check and update buy/sell price on coinbase

coinbase-price

#!/usr/bin/env ruby
# get coinbase price
###
require 'coinbase'
require 'optparse'

# your API key - https://coinbase.com/docs/api/authentication
COINBASE_API = ''
UP_ARROW = "\u25B2".encode('utf-8')
DOWN_ARROW = "\u25BC".encode('utf-8')


if __FILE__ == $0

  options = {}
  OptionParser.new do |opts|
    opts.banner = "Usage #{$0}: [amount] [interval] [-b|--bare - price only]"

    opts.on "-b", "--bare", "bare (price only) output" do |v|
      options[:bare] = v
    end
    
  end.parse!

  coinbase = Coinbase::Client.new(COINBASE_API)
  amount = (ARGV[0] || 1).to_f
  rate = (ARGV[1] || 5).to_i

  buy_price = coinbase.buy_price(amount).to_f
  sell_price = coinbase.sell_price(amount).to_f


  if options[:bare]
    puts "#{ buy_price }\t#{sell_price}"
  else
    puts "[ MONITORING #{ amount } btc @#{ rate }s ]"

    last_buy = buy_price
    last_sell = sell_price

    while true do

      buy_price = coinbase.buy_price(amount).to_f
      sell_price = coinbase.sell_price(amount).to_f

      sell_change = ""
      buy_change = ""

      if last_buy < buy_price
        buy_change = UP_ARROW
      elsif last_buy > buy_price
        buy_change = DOWN_ARROW
      end

      if last_sell < sell_price
        sell_change = UP_ARROW
      elsif last_sell > sell_price
        sell_change = DOWN_ARROW
      end

      system('clear')
      puts "-------- COINBASE PRICE --------"
      puts " amount: #{ amount }btc"
      puts " buy price : $#{ buy_price} #{ buy_change }"
      puts " sell price : $#{ sell_price} #{ sell_change }"
      puts "--------------------------------"

      last_buy = buy_price
      last_sell = sell_price

      sleep(rate)
    end

  end
end