import Trie from "substring-trie";

import { assetHost } from "mastodon/utils/config";

import { autoPlayGif } from "../../initial_state";

import unicodeMapping from "./emoji_unicode_mapping_light";

const trie = new Trie(Object.keys(unicodeMapping));

// Convert to file names from emojis. (For different variation selector emojis)
const emojiFilenames = (emojis) => {
  return emojis.map(v => unicodeMapping[v].filename);
};

// Emoji requiring extra borders depending on theme
const darkEmoji = emojiFilenames(["🎱", "🐜", "⚫", "🖤", "⬛", "◼️", "◾", "◼️", "✒️", "▪️", "💣", "🎳", "📷", "📸", "♣️", "🕶️", "✴️", "🔌", "💂‍♀️", "📽️", "🍳", "🦍", "💂", "🔪", "🕳️", "🕹️", "🕋", "🖊️", "🖋️", "💂‍♂️", "🎤", "🎓", "🎥", "🎼", "♠️", "🎩", "🦃", "📼", "📹", "🎮", "🐃", "🏴", "🐞", "🕺", "📱", "📲", "🚲"]);
const lightEmoji = emojiFilenames(["👽", "⚾", "🐔", "☁️", "💨", "🕊️", "👀", "🍥", "👻", "🐐", "❕", "❔", "⛸️", "🌩️", "🔊", "🔇", "📃", "🌧️", "🐏", "🍚", "🍙", "🐓", "🐑", "💀", "☠️", "🌨️", "🔉", "🔈", "💬", "💭", "🏐", "🏳️", "⚪", "⬜", "◽", "◻️", "▫️"]);

const emojiFilename = (filename) => {
  const borderedEmoji = (document.body && document.body.classList.contains("theme-mastodon-light")) ? lightEmoji : darkEmoji;
  return borderedEmoji.includes(filename) ? (filename + "_border") : filename;
};

const emojifyTextNode = (node, customEmojis) => {
  const VS15 = 0xFE0E;
  const VS16 = 0xFE0F;

  let str = node.textContent;

  const fragment = new DocumentFragment();
  let i = 0;

  for (;;) {
    let unicode_emoji;

    // Skip to the next potential emoji to replace (either custom emoji or custom emoji :shortcode:
    if (customEmojis === null) {
      while (i < str.length && !(unicode_emoji = trie.search(str.slice(i)))) {
        i += str.codePointAt(i) < 65536 ? 1 : 2;
      }
    } else {
      while (i < str.length && str[i] !== ":" && !(unicode_emoji = trie.search(str.slice(i)))) {
        i += str.codePointAt(i) < 65536 ? 1 : 2;
      }
    }

    // We reached the end of the string, nothing to replace
    if (i === str.length) {
      break;
    }

    let rend, replacement = null;
    if (str[i] === ":") { // Potentially the start of a custom emoji :shortcode:
      rend = str.indexOf(":", i + 1) + 1;

      // no matching ending ':', skip
      if (!rend) {
        i++;
        continue;
      }

      const shortcode = str.slice(i, rend);
      const custom_emoji = customEmojis[shortcode];

      // not a recognized shortcode, skip
      if (!custom_emoji) {
        i++;
        continue;
      }

      // now got a replacee as ':shortcode:'
      // if you want additional emoji handler, add statements below which set replacement and return true.
      const filename = autoPlayGif ? custom_emoji.url : custom_emoji.static_url;
      replacement = document.createElement("img");
      replacement.setAttribute("draggable", "false");
      replacement.setAttribute("class", "emojione custom-emoji");
      replacement.setAttribute("alt", shortcode);
      replacement.setAttribute("title", shortcode);
      replacement.setAttribute("src", filename);
      replacement.setAttribute("data-original", custom_emoji.url);
      replacement.setAttribute("data-static", custom_emoji.static_url);
    } else { // start of an unicode emoji
      rend = i + unicode_emoji.length;

      // If the matched character was followed by VS15 (for selecting text presentation), skip it.
      if (str.codePointAt(rend - 1) !== VS16 && str.codePointAt(rend) === VS15) {
        i = rend + 1;
        continue;
      }

      const { filename, shortCode } = unicodeMapping[unicode_emoji];
      const title = shortCode ? `:${shortCode}:` : "";

      replacement = document.createElement("img");
      replacement.setAttribute("draggable", "false");
      replacement.setAttribute("class", "emojione");
      replacement.setAttribute("alt", unicode_emoji);
      replacement.setAttribute("title", title);
      replacement.setAttribute("src", `${assetHost}/emoji/${emojiFilename(filename)}.svg`);
    }

    // Add the processed-up-to-now string and the emoji replacement
    fragment.append(document.createTextNode(str.slice(0, i)));
    fragment.append(replacement);
    str = str.slice(rend);
    i = 0;
  }

  fragment.append(document.createTextNode(str));
  node.parentElement.replaceChild(fragment, node);
};

const emojifyNode = (node, customEmojis) => {
  for (const child of node.childNodes) {
    switch(child.nodeType) {
      case Node.TEXT_NODE:
        emojifyTextNode(child, customEmojis);
        break;
      case Node.ELEMENT_NODE:
        if (!child.classList.contains("invisible")) {
          emojifyNode(child, customEmojis);
        }
        break;
    }
  }
};

const emojify = (str, customEmojis = {}) => {
  const wrapper = document.createElement("div");
  wrapper.innerHTML = str;

  if (!Object.keys(customEmojis).length) {
    customEmojis = null;
  }

  emojifyNode(wrapper, customEmojis);

  return wrapper.innerHTML;
};

export default emojify;

export const buildCustomEmojis = (customEmojis) => {
  const emojis = [];

  customEmojis.forEach(emoji => {
    const shortcode = emoji.get("shortcode");
    const url       = autoPlayGif ? emoji.get("url") : emoji.get("static_url");
    const name      = shortcode.replace(":", "");

    emojis.push({
      id: name,
      name,
      short_names: [name],
      text: "",
      emoticons: [],
      keywords: [name],
      imageUrl: url,
      custom: true,
      customCategory: emoji.get("category"),
    });
  });

  return emojis;
};

export const categoriesFromEmojis = customEmojis => customEmojis.reduce((set, emoji) => set.add(emoji.get("category") ? `custom-${emoji.get("category")}` : "custom"), new Set(["custom"]));