A bot to buy low and sell high bitcoins through Coinbase

botcoin.js

/**
 * Based on the code from Martijn Frazer
 * http://pastebin.com/eZ25L9yw
 */

var fs = require('fs');
var Client = require('coinbase').Client;
var client = new Client({
  'apiKey': '',
  'apiSecret': ''
});

// BTC: Bitcoin Trading Contraption
var btc = {
  config: {
    verbose: true,
    sleep: 15,    // time in minutes between runs
    profit: 1.2,  // threshold factor to sell
    buyAmount: 15, // amount of EUR to buy per transaction
    samples: 500, // size of the sample set
    btcWallet: {
      id: '',
      address: ''
    },
    eurWallet: {
      id: '',
      address: ''
    },
    data: {
      buyRates: 'data/buyrates.json',
      btc: 'data/btc.json'
    }
  },
  go: function() {
    if(btc.config.verbose) {
      console.log("\r\n\n"+Date());
    }

    // first do some buying
    btc.buy();

    // then do some selling
    setTimeout(btc.sell, 10 * 1000);

    setTimeout(btc.go, btc.config.sleep * 60 * 1000);
  },
  buy: function() {
    client.getBuyPrice({currencyPair: "BTC-EUR"}, function(err, price) {
      if(!err) {
        var buyPrice = price.data.amount;

        if(btc.config.verbose) {
          console.log('BUY - current price is: '+buyPrice);
        }

        fs.readFile(btc.config.data.buyRates, function(err, data) {
          if(!err) {
            var buyRates = JSON.parse(data);
            var low = Infinity;

            // add current buy price to the list
            buyRates.push(buyPrice);

            // take action if we have enough samples
            if(buyRates.length >= btc.config.samples) {
              // determine low
              buyRates.forEach(function(value) {
                low = Math.min(parseFloat(value), low);
              });

              // price is low, try to buy some bitcoin
              if(buyPrice <= (low + 0.5) ) {

                if(btc.config.verbose) {
                  console.log('BUY - current price is LOW!');
                }

                // check euro wallet
                client.getAccount(btc.config.eurWallet.id, function(err, euro) {
                  if(!err) {
                    // determine amount to buy
                    var amountToBuy = Math.min(
                      btc.config.buyAmount, euro.balance.amount
                    );

                    // buy bitcoins, minimum = 1 euro
                    if(amountToBuy >= 1) {

                      if(btc.config.verbose) {
                        console.log('BUY - placing order for '+amountToBuy+' euro');
                      }

                      euro.sendMoney({
                        to: btc.config.btcWallet.address,
                        amount: amountToBuy,
                        currency: "EUR"
                      }, function(err, tx) {
                        if(!err) {
                          // get the buy resource for this transaction
                          euro.getBuy(tx.buy.id, function(err, buy) {
                            if(!err) {
                              // get current btc purchases
                              fs.readFile(btc.config.data.btc, function(err, data) {
                                if(!err) {
                                  var btcPurchases = JSON.parse(data);

                                  // add this purchase
                                  btcPurchases.push({
                                    id: buy.id,
                                    timestamp: buy.created_at,
                                    eurValue: buy.total.amount,
                                    btcValue: buy.amount.amount,
                                    rate: buyPrice
                                  });

                                  // update purchase file
                                  fs.writeFile(btc.config.data.btc, JSON.stringify(btcPurchases));
                                }
                              });
                            }
                          });
                        }
                      });
                    }
                  }
                });
              }

              buyRates.shift();
            }

            // store new list of buy rates
            fs.writeFile(btc.config.data.buyRates, JSON.stringify(buyRates));
          }
        });
      }
    });
  },
  sell: function() {
    // get list of purchases
    fs.readFile(btc.config.data.btc, function(err, data) {
      if(!err) {
        var btcPurchases = JSON.parse(data);
        var tmp = [];

        if(btcPurchases.length) {
          // get sell price
          client.getSellPrice({currencyPair: "BTC-EUR"}, function(err, price) {
            if(!err) {
              var sellPrice = price.data.amount;

              if(btc.config.verbose) {
                console.log('SELL - current price is: '+sellPrice);
              }

              btcPurchases.forEach(function(purchase) {
                // sell price is higher than desired profit factor --> SELL!
                if(sellPrice >= (purchase.rate * btc.config.profit)) {

                  client.getAccount(btc.config.btcWallet.id, function(err, bitcoin) {
                    if(!err) {
                      var sellAmount = Math.min(purchase.btcValue, bitcoin.balance.amount);

                      if(sellAmount >= 0.0001) {

                        if(btc.config.verbose) {
                          console.log('SELL - selling '+sellAmount+' btc, bought at: '+purchase.rate);
                        }

                        bitcoin.sendMoney({
                          to: btc.config.eurWallet.address,
                          amount: sellAmount,
                          currency: "BTC"
                        }, function(err, tx) {
                          if(!err) {

                            if(btc.config.verbose) {
                              console.log(
                                'SELL - profit made: '
                                +(tx.native_amount.amount - purchase.eurValue)
                              );
                            }
                          }
                        });
                      }
                    }
                  });
                } else {
                  tmp.push(purchase);
                }
              });

              // store remaining purchases in its file
              fs.writeFile(btc.config.data.btc, JSON.stringify(tmp));
            }
          });
        }
      }
    });
  }
};

btc.go();