import { get as getEmoji } from 'node-emoji';
import { emoticon } from 'emoticon';
import { findAndReplace } from 'mdast-util-find-and-replace';

const RE_EMOJI = /:\+1:|:-1:|:[\w-]+:/g;
const RE_SHORT = /[$@|*'",;.=:\-)([\]\\/<>038BOopPsSdDxXzZ]{2,5}/g;
const RE_PUNCT = /(?:_|-(?!1))/g;

const DEFAULT_SETTINGS = {
    padSpaceAfter: false,
    emoticon: false,
    accessible: false,
};

export default function plugin(options) {
    const settings = Object.assign({}, DEFAULT_SETTINGS, options);
    const pad = !!settings.padSpaceAfter;
    const emoticonEnable = !!settings.emoticon;
    const accessible = !!settings.accessible;

    function aria(text, label) {
        // Creating HTML node in Markdown node is undocumented.
        // https://github.com/syntax-tree/mdast-util-math/blob/e70bb824dc70f5423324b31b0b68581cf6698fe8/index.js#L44-L55
        return {
            type: 'text',
            meta: null,
            value: text,
            data: {
                hName: 'span',
                hProperties: {
                    role: 'img',
                    ariaLabel: label,
                },
                hChildren: [{ type: 'text', value: text }],
            },
        };
    }

    function replaceEmoticon(match) {
        // find emoji by shortcode - full match or with-out last char as it could be from text e.g. :-),
        const iconFull = emoticon.find(e => e.emoticons.includes(match)); // full match
        const iconPart = emoticon.find(e => e.emoticons.includes(match.slice(0, -1))); // second search pattern
        const icon = iconFull || iconPart;
        if (!icon) {
            return false;
        }
        const trimmedChar = !iconFull && iconPart ? match.slice(-1) : '';
        const addPad = pad ? ' ' : '';
        const replaced = icon.emoji + addPad + trimmedChar;
        if (accessible) {
            return aria(replaced, icon.name + ' emoticon');
        }
        return replaced;
    }

    function replaceEmoji(match) {
        let got = getEmoji(match);

        if (typeof got === 'undefined') {
            return false;
        }

        if (pad) {
            got = got + ' ';
        }

        if (accessible) {
            const label = match.slice(1, -1).replace(RE_PUNCT, ' ') + ' emoji';
            return aria(got, label);
        }

        return got;
    }

    const replacers = [[RE_EMOJI, replaceEmoji]];
    if (emoticonEnable) {
        replacers.push([RE_SHORT, replaceEmoticon]);
    }

    function transformer(tree) {
        findAndReplace(tree, replacers);
    }

    return transformer;
}