/**
 * @author n1474335 [n1474335@gmail.com]
 * @copyright Crown Copyright 2016
 * @license Apache-2.0
 */

import Operation from "../Operation";
import Utils from "../Utils";

/**
 * From HTML Entity operation
 */
class FromHTMLEntity extends Operation {

    /**
     * FromHTMLEntity constructor
     */
    constructor() {
        super();

        this.name = "From HTML Entity";
        this.module = "Default";
        this.description = "Converts HTML entities back to characters<br><br>e.g. <code>&amp;<span>amp;</span></code> becomes <code>&amp;</code>";
        this.inputType = "string";
        this.outputType = "string";
        this.args = [];
        this.patterns = [
            {
                match: "&(?:#\\d{2,3}|#x[\\da-f]{2}|[a-z]{2,6});",
                flags: "i",
                args: []
            },
        ];
    }

    /**
     * @param {string} input
     * @param {Object[]} args
     * @returns {string}
     */
    run(input, args) {
        const regex = /&(#?x?[a-zA-Z0-9]{1,8});/g;
        let output = "",
            m,
            i = 0;

        while ((m = regex.exec(input))) {
            // Add up to match
            for (; i < m.index;)
                output += input[i++];

            // Add match
            const bite = entityToByte[m[1]];
            if (bite) {
                output += Utils.chr(bite);
            } else if (!bite && m[1][0] === "#" && m[1].length > 1 && /^#\d{1,6}$/.test(m[1])) {
                // Numeric entity (e.g. &#10;)
                const num = m[1].slice(1, m[1].length);
                output += Utils.chr(parseInt(num, 10));
            } else if (!bite && m[1][0] === "#" && m[1].length > 3 && /^#x[\dA-F]{2,8}$/i.test(m[1])) {
                // Hex entity (e.g. &#x3A;)
                const hex = m[1].slice(2, m[1].length);
                output += Utils.chr(parseInt(hex, 16));
            } else {
                // Not a valid entity, print as normal
                for (; i < regex.lastIndex;)
                    output += input[i++];
            }

            i = regex.lastIndex;
        }
        // Add all after final match
        for (; i < input.length;)
            output += input[i++];

        return output;
    }

}


/**
 * Lookup table to translate HTML entity codes to their byte values.
 */
const entityToByte = {
    "quot": 34,
    "amp": 38,
    "apos": 39,
    "lt": 60,
    "gt": 62,
    "nbsp": 160,
    "iexcl": 161,
    "cent": 162,
    "pound": 163,
    "curren": 164,
    "yen": 165,
    "brvbar": 166,
    "sect": 167,
    "uml": 168,
    "copy": 169,
    "ordf": 170,
    "laquo": 171,
    "not": 172,
    "shy": 173,
    "reg": 174,
    "macr": 175,
    "deg": 176,
    "plusmn": 177,
    "sup2": 178,
    "sup3": 179,
    "acute": 180,
    "micro": 181,
    "para": 182,
    "middot": 183,
    "cedil": 184,
    "sup1": 185,
    "ordm": 186,
    "raquo": 187,
    "frac14": 188,
    "frac12": 189,
    "frac34": 190,
    "iquest": 191,
    "Agrave": 192,
    "Aacute": 193,
    "Acirc": 194,
    "Atilde": 195,
    "Auml": 196,
    "Aring": 197,
    "AElig": 198,
    "Ccedil": 199,
    "Egrave": 200,
    "Eacute": 201,
    "Ecirc": 202,
    "Euml": 203,
    "Igrave": 204,
    "Iacute": 205,
    "Icirc": 206,
    "Iuml": 207,
    "ETH": 208,
    "Ntilde": 209,
    "Ograve": 210,
    "Oacute": 211,
    "Ocirc": 212,
    "Otilde": 213,
    "Ouml": 214,
    "times": 215,
    "Oslash": 216,
    "Ugrave": 217,
    "Uacute": 218,
    "Ucirc": 219,
    "Uuml": 220,
    "Yacute": 221,
    "THORN": 222,
    "szlig": 223,
    "agrave": 224,
    "aacute": 225,
    "acirc": 226,
    "atilde": 227,
    "auml": 228,
    "aring": 229,
    "aelig": 230,
    "ccedil": 231,
    "egrave": 232,
    "eacute": 233,
    "ecirc": 234,
    "euml": 235,
    "igrave": 236,
    "iacute": 237,
    "icirc": 238,
    "iuml": 239,
    "eth": 240,
    "ntilde": 241,
    "ograve": 242,
    "oacute": 243,
    "ocirc": 244,
    "otilde": 245,
    "ouml": 246,
    "divide": 247,
    "oslash": 248,
    "ugrave": 249,
    "uacute": 250,
    "ucirc": 251,
    "uuml": 252,
    "yacute": 253,
    "thorn": 254,
    "yuml": 255,
    "OElig": 338,
    "oelig": 339,
    "Scaron": 352,
    "scaron": 353,
    "Yuml": 376,
    "fnof": 402,
    "circ": 710,
    "tilde": 732,
    "Alpha": 913,
    "Beta": 914,
    "Gamma": 915,
    "Delta": 916,
    "Epsilon": 917,
    "Zeta": 918,
    "Eta": 919,
    "Theta": 920,
    "Iota": 921,
    "Kappa": 922,
    "Lambda": 923,
    "Mu": 924,
    "Nu": 925,
    "Xi": 926,
    "Omicron": 927,
    "Pi": 928,
    "Rho": 929,
    "Sigma": 931,
    "Tau": 932,
    "Upsilon": 933,
    "Phi": 934,
    "Chi": 935,
    "Psi": 936,
    "Omega": 937,
    "alpha": 945,
    "beta": 946,
    "gamma": 947,
    "delta": 948,
    "epsilon": 949,
    "zeta": 950,
    "eta": 951,
    "theta": 952,
    "iota": 953,
    "kappa": 954,
    "lambda": 955,
    "mu": 956,
    "nu": 957,
    "xi": 958,
    "omicron": 959,
    "pi": 960,
    "rho": 961,
    "sigmaf": 962,
    "sigma": 963,
    "tau": 964,
    "upsilon": 965,
    "phi": 966,
    "chi": 967,
    "psi": 968,
    "omega": 969,
    "thetasym": 977,
    "upsih": 978,
    "piv": 982,
    "ensp": 8194,
    "emsp": 8195,
    "thinsp": 8201,
    "zwnj": 8204,
    "zwj": 8205,
    "lrm": 8206,
    "rlm": 8207,
    "ndash": 8211,
    "mdash": 8212,
    "lsquo": 8216,
    "rsquo": 8217,
    "sbquo": 8218,
    "ldquo": 8220,
    "rdquo": 8221,
    "bdquo": 8222,
    "dagger": 8224,
    "Dagger": 8225,
    "bull": 8226,
    "hellip": 8230,
    "permil": 8240,
    "prime": 8242,
    "Prime": 8243,
    "lsaquo": 8249,
    "rsaquo": 8250,
    "oline": 8254,
    "frasl": 8260,
    "euro": 8364,
    "image": 8465,
    "weierp": 8472,
    "real": 8476,
    "trade": 8482,
    "alefsym": 8501,
    "larr": 8592,
    "uarr": 8593,
    "rarr": 8594,
    "darr": 8595,
    "harr": 8596,
    "crarr": 8629,
    "lArr": 8656,
    "uArr": 8657,
    "rArr": 8658,
    "dArr": 8659,
    "hArr": 8660,
    "forall": 8704,
    "part": 8706,
    "exist": 8707,
    "empty": 8709,
    "nabla": 8711,
    "isin": 8712,
    "notin": 8713,
    "ni": 8715,
    "prod": 8719,
    "sum": 8721,
    "minus": 8722,
    "lowast": 8727,
    "radic": 8730,
    "prop": 8733,
    "infin": 8734,
    "ang": 8736,
    "and": 8743,
    "or": 8744,
    "cap": 8745,
    "cup": 8746,
    "int": 8747,
    "there4": 8756,
    "sim": 8764,
    "cong": 8773,
    "asymp": 8776,
    "ne": 8800,
    "equiv": 8801,
    "le": 8804,
    "ge": 8805,
    "sub": 8834,
    "sup": 8835,
    "nsub": 8836,
    "sube": 8838,
    "supe": 8839,
    "oplus": 8853,
    "otimes": 8855,
    "perp": 8869,
    "sdot": 8901,
    "vellip": 8942,
    "lceil": 8968,
    "rceil": 8969,
    "lfloor": 8970,
    "rfloor": 8971,
    "lang": 9001,
    "rang": 9002,
    "loz": 9674,
    "spades": 9824,
    "clubs": 9827,
    "hearts": 9829,
    "diams": 9830,
};

export default FromHTMLEntity;