39 lines
1.5 KiB
Python
39 lines
1.5 KiB
Python
#
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import logging
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import datetime
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import math
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logging.basicConfig(level=logging.DEBUG)
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logg = logging.getLogger()
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class DemurrageCalculator:
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def __init__(self, interest_f_minute):
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self.r_min = interest_f_minute
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self.r_hour = 1 - ((1 -self.r_min) ** 60)
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self.r_day = 1 - ((1 -self.r_hour) ** 24)
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#self.r_week = interest_f_day ** 7
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logg.info('demurrage calculator set with min {:.32f} hour {:.32f} day {:.32f}'.format(self.r_min, self.r_hour, self.r_day))
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def amount_since(self, amount, timestamp):
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delta = datetime.datetime.utcnow() - datetime.datetime.fromtimestamp(timestamp)
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adjusted_amount = amount * ((1 - self.r_day) ** (delta.days))
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logg.debug('adjusted for {} days {} -> {}'.format(delta.days, amount, adjusted_amount))
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remainder = delta.seconds
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remainder_hours = math.floor(remainder / (60 * 60))
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adjusted_delta = adjusted_amount * ((1 - self.r_hour) ** remainder_hours)
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adjusted_amount -= (adjusted_amount - adjusted_delta)
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logg.debug('adjusted for {} hours {} -> {} delta {}'.format(remainder_hours, amount, adjusted_amount, adjusted_delta))
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remainder -= (remainder_hours * (60 * 60))
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remainder_minutes = math.floor(remainder / 60)
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adjusted_delta = adjusted_amount * ((1 - self.r_min) ** remainder_minutes)
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adjusted_amount -= (adjusted_amount - adjusted_delta)
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logg.debug('adjusted for {} hours {} -> {} delta {}'.format(remainder_minutes, amount, adjusted_amount, adjusted_delta))
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return adjusted_amount
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