Class: Bitex::Rates

Inherits:
Object
  • Object
show all
Defined in:
lib/bitex/rates.rb

Overview

Exchange Rates Tree. Example calculation for turning 1000 ARS in cash to USD credited to your bitex balance using more_mt as the funding option.

Bitex::Rates.calculate(1000, [:ars, :cash, :usd, :bitex, :more_mt])

Also available backwards: How many ARS should I deposit using more_mt to end up with 200 USD in my bitex balance?

Bitex::Rates.calculate_back([:ars, :cash, :usd, :bitex, :more_mt], 200)

See Also:

Class Method Summary collapse

Class Method Details

.calculate_path(value, path) ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/bitex/rates.rb', line 26

def self.calculate_path(value, path)
  value = value.to_d
  path_to_calculator(path).each do |step|
    step.symbolize_keys!
    case step[:type].to_sym
    when :exchange
      value *= step[:rate].to_d
    when :percentual_fee
      value *= 1 - (step[:percentage].to_d / 100.to_d)
    when :fixed_fee
      value -= step[:amount].to_d
    when :minimum_fee
      value -= [step[:minimum].to_d, value * step[:percentage].to_d / 100.to_d].max
    end
  end
  value
end

.calculate_path_backwards(path, value) ⇒ Object 



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# File 'lib/bitex/rates.rb', line 44

def self.calculate_path_backwards(path, value)
  value = value.to_d
  path_to_calculator(path).each do |step|
    step.symbolize_keys!
    case step[:type].to_sym
    when :exchange
      value /= step[:rate].to_d
    when :percentual_fee
      value /= 1 - (step[:percentage].to_d / 100.to_d)
    when :fixed_fee
      value += step[:amount].to_d
    when :minimum_fee
      value = [value + step[:minimum].to_d, value / (1 - (step[:percentage].to_d / 100.to_d))].max
    end
  end
  value
end

.clear_tree_cache ⇒ Object 



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# File 'lib/bitex/rates.rb', line 20

def self.clear_tree_cache
  @tree = nil
  @last_tree_fetch = nil
end

.path_to_calculator(path) ⇒ Object

rubocop:enable Metrics/AbcSize



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# File 'lib/bitex/rates.rb', line 63

def self.path_to_calculator(path)
  steps = tree
  begin
    path.each { |step| steps = steps[step] }
  rescue StandardError
    raise "InvalidPath: #{path}"
  end
  steps
end

.tree ⇒ Object

Full exchange rates tree, gets cached locally for 60 seconds.



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# File 'lib/bitex/rates.rb', line 12

def self.tree
  if @tree.nil? || @last_tree_fetch.to_i < (Time.now.to_i - 60)
    @tree = Api.public('/rates/tree').deep_symbolize_keys
    @last_tree_fetch = Time.now.to_i
  end
  @tree
end