/*
Copyright 2019 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import EMOJIBASE from 'emojibase-data/en/compact.json';
import SHORTCODES from 'emojibase-data/en/shortcodes/iamcal.json';

export interface IEmoji {
    annotation: string;
    group?: number;
    hexcode: string;
    order?: number;
    tags?: string[];
    unicode: string;
    emoticon?: string;
}

interface IEmojiWithFilterString extends IEmoji {
    filterString?: string;
}

// The unicode is stored without the variant selector
const UNICODE_TO_EMOJI = new Map<string, IEmojiWithFilterString>(); // not exported as gets for it are handled by getEmojiFromUnicode
export const EMOTICON_TO_EMOJI = new Map<string, IEmojiWithFilterString>();

export const getEmojiFromUnicode = unicode => UNICODE_TO_EMOJI.get(stripVariation(unicode));

const toArray = (shortcodes?: string | string[]): string[] =>
    typeof shortcodes === "string" ? [shortcodes] : (shortcodes ?? []);
export const getShortcodes = (emoji: IEmoji): string[] =>
    toArray(SHORTCODES[emoji.hexcode]);

const EMOJIBASE_GROUP_ID_TO_CATEGORY = [
    "people", // smileys
    "people", // actually people
    "control", // modifiers and such, not displayed in picker
    "nature",
    "foods",
    "places",
    "activity",
    "objects",
    "symbols",
    "flags",
];

export const DATA_BY_CATEGORY = {
    "people": [],
    "nature": [],
    "foods": [],
    "places": [],
    "activity": [],
    "objects": [],
    "symbols": [],
    "flags": [],
};

const ZERO_WIDTH_JOINER = "\u200D";

// Store various mappings from unicode/emoticon/shortcode to the Emoji objects
EMOJIBASE.forEach((emoji: IEmojiWithFilterString) => {
    const shortcodes = getShortcodes(emoji);
    const categoryId = EMOJIBASE_GROUP_ID_TO_CATEGORY[emoji.group];
    if (DATA_BY_CATEGORY.hasOwnProperty(categoryId)) {
        DATA_BY_CATEGORY[categoryId].push(emoji);
    }

    // This is used as the string to match the query against when filtering emojis
    emoji.filterString = (`${emoji.annotation}\n${shortcodes.join('\n')}}\n${emoji.emoticon || ''}\n` +
        `${emoji.unicode.split(ZERO_WIDTH_JOINER).join("\n")}`).toLowerCase();

    // Add mapping from unicode to Emoji object
    // The 'unicode' field that we use in emojibase has either
    // VS15 or VS16 appended to any characters that can take
    // variation selectors. Which one it appends depends
    // on whether emojibase considers their type to be 'text' or
    // 'emoji'. We therefore strip any variation chars from strings
    // both when building the map and when looking up.
    UNICODE_TO_EMOJI.set(stripVariation(emoji.unicode), emoji);

    if (emoji.emoticon) {
        // Add mapping from emoticon to Emoji object
        EMOTICON_TO_EMOJI.set(emoji.emoticon, emoji);
    }
});

/**
 * Strips variation selectors from the end of given string
 * NB. Skin tone modifiers are not variation selectors:
 * this function does not touch them. (Should it?)
 *
 * @param {string} str string to strip
 * @returns {string} stripped string
 */
function stripVariation(str) {
    return str.replace(/[\uFE00-\uFE0F]$/, "");
}

export const EMOJI: IEmoji[] = EMOJIBASE;