var bcoin = require('../bcoin');
var hash = require('hash.js');
var bn = require('bn.js');
var inherits = require('inherits');
var EventEmitter = require('events').EventEmitter;
var utils = bcoin.utils;
var assert = utils.assert;
var constants = bcoin.protocol.constants;

function Wallet(options, passphrase) {
  if (!(this instanceof Wallet))
    return new Wallet(options, passphrase);

  EventEmitter.call(this);

  // bcoin.wallet('scope', 'password')
  if (typeof options === 'string' && typeof passphrase === 'string') {
    options = {
      scope: options,
      passphrase: passphrase
    };
  }
  if (!options)
    options = {};

  this.options = options;
  this.compressed = typeof options.compressed !== 'undefined' ?
      options.compressed : true;
  this.storage = options.storage;
  this.key = null;
  this.loaded = false;
  this.lastTs = 0;

  if (options.priv instanceof bcoin.hd.priv) {
    this.hd = options.priv;
    this.key = this.hd;
  } else if (options.pub instanceof bcoin.hd.pub) {
    this.hd = options.pub;
    this.key = this.hd;
  } else if (options.hd) {
    this.hd = bcoin.hd.priv(options);
    this.key = this.hd;
  } else if (options.key) {
    if ((options.key instanceof bcoin.hd.priv)
        || (options.key instanceof bcoin.hd.pub)) {
      this.hd = options.key;
      this.key = options.key;
    } else {
      this.key = options.key;
    }
  } else if (options.passphrase) {
    this.key = bcoin.ecdsa.genKeyPair({
      pers: options.scope,
      entropy: hash.sha256().update(options.passphrase).digest()
    });
  } else if (options.priv || options.pub) {
    this.key = bcoin.ecdsa.keyPair({
      priv: options.priv,
      pub: options.pub
    });
  } else {
    this.key = bcoin.ecdsa.genKeyPair();
  }

  this.addressType = 'normal';
  this.sharedKeys = [];
  this.m = 1;
  this.n = 1;

  this.multisig(options.multisig || {});

  this.prefix = 'bt/' + this.getAddress() + '/';
  this.tx = new bcoin.txPool(this);

  // Just a constants, actually
  this.fee = 10000;
  this.dust = 5460;

  this._init();
}
inherits(Wallet, EventEmitter);
module.exports = Wallet;

Wallet.prototype._init = function init() {
  if (this.tx._loaded) {
    this.loaded = true;
    return;
  }

  // Notify owners about new accepted transactions
  var self = this;
  var prevBalance = null;
  this.tx.on('update', function(lastTs, tx) {
    var b = this.balance();
    if (prevBalance && prevBalance.cmp(b) !== 0)
      self.emit('balance', b);
    self.emit('update', tx);
    prevBalance = b;
  });

  this.tx.on('tx', function(tx) {
    self.emit('tx', tx);
  });

  this.tx.once('load', function(ts) {
    self.loaded = true;
    self.lastTs = ts;
    self.emit('load', ts);
  });

  this.tx.on('error', function(err) {
    self.emit('error', err);
  });
};

Wallet.prototype.multisig = function multisig(options) {
  var pub = this.key.getPublic(this.compressed, 'array');

  options.type = options.type || options.addressType;
  options.keys = options.keys || options.sharedKeys;

  this.addressType = options.type || 'normal';

  // Multisig
  this.sharedKeys = (options.keys || []).map(utils.toKeyArray);
  this.m = options.m || 1;
  this.n = options.n || 1;

  this.sharedKeys = this.sharedKeys.filter(function(key) {
    return !utils.isEqual(key, pub);
  });

  // Use p2sh multisig by default
  if (!options.addressType && this.sharedKeys.length) {
    this.addressType = 'p2sh';
  }

  if (this.m < 1 || this.m > this.n) {
    throw new Error('m ranges between 1 and n');
  }

  if (this.n < 1 || this.n > 7) {
    throw new Error('n ranges between 1 and 7');
  }

  if (this.sharedKeys.length < this.m - 1) {
    throw new Error(this.m + ' public keys required');
  }
};

Wallet.prototype.derive = function derive() {
  var options = this.options;

  if (!this.hd)
    throw new Error('wallet is not HD');

  options.priv = this.hd.derive.apply(this.hd, arguments);

  return bcoin.wallet(options);
};

Wallet.prototype.getPrivateKey = function getPrivateKey(enc) {
  var priv = this.key.getPrivate();
  if (priv)
    priv = priv.toArray();
  else
    return;
  if (!enc)
    return priv;

  if (enc === 'base58') {
    // We'll be using ncompressed public key as an address
    var arr = [ 128 ];

    // 0-pad key
    while (arr.length + priv.length < 33)
      arr.push(0);
    arr = arr.concat(priv);
    if (this.compressed)
      arr.push(1);
    var chk = utils.checksum(arr);
    return utils.toBase58(arr.concat(chk));
  } else {
    return priv;
  }
};

Wallet.prototype.getPublicKey = function getPublicKey(enc) {
  var pub = this.key.getPublic(this.compressed, 'array');

  if (this.addressType === 'p2sh') {
    var keys = this.getPublicKeys();
    pub = bcoin.script.encode(bcoin.script.multisig(keys, this.m, this.n));
  }

  if (enc === 'base58')
    return utils.toBase58(pub);
  else if (enc === 'hex')
    return utils.toHex(pub);
  else
    return pub;
};

Wallet.prototype._getPublicKey = function _getPublicKey(enc) {
  var pub = this.key.getPublic(this.compressed, 'array');

  if (enc === 'base58')
    return utils.toBase58(pub);
  else if (enc === 'hex')
    return utils.toHex(pub);
  else
    return pub;
};

Wallet.prototype.getPublicKeys = function() {
  var keys = this.sharedKeys.slice().map(utils.toKeyArray);

  // if (keys.length < this.m) {
  var pub = this.key.getPublic(this.compressed, 'array');
  keys.push(pub);

  keys = keys.sort(function(a, b) {
    return new bn(a).cmp(new bn(b)) > 0;
  });

  return keys;
};

Wallet.prototype.getHash = function getHash() {
  return utils.ripesha(this.getPublicKey());
};

Wallet.prototype.getAddress = function getAddress() {
  return Wallet.hash2addr(this.getHash(), this.addressType);
};

Wallet.hash2addr = function hash2addr(hash, version) {
  hash = utils.toArray(hash, 'hex');

  version = constants.addr[version || 'normal'];
  hash = [ version ].concat(hash);

  var addr = hash.concat(utils.checksum(hash));
  return utils.toBase58(addr);
};

Wallet.addr2hash = function addr2hash(addr, version) {
  if (!Array.isArray(addr))
    addr = utils.fromBase58(addr);

  version = constants.addr[version || 'normal'];

  if (addr.length !== 25)
    return [];
  if (addr[0] !== version)
    return [];

  var chk = utils.checksum(addr.slice(0, -4));
  if (utils.readU32(chk, 0) !== utils.readU32(addr, 21))
    return [];

  return addr.slice(1, -4);
};

Wallet.prototype.validateAddress = function validateAddress(addr, version) {
  if (!addr)
    return false;
  var p = Wallet.addr2hash(addr, version);
  return p.length !== 0;
};
Wallet.validateAddress = Wallet.prototype.validateAddress;

Wallet.prototype.ownOutput = function ownOutput(tx, index) {
  var hash = this.getHash();
  var key = this.getPublicKey();

  var outputs = tx.outputs.filter(function(output, i) {
    if (index !== undefined && index !== i)
      return false;

    var s = output.script;

    if (bcoin.script.isPubkeyhash(s, hash))
      return true;

    if (bcoin.script.isSimplePubkeyhash(s, hash))
      return true;

    if (bcoin.script.isMultisig(s, key))
      return true;

    if (bcoin.script.isScripthash(s, hash))
      return true;

    return false;
  }, this);
  if (outputs.length === 0)
    return false;

  return outputs;
};

Wallet.prototype.ownInput = function ownInput(tx, index) {
  var hash = this.getHash();
  var key = this.getPublicKey();

  var inputs = tx.inputs.filter(function(input, i) {
    if (index !== undefined && index !== i)
      return false;

    if (bcoin.script.isPubkeyhashInput(input.script) &&
        utils.isEqual(input.script[1], key))
      return true;

    if (!input.out.tx)
      return false;

    var s = input.out.tx.outputs[input.out.index].script;
    if (bcoin.script.isPubkeyhash(s, hash))
      return true;

    if (bcoin.script.isMultisig(s, key))
      return true;

    if (bcoin.script.isScripthash(s, hash))
      return true;

    return false;
  }, this);
  if (inputs.length === 0)
    return false;

  return inputs;
};

Wallet.prototype.sign = function sign(tx, type, inputs) {
  if (!type)
    type = 'all';

  var pub = this.getPublicKey();
  var key = this.key;

  inputs = inputs || tx.inputs;

  // Add signature script to each input
  inputs = inputs.filter(function(input) {
    // Filter inputs that this wallet own
    if (!input.out.tx || !this.ownOutput(input.out.tx))
      return false;

    tx.scriptSig(input, key, pub, type);

    return true;
  }, this);

  return inputs.length;
};

Wallet.prototype.addTX = function addTX(tx, block) {
  return this.tx.add(tx);
};

Wallet.prototype.all = function all() {
  return this.tx.all();
};

Wallet.prototype.unspent = function unspent() {
  return this.tx.unspent();
};

Wallet.prototype.pending = function pending() {
  return this.tx.pending();
};

Wallet.prototype.balance = function balance() {
  return this.tx.balance();
};

Wallet.prototype.fill = function fill(tx, cb) {
  cb = utils.asyncify(cb);
  var result = tx.fillUnspent(this.unspent(), this.getAddress());
  if (!result) {
    var err = new Error('Not enough funds');
    err.minBalance = tx.cost;
    cb(err);
    return null;
  }
  this.sign(tx);
  cb(null, tx);
  return tx;
};

Wallet.prototype.toJSON = function toJSON() {
  return {
    v: 1,
    type: 'wallet',
    pub: utils.toBase58(this.key.getPublic(this.compressed, 'array')),
    priv: this.getPrivateKey('base58'),
    tx: this.tx.toJSON(),
    addressType: this.addressType,
    sharedKeys: utils.toBase58(this.sharedKeys),
    m: this.m,
    n: this.n
  };
};

Wallet.fromJSON = function fromJSON(json) {
  assert.equal(json.v, 1);
  assert.equal(json.type, 'wallet');

  var priv;
  var pub;
  var compressed;

  if (json.priv) {
    var key = bcoin.utils.fromBase58(json.priv);
    assert(utils.isEqual(key.slice(-4), utils.checksum(key.slice(0, -4))));
    assert.equal(key[0], 128);

    key = key.slice(0, -4);
    if (key.length === 34) {
      assert.equal(key[33], 1);
      priv = key.slice(1, -1);
      compressed = true;
    } else {
      priv = key.slice(1);
      compressed = false;
    }
  } else {
    pub = bcoin.utils.fromBase58(json.pub);
    compressed = pub[0] !== 0x04;
  }

  var w = new Wallet({
    priv: priv,
    pub: pub,
    compressed: compressed,
    addressType: json.addressType,
    sharedKeys: json.sharedKeys,
    m: json.m,
    n: json.n
  });

  w.tx.fromJSON(json.tx);

  return w;
};