115 lines
5.4 KiB
Python
115 lines
5.4 KiB
Python
from django.core.cache import caches
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from pint import UnitRegistry, UndefinedUnitError, PintError
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from decimal import Decimal
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from cookbook.helper.cache_helper import CacheHelper
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from cookbook.models import Ingredient, Unit
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# basic units that should be considered for "to" conversions
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# TODO possible remove this hardcoded units and just add a flag to the unit
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CONVERT_TO_UNITS = {
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'metric': ['g', 'kg', 'ml', 'l'],
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'us': ['ounce', 'pound', 'fluid_ounce', 'pint', 'quart', 'gallon'],
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'uk': ['ounce', 'pound', 'imperial_fluid_ounce', 'imperial_pint', 'imperial_quart', 'imperial_gallon'],
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}
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class UnitConversionHelper:
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space = None
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def __init__(self, space):
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"""
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Initializes unit conversion helper
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:param space: space to perform conversions on
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"""
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self.space = space
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def base_conversions(self, ingredient_list):
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"""
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Calculates all possible base unit conversions for each ingredient give.
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Converts to all common base units IF they exist in the unit database of the space.
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For useful results all ingredients passed should be of the same food, otherwise filtering afterwards might be required.
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:param ingredient_list: list of ingredients to convert
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:return: ingredient list with appended conversions
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"""
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ureg = UnitRegistry()
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pint_converted_list = ingredient_list.copy()
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for i in ingredient_list:
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try:
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conversion_unit = i.unit.name
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if i.unit.base_unit:
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conversion_unit = i.unit.base_unit
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quantitiy = ureg.Quantity(f'{i.amount} {conversion_unit}')
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# TODO allow setting which units to convert to? possibly only once conversions become visible
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units = caches['default'].get(CacheHelper(self.space).BASE_UNITS_CACHE_KEY, None)
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if not units:
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units = Unit.objects.filter(space=self.space, base_unit__in=(CONVERT_TO_UNITS['metric'] + CONVERT_TO_UNITS['us'] + CONVERT_TO_UNITS['uk'])).all()
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caches['default'].set(CacheHelper(self.space).BASE_UNITS_CACHE_KEY, units, 60 * 60) # cache is cleared on unit save signal so long duration is fine
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for u in units:
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try:
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converted = quantitiy.to(u.base_unit)
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ingredient = Ingredient(amount=Decimal(converted.m), unit=u, food=ingredient_list[0].food, )
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if not any((x.unit.name == ingredient.unit.name or x.unit.base_unit == ingredient.unit.name) for x in pint_converted_list):
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pint_converted_list.append(ingredient)
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except PintError:
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pass
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except PintError:
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pass
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return pint_converted_list
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def get_conversions(self, ingredient):
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"""
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Converts an ingredient to all possible conversions based on the custom unit conversion database.
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After that passes conversion to UnitConversionHelper.base_conversions() to get all base conversions possible.
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:param ingredient: Ingredient object
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:return: list of ingredients with all possible custom and base conversions
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"""
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conversions = [ingredient]
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if ingredient.unit:
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for c in ingredient.unit.unit_conversion_base_relation.all():
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r = self._uc_convert(c, ingredient.amount, ingredient.unit, ingredient.food)
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if r and r not in conversions:
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conversions.append(r)
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for c in ingredient.unit.unit_conversion_converted_relation.all():
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r = self._uc_convert(c, ingredient.amount, ingredient.unit, ingredient.food)
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if r and r not in conversions:
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conversions.append(r)
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conversions = self.base_conversions(conversions)
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return conversions
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def _uc_convert(self, uc, amount, unit, food):
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"""
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Helper to calculate values for custom unit conversions.
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Converts given base values using the passed UnitConversion object into a converted Ingredient
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:param uc: UnitConversion object
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:param amount: base amount
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:param unit: base unit
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:param food: base food
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:return: converted ingredient object from base amount/unit/food
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"""
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if uc.food is None or uc.food == food:
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if unit == uc.base_unit:
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return Ingredient(amount=amount * (uc.converted_amount / uc.base_amount), unit=uc.converted_unit, food=food, space=self.space)
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# return {
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# 'amount': amount * (uc.converted_amount / uc.base_amount),
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# 'unit': {
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# 'id': uc.converted_unit.id,
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# 'name': uc.converted_unit.name,
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# 'plural_name': uc.converted_unit.plural_name
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# },
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# }
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else:
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return Ingredient(amount=amount * (uc.base_amount / uc.converted_amount), unit=uc.base_unit, food=food, space=self.space)
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# return {
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# 'amount': amount * (uc.base_amount / uc.converted_amount),
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# 'unit': {
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# 'id': uc.base_unit.id,
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# 'name': uc.base_unit.name,
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# 'plural_name': uc.base_unit.plural_name
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# },
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# }
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