[Issue Report]: Expensive Wirt items are considered invalid and cannot be used

[StephenCWills]

Operating System

Windows x64

DevilutionX version

Custom build (please specify commit ID)

Describe

You can buy an item from Wirt in Diablo and, due to the 1.5x price adjustment, immediately be unable to use it because it's too expensive.

To Reproduce

Note: The following steps will no longer reproduce the issue using the latest commits from master. You will need to either test using a commit before d8811eb or find a way to reproduce in Multiplayer.

1. Download single_0.sv.zip
2. Load game
3. Buy the Great Sword of Haste from Wirt
4. Open your inventory and observe that it cannot be used

Expected Behavior

No response

Additional context

Wirt's price adjustment gets applied to the item's _iIvalue field in BoyBuyEnter().

devilutionX/Source/stores.cpp

Lines 1769 to 1786 in 9427513

	int price = BoyItem._iIvalue;
	if (gbIsHellfire)
	price -= BoyItem._iIvalue / 4;
	else
	price += BoyItem._iIvalue / 2;
	if (!PlayerCanAfford(price)) {
	StartStore(TalkID::NoMoney);
	return;
	}
	if (!StoreAutoPlace(BoyItem, false)) {
	StartStore(TalkID::NoRoom);
	return;
	}
	TempItem = BoyItem;
	TempItem._iIvalue = price;

Since the price goes up in Diablo, the price adjustment can drive the _iIvalue stat above the price limit and cause the logic in IsShopPriceValid() to produce the wrong result.

devilutionX/Source/items/validation.cpp

Lines 59 to 63 in 9427513

	bool IsShopPriceValid(const Item &item)
	{
	const int boyPriceLimit = MaxBoyValue;
	if (!gbIsHellfire && (item._iCreateInfo & CF_BOY) != 0 && item._iIvalue > boyPriceLimit)
	return false;

Introduced by commit cfac786. Prior to that commit, IsShopPriceValid() was only called on items that were just regenerated and therefore not price-adjusted.

Tested using commit f4b6b54

[StephenCWills]

To fix this issue, I'd recommend applying Wirt's price adjustment as-needed rather than storing it directly in _iIvalue. However, I haven't really evaluated that solution to see if it's viable. Given how messy the shop code is, I wouldn't be surprised if it wasn't.

[StephenCWills]

New steps to reproduce in Multiplayer:

1. Download multi_0.sv.zip
2. Force DungeonSeed[0] to 3383747080 in the NetInit() function
3. Start a game, walk to Wirt, and buy the Emerald Axe
4. Open your inventory and observe that it cannot be used