adblockplus.org/ticket/6743
    const link = remainingLinks.next();
    if (link.done)
      continue;

    assignAction([link.value], actions[i]);
  }
}

// Used for visual strings cleanup(ex. tags from messages used in alert())
// Function is not meant to be used together with `innerHTML`
function stripTagsUnsafe(text)
{
  return text.replace(/<\/?[^>]+>/g, "");
}

// Inserts i18n strings into matching elements. Any inner HTML already
// in the element is parsed as JSON and used as parameters to
// substitute into placeholders in the i18n message.
function setElementText(element, stringName, args, children = [])
{
  function processString(str, currentElement)
  {
    const match = /^(.*?)<(a|em|slot|strong)(\d)?>(.*?)<\/\2\3>(.*)$/.exec(str);
    if (match)
    {
      const [, before, name, index, innerText, after] = match;
      processString(before, currentElement);

      if (name == "slot")
      {
        const e = children[index];
        if (e)
        {
          currentElement.appendChild(e);
        }
      }
      else
      {
        const e = document.createElement(name);
        if (typeof index != "undefined")
        {
          e.dataset.i18nIndex = index;
        }
        processString(innerText, e);
        currentElement.appendChild(e);
      }

      processString(after, currentElement);
    }
    else
      currentElement.appendChild(document.createTextNode(str));
  }

  while (element.lastChild)
    element.removeChild(element.lastChild);
  processString(browser.i18n.getMessage(stringName, args), element);
}


function loadI18nStrings()
{
  function resolveStringNames(container)
  {
    {
      const elements = container.querySelectorAll("[data-i18n]");
      for (const element of elements)
      {
        const children = Array.from(element.children);
        setElementText(element, element.dataset.i18n, null, children);
      }
    }

    // Resolve texts for translatable attributes
    for (const attr of i18nAttributes)
    {
      const elements = container.querySelectorAll(`[data-i18n-${attr}]`);
      for (const element of elements)
      {
        const stringName = element.getAttribute(`data-i18n-${attr}`);
        element.setAttribute(attr, browser.i18n.getMessage(stringName));
      }
    }
  }

  resolveStringNames(document);
  // Content of Template is not rendered on runtime so we need to add
  // translation strings for each Template documentFragment content
  // individually.
  for (const template of document.querySelectorAll("template"))
    resolveStringNames(template.content);
}

function initI18n()
{
  // Getting UI locale cannot be done synchronously on Firefox,
  // requires messaging the background page. For Chrome and Safari,
  // we could get the UI locale here, but would need to duplicate
  // the logic implemented in Utils.appLocale.
  browser.runtime.sendMessage({
    type: "app.get",
    what: "localeInfo"
  })
  .then(localeInfo =>
  {
    document.documentElement.lang = localeInfo.locale;
    document.documentElement.dir = localeInfo.bidiDir;
  });

  loadI18nStrings();
}
