'use strict';

const PluginAuth = require('./plugin-auth');
const Crypto = require('crypto');

/**
 * Standard authentication plugin
 */
class Ed25519PasswordAuth extends PluginAuth {
  constructor(packSeq, compressPackSeq, pluginData, resolve, reject, multiAuthResolver) {
    super(resolve, reject, multiAuthResolver);
    this.pluginData = pluginData;
    this.sequenceNo = packSeq;
  }

  start(out, opts, info) {
    //seed is ended with a null byte value.
    const data = this.pluginData;

    const sign = Ed25519PasswordAuth.encryptPassword(opts.password, data);
    out.startPacket(this);
    out.writeBuffer(sign, 0, sign.length);
    out.flushBuffer(true);
    this.emit('send_end');
    this.onPacketReceive = this.successSend;
  }

  static encryptPassword(password, seed) {
    if (!password) return Buffer.alloc(0);

    let i, j;
    let p = [gf(), gf(), gf(), gf()];
    const signedMsg = Buffer.alloc(96);
    const bytePwd = Buffer.from(password);

    let hash = Crypto.createHash('sha512');
    const d = hash.update(bytePwd).digest();
    d[0] &= 248;
    d[31] &= 127;
    d[31] |= 64;

    for (i = 0; i < 32; i++) signedMsg[64 + i] = seed[i];
    for (i = 0; i < 32; i++) signedMsg[32 + i] = d[32 + i];

    hash = Crypto.createHash('sha512');
    const r = hash.update(signedMsg.slice(32, 96)).digest();

    reduce(r);
    scalarbase(p, r);
    pack(signedMsg, p);

    p = [gf(), gf(), gf(), gf()];

    scalarbase(p, d);
    const tt = Buffer.alloc(32);
    pack(tt, p);

    for (i = 32; i < 64; i++) signedMsg[i] = tt[i - 32];

    hash = Crypto.createHash('sha512');
    const h = hash.update(signedMsg).digest();

    reduce(h);

    const x = new Float64Array(64);
    for (i = 0; i < 64; i++) x[i] = 0;
    for (i = 0; i < 32; i++) x[i] = r[i];
    for (i = 0; i < 32; i++) {
      for (j = 0; j < 32; j++) {
        x[i + j] += h[i] * d[j];
      }
    }

    modL(signedMsg.subarray(32), x);

    return signedMsg.slice(0, 64);
  }
}

/*******************************************************
 *
 * This plugin uses the following public domain tweetnacl-js code by Dmitry Chestnykh (from https://github.com/dchest/tweetnacl-js/blob/master/nacl-fast.js).
 * tweetnacl cannot be used directly (secret key mandatory size is 32 in nacl + implementation differ : second scalarbase use hash of secret key, not secret key).
 *
 *******************************************************/

const gf = function (init) {
  const r = new Float64Array(16);
  if (init) for (let i = 0; i < init.length; i++) r[i] = init[i];
  return r;
};

const gf0 = gf(),
  gf1 = gf([1]),
  D2 = gf([
    0xf159,
    0x26b2,
    0x9b94,
    0xebd6,
    0xb156,
    0x8283,
    0x149a,
    0x00e0,
    0xd130,
    0xeef3,
    0x80f2,
    0x198e,
    0xfce7,
    0x56df,
    0xd9dc,
    0x2406
  ]),
  X = gf([
    0xd51a,
    0x8f25,
    0x2d60,
    0xc956,
    0xa7b2,
    0x9525,
    0xc760,
    0x692c,
    0xdc5c,
    0xfdd6,
    0xe231,
    0xc0a4,
    0x53fe,
    0xcd6e,
    0x36d3,
    0x2169
  ]),
  Y = gf([
    0x6658,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666,
    0x6666
  ]);

const L = new Float64Array([
  0xed,
  0xd3,
  0xf5,
  0x5c,
  0x1a,
  0x63,
  0x12,
  0x58,
  0xd6,
  0x9c,
  0xf7,
  0xa2,
  0xde,
  0xf9,
  0xde,
  0x14,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0x10
]);

function reduce(r) {
  const x = new Float64Array(64);
  let i;
  for (i = 0; i < 64; i++) x[i] = r[i];
  for (i = 0; i < 64; i++) r[i] = 0;
  modL(r, x);
}

function modL(r, x) {
  let carry, i, j, k;
  for (i = 63; i >= 32; --i) {
    carry = 0;
    for (j = i - 32, k = i - 12; j < k; ++j) {
      x[j] += carry - 16 * x[i] * L[j - (i - 32)];
      carry = (x[j] + 128) >> 8;
      x[j] -= carry * 256;
    }
    x[j] += carry;
    x[i] = 0;
  }
  carry = 0;
  for (j = 0; j < 32; j++) {
    x[j] += carry - (x[31] >> 4) * L[j];
    carry = x[j] >> 8;
    x[j] &= 255;
  }
  for (j = 0; j < 32; j++) x[j] -= carry * L[j];
  for (i = 0; i < 32; i++) {
    x[i + 1] += x[i] >> 8;
    r[i] = x[i] & 255;
  }
}

function scalarbase(p, s) {
  const q = [gf(), gf(), gf(), gf()];
  set25519(q[0], X);
  set25519(q[1], Y);
  set25519(q[2], gf1);
  M(q[3], X, Y);
  scalarmult(p, q, s);
}

function set25519(r, a) {
  for (let i = 0; i < 16; i++) r[i] = a[i] | 0;
}

function M(o, a, b) {
  let v,
    c,
    t0 = 0,
    t1 = 0,
    t2 = 0,
    t3 = 0,
    t4 = 0,
    t5 = 0,
    t6 = 0,
    t7 = 0,
    t8 = 0,
    t9 = 0,
    t10 = 0,
    t11 = 0,
    t12 = 0,
    t13 = 0,
    t14 = 0,
    t15 = 0,
    t16 = 0,
    t17 = 0,
    t18 = 0,
    t19 = 0,
    t20 = 0,
    t21 = 0,
    t22 = 0,
    t23 = 0,
    t24 = 0,
    t25 = 0,
    t26 = 0,
    t27 = 0,
    t28 = 0,
    t29 = 0,
    t30 = 0;
  const b0 = b[0],
    b1 = b[1],
    b2 = b[2],
    b3 = b[3],
    b4 = b[4],
    b5 = b[5],
    b6 = b[6],
    b7 = b[7],
    b8 = b[8],
    b9 = b[9],
    b10 = b[10],
    b11 = b[11],
    b12 = b[12],
    b13 = b[13],
    b14 = b[14],
    b15 = b[15];

  v = a[0];
  t0 += v * b0;
  t1 += v * b1;
  t2 += v * b2;
  t3 += v * b3;
  t4 += v * b4;
  t5 += v * b5;
  t6 += v * b6;
  t7 += v * b7;
  t8 += v * b8;
  t9 += v * b9;
  t10 += v * b10;
  t11 += v * b11;
  t12 += v * b12;
  t13 += v * b13;
  t14 += v * b14;
  t15 += v * b15;
  v = a[1];
  t1 += v * b0;
  t2 += v * b1;
  t3 += v * b2;
  t4 += v * b3;
  t5 += v * b4;
  t6 += v * b5;
  t7 += v * b6;
  t8 += v * b7;
  t9 += v * b8;
  t10 += v * b9;
  t11 += v * b10;
  t12 += v * b11;
  t13 += v * b12;
  t14 += v * b13;
  t15 += v * b14;
  t16 += v * b15;
  v = a[2];
  t2 += v * b0;
  t3 += v * b1;
  t4 += v * b2;
  t5 += v * b3;
  t6 += v * b4;
  t7 += v * b5;
  t8 += v * b6;
  t9 += v * b7;
  t10 += v * b8;
  t11 += v * b9;
  t12 += v * b10;
  t13 += v * b11;
  t14 += v * b12;
  t15 += v * b13;
  t16 += v * b14;
  t17 += v * b15;
  v = a[3];
  t3 += v * b0;
  t4 += v * b1;
  t5 += v * b2;
  t6 += v * b3;
  t7 += v * b4;
  t8 += v * b5;
  t9 += v * b6;
  t10 += v * b7;
  t11 += v * b8;
  t12 += v * b9;
  t13 += v * b10;
  t14 += v * b11;
  t15 += v * b12;
  t16 += v * b13;
  t17 += v * b14;
  t18 += v * b15;
  v = a[4];
  t4 += v * b0;
  t5 += v * b1;
  t6 += v * b2;
  t7 += v * b3;
  t8 += v * b4;
  t9 += v * b5;
  t10 += v * b6;
  t11 += v * b7;
  t12 += v * b8;
  t13 += v * b9;
  t14 += v * b10;
  t15 += v * b11;
  t16 += v * b12;
  t17 += v * b13;
  t18 += v * b14;
  t19 += v * b15;
  v = a[5];
  t5 += v * b0;
  t6 += v * b1;
  t7 += v * b2;
  t8 += v * b3;
  t9 += v * b4;
  t10 += v * b5;
  t11 += v * b6;
  t12 += v * b7;
  t13 += v * b8;
  t14 += v * b9;
  t15 += v * b10;
  t16 += v * b11;
  t17 += v * b12;
  t18 += v * b13;
  t19 += v * b14;
  t20 += v * b15;
  v = a[6];
  t6 += v * b0;
  t7 += v * b1;
  t8 += v * b2;
  t9 += v * b3;
  t10 += v * b4;
  t11 += v * b5;
  t12 += v * b6;
  t13 += v * b7;
  t14 += v * b8;
  t15 += v * b9;
  t16 += v * b10;
  t17 += v * b11;
  t18 += v * b12;
  t19 += v * b13;
  t20 += v * b14;
  t21 += v * b15;
  v = a[7];
  t7 += v * b0;
  t8 += v * b1;
  t9 += v * b2;
  t10 += v * b3;
  t11 += v * b4;
  t12 += v * b5;
  t13 += v * b6;
  t14 += v * b7;
  t15 += v * b8;
  t16 += v * b9;
  t17 += v * b10;
  t18 += v * b11;
  t19 += v * b12;
  t20 += v * b13;
  t21 += v * b14;
  t22 += v * b15;
  v = a[8];
  t8 += v * b0;
  t9 += v * b1;
  t10 += v * b2;
  t11 += v * b3;
  t12 += v * b4;
  t13 += v * b5;
  t14 += v * b6;
  t15 += v * b7;
  t16 += v * b8;
  t17 += v * b9;
  t18 += v * b10;
  t19 += v * b11;
  t20 += v * b12;
  t21 += v * b13;
  t22 += v * b14;
  t23 += v * b15;
  v = a[9];
  t9 += v * b0;
  t10 += v * b1;
  t11 += v * b2;
  t12 += v * b3;
  t13 += v * b4;
  t14 += v * b5;
  t15 += v * b6;
  t16 += v * b7;
  t17 += v * b8;
  t18 += v * b9;
  t19 += v * b10;
  t20 += v * b11;
  t21 += v * b12;
  t22 += v * b13;
  t23 += v * b14;
  t24 += v * b15;
  v = a[10];
  t10 += v * b0;
  t11 += v * b1;
  t12 += v * b2;
  t13 += v * b3;
  t14 += v * b4;
  t15 += v * b5;
  t16 += v * b6;
  t17 += v * b7;
  t18 += v * b8;
  t19 += v * b9;
  t20 += v * b10;
  t21 += v * b11;
  t22 += v * b12;
  t23 += v * b13;
  t24 += v * b14;
  t25 += v * b15;
  v = a[11];
  t11 += v * b0;
  t12 += v * b1;
  t13 += v * b2;
  t14 += v * b3;
  t15 += v * b4;
  t16 += v * b5;
  t17 += v * b6;
  t18 += v * b7;
  t19 += v * b8;
  t20 += v * b9;
  t21 += v * b10;
  t22 += v * b11;
  t23 += v * b12;
  t24 += v * b13;
  t25 += v * b14;
  t26 += v * b15;
  v = a[12];
  t12 += v * b0;
  t13 += v * b1;
  t14 += v * b2;
  t15 += v * b3;
  t16 += v * b4;
  t17 += v * b5;
  t18 += v * b6;
  t19 += v * b7;
  t20 += v * b8;
  t21 += v * b9;
  t22 += v * b10;
  t23 += v * b11;
  t24 += v * b12;
  t25 += v * b13;
  t26 += v * b14;
  t27 += v * b15;
  v = a[13];
  t13 += v * b0;
  t14 += v * b1;
  t15 += v * b2;
  t16 += v * b3;
  t17 += v * b4;
  t18 += v * b5;
  t19 += v * b6;
  t20 += v * b7;
  t21 += v * b8;
  t22 += v * b9;
  t23 += v * b10;
  t24 += v * b11;
  t25 += v * b12;
  t26 += v * b13;
  t27 += v * b14;
  t28 += v * b15;
  v = a[14];
  t14 += v * b0;
  t15 += v * b1;
  t16 += v * b2;
  t17 += v * b3;
  t18 += v * b4;
  t19 += v * b5;
  t20 += v * b6;
  t21 += v * b7;
  t22 += v * b8;
  t23 += v * b9;
  t24 += v * b10;
  t25 += v * b11;
  t26 += v * b12;
  t27 += v * b13;
  t28 += v * b14;
  t29 += v * b15;
  v = a[15];
  t15 += v * b0;
  t16 += v * b1;
  t17 += v * b2;
  t18 += v * b3;
  t19 += v * b4;
  t20 += v * b5;
  t21 += v * b6;
  t22 += v * b7;
  t23 += v * b8;
  t24 += v * b9;
  t25 += v * b10;
  t26 += v * b11;
  t27 += v * b12;
  t28 += v * b13;
  t29 += v * b14;
  t30 += v * b15;

  t0 += 38 * t16;
  t1 += 38 * t17;
  t2 += 38 * t18;
  t3 += 38 * t19;
  t4 += 38 * t20;
  t5 += 38 * t21;
  t6 += 38 * t22;
  t7 += 38 * t23;
  t8 += 38 * t24;
  t9 += 38 * t25;
  t10 += 38 * t26;
  t11 += 38 * t27;
  t12 += 38 * t28;
  t13 += 38 * t29;
  t14 += 38 * t30;
  // t15 left as is

  // first car
  c = 1;
  v = t0 + c + 65535;
  c = Math.floor(v / 65536);
  t0 = v - c * 65536;
  v = t1 + c + 65535;
  c = Math.floor(v / 65536);
  t1 = v - c * 65536;
  v = t2 + c + 65535;
  c = Math.floor(v / 65536);
  t2 = v - c * 65536;
  v = t3 + c + 65535;
  c = Math.floor(v / 65536);
  t3 = v - c * 65536;
  v = t4 + c + 65535;
  c = Math.floor(v / 65536);
  t4 = v - c * 65536;
  v = t5 + c + 65535;
  c = Math.floor(v / 65536);
  t5 = v - c * 65536;
  v = t6 + c + 65535;
  c = Math.floor(v / 65536);
  t6 = v - c * 65536;
  v = t7 + c + 65535;
  c = Math.floor(v / 65536);
  t7 = v - c * 65536;
  v = t8 + c + 65535;
  c = Math.floor(v / 65536);
  t8 = v - c * 65536;
  v = t9 + c + 65535;
  c = Math.floor(v / 65536);
  t9 = v - c * 65536;
  v = t10 + c + 65535;
  c = Math.floor(v / 65536);
  t10 = v - c * 65536;
  v = t11 + c + 65535;
  c = Math.floor(v / 65536);
  t11 = v - c * 65536;
  v = t12 + c + 65535;
  c = Math.floor(v / 65536);
  t12 = v - c * 65536;
  v = t13 + c + 65535;
  c = Math.floor(v / 65536);
  t13 = v - c * 65536;
  v = t14 + c + 65535;
  c = Math.floor(v / 65536);
  t14 = v - c * 65536;
  v = t15 + c + 65535;
  c = Math.floor(v / 65536);
  t15 = v - c * 65536;
  t0 += c - 1 + 37 * (c - 1);

  // second car
  c = 1;
  v = t0 + c + 65535;
  c = Math.floor(v / 65536);
  t0 = v - c * 65536;
  v = t1 + c + 65535;
  c = Math.floor(v / 65536);
  t1 = v - c * 65536;
  v = t2 + c + 65535;
  c = Math.floor(v / 65536);
  t2 = v - c * 65536;
  v = t3 + c + 65535;
  c = Math.floor(v / 65536);
  t3 = v - c * 65536;
  v = t4 + c + 65535;
  c = Math.floor(v / 65536);
  t4 = v - c * 65536;
  v = t5 + c + 65535;
  c = Math.floor(v / 65536);
  t5 = v - c * 65536;
  v = t6 + c + 65535;
  c = Math.floor(v / 65536);
  t6 = v - c * 65536;
  v = t7 + c + 65535;
  c = Math.floor(v / 65536);
  t7 = v - c * 65536;
  v = t8 + c + 65535;
  c = Math.floor(v / 65536);
  t8 = v - c * 65536;
  v = t9 + c + 65535;
  c = Math.floor(v / 65536);
  t9 = v - c * 65536;
  v = t10 + c + 65535;
  c = Math.floor(v / 65536);
  t10 = v - c * 65536;
  v = t11 + c + 65535;
  c = Math.floor(v / 65536);
  t11 = v - c * 65536;
  v = t12 + c + 65535;
  c = Math.floor(v / 65536);
  t12 = v - c * 65536;
  v = t13 + c + 65535;
  c = Math.floor(v / 65536);
  t13 = v - c * 65536;
  v = t14 + c + 65535;
  c = Math.floor(v / 65536);
  t14 = v - c * 65536;
  v = t15 + c + 65535;
  c = Math.floor(v / 65536);
  t15 = v - c * 65536;
  t0 += c - 1 + 37 * (c - 1);

  o[0] = t0;
  o[1] = t1;
  o[2] = t2;
  o[3] = t3;
  o[4] = t4;
  o[5] = t5;
  o[6] = t6;
  o[7] = t7;
  o[8] = t8;
  o[9] = t9;
  o[10] = t10;
  o[11] = t11;
  o[12] = t12;
  o[13] = t13;
  o[14] = t14;
  o[15] = t15;
}

function scalarmult(p, q, s) {
  let b, i;
  set25519(p[0], gf0);
  set25519(p[1], gf1);
  set25519(p[2], gf1);
  set25519(p[3], gf0);
  for (i = 255; i >= 0; --i) {
    b = (s[(i / 8) | 0] >> (i & 7)) & 1;
    cswap(p, q, b);
    add(q, p);
    add(p, p);
    cswap(p, q, b);
  }
}

function pack(r, p) {
  const tx = gf(),
    ty = gf(),
    zi = gf();
  inv25519(zi, p[2]);
  M(tx, p[0], zi);
  M(ty, p[1], zi);
  pack25519(r, ty);
  r[31] ^= par25519(tx) << 7;
}

function inv25519(o, i) {
  const c = gf();
  let a;
  for (a = 0; a < 16; a++) c[a] = i[a];
  for (a = 253; a >= 0; a--) {
    S(c, c);
    if (a !== 2 && a !== 4) M(c, c, i);
  }
  for (a = 0; a < 16; a++) o[a] = c[a];
}

function S(o, a) {
  M(o, a, a);
}

function par25519(a) {
  const d = new Uint8Array(32);
  pack25519(d, a);
  return d[0] & 1;
}
function car25519(o) {
  let i,
    v,
    c = 1;
  for (i = 0; i < 16; i++) {
    v = o[i] + c + 65535;
    c = Math.floor(v / 65536);
    o[i] = v - c * 65536;
  }
  o[0] += c - 1 + 37 * (c - 1);
}

function pack25519(o, n) {
  let i, j, b;
  const m = gf(),
    t = gf();
  for (i = 0; i < 16; i++) t[i] = n[i];
  car25519(t);
  car25519(t);
  car25519(t);
  for (j = 0; j < 2; j++) {
    m[0] = t[0] - 0xffed;
    for (i = 1; i < 15; i++) {
      m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
      m[i - 1] &= 0xffff;
    }
    m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
    b = (m[15] >> 16) & 1;
    m[14] &= 0xffff;
    sel25519(t, m, 1 - b);
  }
  for (i = 0; i < 16; i++) {
    o[2 * i] = t[i] & 0xff;
    o[2 * i + 1] = t[i] >> 8;
  }
}

function cswap(p, q, b) {
  for (let i = 0; i < 4; i++) {
    sel25519(p[i], q[i], b);
  }
}

function A(o, a, b) {
  for (let i = 0; i < 16; i++) o[i] = a[i] + b[i];
}

function Z(o, a, b) {
  for (let i = 0; i < 16; i++) o[i] = a[i] - b[i];
}

function add(p, q) {
  const a = gf(),
    b = gf(),
    c = gf(),
    d = gf(),
    e = gf(),
    f = gf(),
    g = gf(),
    h = gf(),
    t = gf();

  Z(a, p[1], p[0]);
  Z(t, q[1], q[0]);
  M(a, a, t);
  A(b, p[0], p[1]);
  A(t, q[0], q[1]);
  M(b, b, t);
  M(c, p[3], q[3]);
  M(c, c, D2);
  M(d, p[2], q[2]);
  A(d, d, d);
  Z(e, b, a);
  Z(f, d, c);
  A(g, d, c);
  A(h, b, a);

  M(p[0], e, f);
  M(p[1], h, g);
  M(p[2], g, f);
  M(p[3], e, h);
}

function sel25519(p, q, b) {
  const c = ~(b - 1);
  let t;
  for (let i = 0; i < 16; i++) {
    t = c & (p[i] ^ q[i]);
    p[i] ^= t;
    q[i] ^= t;
  }
}

module.exports = Ed25519PasswordAuth;