Feat: Add a hotkey to enable price tooltip

[mattpsvreis]

As described in #5 and #11, the game stutters heavily when playing the multiplayer version of SPT, FIKA, more evident with weapons which has a bunch of mods that generates a bunch of calls to the server causing a considerable freeze on the game if you're also playing with people overseas with over a hundred ping, sometimes it being 5 seconds freezes during raids or whatnot (my case). This is very bad and I understand you're looking into a way of fixing this - a price caching approach isn't that bad but for now we really need a band-aid fix to at least put it at bay and have us control when we want the game to actually freeze to check the flea market prices through a hotkey.

In the PR #8, this hotkey was added but it wasn't merged in for some reason and the code got stale and needed to be updated. I went ahead and fixed the conflicts myself through this fork and urge for this to be merged at your earliest convenience.

Furthermore, I'll make a suggestion of how I'd approach the fetching based on my developer knowledge. I'm not that knowledgeable with SPT/FIKA/EFT coding so bear with me:

private static async Task PrefixAsync(ref string text, ref float delay, SimpleTooltip __instance)
{
    bool isFleaEligible = false;
    double lowestFleaOffer = 0;

    bool modifierKeyHeld = Input.GetKey((KeyCode)LootValueMod.showPriceKey.Value) || LootValueMod.showPriceKey.Value == 0;
    bool inRaidAndCanShowInRaid = HasRaidStarted() && LootValueMod.showFleaPricesInRaid.Value;

    // Early exit if conditions aren't met
    if (hoveredItem == null || !Session.Profile.Examined(hoveredItem) || !LootValueMod.showPrices.Value || (!HasRaidStarted() && !inRaidAndCanShowInRaid) || !modifierKeyHeld)
    {
        return;
    }

    delay = 0; // Show tooltip immediately if showing price
    tooltip = __instance;

    TraderOffer bestTraderOffer = GetBestTraderOffer(hoveredItem);
    int fleaPricePerSlot = 0, traderPricePerSlot = 0;

    // Fetch flea prices asynchronously
    if (hoveredItem is Weapon weapon)
    {
        double totalFleaPrice = await FetchWeaponModsFleaPrices(weapon);

        if (totalFleaPrice > 0)
        {
            isFleaEligible = true;
            lowestFleaOffer = totalFleaPrice;
        }
    }
    else
    {
        double? fleaPrice = await FleaPriceCache.FetchPriceAsync(hoveredItem.TemplateId);

        if (fleaPrice.HasValue)
        {
            isFleaEligible = true;
            lowestFleaOffer = fleaPrice.Value * hoveredItem.StackObjectsCount;
        }
    }

    // Calculate prices per slot and set text
    var size = hoveredItem.CalculateCellSize();
    int slots = size.X * size.Y;

    if (isFleaEligible)
        fleaPricePerSlot = (int)Math.Round(lowestFleaOffer / slots);

    if (bestTraderOffer != null)
    {
        double totalTraderPrice = bestTraderOffer.Price;
        traderPricePerSlot = (int)Math.Round(totalTraderPrice / slots);
        SetText(traderPricePerSlot, fleaPricePerSlot, totalTraderPrice, slots, ref text, bestTraderOffer.TraderName);
    }

    if (isFleaEligible)
        SetText(fleaPricePerSlot, traderPricePerSlot, lowestFleaOffer, slots, ref text, "Flea");
}

private static async Task<double> FetchWeaponModsFleaPrices(Weapon weapon)
{
    double totalFleaPrice = 0;

    // Create tasks for each mod's flea price fetching
    List<Task<double?>> priceTasks = new();
    foreach (Mod mod in weapon.Mods)
    {
        priceTasks.Add(FleaPriceCache.FetchPriceAsync(mod.TemplateId));
    }

    // Await all tasks simultaneously
    double?[] prices = await Task.WhenAll(priceTasks);

    for (int i = 0; i < prices.Length; i++)
    {
        if (prices[i].HasValue)
        {
            totalFleaPrice += prices[i].Value * weapon.Mods[i].StackObjectsCount;
        }
    }

    return totalFleaPrice;
}

What key improvements I suggest are:

1. Asynchronous Price Fetching: Using Task.WhenAll in FetchWeaponModsFleaPrices allows all flea price requests to run concurrently.
2. Reduced Blocking with await: No .Result calls prevent blocking the main thread, allowing smoother gameplay.
3. Early Exit: Conditions are checked upfront, exiting early if prices shouldn’t be shown.

Obviously this depends on adaptation to your mod and some tweaks here and there for actual usage - but this is what I could think of in my current knowledge.

[mattpsvreis]

@IhanaMies