lackac/justcoin

require "faraday"
require "faraday_middleware"

require "justcoin/version"
require "justcoin/body_extractor"
require "justcoin/decimal_converter"

class Justcoin

  DEFAULT_URL = "https://justcoin.com/api/v1".freeze

  attr_reader :key, :options, :client

  # Creates a new Justcoin client.
  #
  # @param key the API key, get it from
  #   https://justcoin.com/client/#settings/apikeys
  # @param options the client can receive the following options
  #   * `:log` [true/false] – whether to log requests and responses
  #   * `:logger` [Logger] – a custom logger instance, implies `log: true`
  #   * `:raw` [true/false] – whether to return the raw Faraday::Response object instead of a parsed value
  #   * any other options are passed on to the Faraday client
  def initialize(key, options={})
    @key = key

    options[:url] ||= DEFAULT_URL
    options[:params] ||= {}
    options[:params][:key] ||= key
    options[:headers] ||= {}
    options[:headers][:user_agent] ||= "Justcoin ruby client v#{Justcoin::VERSION}"
    @options = options

    @client = build_client
  end

  # List balances
  #
  # @return [Array] an array of current balances
  def balances
    client.get "balances"
  end

  # List markets
  #
  # @return [Array] an array of markets with current statistics
  def markets
    client.get "markets"
  end

  # Retrieve market depth
  #
  # @param [String/Symbol] id the id of the market (e.g. `:btcstr`)
  # @return [Hashie::Mash] `bids` and `asks` as arrays of `[price, volume]` pairs
  def market_depth(id)
    client.get "markets/#{id.upcase}/depth"
  end

  # Retrieve active user orders
  #
  # @return [Array] an array of the user's active orders
  def orders
    client.get "orders"
  end

  # Retrieve a specific user order
  #
  # Works for all kinds of orders: active, cancelled, or historical.
  #
  # @param id the id of the order
  # @return [Hashie::Mash] information about the order including matches
  def order(id)
    client.get "orders/#{id}"
  end

  # Create an order
  #
  # @param [String/Symbol] market the id of the market (e.g. `:btcstr`)
  # @param type the order type; can be `:bid` (buy base currency) or `:ask` (sell base currency)
  # @param [Numeric/String/nil] price the order price; if set to `nil`,
  #   the order is placed as a market order
  # @param [Numeric/String] amount the amount of base currency
  #   (identified by the first three letters of the market id) to buy/sell
  # @return [Hashie::Mash] includes the order id if the order is successfully created
  def create_order(market, type, price, amount)
    type = type.downcase.to_sym
    raise ArgumentError, "type must be either :bid or :ask" unless [:bid, :ask].include?(type)

    params = {
      market: market.upcase,
      type: type,
      price: price,
      amount: amount
    }

    client.post "orders", params
  end
  alias_method :place_order, :create_order

  # Cancel the remainder of the specified order
  #
  # @param id the id of the order
  # @return true if cancelling the order was successful
  def cancel_order(id)
    client.delete("orders/#{id}") == ""
  end

  private

  def client_options
    options.select { |k,v| Faraday::ConnectionOptions.members.include?(k) }
  end

  def build_client
    Faraday.new(client_options) do |f|
      unless options[:raw]
        # This extracts the body and discards all other data from the
        # Faraday::Response object. It should be placed here in the middle
        # of the stack so that it runs as the last one.
        f.use Justcoin::BodyExtractor
        f.use Justcoin::DecimalConverter
      end

      f.request :json
      f.response :mashify
      f.response :dates
      f.response :json, content_type: /\bjson$/
      f.response :logger, options[:logger] if options[:logger] || options[:log]
      f.response :raise_error

      f.adapter Faraday.default_adapter
    end
  end

end