Craft Dynamic Upgrades in Minecraft

repositories {
    flatDir {
        dir 'libs'
    }
}

dependencies {
    //fg.deobf is required to remap the jar correctly in your development environment
    implementation fg.deobf("card_engine:card_engine:1.0.0")
}

@Mod(MyMod.MODID)
public class MyMod {
    public static final String MODID = "my_mod";

    public MyMod() {
        var bus = FMLJavaModLoadingContext.get().getModEventBus();
        bus.addListener(this::commonSetup);
        MinecraftForge.EVENT_BUS.register(this);
    }

    private void commonSetup(FMLCommonSetupEvent event) {
        event.enqueueWork(() -> {
            MyDashSkill.register();
            MyPassiveSkill.register();
        });
    }
}

// Line 1: Register the mechanism (binds key to vanilla Attribute)
CardRegistry.registerCard("my_mod:attack_damage", Attributes.ATTACK_DAMAGE);

// Line 2: Register the card (CardEngine handles rendering & JSON generation!)
CardRegistry.register("my_mod:attack_damage_rare", "my_mod:attack_damage");

// 1. Write your custom class implementing CardEngine
public class VampirismUpgrade implements CardEngine {
    @CardParam(10.0) // Exports "heal_ratio" (default 10.0) to JSON config automatically!
    private double heal_ratio;

    @Override
    public void apply(ServerPlayer player) {
        // heal_ratio is automatically injected with the value configured in the JSON file
        player.heal((float) (player.getMaxHealth() * (heal_ratio / 100.0)));
    }
}

// 2. Register both the mechanism class and the card:
CardRegistry.registerCard("my_mod:vampirism", VampirismUpgrade.class);
CardRegistry.register("my_mod:vamp_card", "my_mod:vampirism");

// 1. Register the active skill logic & base cooldown (e.g. 100 ticks = 5s)
CardRegistry.registerActiveSkill("my_mod:dash", 100, (player) -> {
    Vec3 look = player.getLookAngle();
    player.setDeltaMovement(look.x * 1.5, 0.2, look.z * 1.5);
    player.hurtMarked = true; // Sync movement to client

    // Play sound
    player.level().playSound(null, player.getX(), player.getY(), player.getZ(),
        SoundEvents.ENDERMAN_TELEPORT, SoundSource.PLAYERS, 1.0F, 1.0F);
});

// 2. Link the card to the active skill
CardRegistry.registerASkillCard("my_mod:dash_card", "my_mod:dash");

public class MyBuffPassiveSkill implements IPassiveSkill {
    public static final String CARD_ID = "my_mod:my_passive_card";

    @Override
    public void onEquip(ServerPlayer player, int starLevel) {
        // Attach attribute modifiers / start buffs
    }

    @Override
    public void onTick(ServerPlayer player, int starLevel) {
        // Runs every 10 ticks
    }

    @Override
    public void onUpgrade(ServerPlayer player, int newStarLevel) {
        // Refresh buff strength when the card is upgraded (1★ to 5★)
    }

    @Override
    public void onUnequip(ServerPlayer player) {
        // Remove attribute modifiers.
        // CardEngine calls CardResourceManager.cleanupBySkill() for you afterwards.
    }

    public static void register() {
        CardRegistry.registerPassiveSkill(CARD_ID, new MyBuffPassiveSkill());
        CardRegistry.registerPSkillCard(CARD_ID, "my_mod:my_passive_mech");
    }
}

public class MySummonSkill implements IActiveSkill {
    public static final String SKILL_ID = "my_mod:my_skill";
    private final List<CustomBombData> activeBombs = new CopyOnWriteArrayList<>();

    @Override
    public void trigger(ServerPlayer player) {
        // List / Set / Map: cleared automatically
        CardResourceManager.bindState(player, SKILL_ID, activeBombs);

        // Summoned entity / projectile: discarded automatically (optional TTL in ticks)
        Entity minion = spawnMinion(player);
        CardResourceManager.bindEntity(player, SKILL_ID, minion, 400);

        // NBT marker on a target: removed when the target dies or the skill is unequipped
        CardResourceManager.bindEntityNbt(targetMob, "my_custom_tag", SKILL_ID);

        // Custom cleanup callback with TTL (400 ticks = 20s)
        CardResourceManager.bindTask(player, SKILL_ID, () -> { /* custom cleanup */ }, 400);
    }

    @Override
    public void onUnequip(ServerPlayer player, int slot) {
        // cleanupBySkill() runs automatically afterwards.
        // Only clear your own local caches here.
        activeBombs.clear();
    }
}

"icon": "minecraft:nether_star"

"icon": "cardengine:textures/gui/icons/my_icon.png"
"icon": "my_addon:textures/gui/icons/my_icon.png"

@SubscribeEvent
public static void onLivingHurt(LivingHurtEvent event) {
    if (event.getSource().getEntity() instanceof Player player) {
        player.getCapability(PlayerUpgradeProvider.PLAYER_UPGRADE).ifPresent(upgrade -> {
            // Read accumulated stats from the player
            double critChance = upgrade.getStats().getOrDefault("my_mod:crit_chance", 0.0);
            if (critChance > 0.0 && player.getRandom().nextFloat() < critChance) {
                event.setAmount(event.getAmount() * 2.0f); // Deal critical double damage!
            }
        });
    }
}