Class: ExchangeRateConverter

Inherits:
Object
  • Object
show all
Defined in:
lib/dollar_to_euro/exchange_rate_converter.rb

Class Method Summary collapse

Class Method Details

.calculate_with_default_rate(amount, parsed_date) ⇒ Object 



22
23
24
25
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 22

def calculate_with_default_rate(amount, parsed_date)
  return Dollar.last.value * amount if parsed_date >= Date.today
  return Dollar.first.value * amount if parsed_date < Dollar.first.date
end

.convert(amount, date) ⇒ Object 



11
12
13
14
15
16
17
18
19
20
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 11

def convert(amount, date)
  parsed_date = Date.parse(date)
  # if converting at oldest or latest rate
  return calculate_with_default_rate(amount, parsed_date) if default_date?(parsed_date)
  # if exchange rate exists for the given date return the exchange
  register = Dollar.where(date: parsed_date)
  return register.first.value * amount if register.exists?
  # if the date is holiday or weekend pick the previous available rate exchange
  previous_rate_available(parsed_date) * amount if date_is_holiday_or_weekend?(date)
end

.database_is_out_of_date? ⇒ Boolean

Returns:

  • (Boolean) 


52
53
54
55
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 52

def database_is_out_of_date?
  # TODO: handle more complex scenarios
  Dollar.count.zero?
end

.date_is_holiday_or_weekend?(date) ⇒ Boolean

Returns:

  • (Boolean) 


37
38
39
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 37

def date_is_holiday_or_weekend?(date)
  weekend?(date) || holiday?(date)
end

.default_date?(parsed_date) ⇒ Boolean

returns true if date is oldest than the oldest register we have returns true if date is todays date

Returns:

  • (Boolean) 


29
30
31
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 29

def default_date?(parsed_date)
  parsed_date >= Date.today || parsed_date < Dollar.first.date
end

.holiday?(date) ⇒ Boolean

Returns:

  • (Boolean) 


41
42
43
44
45
46
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 41

def holiday?(date)
  Holidays.cache_between(Time.now, 2.years.from_now, :us, :observed)
  y, m, d = date.split '-'
  parsed_date = Date.civil(y.to_i, m.to_i, d.to_i)
  parsed_date.holiday?(:us)
end

.previous_rate_available(date) ⇒ Object 



33
34
35
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 33

def previous_rate_available(date)
  Dollar.where(:date.lte => date).last.value
end

.weekend?(date) ⇒ Boolean

Returns:

  • (Boolean) 


48
49
50
 
# File 'lib/dollar_to_euro/exchange_rate_converter.rb', line 48

def weekend?(date)
  [6, 7].include?(Date.parse(date).cwday)
end