# frozen_string_literal: true

require('openssl')
require('base64')
require('curb')
require('json')

# @author Hernani Rodrigues Vaz
module Cex
  # classe para processar dados no kraken
  class Client
    # @return [String] API key
    attr_reader :aky
    # @return [String] API secret
    attr_reader :asc
    # @return [String] API public url
    attr_reader :puu
    # @return [String] API private url
    attr_reader :pru
    # @return [String] API private path
    attr_reader :pth

    # @param [String] pky API key
    # @param [String] psc API secret
    # @return [Client] API kraken base
    def initialize(pky: ENV['KRAKEN_API_KEY'], psc: ENV['KRAKEN_API_SECRET'], options: {})
      b = options.fetch(:base_uri, 'https://api.kraken.com')
      v = options.fetch(:version, 0)
      @aky = pky
      @asc = psc
      @puu = "#{b}/#{v}/public/"
      @pru = "#{b}/#{v}/private/"
      @pth = "/#{v}/private/"
    end

    # @return [Hash] resultados ultimas transacoes trades no kraken
    # @example
    #  {
    #    'trades' => {
    #      'TLADFV-QIUTN-QDNCBR' => {
    #        'ordertxid' => 'O2CRFG-5PCJA-EMX7VC',
    #        'pair' => 'XETHXXBT',
    #        'time' => 1_463_422_494.7069,
    #        'type' => 'buy',
    #        'ordertype' => 'market',
    #        'price' => '0.024400',
    #        'cost' => '1.358424',
    #        'fee' => '0.003532',
    #        'vol' => '55.67311475',
    #        'margin' => '0.000000',
    #        'misc' => ''
    #      },
    #      ...
    #    },
    #    'count' => 156
    #  }
    def trades_history
      post_private('TradesHistory')['result']
    end

    # @return [Hash] resultados ultimas transacoes ledger no kraken
    # @example
    #  {
    #    'ledger' => {
    #      'LUK3QC-QW6TA-27B7NI' => {
    #        'refid' => 'A2BNCQS-CHCETZ-JYCER6',
    #        'time' => 1_584_349_306.9479,
    #        'type' => 'withdrawal',
    #        'subtype' => '',
    #        'aclass' => 'currency',
    #        'asset' => 'XETH',
    #        'amount' => '-29.2659039100',
    #        'fee' => '0.0050000000',
    #        'balance' => '1.1806988100'
    #      }
    #      ,
    #      ...
    #    },
    #    'count' => 373
    #  }
    def ledger
      post_private('Ledgers')['result']
    end

    # @return [Hash] saldos no kraken
    # @example
    #  {
    #    'ZEUR' => '0.0000',
    #    'XXBT' => '0.0000000000',
    #    'XETH' => '1.1806988100',
    #    'XETC' => '0.0000000000',
    #    'EOS' => '0.0000001700',
    #    'BCH' => '0.0000000000'
    #  }
    def balance
      post_private('Balance')['result']
    end

    # @return [Hash] data hora kraken
    # @example
    #  {
    #    'unixtime' => 1_598_956_727,
    #    'rfc1123' => 'Tue,  1 Sep 20 10:38:47 +0000'
    #  }
    def server_time
      get_public('Time')['result']
    end

    private

    # HTTP GET request for public API queries.
    def get_public(method, **opts)
      parse_response(Curl.get("#{puu}#{method}", opts))
    end

    # HTTP POST request for private API queries involving user credentials.
    def post_private(method, **opts)
      # Generate a continually-increasing unsigned 51-bit integer nonce from the current Unix Time.
      opts.merge!({ nonce: Integer(Time.now) * 1_000_000 })

      parse_response(Curl.post("#{pru}#{method}", opts) do |r|
                       r.headers = {
                         'api-key': aky,
                         'api-sign': authenticate(method, opts[:nonce], opts.map { |p| p.join('=') }.join('&'))
                       }
                     end)
    end

    def authenticate(method, nonce, params)
      raise(ArgumentError, 'API Key is not set') unless aky
      raise(ArgumentError, 'API Secret is not set') unless asc

      Base64.strict_encode64(OpenSSL::HMAC.digest(
                               'sha512',
                               Base64.decode64(asc),
                               "#{pth}#{method}#{Digest::SHA256.digest("#{nonce}#{params}")}"
                             ))
    end

    def parse_response(http)
      # HTTP_SUCCESS = 200
      http.response_code == 200 ? JSON.parse(http.body) : http.status
    rescue JSON::ParserError,
           EOFError,
           Errno::ECONNRESET,
           Errno::EINVAL,
           Net::HTTPBadResponse,
           Net::HTTPHeaderSyntaxError,
           Net::ProtocolError,
           Timeout::Error => e
      "Erro da API #{e.inspect}"
    end
  end
end