From a0c30cea4665abb7f021db7fb54878ec37568430 Mon Sep 17 00:00:00 2001
From: SikongJueluo <selfconfusion@gmail.com>
Date: Mon, 1 Dec 2025 20:50:15 +0800
Subject: [PATCH] feat(C4): add basic C4 item with its blocks

---
 src/startup_scripts/C4.js | 188 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 188 insertions(+)
 create mode 100644 src/startup_scripts/C4.js

diff --git a/src/startup_scripts/C4.js b/src/startup_scripts/C4.js
new file mode 100644
index 0000000..8539dbd
--- /dev/null
+++ b/src/startup_scripts/C4.js
@@ -0,0 +1,188 @@
+const C4_EXPLOSION_TIME = 3 * 20;
+const C4_EXPLOSION_RANGE = 256;
+
+/**
+ * @type {Map<Internal.UUID, {
+ *  angle: {x: number, y:number, z:number},
+ *  pos: {x: number, y: number, z: number}
+ * }>}
+ */
+const lastPlayerInfoMap = new Map();
+
+/**
+ * @param {Internal.ItemStack} itemstack
+ * @param {Internal.Level} level
+ * @param {Internal.Player} player
+ * @returns {boolean}
+ */
+function shouldActivateC4(itemstack, level, player) {
+    const playerPos = player.position();
+    const block = level.getBlock(
+        playerPos.x() - 1, // Must subtract 1, is it a Bug ???
+        playerPos.y() - 1, // The block under the player
+        playerPos.z(),
+    );
+
+    const lookAngle = player.lookAngle;
+    const lastPlayerInfo = lastPlayerInfoMap.get(player.UUID);
+    if (lastPlayerInfo === undefined) return false;
+    const isPlayerInfoChanged =
+        lookAngle.x() !== lastPlayerInfo.angle.x ||
+        lookAngle.y() !== lastPlayerInfo.angle.y ||
+        lookAngle.z() !== lastPlayerInfo.angle.z ||
+        playerPos.x() !== lastPlayerInfo.pos.x ||
+        playerPos.y() !== lastPlayerInfo.pos.y ||
+        playerPos.z() !== lastPlayerInfo.pos.z;
+
+    return (
+        /** @type {string} */ (block.id) === "kubejs:c4_target" &&
+        !isPlayerInfoChanged
+    );
+}
+
+StartupEvents.registry("block", (event) => {
+    event
+        .create("c4_target") // Create a new block
+        .soundType(SoundType.WOOD) // Set a material (affects the sounds and some properties)
+        .unbreakable()
+        .textureAll("minecraft:block/target_top")
+        .displayName(/** @type {any} */ ("C4 Target Block")); // Set a custom name
+});
+
+StartupEvents.registry("block", (event) => {
+    event
+        .create("c4") // Create a new block
+        .soundType(SoundType.GRASS) // Set a material (affects the sounds and some properties)
+        .hardness(1) // Set hardness (affects mining time)
+        .resistance(1) // Set resistance (to explosions, etc)
+        .noItem() // Player cannot hold or place the item
+        .noDrops()
+        .noCollision() // Set no hitbox
+        .textureAll("minecraft:block/tnt_top")
+        .displayName(/** @type {any} */ ("C4")); // Set a custom name
+});
+
+let c4PlacedGameTime = 0;
+StartupEvents.registry("item", (event) => {
+    event
+        .create("c4_item")
+        .unstackable()
+        .useAnimation("eat")
+        .useDuration((itemStack) => 100) // 5 Seconds
+        .use((level, player, hand) => {
+            const playerPos = player.position();
+            const block = level.getBlock(
+                playerPos.x() - 1, // Must subtract 1, is it a Bug ???
+                playerPos.y() - 1, // The block under the player
+                playerPos.z(),
+            );
+
+            if (/** @type {string} */ (block.id) === "kubejs:c4_target") {
+                const itemstack = player.getUseItem();
+
+                const lookAngle = player.lookAngle;
+                lastPlayerInfoMap.set(player.UUID, {
+                    angle: {
+                        x: lookAngle.x(),
+                        y: lookAngle.y(),
+                        z: lookAngle.z(),
+                    },
+                    pos: {
+                        x: playerPos.x(),
+                        y: playerPos.y(),
+                        z: playerPos.z(),
+                    },
+                });
+
+                return true;
+            } else {
+                return false;
+            }
+        })
+        .finishUsing((itemstack, level, entity) => {
+            if (!entity.isPlayer()) {
+                itemstack.shrink(1);
+                return itemstack;
+            }
+
+            if (
+                !shouldActivateC4(itemstack, level, /** @type {any} */ (entity))
+            ) {
+                return itemstack; // Do nothing
+            }
+
+            const playerPos = entity.position();
+            const newBlock = level.getBlock(playerPos);
+            newBlock.set(/** @type {any} */ ("kubejs:c4"));
+
+            itemstack.shrink(1);
+            itemstack.resetHoverName();
+
+            const server = level.server;
+            c4PlacedGameTime = level.levelData.getGameTime();
+            server.scheduleInTicks(20, (event) => {
+                const gameTime = level.levelData.getGameTime();
+                const explosionRestTime =
+                    C4_EXPLOSION_RANGE - gameTime - c4PlacedGameTime;
+                if (explosionRestTime > 0) {
+                    server.tell(
+                        /** @type {Component} */ (
+                            Component.literal(
+                                `C4还剩 ${Math.floor(explosionRestTime / 20)} 秒`,
+                            )
+                        ),
+                    );
+                    event.reschedule(20);
+                } else {
+                    const blockPos = newBlock.pos;
+                    level.explode(
+                        /** @type {any} */ (null),
+                        blockPos.x,
+                        blockPos.y,
+                        blockPos.z,
+                        C4_EXPLOSION_RANGE,
+                        "block",
+                    );
+                }
+            });
+
+            return itemstack;
+        })
+        .releaseUsing((itemstack, level, entity, count) => {
+            itemstack.resetHoverName();
+            if (!entity.isPlayer()) return;
+            lastPlayerInfoMap.delete(entity.UUID);
+        })
+        .displayName(/** @type {any} */ ("C4"));
+});
+
+let useItemTickCnt = 0;
+const useItemTickInterval = 5;
+ForgeEvents.onEvent(
+    "net.minecraftforge.event.entity.living.LivingEntityUseItemEvent$Tick",
+    (event) => {
+        // Check every 5 ticks (0.25s)
+        if (useItemTickCnt++ % useItemTickInterval !== 0) return;
+
+        const itemstack = event.getItem();
+        if (/** @type {string} */ (itemstack.id) !== "kubejs:c4_item") return;
+
+        if (
+            !shouldActivateC4(
+                itemstack,
+                event.entity.level,
+                /** @type {any} */ (event.entity),
+            )
+        ) {
+            event.setCanceled(true);
+        }
+
+        const useDuration = event.duration;
+        if (useDuration <= 0) return;
+        itemstack.setHoverName(
+            /** @type {any} */ (
+                Component.literal(`C4 - ${(useDuration / 20.0).toFixed(2)}s`)
+            ),
+        );
+    },
+);