/*
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
 * Digest Algorithm, as defined in RFC 1321.
 * Version 2.2 Copyright (C) Paul Johnston 1999 - 2009
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for more info.
 */

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */
let hexcase: number = 0; /* hex output format. 0 - lowercase; 1 - uppercase        */
let b64pad: string = ''; /* base-64 pad character. "=" for strict RFC compliance   */

/**
 * 这些是通常需要调用的函数
 * @param s 输入字符串
 * @returns 十六进制/BASE64/任意编码的MD5字符串
 */
function hex_md5(s: string): string {
    return rstr2hex(rstr_md5(str2rstr_utf8(s)));
}
function b64_md5(s: string): string {
    return rstr2b64(rstr_md5(str2rstr_utf8(s)));
}
function any_md5(s: string, e: string): string {
    return rstr2any(rstr_md5(str2rstr_utf8(s)), e);
}
function hex_hmac_md5(k: string, d: string): string {
    return rstr2hex(rstr_hmac_md5(str2rstr_utf8(k), str2rstr_utf8(d)));
}
function b64_hmac_md5(k: string, d: string): string {
    return rstr2b64(rstr_hmac_md5(str2rstr_utf8(k), str2rstr_utf8(d)));
}
function any_hmac_md5(k: string, d: string, e: string): string {
    return rstr2any(rstr_hmac_md5(str2rstr_utf8(k), str2rstr_utf8(d)), e);
}

/**
 * 执行简单自测，判断 VM 是否正常
 * @returns 是否通过测试
 */
function md5_vm_test(): boolean {
    return hex_md5('abc').toLowerCase() == '900150983cd24fb0d6963f7d28e17f72';
}

/**
 * 计算原始字符串的 MD5
 * @param s 原始字符串
 * @returns MD5 结果字符串
 */
function rstr_md5(s: string): string {
    return binl2rstr(binl_md5(rstr2binl(s), s.length * 8));
}

/**
 * 计算 HMAC-MD5
 * @param key 密钥
 * @param data 数据
 * @returns HMAC-MD5 结果字符串
 */
function rstr_hmac_md5(key: string, data: string): string {
    let bkey: number[] = rstr2binl(key);
    if (bkey.length > 16) bkey = binl_md5(bkey, key.length * 8);

    const ipad: number[] = Array(16),
        opad: number[] = Array(16);
    for (let i = 0; i < 16; i++) {
        ipad[i] = bkey[i] ^ 0x36363636;
        opad[i] = bkey[i] ^ 0x5c5c5c5c;
    }

    const hash: number[] = binl_md5(ipad.concat(rstr2binl(data)), 512 + data.length * 8);
    return binl2rstr(binl_md5(opad.concat(hash), 512 + 128));
}

/**
 * 原始字符串转十六进制字符串
 * @param input 输入字符串
 * @returns 十六进制字符串
 */
function rstr2hex(input: string): string {
    try {
        hexcase;
    } catch (e) {
        hexcase = 0;
    }
    const hex_tab: string = hexcase ? '0123456789ABCDEF' : '0123456789abcdef';
    let output = '';
    let x: number;
    for (let i = 0; i < input.length; i++) {
        x = input.charCodeAt(i);
        output += hex_tab.charAt((x >>> 4) & 0x0f) + hex_tab.charAt(x & 0x0f);
    }
    return output;
}

/**
 * 原始字符串转 BASE64 字符串
 * @param input 输入字符串
 * @returns BASE64 字符串
 */
function rstr2b64(input: string): string {
    try {
        b64pad;
    } catch (e) {
        b64pad = '';
    }
    const tab: string = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
    let output = '';
    const len: number = input.length;
    for (let i = 0; i < len; i += 3) {
        const triplet: number =
            (input.charCodeAt(i) << 16) |
            (i + 1 < len ? input.charCodeAt(i + 1) << 8 : 0) |
            (i + 2 < len ? input.charCodeAt(i + 2) : 0);
        for (let j = 0; j < 4; j++) {
            if (i * 8 + j * 6 > input.length * 8) output += b64pad;
            else output += tab.charAt((triplet >>> (6 * (3 - j))) & 0x3f);
        }
    }
    return output;
}

/**
 * 原始字符串转任意编码字符串
 * @param input 输入字符串
 * @param encoding 编码表
 * @returns 编码后的字符串
 */
function rstr2any(input: string, encoding: string): string {
    const divisor: number = encoding.length;
    let i: number, j: number, q: number, x: number, quotient: number[];

    /* Convert to an array of 16-bit big-endian values, forming the dividend */
    let dividend: number[] = Array(Math.ceil(input.length / 2));
    for (i = 0; i < dividend.length; i++) {
        dividend[i] = (input.charCodeAt(i * 2) << 8) | input.charCodeAt(i * 2 + 1);
    }

    /*
     * Repeatedly perform a long division. The binary array forms the dividend,
     * the length of the encoding is the divisor. Once computed, the quotient
     * forms the dividend for the next step. All remainders are stored for later
     * use.
     */
    const full_length: number = Math.ceil((input.length * 8) / (Math.log(encoding.length) / Math.log(2)));
    const remainders: number[] = Array(full_length);
    for (j = 0; j < full_length; j++) {
        quotient = [];
        x = 0;
        for (i = 0; i < dividend.length; i++) {
            x = (x << 16) + dividend[i];
            q = Math.floor(x / divisor);
            x -= q * divisor;
            if (quotient.length > 0 || q > 0) quotient[quotient.length] = q;
        }
        remainders[j] = x;
        dividend = quotient;
    }

    /* Convert the remainders to the output string */
    let output = '';
    for (i = remainders.length - 1; i >= 0; i--) output += encoding.charAt(remainders[i]);

    return output;
}

/**
 * 字符串转 UTF-8 编码
 * @param input 输入字符串
 * @returns UTF-8 编码字符串
 */
function str2rstr_utf8(input: string): string {
    let output = '';
    let i = -1;
    let x: number, y: number;

    while (++i < input.length) {
        /* Decode utf-16 surrogate pairs */
        x = input.charCodeAt(i);
        y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
        if (0xd800 <= x && x <= 0xdbff && 0xdc00 <= y && y <= 0xdfff) {
            x = 0x10000 + ((x & 0x03ff) << 10) + (y & 0x03ff);
            i++;
        }

        /* Encode output as utf-8 */
        if (x <= 0x7f) output += String.fromCharCode(x);
        else if (x <= 0x7ff) output += String.fromCharCode(0xc0 | ((x >>> 6) & 0x1f), 0x80 | (x & 0x3f));
        else if (x <= 0xffff)
            output += String.fromCharCode(0xe0 | ((x >>> 12) & 0x0f), 0x80 | ((x >>> 6) & 0x3f), 0x80 | (x & 0x3f));
        else if (x <= 0x1fffff)
            output += String.fromCharCode(
                0xf0 | ((x >>> 18) & 0x07),
                0x80 | ((x >>> 12) & 0x3f),
                0x80 | ((x >>> 6) & 0x3f),
                0x80 | (x & 0x3f)
            );
    }
    return output;
}

/**
 * 字符串转 UTF-16LE 编码
 * @param input 输入字符串
 * @returns UTF-16LE 编码字符串
 */
function str2rstr_utf16le(input: string): string {
    let output = '';
    for (let i = 0; i < input.length; i++)
        output += String.fromCharCode(input.charCodeAt(i) & 0xff, (input.charCodeAt(i) >>> 8) & 0xff);
    return output;
}

/**
 * 字符串转 UTF-16BE 编码
 * @param input 输入字符串
 * @returns UTF-16BE 编码字符串
 */
function str2rstr_utf16be(input: string): string {
    let output = '';
    for (let i = 0; i < input.length; i++)
        output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xff, input.charCodeAt(i) & 0xff);
    return output;
}

/**
 * 原始字符串转小端字数组
 * @param input 输入字符串
 * @returns 小端字数组
 */
function rstr2binl(input: string): number[] {
    const output: number[] = Array(input.length >> 2);
    for (let i = 0; i < output.length; i++) output[i] = 0;
    for (let i = 0; i < input.length * 8; i += 8) output[i >> 5] |= (input.charCodeAt(i / 8) & 0xff) << i % 32;
    return output;
}

/**
 * 小端字数组转字符串
 * @param input 小端字数组
 * @returns 字符串
 */
function binl2rstr(input: number[]): string {
    let output = '';
    for (let i = 0; i < input.length * 32; i += 8) output += String.fromCharCode((input[i >> 5] >>> i % 32) & 0xff);
    return output;
}

/**
 * 计算小端字数组的 MD5
 * @param x 小端字数组
 * @param len 位长度
 * @returns MD5 结果数组
 */
function binl_md5(x: number[], len: number): number[] {
    /* append padding */
    x[len >> 5] |= 0x80 << len % 32;
    x[(((len + 64) >>> 9) << 4) + 14] = len;

    let a = 1732584193;
    let b = -271733879;
    let c = -1732584194;
    let d = 271733878;

    for (let i = 0; i < x.length; i += 16) {
        const olda = a;
        const oldb = b;
        const oldc = c;
        const oldd = d;

        a = md5_ff(a, b, c, d, x[i + 0], 7, -680876936);
        d = md5_ff(d, a, b, c, x[i + 1], 12, -389564586);
        c = md5_ff(c, d, a, b, x[i + 2], 17, 606105819);
        b = md5_ff(b, c, d, a, x[i + 3], 22, -1044525330);
        a = md5_ff(a, b, c, d, x[i + 4], 7, -176418897);
        d = md5_ff(d, a, b, c, x[i + 5], 12, 1200080426);
        c = md5_ff(c, d, a, b, x[i + 6], 17, -1473231341);
        b = md5_ff(b, c, d, a, x[i + 7], 22, -45705983);
        a = md5_ff(a, b, c, d, x[i + 8], 7, 1770035416);
        d = md5_ff(d, a, b, c, x[i + 9], 12, -1958414417);
        c = md5_ff(c, d, a, b, x[i + 10], 17, -42063);
        b = md5_ff(b, c, d, a, x[i + 11], 22, -1990404162);
        a = md5_ff(a, b, c, d, x[i + 12], 7, 1804603682);
        d = md5_ff(d, a, b, c, x[i + 13], 12, -40341101);
        c = md5_ff(c, d, a, b, x[i + 14], 17, -1502002290);
        b = md5_ff(b, c, d, a, x[i + 15], 22, 1236535329);

        a = md5_gg(a, b, c, d, x[i + 1], 5, -165796510);
        d = md5_gg(d, a, b, c, x[i + 6], 9, -1069501632);
        c = md5_gg(c, d, a, b, x[i + 11], 14, 643717713);
        b = md5_gg(b, c, d, a, x[i + 0], 20, -373897302);
        a = md5_gg(a, b, c, d, x[i + 5], 5, -701558691);
        d = md5_gg(d, a, b, c, x[i + 10], 9, 38016083);
        c = md5_gg(c, d, a, b, x[i + 15], 14, -660478335);
        b = md5_gg(b, c, d, a, x[i + 4], 20, -405537848);
        a = md5_gg(a, b, c, d, x[i + 9], 5, 568446438);
        d = md5_gg(d, a, b, c, x[i + 14], 9, -1019803690);
        c = md5_gg(c, d, a, b, x[i + 3], 14, -187363961);
        b = md5_gg(b, c, d, a, x[i + 8], 20, 1163531501);
        a = md5_gg(a, b, c, d, x[i + 13], 5, -1444681467);
        d = md5_gg(d, a, b, c, x[i + 2], 9, -51403784);
        c = md5_gg(c, d, a, b, x[i + 7], 14, 1735328473);
        b = md5_gg(b, c, d, a, x[i + 12], 20, -1926607734);

        a = md5_hh(a, b, c, d, x[i + 5], 4, -378558);
        d = md5_hh(d, a, b, c, x[i + 8], 11, -2022574463);
        c = md5_hh(c, d, a, b, x[i + 11], 16, 1839030562);
        b = md5_hh(b, c, d, a, x[i + 14], 23, -35309556);
        a = md5_hh(a, b, c, d, x[i + 1], 4, -1530992060);
        d = md5_hh(d, a, b, c, x[i + 4], 11, 1272893353);
        c = md5_hh(c, d, a, b, x[i + 7], 16, -155497632);
        b = md5_hh(b, c, d, a, x[i + 10], 23, -1094730640);
        a = md5_hh(a, b, c, d, x[i + 13], 4, 681279174);
        d = md5_hh(d, a, b, c, x[i + 0], 11, -358537222);
        c = md5_hh(c, d, a, b, x[i + 3], 16, -722521979);
        b = md5_hh(b, c, d, a, x[i + 6], 23, 76029189);
        a = md5_hh(a, b, c, d, x[i + 9], 4, -640364487);
        d = md5_hh(d, a, b, c, x[i + 12], 11, -421815835);
        c = md5_hh(c, d, a, b, x[i + 15], 16, 530742520);
        b = md5_hh(b, c, d, a, x[i + 2], 23, -995338651);

        a = md5_ii(a, b, c, d, x[i + 0], 6, -198630844);
        d = md5_ii(d, a, b, c, x[i + 7], 10, 1126891415);
        c = md5_ii(c, d, a, b, x[i + 14], 15, -1416354905);
        b = md5_ii(b, c, d, a, x[i + 5], 21, -57434055);
        a = md5_ii(a, b, c, d, x[i + 12], 6, 1700485571);
        d = md5_ii(d, a, b, c, x[i + 3], 10, -1894986606);
        c = md5_ii(c, d, a, b, x[i + 10], 15, -1051523);
        b = md5_ii(b, c, d, a, x[i + 1], 21, -2054922799);
        a = md5_ii(a, b, c, d, x[i + 8], 6, 1873313359);
        d = md5_ii(d, a, b, c, x[i + 15], 10, -30611744);
        c = md5_ii(c, d, a, b, x[i + 6], 15, -1560198380);
        b = md5_ii(b, c, d, a, x[i + 13], 21, 1309151649);
        a = md5_ii(a, b, c, d, x[i + 4], 6, -145523070);
        d = md5_ii(d, a, b, c, x[i + 11], 10, -1120210379);
        c = md5_ii(c, d, a, b, x[i + 2], 15, 718787259);
        b = md5_ii(b, c, d, a, x[i + 9], 21, -343485551);

        a = safe_add(a, olda);
        b = safe_add(b, oldb);
        c = safe_add(c, oldc);
        d = safe_add(d, oldd);
    }
    return [a, b, c, d];
}

/**
 * 四种基本操作
 */
function md5_cmn(q: number, a: number, b: number, x: number, s: number, t: number): number {
    return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
}
function md5_ff(a: number, b: number, c: number, d: number, x: number, s: number, t: number): number {
    return md5_cmn((b & c) | (~b & d), a, b, x, s, t);
}
function md5_gg(a: number, b: number, c: number, d: number, x: number, s: number, t: number): number {
    return md5_cmn((b & d) | (c & ~d), a, b, x, s, t);
}
function md5_hh(a: number, b: number, c: number, d: number, x: number, s: number, t: number): number {
    return md5_cmn(b ^ c ^ d, a, b, x, s, t);
}
function md5_ii(a: number, b: number, c: number, d: number, x: number, s: number, t: number): number {
    return md5_cmn(c ^ (b | ~d), a, b, x, s, t);
}

/**
 * 安全整数加法，防止溢出
 * @param x 整数
 * @param y 整数
 * @returns 加法结果
 */
function safe_add(x: number, y: number): number {
    const lsw: number = (x & 0xffff) + (y & 0xffff);
    const msw: number = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xffff);
}

/**
 * 左移位操作
 * @param num 数字
 * @param cnt 位数
 * @returns 结果
 */
function bit_rol(num: number, cnt: number): number {
    return (num << cnt) | (num >>> (32 - cnt));
}

/**
 * 计算字符串的 MD5 值
 * @param str 输入字符串
 * @returns MD5 十六进制字符串
 */
function md5(str: string): string {
    return hex_md5(str);
}

export default {
    md5
};