ShopGui

A shop in a custom GUI

Source: src/scripting/managed/samples/ShopGui/ · version 1.0.0. The code below is read from the repository at build time.

What it shows

commands
Brigadier command trees (v1)
config (v1)
permissions (v1)

Build and run

dotnet build src/scripting/managed/samples/ShopGui -c Release
# the output lands in build/bin/dotnet/samples/ShopGui/ when built through CMake (MC_BUILD_SCRIPTING);
# copy the dll into your plugins folder and start the server with --plugins

Source

ShopGui.cs

using System.Text.Json.Serialization;

namespace ShopGui;

/// <summary>One thing the shop sells.</summary>
public sealed class ShopItem
{
    /// <summary>The item key, e.g. <c>minecraft:bread</c>.</summary>
    public string Item { get; set; } = "minecraft:bread";
    /// <summary>How many the player gets for one purchase.</summary>
    public int Count { get; set; } = 1;
    /// <summary>The price in units of the currency item.</summary>
    public int Price { get; set; } = 1;
}

/// <summary>The settings of the ShopGui plugin.</summary>
public sealed class ShopConfig
{
    /// <summary>The item players pay with.</summary>
    public string Currency { get; set; } = "minecraft:gold_ingot";
    /// <summary>The title of the shop window.</summary>
    public string Title { get; set; } = "Shop";
    /// <summary>What the shop sells, in slot order (at most 21 entries: three rows of seven).</summary>
    public List<ShopItem> Items { get; set; } =
    [
        new() { Item = "minecraft:bread", Count = 8, Price = 1 },
        new() { Item = "minecraft:arrow", Count = 16, Price = 2 },
        new() { Item = "minecraft:iron_pickaxe", Count = 1, Price = 6 },
        new() { Item = "minecraft:golden_apple", Count = 1, Price = 12 },
        new() { Item = "minecraft:diamond", Count = 1, Price = 20 },
    ];
}

[JsonSerializable(typeof(ShopConfig))]
internal sealed partial class ShopJson : JsonSerializerContext;

/// <summary>Sample: <c>/shop</c> opens a custom chest GUI. Every product is an icon with a price in its lore; clicking it pays with a currency item from the player's inventory
/// (<see cref="EngineInventory.RemoveItem"/>) and hands over the product (<see cref="PlayerInventory.Give"/>). The menu is locked by the engine: nothing in it can be taken out, shift clicked,
/// dragged or swapped away, whatever a handler does or forgets to do, so a shop has no duplication holes. It also shows <c>OnClose</c> and the config file with its live reload.</summary>
[PluginInfo("ShopGui", Version = "1.0.0", Author = "Ramjet", Description = "A shop in a custom GUI")]
public sealed class ShopGuiPlugin : Plugin
{
    private Config<ShopConfig> _config = null!;
    private Menu? _menu;

    protected override void OnEnable()
    {
        _config = Config.Load(ShopJson.Default.ShopConfig);
        _config.Watch = true;
        _config.Changed += _ => Rebuild();
        Permissions.Register("shop.use", PermissionDefault.True, "Open the shop");
        Rebuild();

        Commands.Register(Command.Literal("shop").Permission("shop.use").Executes(ctx =>
        {
            var player = ctx.RequirePlayer();
            _menu!.Open(player);
            return 1;
        }), description: "Open the shop");
    }

    // The menu is rebuilt when the config changes: the old one is closed for its viewers and the new one is opened for them again.
    private void Rebuild()
    {
        var viewers = _menu?.Viewers.ToList() ?? [];
        _menu?.Dispose();
        var config = _config.Value;
        var menu = Menus.Chest(3, Component.Text(config.Title).Color(TextColor.DarkGreen));
        menu.FillEmpty(new ItemStack("minecraft:gray_stained_glass_pane").WithName(Component.Text(" ")));
        for (int i = 0; i < Math.Min(config.Items.Count, 21); i++)
        {
            var product = config.Items[i];
            int slot = (i / 7) * 9 + 1 + (i % 7);  // three rows, columns 1-7
            var stack = new ItemStack(product.Item, product.Count);
            var icon = stack.WithLore(
                Component.Text($"Price: {product.Price} x {Pretty(config.Currency)}").Color(TextColor.Gold).Italic(false),
                Component.Text("Click to buy").Color(TextColor.Gray).Italic(false));
            menu.Slot(slot, icon, click => Buy(click, product, stack));
        }
        menu.OnClose((player, reason) => Log.Info($"{player.Name} left the shop ({reason})"));
        _menu = menu;
        foreach (var viewer in viewers)
            if (viewer.IsOnline) menu.Open(viewer);
    }

    private void Buy(MenuClick click, ShopItem product, ItemStack stack)
    {
        var player = click.Player;
        var inventory = player.Inventory;
        var price = new ItemStack(_config.Value.Currency, Math.Max(product.Price, 1));
        if (inventory.Count(price) < price.Count)
        {
            player.SendActionBar(Component.Text($"You need {price.Count} x {Pretty(price.Type)}").Color(TextColor.Red));
            player.PlaySound("minecraft:entity.villager.no", SoundCategory.Players);
            return;
        }
        inventory.RemoveItem(price);
        int dropped = inventory.Give(stack);
        player.SendActionBar(Component.Text($"Bought {stack.Count} x {Pretty(stack.Type)}" + (dropped > 0 ? " (your inventory was full: it is at your feet)" : "")).Color(TextColor.Green));
        player.PlaySound("minecraft:entity.villager.yes", SoundCategory.Players);
    }

    private static string Pretty(string key) => key[(key.IndexOf(':') + 1)..].Replace('_', ' ');
}

ShopGui.csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <McApiProject>$(MSBuildThisFileDirectory)..\..\Mc.Scripting.Api\Mc.Scripting.Api.csproj</McApiProject>
  </PropertyGroup>
  <Import Project="..\..\Mc.Scripting.Plugin.props" />
  <PropertyGroup Condition="'$(McOutDir)' != ''">
    <OutputPath>$(McOutDir)samples/ShopGui/</OutputPath>
  </PropertyGroup>
</Project>