text: 'use strict';
  
  //  ---------------------------------------------------------------------------
  
  const Exchange = require ('./base/Exchange');
  const { ExchangeError, DDoSProtection, InsufficientFunds, InvalidOrder, OrderNotFound, AuthenticationError } = require ('./base/errors');
  
  //  ---------------------------------------------------------------------------
  
  module.exports = class okcoinusd extends Exchange {
      describe () {
          return this.deepExtend (super.describe (), {
              'id': 'okcoinusd',
              'name': 'OKCoin USD',
              'countries': [ 'CN', 'US' ],
              'version': 'v1',
              'rateLimit': 1000, // up to 3000 requests per 5 minutes ≈ 600 requests per minute ≈ 10 requests per second ≈ 100 ms
              'has': {
                  'CORS': false,
                  'fetchOHLCV': true,
                  'fetchOrder': true,
                  'fetchOrders': false,
                  'fetchOpenOrders': true,
                  'fetchClosedOrders': true,
                  'withdraw': true,
                  'futures': false,
              },
              'extension': '.do', // appended to endpoint URL
              'timeframes': {
                  '1m': '1min',
                  '3m': '3min',
                  '5m': '5min',
                  '15m': '15min',
                  '30m': '30min',
                  '1h': '1hour',
                  '2h': '2hour',
                  '4h': '4hour',
                  '6h': '6hour',
                  '12h': '12hour',
                  '1d': '1day',
                  '3d': '3day',
                  '1w': '1week',
              },
              'api': {
                  'web': {
                      'get': [
                          'futures/pc/market/marketOverview', // todo: merge in fetchMarkets
                          'spot/markets/index-tickers', // todo: add fetchTickers
                          'spot/markets/currencies',
                          'spot/markets/products',
                          'spot/markets/tickers',
                      ],
                  },
                  'public': {
                      'get': [
                          'depth',
                          'exchange_rate',
                          'future_depth',
                          'future_estimated_price',
                          'future_hold_amount',
                          'future_index',
                          'future_kline',
                          'future_price_limit',
                          'future_ticker',
                          'future_trades',
                          'kline',
                          'otcs',
                          'ticker',
                          'tickers', // todo: add fetchTickers
                          'trades',
                      ],
                  },
                  'private': {
                      'post': [
                          'account_records',
                          'batch_trade',
                          'borrow_money',
                          'borrow_order_info',
                          'borrows_info',
                          'cancel_borrow',
                          'cancel_order',
                          'cancel_otc_order',
                          'cancel_withdraw',
                          'funds_transfer',
                          'future_batch_trade',
                          'future_cancel',
                          'future_devolve',
                          'future_explosive',
                          'future_order_info',
                          'future_orders_info',
                          'future_position',
                          'future_position_4fix',
                          'future_trade',
                          'future_trades_history',
                          'future_userinfo',
                          'future_userinfo_4fix',
                          'lend_depth',
                          'order_fee',
                          'order_history',
                          'order_info',
                          'orders_info',
                          'otc_order_history',
                          'otc_order_info',
                          'repayment',
                          'submit_otc_order',
                          'trade',
                          'trade_history',
                          'trade_otc_order',
                          'wallet_info',
                          'withdraw',
                          'withdraw_info',
                          'unrepayments_info',
                          'userinfo',
                      ],
                  },
              },
              'urls': {
                  'logo': 'https://user-images.githubusercontent.com/1294454/27766791-89ffb502-5ee5-11e7-8a5b-c5950b68ac65.jpg',
                  'api': {
                      'web': 'https://www.okcoin.com/v2',
                      'public': 'https://www.okcoin.com/api',
                      'private': 'https://www.okcoin.com/api',
                  },
                  'www': 'https://www.okcoin.com',
                  'doc': [
                      'https://www.okcoin.com/rest_getStarted.html',
                      'https://www.npmjs.com/package/okcoin.com',
                  ],
              },
              'fees': {
                  'trading': {
                      'taker': 0.002,
                      'maker': 0.002,
                  },
              },
              'exceptions': {
                  // see https://github.com/okcoin-okex/API-docs-OKEx.com/blob/master/API-For-Spot-EN/Error%20Code%20For%20Spot.md
                  '10000': ExchangeError, // "Required field, can not be null"
                  '10001': DDoSProtection, // "Request frequency too high to exceed the limit allowed"
                  '10005': AuthenticationError, // "'SecretKey' does not exist"
                  '10006': AuthenticationError, // "'Api_key' does not exist"
                  '10007': AuthenticationError, // "Signature does not match"
                  '1002': InsufficientFunds, // "The transaction amount exceed the balance"
                  '1003': InvalidOrder, // "The transaction amount is less than the minimum requirement"
                  '1004': InvalidOrder, // "The transaction amount is less than 0"
                  '1013': InvalidOrder, // no contract type (PR-1101)
                  '1027': InvalidOrder, // createLimitBuyOrder(symbol, 0, 0): Incorrect parameter may exceeded limits
                  '1050': InvalidOrder, // returned when trying to cancel an order that was filled or canceled previously
                  '1217': InvalidOrder, // "Order was sent at ±5% of the current market price. Please resend"
                  '10014': InvalidOrder, // "Order price must be between 0 and 1,000,000"
                  '1009': OrderNotFound, // for spot markets, cancelling closed order
                  '1019': OrderNotFound, // order closed? ("Undo order failed")
                  '1051': OrderNotFound, // for spot markets, cancelling "just closed" order
                  '10009': OrderNotFound, // for spot markets, "Order does not exist"
                  '20015': OrderNotFound, // for future markets
                  '10008': ExchangeError, // Illegal URL parameter
                  // todo: sort out below
                  // 10000 Required parameter is empty
                  // 10001 Request frequency too high to exceed the limit allowed
                  // 10002 Authentication failure
                  // 10002 System error
                  // 10003 This connection has requested other user data
                  // 10004 Request failed
                  // 10005 api_key or sign is invalid, 'SecretKey' does not exist
                  // 10006 'Api_key' does not exist
                  // 10007 Signature does not match
                  // 10008 Illegal parameter, Parameter erorr
                  // 10009 Order does not exist
                  // 10010 Insufficient funds
                  // 10011 Amount too low
                  // 10012 Only btc_usd ltc_usd supported
                  // 10013 Only support https request
                  // 10014 Order price must be between 0 and 1,000,000
                  // 10015 Order price differs from current market price too much / Channel subscription temporally not available
                  // 10016 Insufficient coins balance
                  // 10017 API authorization error / WebSocket authorization error
                  // 10018 borrow amount less than lower limit [usd:100,btc:0.1,ltc:1]
                  // 10019 loan agreement not checked
                  // 1002 The transaction amount exceed the balance
                  // 10020 rate cannot exceed 1%
                  // 10021 rate cannot less than 0.01%
                  // 10023 fail to get latest ticker
                  // 10024 balance not sufficient
                  // 10025 quota is full, cannot borrow temporarily
                  // 10026 Loan (including reserved loan) and margin cannot be withdrawn
                  // 10027 Cannot withdraw within 24 hrs of authentication information modification
                  // 10028 Withdrawal amount exceeds daily limit
                  // 10029 Account has unpaid loan, please cancel/pay off the loan before withdraw
                  // 1003 The transaction amount is less than the minimum requirement
                  // 10031 Deposits can only be withdrawn after 6 confirmations
                  // 10032 Please enabled phone/google authenticator
                  // 10033 Fee higher than maximum network transaction fee
                  // 10034 Fee lower than minimum network transaction fee
                  // 10035 Insufficient BTC/LTC
                  // 10036 Withdrawal amount too low
                  // 10037 Trade password not set
                  // 1004 The transaction amount is less than 0
                  // 10040 Withdrawal cancellation fails
                  // 10041 Withdrawal address not exsit or approved
                  // 10042 Admin password error
                  // 10043 Account equity error, withdrawal failure
                  // 10044 fail to cancel borrowing order
                  // 10047 this function is disabled for sub-account
                  // 10048 withdrawal information does not exist
                  // 10049 User can not have more than 50 unfilled small orders (amount<0.15BTC)
                  // 10050 can't cancel more than once
                  // 10051 order completed transaction
                  // 10052 not allowed to withdraw
                  // 10064 after a USD deposit, that portion of assets will not be withdrawable for the next 48 hours
                  // 1007 No trading market information
                  // 1008 No latest market information
                  // 1009 No order
                  // 1010 Different user of the cancelled order and the original order
                  // 10100 User account frozen
                  // 10101 order type is wrong
                  // 10102 incorrect ID
                  // 10103 the private otc order's key incorrect
                  // 10106 API key domain not matched
                  // 1011 No documented user
                  // 1013 No order type
                  // 1014 No login
                  // 1015 No market depth information
                  // 1017 Date error
                  // 1018 Order failed
                  // 1019 Undo order failed
                  // 10216 Non-available API / non-public API
                  // 1024 Currency does not exist
                  // 1025 No chart type
                  // 1026 No base currency quantity
                  // 1027 Incorrect parameter may exceeded limits
                  // 1028 Reserved decimal failed
                  // 1029 Preparing
                  // 1030 Account has margin and futures, transactions can not be processed
                  // 1031 Insufficient Transferring Balance
                  // 1032 Transferring Not Allowed
                  // 1035 Password incorrect
                  // 1036 Google Verification code Invalid
                  // 1037 Google Verification code incorrect
                  // 1038 Google Verification replicated
                  // 1039 Message Verification Input exceed the limit
                  // 1040 Message Verification invalid
                  // 1041 Message Verification incorrect
                  // 1042 Wrong Google Verification Input exceed the limit
                  // 1043 Login password cannot be same as the trading password
                  // 1044 Old password incorrect
                  // 1045 2nd Verification Needed
                  // 1046 Please input old password
                  // 1048 Account Blocked
                  // 1050 Orders have been withdrawn or withdrawn
                  // 1051 Order completed
                  // 1201 Account Deleted at 00: 00
                  // 1202 Account Not Exist
                  // 1203 Insufficient Balance
                  // 1204 Invalid currency
                  // 1205 Invalid Account
                  // 1206 Cash Withdrawal Blocked
                  // 1207 Transfer Not Support
                  // 1208 No designated account
                  // 1209 Invalid api
                  // 1216 Market order temporarily suspended. Please send limit order
                  // 1217 Order was sent at ±5% of the current market price. Please resend
                  // 1218 Place order failed. Please try again later
                  // 20001 User does not exist
                  // 20002 Account frozen
                  // 20003 Account frozen due to forced liquidation
                  // 20004 Contract account frozen
                  // 20005 User contract account does not exist
                  // 20006 Required field missing
                  // 20007 Illegal parameter
                  // 20008 Contract account balance is too low
                  // 20009 Contract status error
                  // 20010 Risk rate ratio does not exist
                  // 20011 Risk rate lower than 90%/80% before opening BTC position with 10x/20x leverage. or risk rate lower than 80%/60% before opening LTC position with 10x/20x leverage
                  // 20012 Risk rate lower than 90%/80% after opening BTC position with 10x/20x leverage. or risk rate lower than 80%/60% after opening LTC position with 10x/20x leverage
                  // 20013 Temporally no counter party price
                  // 20014 System error
                  // 20015 Order does not exist
                  // 20016 Close amount bigger than your open positions, liquidation quantity bigger than holding
                  // 20017 Not authorized/illegal operation/illegal order ID
                  // 20018 Order price cannot be more than 103-105% or less than 95-97% of the previous minute price
                  // 20019 IP restricted from accessing the resource
                  // 20020 Secret key does not exist
                  // 20021 Index information does not exist
                  // 20022 Wrong API interface (Cross margin mode shall call cross margin API, fixed margin mode shall call fixed margin API)
                  // 20023 Account in fixed-margin mode
                  // 20024 Signature does not match
                  // 20025 Leverage rate error
                  // 20026 API Permission Error
                  // 20027 no transaction record
                  // 20028 no such contract
                  // 20029 Amount is large than available funds
                  // 20030 Account still has debts
                  // 20038 Due to regulation, this function is not availavle in the country/region your currently reside in.
                  // 20049 Request frequency too high
                  // 20100 request time out
                  // 20101 the format of data is error
                  // 20102 invalid login
                  // 20103 event type error
                  // 20104 subscription type error
                  // 20107 JSON format error
                  // 20115 The quote is not match
                  // 20116 Param not match
                  // 21020 Contracts are being delivered, orders cannot be placed
                  // 21021 Contracts are being settled, contracts cannot be placed
              },
              'options': {
                  'marketBuyPrice': false,
                  'defaultContractType': 'this_week', // next_week, quarter
                  'warnOnFetchOHLCVLimitArgument': true,
                  'fiats': [ 'USD', 'CNY' ],
                  'futures': {
                      'BCH': true,
                      'BTC': true,
                      'BTG': true,
                      'EOS': true,
                      'ETC': true,
                      'ETH': true,
                      'LTC': true,
                      'NEO': true,
                      'QTUM': true,
                      'USDT': true,
                      'XUC': true,
                  },
              },
          });
      }
  
      async fetchMarkets () {
          let response = await this.webGetSpotMarketsProducts ();
          let markets = response['data'];
          let result = [];
          for (let i = 0; i < markets.length; i++) {
              let id = markets[i]['symbol'];
              let [ baseId, quoteId ] = id.split ('_');
              let baseIdUppercase = baseId.toUpperCase ();
              let quoteIdUppercase = quoteId.toUpperCase ();
              let base = this.commonCurrencyCode (baseIdUppercase);
              let quote = this.commonCurrencyCode (quoteIdUppercase);
              let symbol = base + '/' + quote;
              let precision = {
                  'amount': markets[i]['maxSizeDigit'],
                  'price': markets[i]['maxPriceDigit'],
              };
              let minAmount = markets[i]['minTradeSize'];
              let minPrice = Math.pow (10, -precision['price']);
              let active = (markets[i]['online'] !== 0);
              let baseNumericId = markets[i]['baseCurrency'];
              let quoteNumericId = markets[i]['quoteCurrency'];
              let market = this.extend (this.fees['trading'], {
                  'id': id,
                  'symbol': symbol,
                  'base': base,
                  'quote': quote,
                  'baseId': baseId,
                  'quoteId': quoteId,
                  'baseNumericId': baseNumericId,
                  'quoteNumericId': quoteNumericId,
                  'info': markets[i],
                  'type': 'spot',
                  'spot': true,
                  'future': false,
                  'active': active,
                  'precision': precision,
                  'limits': {
                      'amount': {
                          'min': minAmount,
                          'max': undefined,
                      },
                      'price': {
                          'min': minPrice,
                          'max': undefined,
                      },
                      'cost': {
                          'min': minAmount * minPrice,
                          'max': undefined,
                      },
                  },
              });
              result.push (market);
              if ((this.has['futures']) && (market['base'] in this.options['futures'])) {
                  let fiats = this.options['fiats'];
                  for (let j = 0; j < fiats.length; j++) {
                      const fiat = fiats[j];
                      const lowercaseFiat = fiat.toLowerCase ();
                      result.push (this.extend (market, {
                          'quote': fiat,
                          'symbol': market['base'] + '/' + fiat,
                          'id': market['base'].toLowerCase () + '_' + lowercaseFiat,
                          'quoteId': lowercaseFiat,
                          'type': 'future',
                          'spot': false,
                          'future': true,
                      }));
                  }
              }
          }
          return result;
      }
  
      async fetchOrderBook (symbol, limit = undefined, params = {}) {
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'publicGet';
          let request = {
              'symbol': market['id'],
          };
          if (limit !== undefined)
              request['size'] = limit;
          if (market['future']) {
              method += 'Future';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
          }
          method += 'Depth';
          let orderbook = await this[method] (this.extend (request, params));
          return this.parseOrderBook (orderbook);
      }
  
      parseTicker (ticker, market = undefined) {
          //
          //     {              buy:   "48.777300",
          //                 change:   "-1.244500",
          //       changePercentage:   "-2.47%",
          //                  close:   "49.064000",
          //            createdDate:    1531704852254,
          //             currencyId:    527,
          //                dayHigh:   "51.012500",
          //                 dayLow:   "48.124200",
          //                   high:   "51.012500",
          //                inflows:   "0",
          //                   last:   "49.064000",
          //                    low:   "48.124200",
          //             marketFrom:    627,
          //                   name: {  },
          //                   open:   "50.308500",
          //               outflows:   "0",
          //              productId:    527,
          //                   sell:   "49.064000",
          //                 symbol:   "zec_okb",
          //                 volume:   "1049.092535"   }
          //
          let timestamp = this.safeInteger2 (ticker, 'timestamp', 'createdDate');
          let symbol = undefined;
          if (market === undefined) {
              if ('symbol' in ticker) {
                  let marketId = ticker['symbol'];
                  if (marketId in this.markets_by_id) {
                      market = this.markets_by_id[marketId];
                  } else {
                      let [ baseId, quoteId ] = ticker['symbol'].split ('_');
                      let base = baseId.toUpperCase ();
                      let quote = quoteId.toUpperCase ();
                      base = this.commonCurrencyCode (base);
                      quote = this.commonCurrencyCode (quote);
                      symbol = base + '/' + quote;
                  }
              }
          }
          if (market !== undefined) {
              symbol = market['symbol'];
          }
          let last = this.safeFloat (ticker, 'last');
          let open = this.safeFloat (ticker, 'open');
          let change = this.safeFloat (ticker, 'change');
          let percentage = this.safeFloat (ticker, 'changePercentage');
          return {
              'symbol': symbol,
              'timestamp': timestamp,
              'datetime': this.iso8601 (timestamp),
              'high': this.safeFloat (ticker, 'high'),
              'low': this.safeFloat (ticker, 'low'),
              'bid': this.safeFloat (ticker, 'buy'),
              'bidVolume': undefined,
              'ask': this.safeFloat (ticker, 'sell'),
              'askVolume': undefined,
              'vwap': undefined,
              'open': open,
              'close': last,
              'last': last,
              'previousClose': undefined,
              'change': change,
              'percentage': percentage,
              'average': undefined,
              'baseVolume': this.safeFloat2 (ticker, 'vol', 'volume'),
              'quoteVolume': undefined,
              'info': ticker,
          };
      }
  
      async fetchTicker (symbol, params = {}) {
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'publicGet';
          let request = {
              'symbol': market['id'],
          };
          if (market['future']) {
              method += 'Future';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
          }
          method += 'Ticker';
          let response = await this[method] (this.extend (request, params));
          let ticker = this.safeValue (response, 'ticker');
          if (ticker === undefined)
              throw new ExchangeError (this.id + ' fetchTicker returned an empty response: ' + this.json (response));
          let timestamp = this.safeInteger (response, 'date');
          if (timestamp !== undefined) {
              timestamp *= 1000;
              ticker = this.extend (ticker, { 'timestamp': timestamp });
          }
          return this.parseTicker (ticker, market);
      }
  
      parseTrade (trade, market = undefined) {
          let symbol = undefined;
          if (market)
              symbol = market['symbol'];
          return {
              'info': trade,
              'timestamp': trade['date_ms'],
              'datetime': this.iso8601 (trade['date_ms']),
              'symbol': symbol,
              'id': trade['tid'].toString (),
              'order': undefined,
              'type': undefined,
              'side': trade['type'],
              'price': this.safeFloat (trade, 'price'),
              'amount': this.safeFloat (trade, 'amount'),
          };
      }
  
      async fetchTrades (symbol, since = undefined, limit = undefined, params = {}) {
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'publicGet';
          let request = {
              'symbol': market['id'],
          };
          if (market['future']) {
              method += 'Future';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
          }
          method += 'Trades';
          let response = await this[method] (this.extend (request, params));
          return this.parseTrades (response, market, since, limit);
      }
  
      parseOHLCV (ohlcv, market = undefined, timeframe = '1m', since = undefined, limit = undefined) {
          let numElements = ohlcv.length;
          let volumeIndex = (numElements > 6) ? 6 : 5;
          return [
              ohlcv[0], // timestamp
              ohlcv[1], // Open
              ohlcv[2], // High
              ohlcv[3], // Low
              ohlcv[4], // Close
              // ohlcv[5], // quote volume
              // ohlcv[6], // base volume
              ohlcv[volumeIndex], // okex will return base volume in the 7th element for future markets
          ];
      }
  
      async fetchOHLCV (symbol, timeframe = '1m', since = undefined, limit = undefined, params = {}) {
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'publicGet';
          let request = {
              'symbol': market['id'],
              'type': this.timeframes[timeframe],
          };
          if (market['future']) {
              method += 'Future';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
          }
          method += 'Kline';
          if (limit !== undefined) {
              if (this.options['warnOnFetchOHLCVLimitArgument'])
                  throw new ExchangeError (this.id + ' fetchOHLCV counts "limit" candles from current time backwards, therefore the "limit" argument for ' + this.id + ' is disabled. Set ' + this.id + '.options["warnOnFetchOHLCVLimitArgument"] = false to suppress this warning message.');
              request['size'] = parseInt (limit); // max is 1440 candles
          }
          if (since !== undefined)
              request['since'] = since;
          else
              request['since'] = this.milliseconds () - 86400000; // last 24 hours
          let response = await this[method] (this.extend (request, params));
          return this.parseOHLCVs (response, market, timeframe, since, limit);
      }
  
      async fetchBalance (params = {}) {
          await this.loadMarkets ();
          let response = await this.privatePostUserinfo (params);
          let balances = response['info']['funds'];
          let result = { 'info': response };
          let ids = Object.keys (balances['free']);
          let usedField = 'freezed';
          // wtf, okex?
          // https://github.com/okcoin-okex/API-docs-OKEx.com/commit/01cf9dd57b1f984a8737ef76a037d4d3795d2ac7
          if (!(usedField in balances))
              usedField = 'holds';
          let usedKeys = Object.keys (balances[usedField]);
          ids = this.arrayConcat (ids, usedKeys);
          for (let i = 0; i < ids.length; i++) {
              let id = ids[i];
              let code = id.toUpperCase ();
              if (id in this.currencies_by_id) {
                  code = this.currencies_by_id[id]['code'];
              } else {
                  code = this.commonCurrencyCode (code);
              }
              let account = this.account ();
              account['free'] = this.safeFloat (balances['free'], id, 0.0);
              account['used'] = this.safeFloat (balances[usedField], id, 0.0);
              account['total'] = this.sum (account['free'], account['used']);
              result[code] = account;
          }
          return this.parseBalance (result);
      }
  
      async createOrder (symbol, type, side, amount, price = undefined, params = {}) {
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'privatePost';
          let order = {
              'symbol': market['id'],
              'type': side,
          };
          if (market['future']) {
              method += 'Future';
              order = this.extend (order, {
                  'contract_type': this.options['defaultContractType'], // this_week, next_week, quarter
                  'match_price': 0, // match best counter party price? 0 or 1, ignores price if 1
                  'lever_rate': 10, // leverage rate value: 10 or 20 (10 by default)
                  'price': price,
                  'amount': amount,
              });
          } else {
              if (type === 'limit') {
                  order['price'] = price;
                  order['amount'] = amount;
              } else {
                  order['type'] += '_market';
                  if (side === 'buy') {
                      if (this.options['marketBuyPrice']) {
                          if (price === undefined) {
                              // eslint-disable-next-line quotes
                              throw new ExchangeError (this.id + " market buy orders require a price argument (the amount you want to spend or the cost of the order) when this.options['marketBuyPrice'] is true.");
                          }
                          order['price'] = price;
                      } else {
                          order['price'] = this.safeFloat (params, 'cost');
                          if (!order['price']) {
                              // eslint-disable-next-line quotes
                              throw new ExchangeError (this.id + " market buy orders require an additional cost parameter, cost = price * amount. If you want to pass the cost of the market order (the amount you want to spend) in the price argument (the default " + this.id + " behaviour), set this.options['marketBuyPrice'] = true. It will effectively suppress this warning exception as well.");
                          }
                      }
                  } else {
                      order['amount'] = amount;
                  }
              }
          }
          params = this.omit (params, 'cost');
          method += 'Trade';
          let response = await this[method] (this.extend (order, params));
          let timestamp = this.milliseconds ();
          return {
              'info': response,
              'id': response['order_id'].toString (),
              'timestamp': timestamp,
              'datetime': this.iso8601 (timestamp),
              'lastTradeTimestamp': undefined,
              'status': undefined,
              'symbol': symbol,
              'type': type,
              'side': side,
              'price': price,
              'amount': amount,
              'filled': undefined,
              'remaining': undefined,
              'cost': undefined,
              'trades': undefined,
              'fee': undefined,
          };
      }
  
      async cancelOrder (id, symbol = undefined, params = {}) {
          if (symbol === undefined)
              throw new ExchangeError (this.id + ' cancelOrder() requires a symbol argument');
          await this.loadMarkets ();
          let market = this.market (symbol);
          let request = {
              'symbol': market['id'],
              'order_id': id,
          };
          let method = 'privatePost';
          if (market['future']) {
              method += 'FutureCancel';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
          } else {
              method += 'CancelOrder';
          }
          let response = await this[method] (this.extend (request, params));
          return response;
      }
  
      parseOrderStatus (status) {
          let statuses = {
              '-1': 'canceled',
              '0': 'open',
              '1': 'open',
              '2': 'closed',
              '3': 'open',
              '4': 'canceled',
          };
          return this.safeValue (statuses, status, status);
      }
  
      parseOrderSide (side) {
          if (side === 1)
              return 'buy'; // open long position
          if (side === 2)
              return 'sell'; // open short position
          if (side === 3)
              return 'sell'; // liquidate long position
          if (side === 4)
              return 'buy'; // liquidate short position
          return side;
      }
  
      parseOrder (order, market = undefined) {
          let side = undefined;
          let type = undefined;
          if ('type' in order) {
              if ((order['type'] === 'buy') || (order['type'] === 'sell')) {
                  side = order['type'];
                  type = 'limit';
              } else if (order['type'] === 'buy_market') {
                  side = 'buy';
                  type = 'market';
              } else if (order['type'] === 'sell_market') {
                  side = 'sell';
                  type = 'market';
              } else {
                  side = this.parseOrderSide (order['type']);
                  if (('contract_name' in order) || ('lever_rate' in order))
                      type = 'margin';
              }
          }
          let status = this.parseOrderStatus (this.safeString (order, 'status'));
          let symbol = undefined;
          if (market === undefined) {
              let marketId = this.safeString (order, 'symbol');
              if (marketId in this.markets_by_id) {
                  market = this.markets_by_id[marketId];
              }
          }
          if (market)
              symbol = market['symbol'];
          let timestamp = undefined;
          let createDateField = this.getCreateDateField ();
          if (createDateField in order)
              timestamp = order[createDateField];
          let amount = this.safeFloat (order, 'amount');
          let filled = this.safeFloat (order, 'deal_amount');
          amount = Math.max (amount, filled);
          let remaining = Math.max (0, amount - filled);
          if (type === 'market') {
              remaining = 0;
          }
          let average = this.safeFloat (order, 'avg_price');
          // https://github.com/ccxt/ccxt/issues/2452
          average = this.safeFloat (order, 'price_avg', average);
          let cost = average * filled;
          let result = {
              'info': order,
              'id': order['order_id'].toString (),
              'timestamp': timestamp,
              'datetime': this.iso8601 (timestamp),
              'lastTradeTimestamp': undefined,
              'symbol': symbol,
              'type': type,
              'side': side,
              'price': order['price'],
              'average': average,
              'cost': cost,
              'amount': amount,
              'filled': filled,
              'remaining': remaining,
              'status': status,
              'fee': undefined,
          };
          return result;
      }
  
      getCreateDateField () {
          // needed for derived exchanges
          // allcoin typo create_data instead of create_date
          return 'create_date';
      }
  
      getOrdersField () {
          // needed for derived exchanges
          // allcoin typo order instead of orders (expected based on their API docs)
          return 'orders';
      }
  
      async fetchOrder (id, symbol = undefined, params = {}) {
          if (symbol === undefined)
              throw new ExchangeError (this.id + ' fetchOrder requires a symbol parameter');
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'privatePost';
          let request = {
              'order_id': id,
              'symbol': market['id'],
              // 'status': 0, // 0 for unfilled orders, 1 for filled orders
              // 'current_page': 1, // current page number
              // 'page_length': 200, // number of orders returned per page, maximum 200
          };
          if (market['future']) {
              method += 'Future';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
          }
          method += 'OrderInfo';
          let response = await this[method] (this.extend (request, params));
          let ordersField = this.getOrdersField ();
          let numOrders = response[ordersField].length;
          if (numOrders > 0)
              return this.parseOrder (response[ordersField][0]);
          throw new OrderNotFound (this.id + ' order ' + id + ' not found');
      }
  
      async fetchOrders (symbol = undefined, since = undefined, limit = undefined, params = {}) {
          if (symbol === undefined)
              throw new ExchangeError (this.id + ' fetchOrders requires a symbol parameter');
          await this.loadMarkets ();
          let market = this.market (symbol);
          let method = 'privatePost';
          let request = {
              'symbol': market['id'],
          };
          let order_id_in_params = ('order_id' in params);
          if (market['future']) {
              method += 'FutureOrdersInfo';
              request['contract_type'] = this.options['defaultContractType']; // this_week, next_week, quarter
              if (!order_id_in_params)
                  throw new ExchangeError (this.id + ' fetchOrders() requires order_id param for futures market ' + symbol + ' (a string of one or more order ids, comma-separated)');
          } else {
              let status = undefined;
              if ('type' in params) {
                  status = params['type'];
              } else if ('status' in params) {
                  status = params['status'];
              } else {
                  let name = order_id_in_params ? 'type' : 'status';
                  throw new ExchangeError (this.id + ' fetchOrders() requires ' + name + ' param for spot market ' + symbol + ' (0 - for unfilled orders, 1 - for filled/canceled orders)');
              }
              if (order_id_in_params) {
                  method += 'OrdersInfo';
                  request = this.extend (request, {
                      'type': status,
                      'order_id': params['order_id'],
                  });
              } else {
                  method += 'OrderHistory';
                  request = this.extend (request, {
                      'status': status,
                      'current_page': 1, // current page number
                      'page_length': 200, // number of orders returned per page, maximum 200
                  });
              }
              params = this.omit (params, [ 'type', 'status' ]);
          }
          let response = await this[method] (this.extend (request, params));
          let ordersField = this.getOrdersField ();
          return this.parseOrders (response[ordersField], market, since, limit);
      }
  
      async fetchOpenOrders (symbol = undefined, since = undefined, limit = undefined, params = {}) {
          let open = 0; // 0 for unfilled orders, 1 for filled orders
          return await this.fetchOrders (symbol, since, limit, this.extend ({
              'status': open,
          }, params));
      }
  
      async fetchClosedOrders (symbol = undefined, since = undefined, limit = undefined, params = {}) {
          let closed = 1; // 0 for unfilled orders, 1 for filled orders
          let orders = await this.fetchOrders (symbol, since, limit, this.extend ({
              'status': closed,
          }, params));
          return orders;
      }
  
      async withdraw (code, amount, address, tag = undefined, params = {}) {
          this.checkAddress (address);
          await this.loadMarkets ();
          let currency = this.currency (code);
          // if (amount < 0.01)
          //     throw new ExchangeError (this.id + ' withdraw() requires amount > 0.01');
          // for some reason they require to supply a pair of currencies for withdrawing one currency
          let currencyId = currency['id'] + '_usd';
          if (tag) {
              address = address + ':' + tag;
          }
          let request = {
              'symbol': currencyId,
              'withdraw_address': address,
              'withdraw_amount': amount,
              'target': 'address', // or 'okcn', 'okcom', 'okex'
          };
          let query = params;
          if ('chargefee' in query) {
              request['chargefee'] = query['chargefee'];
              query = this.omit (query, 'chargefee');
          } else {
              throw new ExchangeError (this.id + ' withdraw() requires a `chargefee` parameter');
          }
          if (this.password) {
              request['trade_pwd'] = this.password;
          } else if ('password' in query) {
              request['trade_pwd'] = query['password'];
              query = this.omit (query, 'password');
          } else if ('trade_pwd' in query) {
              request['trade_pwd'] = query['trade_pwd'];
              query = this.omit (query, 'trade_pwd');
          }
          let passwordInRequest = ('trade_pwd' in request);
          if (!passwordInRequest)
              throw new ExchangeError (this.id + ' withdraw() requires this.password set on the exchange instance or a password / trade_pwd parameter');
          let response = await this.privatePostWithdraw (this.extend (request, query));
          return {
              'info': response,
              'id': this.safeString (response, 'withdraw_id'),
          };
      }
  
      sign (path, api = 'public', method = 'GET', params = {}, headers = undefined, body = undefined) {
          let url = '/';
          if (api !== 'web')
              url += this.version + '/';
          url += path;
          if (api !== 'web')
              url += this.extension;
          if (api === 'private') {
              this.checkRequiredCredentials ();
              let query = this.keysort (this.extend ({
                  'api_key': this.apiKey,
              }, params));
              // secret key must be at the end of query
              let queryString = this.rawencode (query) + '&secret_key=' + this.secret;
              query['sign'] = this.hash (this.encode (queryString)).toUpperCase ();
              body = this.urlencode (query);
              headers = { 'Content-Type': 'application/x-www-form-urlencoded' };
          } else {
              if (Object.keys (params).length)
                  url += '?' + this.urlencode (params);
          }
          url = this.urls['api'][api] + url;
          return { 'url': url, 'method': method, 'body': body, 'headers': headers };
      }
  
      handleErrors (code, reason, url, method, headers, body) {
          if (body.length < 2)
              return; // fallback to default error handler
          if (body[0] === '{') {
              let response = JSON.parse (body);
              if ('error_code' in response) {
                  let error = this.safeString (response, 'error_code');
                  let message = this.id + ' ' + this.json (response);
                  if (error in this.exceptions) {
                      let ExceptionClass = this.exceptions[error];
                      throw new ExceptionClass (message);
                  } else {
                      throw new ExchangeError (message);
                  }
              }
              if ('result' in response)
                  if (!response['result'])
                      throw new ExchangeError (this.id + ' ' + this.json (response));
          }
      }
  };
  