'use strict';

var rlp = require('rlp');

var BN = require('../node_modules/elliptic/node_modules/bn.js/lib/bn.js');
var hash = require('../node_modules/elliptic/node_modules/hash.js/lib/hash.js');


// See: https://github.com/emn178/js-sha3
var padding = [1, 256, 65536, 16777216];
var HEX_CHARS = '0123456789abcdef'.split('');
var SHIFT = [0, 8, 16, 24];
var RC = [1, 0, 32898, 0, 32906, 2147483648, 2147516416, 2147483648, 32907, 0, 2147483649,
          0, 2147516545, 2147483648, 32777, 2147483648, 138, 0, 136, 0, 2147516425, 0,
          2147483658, 0, 2147516555, 0, 139, 2147483648, 32905, 2147483648, 32771,
          2147483648, 32770, 2147483648, 128, 2147483648, 32778, 0, 2147483658, 2147483648,
          2147516545, 2147483648, 32896, 2147483648, 2147483649, 0, 2147516424, 2147483648];

var blocks = [], s = [];

function keccak(message) {

    var block, code, end = false, index = 0, start = 0, length = message.length,
        n, i, h, l, c0, c1, c2, c3, c4, c5, c6, c7, c8, c9,
        b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17,
        b18, b19, b20, b21, b22, b23, b24, b25, b26, b27, b28, b29, b30, b31, b32, b33,
        b34, b35, b36, b37, b38, b39, b40, b41, b42, b43, b44, b45, b46, b47, b48, b49;
    var blockCount = 34;
    var byteCount = blockCount * 4;

    for (i = 0; i < 50; ++i) { s[i] = 0; }

    block = 0;
    do {
        blocks[0] = block;
        for (i = 1; i < blockCount + 1; ++i) { blocks[i] = 0; }

        for (i = start; index < length && i < byteCount; ++index) {
            blocks[i >> 2] |= message[index] << SHIFT[i++ & 3];
        }

        start = i - byteCount;
        if (index == length) {
            blocks[i >> 2] |= padding[i & 3];
            ++index;
        }

        block = blocks[blockCount];
        if (index > length && i < byteCount) {
            blocks[blockCount - 1] |= 0x80000000;
            end = true;
        }

        for (i = 0;i < blockCount;++i) { s[i] ^= blocks[i]; }

        for (n = 0; n < 48; n += 2) {
            c0 = s[0] ^ s[10] ^ s[20] ^ s[30] ^ s[40];
            c1 = s[1] ^ s[11] ^ s[21] ^ s[31] ^ s[41];
            c2 = s[2] ^ s[12] ^ s[22] ^ s[32] ^ s[42];
            c3 = s[3] ^ s[13] ^ s[23] ^ s[33] ^ s[43];
            c4 = s[4] ^ s[14] ^ s[24] ^ s[34] ^ s[44];
            c5 = s[5] ^ s[15] ^ s[25] ^ s[35] ^ s[45];
            c6 = s[6] ^ s[16] ^ s[26] ^ s[36] ^ s[46];
            c7 = s[7] ^ s[17] ^ s[27] ^ s[37] ^ s[47];
            c8 = s[8] ^ s[18] ^ s[28] ^ s[38] ^ s[48];
            c9 = s[9] ^ s[19] ^ s[29] ^ s[39] ^ s[49];

            h = c8 ^ ((c2 << 1) | (c3 >>> 31));
            l = c9 ^ ((c3 << 1) | (c2 >>> 31));
            s[0] ^= h;      s[1] ^= l;      s[10] ^= h;     s[11] ^= l;
            s[20] ^= h;     s[21] ^= l;     s[30] ^= h;     s[31] ^= l;
            s[40] ^= h;     s[41] ^= l;
            h = c0 ^ ((c4 << 1) | (c5 >>> 31));
            l = c1 ^ ((c5 << 1) | (c4 >>> 31));
            s[2] ^= h;       s[3] ^= l;      s[12] ^= h;    s[13] ^= l;
            s[22] ^= h;      s[23] ^= l;     s[32] ^= h;    s[33] ^= l;
            s[42] ^= h;      s[43] ^= l;
            h = c2 ^ ((c6 << 1) | (c7 >>> 31));
            l = c3 ^ ((c7 << 1) | (c6 >>> 31));
            s[4] ^= h;       s[5] ^= l;       s[14] ^= h;   s[15] ^= l;
            s[24] ^= h;      s[25] ^= l;      s[34] ^= h;   s[35] ^= l;
            s[44] ^= h;      s[45] ^= l;
            h = c4 ^ ((c8 << 1) | (c9 >>> 31));
            l = c5 ^ ((c9 << 1) | (c8 >>> 31));
            s[6] ^= h;       s[7] ^= l;       s[16] ^= h;   s[17] ^= l;
            s[26] ^= h;      s[27] ^= l;      s[36] ^= h;   s[37] ^= l;
            s[46] ^= h;      s[47] ^= l;
            h = c6 ^ ((c0 << 1) | (c1 >>> 31));
            l = c7 ^ ((c1 << 1) | (c0 >>> 31));
            s[8] ^= h;       s[9] ^= l;       s[18] ^= h;   s[19] ^= l;
            s[28] ^= h;      s[29] ^= l;      s[38] ^= h;   s[39] ^= l;
            s[48] ^= h;      s[49] ^= l;

            b0 = s[0];       b1 = s[1];
            b32 = (s[11] << 4) | (s[10] >>> 28);
            b33 = (s[10] << 4) | (s[11] >>> 28);
            b14 = (s[20] << 3) | (s[21] >>> 29);
            b15 = (s[21] << 3) | (s[20] >>> 29);
            b46 = (s[31] << 9) | (s[30] >>> 23);
            b47 = (s[30] << 9) | (s[31] >>> 23);
            b28 = (s[40] << 18) | (s[41] >>> 14);
            b29 = (s[41] << 18) | (s[40] >>> 14);
            b20 = (s[2] << 1) | (s[3] >>> 31);
            b21 = (s[3] << 1) | (s[2] >>> 31);
            b2 = (s[13] << 12) | (s[12] >>> 20);
            b3 = (s[12] << 12) | (s[13] >>> 20);
            b34 = (s[22] << 10) | (s[23] >>> 22);
            b35 = (s[23] << 10) | (s[22] >>> 22);
            b16 = (s[33] << 13) | (s[32] >>> 19);
            b17 = (s[32] << 13) | (s[33] >>> 19);
            b48 = (s[42] << 2) | (s[43] >>> 30);
            b49 = (s[43] << 2) | (s[42] >>> 30);
            b40 = (s[5] << 30) | (s[4] >>> 2);
            b41 = (s[4] << 30) | (s[5] >>> 2);
            b22 = (s[14] << 6) | (s[15] >>> 26);
            b23 = (s[15] << 6) | (s[14] >>> 26);
            b4 = (s[25] << 11) | (s[24] >>> 21);
            b5 = (s[24] << 11) | (s[25] >>> 21);
            b36 = (s[34] << 15) | (s[35] >>> 17);
            b37 = (s[35] << 15) | (s[34] >>> 17);
            b18 = (s[45] << 29) | (s[44] >>> 3);
            b19 = (s[44] << 29) | (s[45] >>> 3);
            b10 = (s[6] << 28) | (s[7] >>> 4);
            b11 = (s[7] << 28) | (s[6] >>> 4);
            b42 = (s[17] << 23) | (s[16] >>> 9);
            b43 = (s[16] << 23) | (s[17] >>> 9);
            b24 = (s[26] << 25) | (s[27] >>> 7);
            b25 = (s[27] << 25) | (s[26] >>> 7);
            b6 = (s[36] << 21) | (s[37] >>> 11);
            b7 = (s[37] << 21) | (s[36] >>> 11);
            b38 = (s[47] << 24) | (s[46] >>> 8);
            b39 = (s[46] << 24) | (s[47] >>> 8);
            b30 = (s[8] << 27) | (s[9] >>> 5);
            b31 = (s[9] << 27) | (s[8] >>> 5);
            b12 = (s[18] << 20) | (s[19] >>> 12);
            b13 = (s[19] << 20) | (s[18] >>> 12);
            b44 = (s[29] << 7) | (s[28] >>> 25);
            b45 = (s[28] << 7) | (s[29] >>> 25);
            b26 = (s[38] << 8) | (s[39] >>> 24);
            b27 = (s[39] << 8) | (s[38] >>> 24);
            b8 = (s[48] << 14) | (s[49] >>> 18);
            b9 = (s[49] << 14) | (s[48] >>> 18);

            s[0] = b0 ^ (~b2 & b4);         s[1] = b1 ^ (~b3 & b5);
            s[10] = b10 ^ (~b12 & b14);     s[11] = b11 ^ (~b13 & b15);
            s[20] = b20 ^ (~b22 & b24);     s[21] = b21 ^ (~b23 & b25);
            s[30] = b30 ^ (~b32 & b34);     s[31] = b31 ^ (~b33 & b35);
            s[40] = b40 ^ (~b42 & b44);     s[41] = b41 ^ (~b43 & b45);
            s[2] = b2 ^ (~b4 & b6);         s[3] = b3 ^ (~b5 & b7);
            s[12] = b12 ^ (~b14 & b16);     s[13] = b13 ^ (~b15 & b17);
            s[22] = b22 ^ (~b24 & b26);     s[23] = b23 ^ (~b25 & b27);
            s[32] = b32 ^ (~b34 & b36);     s[33] = b33 ^ (~b35 & b37);
            s[42] = b42 ^ (~b44 & b46);     s[43] = b43 ^ (~b45 & b47);
            s[4] = b4 ^ (~b6 & b8);         s[5] = b5 ^ (~b7 & b9);
            s[14] = b14 ^ (~b16 & b18);     s[15] = b15 ^ (~b17 & b19);
            s[24] = b24 ^ (~b26 & b28);     s[25] = b25 ^ (~b27 & b29);
            s[34] = b34 ^ (~b36 & b38);     s[35] = b35 ^ (~b37 & b39);
            s[44] = b44 ^ (~b46 & b48);     s[45] = b45 ^ (~b47 & b49);
            s[6] = b6 ^ (~b8 & b0);         s[7] = b7 ^ (~b9 & b1);
            s[16] = b16 ^ (~b18 & b10);     s[17] = b17 ^ (~b19 & b11);
            s[26] = b26 ^ (~b28 & b20);     s[27] = b27 ^ (~b29 & b21);
            s[36] = b36 ^ (~b38 & b30);     s[37] = b37 ^ (~b39 & b31);
            s[46] = b46 ^ (~b48 & b40);     s[47] = b47 ^ (~b49 & b41);
            s[8] = b8 ^ (~b0 & b2);         s[9] = b9 ^ (~b1 & b3);
            s[18] = b18 ^ (~b10 & b12);     s[19] = b19 ^ (~b11 & b13);
            s[28] = b28 ^ (~b20 & b22);     s[29] = b29 ^ (~b21 & b23);
            s[38] = b38 ^ (~b30 & b32);     s[39] = b39 ^ (~b31 & b33);
            s[48] = b48 ^ (~b40 & b42);     s[49] = b49 ^ (~b41 & b43);

            s[0] ^= RC[n];                  s[1] ^= RC[n + 1];
        }
    } while(!end);

    var hex = '';
    for (i = 0, n = 8; i < n; ++i) {
        h = s[i];
        hex += HEX_CHARS[(h >> 4) & 0x0F] + HEX_CHARS[h & 0x0F] +
               HEX_CHARS[(h >> 12) & 0x0F] + HEX_CHARS[(h >> 8) & 0x0F] +
               HEX_CHARS[(h >> 20) & 0x0F] + HEX_CHARS[(h >> 16) & 0x0F] +
               HEX_CHARS[(h >> 28) & 0x0F] + HEX_CHARS[(h >> 24) & 0x0F];
    }

    return hex;
};

// Quick sanity check
//if (keccak(new Buffer('ricmoo')) !== 'b05e424817fb90aa7a79e9da5c5f94070a316219c6ebb863a9ff7ca357dc9fa9') {
//    throw new Error('problem with sh3?!');
//}

function sha256(data) {
    if (typeof(data) === 'string') {
        data = new Buffer(data, 'utf8');
    } else if (!Buffer.isBuffer(data)) {
        throw new Error('must be a sting');
    }

    return (new Buffer(hash.sha256().update(data).digest('hex'), 'hex'));
}

function sha3(data) {
    if (typeof(data) === 'string') {
        data = new Buffer(data, 'utf8');
    } else if (!Buffer.isBuffer(data)) {
        throw new Error('must be a sting');
    }

    return new Buffer(keccak(data), 'hex');
}

function defineProperty(object, name, value) {
    Object.defineProperty(object, name, {
        enumerable: true,
        value: value
    });
}

function getChecksumAddress(address) {
    if (typeof(address) !== 'string' || !address.match(/^0x[0-9A-Fa-f]{40}$/)) {
        throw new Error('invalid address');
    }

    address = address.substring(2).toLowerCase();
    var hashed = sha3(address);

    address = address.split('');
    for (var i = 0; i < 40; i += 2) {
        if ((hashed[i >> 1] >> 4) >= 8) {
            address[i] = address[i].toUpperCase();
        }
        if ((hashed[i >> 1] & 0x0f) >= 8) {
            address[i + 1] = address[i + 1].toUpperCase();
        }
    }

    return '0x' + address.join('');
}

function getAddress(address) {
    var result = null;

    if (typeof(address) !== 'string') { throw new Error('invalid address'); }

    if (address.match(/^(0x)?[0-9a-fA-F]{40}$/)) {

        // Missing the 0x prefix
        if (address.substring(0, 2) !== '0x') { address = '0x' + address; }

        result = getChecksumAddress(address);

        // It is a checksummed address with a bad checksum
        if (address.match(/([A-F].*[a-f])|([a-f].*[A-F])/) && result !== address) {
            throw new Error('invalid address checksum');
        }

    // Maybe ICAP? (we only support direct mode)
    } else if (address.match(/^XE[0-9]{2}[0-9A-Za-z]{30,31}$/)) {

        // It is an ICAP address with a bad checksum
        if (address.substring(2, 4) !== ibanChecksum(address)) {
            throw new Error('invalid address icap checksum');
        }

        result = (new BN(address.substring(4), 36)).toString(16);
        while (result.length < 40) { result = '0' + result; }
        result = getChecksumAddress('0x' + result);

    } else {
        throw new Error('invalid address');
    }

    return result;
}

// See: https://en.wikipedia.org/wiki/International_Bank_Account_Number
var ibanChecksum = (function() {

    // Create lookup table
    var ibanLookup = {};
    for (var i = 0; i < 10; i++) { ibanLookup[String(i)] = String(i); }
    for (var i = 0; i < 26; i++) { ibanLookup[String.fromCharCode(65 + i)] = String(10 + i); }

    // How many decimal digits can we process? (for 64-bit float, this is 15)
    var safeDigits = Math.floor(Math.log10(Number.MAX_SAFE_INTEGER));

    return function(address) {
        address = address.toUpperCase();
        address = address.substring(4) + address.substring(0, 2) + '00';

        var expanded = address.split('');
        for (var i = 0; i < expanded.length; i++) {
            expanded[i] = ibanLookup[expanded[i]];
        }
        expanded = expanded.join('');

        // Javascript can handle integers safely up to 15 (decimal) digits
        while (expanded.length >= safeDigits){
            var block = expanded.substring(0, safeDigits);
            expanded = parseInt(block, 10) % 97 + expanded.substring(block.length);
        }

        var checksum = String(98 - (parseInt(expanded, 10) % 97));
        while (checksum.length < 2) { checksum = '0' + checksum; }

        return checksum;
    };
})();


function getIcapAddress(address) {
    address = getAddress(address).substring(2);
    var base36 = (new BN(address, 16)).toString(36).toUpperCase();
    while (base36.length < 30) { base36 = '0' + base36; }
    return 'XE' + ibanChecksum('XE00' + base36) + base36;
}

// http://ethereum.stackexchange.com/questions/760/how-is-the-address-of-an-ethereum-contract-computed
function getContractAddress(transaction) {
    return getAddress('0x' + sha3(rlp.encode([
        hexOrBuffer(getAddress(transaction.from)),
        hexOrBuffer(hexlify(transaction.nonce, 'nonce'))
    ])).slice(12).toString('hex'));
}

function cloneObject(object) {
    var clone = {};
    for (var key in object) { clone[key] = object[key]; }
    return clone;
}

function stripZeros(buffer) {
    var i = 0;
    for (i = 0; i < buffer.length; i++) {
        if (buffer[i] !== 0) { break; }
    }
    return (i > 0) ? buffer.slice(i): buffer;
}

function bnToBuffer(bn) {
    var hex = bn.toString(16);
    if (hex.length % 2) { hex = '0' + hex; }
    return stripZeros(new Buffer(hex, 'hex'));
}

function isHexString(value, length) {
    if (typeof(value) !== 'string' || !value.match(/^0x[0-9A-Fa-f]*$/)) {
        return false
    }
    if (length && value.length !== 2 + 2 * length) { return false; }
    return true;
}

function hexOrBuffer(value, name) {
    if (!Buffer.isBuffer(value)) {
        if (!isHexString(value)) {
            var error = new Error(name ? ('invalid ' + name) : 'invalid hex or buffer');
            error.reason = 'invalid hex string';
            error.value = value;
            throw error;
        }

        value = value.substring(2);
        if (value.length % 2) { value = '0' + value; }
        value = new Buffer(value, 'hex');
    }

    return value;
}

function hexlify(value, name) {
    if (typeof(value) === 'number') {
        return '0x' + bnToBuffer(new BN(value)).toString('hex');
    } else if (value.mod || value.modulo) {
        return '0x' + bnToBuffer(value).toString('hex')
    } else {
        return '0x' + hexOrBuffer(value).toString('hex');
    }
    throw new Error('invalid value');
}


module.exports = {
    BN: BN,

    defineProperty: defineProperty,

    getAddress: getAddress,
    getIcapAddress: getIcapAddress,

    getContractAddress: getContractAddress,

    cloneObject: cloneObject,

    bnToBuffer: bnToBuffer,
    isHexString: isHexString,
    hexOrBuffer: hexOrBuffer,
    hexlify: hexlify,
    stripZeros: stripZeros,

    sha256: sha256,
    sha3: sha3,
}