const visit = require('unist-util-visit');
const emoji = require('node-emoji');
const emoticon = require('emoticon');

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

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

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

    function getEmojiByShortCode(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 trimmedChar = iconPart ? match.slice(-1): '';
        const addPad = pad ? ' ': '';
        let icon = iconFull ?
            iconFull.emoji + addPad: 
            iconPart && (iconPart.emoji + addPad +  trimmedChar);
        return icon || match;
    }

    function getEmoji(match) {
        const got = emoji.get(match);
        if (pad && got !== match) {
            return got + ' ';
        }
        return got;
    }

    function transformer(tree) {
        visit(tree, 'text', function(node) {
            node.value = node.value.replace(RE_EMOJI, getEmoji);
            
            if (emoticonEnable) {
                node.value = node.value.replace(RE_SHORT, getEmojiByShortCode);
            }
        });
    }

    return transformer;
}

module.exports = plugin;