/*
 * comment-reaction.js -- Simple emoji picker and glue for reaction endpoint
 * Copyright © 2023 Jakob L. Kreuze <zerodaysfordays@sdf.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program 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 this program. If not, see
 * <http://www.gnu.org/licenses/>.
 */

function encodeAsFormData(obj) {
  // Turn the data object into an array of URL-encoded key/value pairs.
  let urlEncodedDataPairs = [];
  for (let key in obj) {
    urlEncodedDataPairs.push(encodeURIComponent(key) + '=' + encodeURIComponent(obj[key]));
  }
  return urlEncodedDataPairs.join('&');
}

function postReaction(reaction, callback) {
  let xhr = new XMLHttpRequest();
  xhr.open('POST', "/api/comment/react", true);

  // Endpoint expects HTML form data.
  xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');

  xhr.onload = function(data) {
    switch (xhr.status) {
    case 200:
      callback();
      break;
    case 429:
      alert("Failed -- you can react at most once an hour.");
      break;
    default:
      let resp = JSON.parse(xhr.response);
      alert("Failed -- " + resp.error);
      break;
    }
  }
  xhr.onerror = function(error) {
    throw new Error(`Request failed: ${error}`);
  }

  xhr.send(encodeAsFormData(reaction));
}

function selectorWidgetName(id) {
  return `emoji-picker-${id}`;
}

// Simple Emoji picker widget.
function selectorWidget(id) {
  function emojiButton(codepoint) {
    let span = document.createElement("span");
    span.innerHTML = String.fromCodePoint(codepoint);
    return span;
  }

  let selector = document.createElement("div");
  selector.setAttribute("id", selectorWidgetName(id));
  selector.setAttribute("class", "emoji-picker");

  for (let i = 0x1F600; i < 0x1F64F; i++) {
    selector.appendChild(emojiButton(i));
  }
  selector.appendChild(emojiButton(0x1F37B));
  selector.appendChild(emojiButton(0x1F440));
  selector.appendChild(emojiButton(0x1F446));
  selector.appendChild(emojiButton(0x1F447));
  selector.appendChild(emojiButton(0x1F448));
  selector.appendChild(emojiButton(0x1F449));
  selector.appendChild(emojiButton(0x1F450));
  selector.appendChild(emojiButton(0x270A));
  selector.appendChild(emojiButton(0x270B));
  selector.appendChild(emojiButton(0x270C));
  selector.appendChild(emojiButton(0x270D));
  for (let i = 0x1F90C; i < 0x1F9FF; i++) {
    selector.appendChild(emojiButton(i));
  }
  return selector;
}

// Add a "react" button to every local comment.
window.addEventListener("load", () => {
  // Unhide additional comment actions if Javascript is enabled.
  let additionalActionsRows = document.querySelectorAll(".comment-additional-actions");
  for (let row of additionalActionsRows) {
    row.removeAttribute("hidden");
  }

  let reactButtons = document.querySelectorAll(".comment-react-button");
  for (let button of reactButtons) {
    let id = button.getAttribute("data-reply-to-id");

    button.addEventListener('click', (e) => {
      // If we already made a selector widget for this comment, let's "hide" the
      // one that exists.
      let existingSelectorWidget = document.getElementById(selectorWidgetName(id));
      if (existingSelectorWidget !== null) {
        existingSelectorWidget.remove();
        e.preventDefault();
        return;
      }

      let emojiPicker = selectorWidget(id);
      button.parentNode.parentNode.insertBefore(emojiPicker, button.parentNode);
      for (let button of emojiPicker.children) {
        button.addEventListener('click', (e) => {
          postReaction({
            "id": button.getAttribute("data-react-to-id"),
            "reaction": button.innerHTML
          }, () => {
            let reactAcknowledgement = document.createElement("span");
            reactAcknowledgement.innerHTML = "successfully reacted!"
            button.replaceWith(reactAcknowledgement);
          });
          emojiPicker.remove();
        });
      }

      e.preventDefault();
    });
  }
});