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https://github.com/emilybache/GildedRose-Refactoring-Kata.git
synced 2026-10-14 18:15:41 +00:00
uzairarslan
fc9ceaad09
ItemUpdater has the normal rules. Brie, backstage passes and Sulfuras subclass it and override only what differs. GildedRose picks the right one through updater_for. Tests and approved output unchanged.
95 lines
2.5 KiB
Python
Executable File
95 lines
2.5 KiB
Python
Executable File
# -*- coding: utf-8 -*-
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AGED_BRIE = "Aged Brie"
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BACKSTAGE_PASS = "Backstage passes to a TAFKAL80ETC concert"
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SULFURAS = "Sulfuras, Hand of Ragnaros"
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MIN_QUALITY = 0
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MAX_QUALITY = 50
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class GildedRose(object):
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def __init__(self, items):
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self.items = items
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def update_quality(self):
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for item in self.items:
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updater_for(item).update(item)
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class ItemUpdater:
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"""End-of-day rules for an ordinary item.
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Subclasses override only the part that differs for their category. Quality
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is assumed to start within [MIN_QUALITY, MAX_QUALITY] as the requirements
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state; it is clamped to that range after every change.
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"""
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def update(self, item):
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self._change_quality(item, self._quality_delta(item))
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item.sell_in -= 1
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def _quality_delta(self, item):
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return -2 if self._sell_by_date_passed(item) else -1
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@staticmethod
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def _sell_by_date_passed(item):
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# sell_in is the number of days left to sell, so on the day it reaches
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# 0 the item goes past its sell-by date as this update runs.
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return item.sell_in <= 0
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@staticmethod
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def _change_quality(item, delta):
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item.quality = max(MIN_QUALITY, min(MAX_QUALITY, item.quality + delta))
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class AgedBrieUpdater(ItemUpdater):
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"""Appreciates at the same rate ordinary items degrade."""
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def _quality_delta(self, item):
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return 2 if self._sell_by_date_passed(item) else 1
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class BackstagePassUpdater(ItemUpdater):
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"""Appreciates faster as the concert approaches, then becomes worthless."""
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def _quality_delta(self, item):
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if self._sell_by_date_passed(item):
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return -item.quality
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if item.sell_in <= 5:
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return 3
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if item.sell_in <= 10:
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return 2
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return 1
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class SulfurasUpdater(ItemUpdater):
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"""Legendary: never has to be sold and never changes."""
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def update(self, item):
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pass
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_UPDATERS_BY_NAME = {
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AGED_BRIE: AgedBrieUpdater(),
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BACKSTAGE_PASS: BackstagePassUpdater(),
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SULFURAS: SulfurasUpdater(),
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}
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_DEFAULT_UPDATER = ItemUpdater()
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def updater_for(item):
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"""Pick the rule set that applies to an item. Updaters are stateless."""
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return _UPDATERS_BY_NAME.get(item.name, _DEFAULT_UPDATER)
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class Item:
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def __init__(self, name, sell_in, quality):
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self.name = name
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self.sell_in = sell_in
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self.quality = quality
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def __repr__(self):
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return "%s, %s, %s" % (self.name, self.sell_in, self.quality)
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