CNPC+ Debug Command for Energy Projectiles + Compile Fixes

src/main/java/kamkeel/npcs/client/command/CommandCNPCDebugger.java

@@ -0,0 +1,42 @@
+package kamkeel.npcs.client.command;
+
+import kamkeel.npcs.util.CNPCDebug;
+import net.minecraft.command.CommandBase;
+import net.minecraft.command.ICommandSender;
+import net.minecraft.util.ChatComponentText;
+
+/**
+ * Client-only command to toggle debug logging.
+ * Registered via ClientCommandHandler so it runs entirely on the client
+ * without sending a packet to the server.
+ */
+public class CommandCNPCDebugger extends CommandBase {
+
+    @Override
+    public String getCommandName() {
+        return "cnpcdebugger";
+    }
+
+    @Override
+    public String getCommandUsage(ICommandSender sender) {
+        return "/cnpcdebugger <type> - Toggle client debug logging for a type (e.g. energy)";
+    }
+
+    @Override
+    public int getRequiredPermissionLevel() {
+        return 0;
+    }
+
+    @Override
+    public void processCommand(ICommandSender sender, String[] args) {
+        if (args.length == 0) {
+            sender.addChatMessage(new ChatComponentText("\u00A7cUsage: /cnpcdebugger <type>"));
+            return;
+        }
+
+        String type = args[0].toLowerCase();
+        boolean newState = CNPCDebug.toggleClient(type);
+        String stateText = newState ? "\u00A7aENABLED" : "\u00A7cDISABLED";
+        sender.addChatMessage(new ChatComponentText("\u00A77[CNPC+] \u00A7eClient debug '" + type + "' " + stateText));
+    }
+}

src/main/java/kamkeel/npcs/command/CommandKamkeel.java

@@ -52,6 +52,7 @@ public class CommandKamkeel extends CommandBase {
             registerCommand(new AuctionCommand());
         if (ConfigMain.AttributesEnabled)
             registerCommand(new AttributeCommand());
+        registerCommand(new DebugCommand());
     }
 
     public void registerCommand(CommandKamkeelBase command) {

src/main/java/kamkeel/npcs/command/DebugCommand.java

@@ -0,0 +1,41 @@
+package kamkeel.npcs.command;
+
+import kamkeel.npcs.util.CNPCDebug;
+import net.minecraft.command.CommandException;
+import net.minecraft.command.ICommandSender;
+
+import static kamkeel.npcs.util.ColorUtil.sendResult;
+
+public class DebugCommand extends CommandKamkeelBase {
+
+    @Override
+    public String getCommandName() {
+        return "debug";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Toggle debug logging types";
+    }
+
+    @Override
+    public String getUsage() {
+        return "<type>";
+    }
+
+    @Override
+    public boolean runSubCommands() {
+        return false;
+    }
+
+    @Override
+    public void processCommand(ICommandSender sender, String[] args) throws CommandException {
+        if (args.length == 0) {
+            throw new CommandException("Usage: /kam debug <type> (e.g. energy)");
+        }
+
+        String type = args[0].toLowerCase();
+        boolean newState = CNPCDebug.toggleServer(type);
+        sendResult(sender, "Server debug '" + type + "' " + (newState ? "\u00A7aENABLED" : "\u00A7cDISABLED"));
+    }
+}

src/main/java/kamkeel/npcs/entity/EntityAbilityBarrier.java

@@ -2,6 +2,7 @@ package kamkeel.npcs.entity;
 
 import kamkeel.npcs.controllers.data.ability.util.AbilityTargetHelper;
 import kamkeel.npcs.controllers.data.ability.data.energy.EnergyBarrierData;
+import kamkeel.npcs.util.CNPCDebug;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
@@ -617,4 +618,31 @@ public abstract class EntityAbilityBarrier extends EntityEnergyAbility {
         this.dataWatcher.updateObject(DW_CHARGING, (byte) (charging ? 1 : 0));
         barrierData.readNBT(nbt);
     }
+
+    // ==================== DEBUG LOGGING ====================
+
+    /**
+     * Debug log called every tick for barriers. Subclasses override debugLogBarrierExtra().
+     */
+    protected void debugLogBarrierTick() {
+        boolean isClient = worldObj.isRemote;
+        if (isClient ? !CNPCDebug.isClientEnabled("energy") : !CNPCDebug.isServerEnabled("energy"))
+            return;
+
+        String className = getClass().getSimpleName();
+        String base = String.format("[%s id=%d tick=%d] pos=(%.2f,%.2f,%.2f) charging=%b health=%.1f",
+            className, getEntityId(), ticksAlive,
+            posX, posY, posZ, isCharging(), currentHealth);
+
+        String extra = debugLogBarrierExtra();
+        String full = extra.isEmpty() ? base : base + " " + extra;
+        CNPCDebug.log("energy", isClient, full);
+    }
+
+    /**
+     * Subclass hook for barrier-specific debug data.
+     */
+    protected String debugLogBarrierExtra() {
+        return "";
+    }
 }

src/main/java/kamkeel/npcs/entity/EntityAbilityBeam.java

@@ -16,7 +16,6 @@ import net.minecraft.nbt.NBTTagList;
 import net.minecraft.util.AxisAlignedBB;
 import net.minecraft.util.Vec3;
 import net.minecraft.world.World;
-import noppes.npcs.LogWriter;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -61,9 +60,6 @@ public class EntityAbilityBeam extends EntityEnergyProjectile {
     private int trailFadeTime = 20; // Ticks for trail to fully fade
     private List<Integer> trailPointAges = new ArrayList<>();
 
-    // Debug logging
-    private static final boolean DEBUG_LOGGING = false;
-
     public EntityAbilityBeam(World world) {
         super(world);
     }
@@ -160,10 +156,6 @@ public class EntityAbilityBeam extends EntityEnergyProjectile {
         // Add initial trail point at origin (relative 0,0,0)
         trailPoints.add(Vec3.createVectorHelper(0, 0, 0));
 
-        if (DEBUG_LOGGING && !world.isRemote) {
-            LogWriter.info("[Beam] Created at origin " + x + ", " + y + ", " + z + " maxDist=" + lifespan.maxDistance);
-        }
-
         // Calculate initial velocity toward target
         calculateInitialVelocity(owner, target, x, y, z);
     }
@@ -222,11 +214,6 @@ public class EntityAbilityBeam extends EntityEnergyProjectile {
         trailPoints.add(Vec3.createVectorHelper(0, 0, 0));
         if (isFadingMode()) trailPointAges.add(0);
 
-        if (DEBUG_LOGGING && !worldObj.isRemote) {
-            LogWriter.info("[Beam] startFiring: origin=(" + startX + "," + startY + "," + startZ +
-                ") headOffset=(" + headOffsetX + "," + headOffsetY + "," + headOffsetZ +
-                ") motion=(" + motionX + "," + motionY + "," + motionZ + ")");
-        }
     }
 
     @Override
@@ -237,11 +224,7 @@ public class EntityAbilityBeam extends EntityEnergyProjectile {
                 headOffsetY * headOffsetY +
                 headOffsetZ * headOffsetZ
         );
-        boolean exceeded = distFromOrigin >= getMaxDistance();
-        if (exceeded && !worldObj.isRemote && DEBUG_LOGGING) {
-            LogWriter.info("[Beam] DEAD: Max distance exceeded. dist=" + distFromOrigin + " max=" + getMaxDistance());
-        }
-        return exceeded;
+        return distFromOrigin >= getMaxDistance();
     }
 
     @Override
@@ -312,17 +295,6 @@ public class EntityAbilityBeam extends EntityEnergyProjectile {
             // Add trail point
             addTrailPoint();
 
-            // Debug log periodically
-            if (DEBUG_LOGGING && ticksExisted % 20 == 0) {
-                LogWriter.info("[Beam] Server tick=" + ticksExisted + " headOffset=(" +
-                    String.format("%.2f", headOffsetX) + "," +
-                    String.format("%.2f", headOffsetY) + "," +
-                    String.format("%.2f", headOffsetZ) + ") origin=(" +
-                    String.format("%.2f", startX) + "," +
-                    String.format("%.2f", startY) + "," +
-                    String.format("%.2f", startZ) + ") trail=" + getActiveTrailSize());
-            }
-
             // Skip collision checks on first few ticks
             if (ticksExisted > 2) {
                 checkBlockCollision(headWorldX, headWorldY, headWorldZ);
@@ -528,9 +500,27 @@ public class EntityAbilityBeam extends EntityEnergyProjectile {
             Math.max(prevHeadWorldZ, headZ) + hitSize
         );
 
-        if (processEntitiesInHitBox(hitBox, headX, headY, headZ) && DEBUG_LOGGING) {
-            LogWriter.info("[Beam] DEAD: Entity collision at tick " + ticksExisted);
-        }
+        processEntitiesInHitBox(hitBox, headX, headY, headZ);
+    }
+
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogExtra() {
+        double headWorldX = startX + headOffsetX;
+        double headWorldY = startY + headOffsetY;
+        double headWorldZ = startZ + headOffsetZ;
+        return String.format("headOff=(%.2f,%.2f,%.2f) prevHead=(%.2f,%.2f,%.2f) " +
+                "origin=(%.2f,%.2f,%.2f) headWorld=(%.2f,%.2f,%.2f) " +
+                "trail=%d mode=%s anchored=%b beamW=%.2f headSz=%.2f " +
+                "motion=(%.3f,%.3f,%.3f)",
+            headOffsetX, headOffsetY, headOffsetZ,
+            prevHeadOffsetX, prevHeadOffsetY, prevHeadOffsetZ,
+            startX, startY, startZ,
+            headWorldX, headWorldY, headWorldZ,
+            getActiveTrailSize(),
+            beamMode.name(), isAnchoredMode(), beamWidth, headSize,
+            motionX, motionY, motionZ);
     }
 
     // ==================== GETTERS FOR RENDERER ====================

src/main/java/kamkeel/npcs/entity/EntityAbilityDisc.java

@@ -330,6 +330,17 @@ public class EntityAbilityDisc extends EntityEnergyProjectile {
         updateRotation();
     }
 
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogExtra() {
+        return String.format("motion=(%.3f,%.3f,%.3f) radius=%.2f thickness=%.2f " +
+                "boomerang=%b returning=%b vertical=%b ticksSinceMiss=%d",
+            motionX, motionY, motionZ,
+            discRadius, discThickness,
+            boomerang, returning, vertical, ticksSinceMiss);
+    }
+
     // ==================== GETTERS ====================
 
     public float getDiscRadius() {

src/main/java/kamkeel/npcs/entity/EntityAbilityDome.java

@@ -122,6 +122,8 @@ public class EntityAbilityDome extends EntityAbilityBarrier {
         if (worldObj.isRemote && barrierData.meleeEnabled && !isCharging()) {
             adjustMeleeBoundingBox();
         }
+
+        debugLogBarrierTick();
     }
 
     // ==================== INCOMING CHECK ====================
@@ -548,6 +550,14 @@ public class EntityAbilityDome extends EntityAbilityBarrier {
         return surfaceDist * surfaceDist;
     }
 
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogBarrierExtra() {
+        return String.format("radius=%.2f targetRadius=%.2f follow=%b",
+            domeRadius, targetDomeRadius, followCaster);
+    }
+
     // ==================== GETTERS ====================
 
     public float getDomeRadius() {

src/main/java/kamkeel/npcs/entity/EntityAbilityLaser.java

@@ -624,6 +624,17 @@ public class EntityAbilityLaser extends EntityEnergyProjectile {
         return -1;
     }
 
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogExtra() {
+        return String.format("dir=(%.3f,%.3f,%.3f) desired=%.2f current=%.2f max=%.2f " +
+                "fullyExtended=%b end=(%.2f,%.2f,%.2f) width=%.2f expSpd=%.2f origin=(%.2f,%.2f,%.2f)",
+            dirX, dirY, dirZ, desiredLength, currentLength, maxLength,
+            fullyExtended, endX, endY, endZ, laserWidth, expansionSpeed,
+            startX, startY, startZ);
+    }
+
     // ==================== GETTERS / SETTERS ====================
 
     public float getLaserWidth() {

src/main/java/kamkeel/npcs/entity/EntityAbilityOrb.java

@@ -150,6 +150,16 @@ public class EntityAbilityOrb extends EntityEnergyProjectile {
         processEntitiesInHitBox(hitBox, nextX, nextY, nextZ);
     }
 
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogExtra() {
+        return String.format("motion=(%.3f,%.3f,%.3f) homing=%b start=(%.2f,%.2f,%.2f)",
+            motionX, motionY, motionZ,
+            homingData != null && homingData.isHoming(),
+            startX, startY, startZ);
+    }
+
     // ==================== GETTERS ====================
 
     // Legacy getter for renderer compatibility

src/main/java/kamkeel/npcs/entity/EntityAbilityPanel.java

@@ -143,6 +143,8 @@ public class EntityAbilityPanel extends EntityAbilityBarrier {
                 // Stationary, no update needed
                 break;
         }
+
+        debugLogBarrierTick();
     }
 
     private void updateHeld() {
@@ -548,6 +550,14 @@ public class EntityAbilityPanel extends EntityAbilityBarrier {
         return df * df + dr * dr + du * du;
     }
 
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogBarrierExtra() {
+        return String.format("mode=%s yaw=%.1f w=%.2f h=%.2f",
+            mode.name(), panelYaw, panelData.panelWidth, panelData.panelHeight);
+    }
+
     // ==================== GETTERS ====================
 
     public PanelMode getMode() {

src/main/java/kamkeel/npcs/entity/EntityAbilitySweeper.java

@@ -3,6 +3,7 @@ package kamkeel.npcs.entity;
 import cpw.mods.fml.relauncher.Side;
 import cpw.mods.fml.relauncher.SideOnly;
 import kamkeel.npcs.controllers.data.ability.data.energy.EnergyDisplayData;
+import kamkeel.npcs.util.CNPCDebug;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
@@ -168,6 +169,19 @@ public class EntityAbilitySweeper extends EntityEnergyAbility {
         if (!worldObj.isRemote) {
             handleDamage(owner);
         }
+
+        // Debug logging
+        {
+            boolean isClient = worldObj.isRemote;
+            if (isClient ? CNPCDebug.isClientEnabled("energy") : CNPCDebug.isServerEnabled("energy")) {
+                CNPCDebug.log("energy", isClient, String.format(
+                    "[Sweeper id=%d tick=%d] pos=(%.2f,%.2f,%.2f) angle=%.1f prevAngle=%.1f " +
+                    "speed=%.1f rotations=%d/%d length=%.2f width=%.2f",
+                    getEntityId(), ticksExisted, posX, posY, posZ,
+                    currentAngle, prevAngle, sweepSpeed,
+                    completedRotations, numberOfRotations, beamLength, beamWidth));
+            }
+        }
     }
 
     /**

src/main/java/kamkeel/npcs/entity/EntityEnergyExplosion.java

@@ -4,6 +4,7 @@ import cpw.mods.fml.relauncher.Side;
 import cpw.mods.fml.relauncher.SideOnly;
 import kamkeel.npcs.controllers.data.ability.data.energy.EnergyDisplayData;
 import kamkeel.npcs.controllers.data.ability.data.energy.EnergyLightningData;
+import kamkeel.npcs.util.CNPCDebug;
 import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.util.MathHelper;
 import net.minecraft.world.World;
@@ -57,6 +58,17 @@ public class EntityEnergyExplosion extends EntityEnergyAbility {
         float eased = 1.0f - (1.0f - progress) * (1.0f - progress);
         this.renderRadius = maxRadius * eased;
 
+        // Debug logging
+        {
+            boolean isClient = worldObj.isRemote;
+            if (isClient ? CNPCDebug.isClientEnabled("energy") : CNPCDebug.isServerEnabled("energy")) {
+                CNPCDebug.log("energy", isClient, String.format(
+                    "[Explosion id=%d tick=%d] pos=(%.2f,%.2f,%.2f) renderRadius=%.2f maxRadius=%.2f progress=%.2f",
+                    getEntityId(), ticksExisted, posX, posY, posZ,
+                    renderRadius, maxRadius, getLifeProgress(0f)));
+            }
+        }
+
         if (ticksExisted >= durationTicks) {
             setDead();
         }

src/main/java/kamkeel/npcs/entity/EntityEnergyProjectile.java

@@ -16,6 +16,7 @@ import kamkeel.npcs.controllers.data.ability.data.energy.EnergyLightningData;
 import kamkeel.npcs.network.packets.data.energy.ProjectileReflectPacket;
 import kamkeel.npcs.network.packets.data.energyexplosion.EnergyExplosionSpawnPacket;
 import kamkeel.npcs.util.AnchorPointHelper;
+import kamkeel.npcs.util.CNPCDebug;
 import net.minecraft.block.Block;
 import net.minecraft.block.material.Material;
 import net.minecraft.entity.Entity;
@@ -334,6 +335,8 @@ public abstract class EntityEnergyProjectile extends EntityEnergyAbility {
         if (!previewMode && !worldObj.isRemote) {
             EventHooks.onEnergyProjectileTick(this);
         }
+
+        debugLogTick();
     }
 
     /**
@@ -349,6 +352,53 @@ public abstract class EntityEnergyProjectile extends EntityEnergyAbility {
         if (this.rotationValZ > 360.0f) this.rotationValZ -= 360.0f;
     }
 
+    // ==================== DEBUG LOGGING ====================
+
+    /**
+     * Debug log called every tick. Logs position/size/charging state.
+     * Subclasses override debugLogExtra() for type-specific data.
+     */
+    protected void debugLogTick() {
+        boolean isClient = worldObj.isRemote;
+        if (isClient ? !CNPCDebug.isClientEnabled("energy") : !CNPCDebug.isServerEnabled("energy"))
+            return;
+
+        String className = getClass().getSimpleName();
+        boolean dwCharging = isCharging();   // DataWatcher value (what client sees)
+        boolean localCharging = this.charging; // Local field (server truth)
+
+        String base = String.format("[%s id=%d tick=%d] pos=(%.2f,%.2f,%.2f) prev=(%.2f,%.2f,%.2f) " +
+                "size=%.3f renderSize=%.3f prevRenderSize=%.3f " +
+                "charging(dw)=%b charging(local)=%b chargeTick=%d/%d chargeProgress=%.3f",
+            className, getEntityId(), ticksExisted,
+            posX, posY, posZ, prevPosX, prevPosY, prevPosZ,
+            size, renderCurrentSize, prevRenderSize,
+            dwCharging, localCharging, chargeTick, chargeDuration, getChargeProgress());
+
+        // Flag mismatch between DataWatcher and local field
+        if (dwCharging != localCharging) {
+            base += " !!CHARGE_MISMATCH!!";
+        }
+
+        // Client interpolation state (only meaningful on client)
+        if (isClient) {
+            base += String.format(" interp(steps=%d target=(%.2f,%.2f,%.2f))",
+                interpSteps, interpTargetX, interpTargetY, interpTargetZ);
+        }
+
+        String extra = debugLogExtra();
+        String full = extra.isEmpty() ? base : base + " " + extra;
+        CNPCDebug.log("energy", isClient, full);
+    }
+
+    /**
+     * Subclass hook for type-specific debug data.
+     * Return empty string if nothing extra to log.
+     */
+    protected String debugLogExtra() {
+        return "";
+    }
+
     /**
      * Check if projectile has exceeded max distance.
      *

src/main/java/kamkeel/npcs/entity/EntityEnergySlicer.java

@@ -192,6 +192,14 @@ public class EntityEnergySlicer extends EntityEnergyProjectile {
         return lastTravelPitch;
     }
 
+    // ==================== DEBUG ====================
+
+    @Override
+    protected String debugLogExtra() {
+        return String.format("motion=(%.3f,%.3f,%.3f) sliceW=%.2f sliceT=%.2f",
+            motionX, motionY, motionZ, sliceWidth, sliceThickness);
+    }
+
     // ==================== GETTERS ====================
 
     public float getSliceWidth() {

src/main/java/kamkeel/npcs/util/CNPCDebug.java

@@ -0,0 +1,163 @@
+package kamkeel.npcs.util;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Formatter;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+import java.util.logging.StreamHandler;
+
+/**
+ * Debug logging system for CNPC+ entities.
+ * Writes to logs/cnpc_debug/[type]_[side].log (file only, no console output).
+ * Toggle at runtime via /cnpcdebugger [type] (client) or /kam debug [type] (server).
+ */
+public class CNPCDebug {
+
+    private static final String DIR = "logs/cnpc_debug";
+    private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("HH:mm:ss");
+
+    // Runtime toggle state per type, separate for client and server
+    private static final Map<String, Boolean> serverToggles = new ConcurrentHashMap<>();
+    private static final Map<String, Boolean> clientToggles = new ConcurrentHashMap<>();
+
+    // Per-type file handlers (lazily initialized)
+    private static final Map<String, Handler> serverHandlers = new ConcurrentHashMap<>();
+    private static final Map<String, Handler> clientHandlers = new ConcurrentHashMap<>();
+
+    // ==================== TOGGLE API ====================
+
+    /**
+     * Toggle server-side debug for given type. Returns new state.
+     */
+    public static boolean toggleServer(String type) {
+        type = type.toLowerCase();
+        boolean newState = !isServerEnabled(type);
+        serverToggles.put(type, newState);
+        if (newState) {
+            ensureHandler(type, false);
+        }
+        return newState;
+    }
+
+    /**
+     * Toggle client-side debug for given type. Returns new state.
+     */
+    public static boolean toggleClient(String type) {
+        type = type.toLowerCase();
+        boolean newState = !isClientEnabled(type);
+        clientToggles.put(type, newState);
+        if (newState) {
+            ensureHandler(type, true);
+        }
+        return newState;
+    }
+
+    public static boolean isServerEnabled(String type) {
+        Boolean val = serverToggles.get(type.toLowerCase());
+        return val != null && val;
+    }
+
+    public static boolean isClientEnabled(String type) {
+        Boolean val = clientToggles.get(type.toLowerCase());
+        return val != null && val;
+    }
+
+    // ==================== LOGGING API ====================
+
+    /**
+     * Log a debug message for the given type on the given side.
+     * Callers should guard with isServerEnabled/isClientEnabled for performance.
+     */
+    public static void log(String type, boolean client, String msg) {
+        type = type.toLowerCase();
+        Map<String, Boolean> toggles = client ? clientToggles : serverToggles;
+        Boolean enabled = toggles.get(type);
+        if (enabled == null || !enabled) return;
+
+        Handler handler = ensureHandler(type, client);
+        if (handler == null) return;
+
+        String side = client ? "CLIENT" : "SERVER";
+        String timestamp;
+        synchronized (DATE_FORMAT) {
+            timestamp = DATE_FORMAT.format(new Date());
+        }
+        String formatted = "[" + timestamp + "][" + side + "][DEBUG-" + type.toUpperCase() + "] " + msg + System.lineSeparator();
+
+        LogRecord record = new LogRecord(Level.INFO, formatted);
+        handler.publish(record);
+        handler.flush();
+    }
+
+    /**
+     * Log on server side.
+     */
+    public static void logServer(String type, String msg) {
+        log(type, false, msg);
+    }
+
+    /**
+     * Log on client side.
+     */
+    public static void logClient(String type, String msg) {
+        log(type, true, msg);
+    }
+
+    // ==================== INTERNALS ====================
+
+    private static Handler ensureHandler(String type, boolean client) {
+        Map<String, Handler> handlers = client ? clientHandlers : serverHandlers;
+        Handler existing = handlers.get(type);
+        if (existing != null) return existing;
+
+        synchronized (CNPCDebug.class) {
+            existing = handlers.get(type);
+            if (existing != null) return existing;
+
+            try {
+                File dir = new File(DIR);
+                if (!dir.exists()) dir.mkdirs();
+
+                String side = client ? "client" : "server";
+                File file = new File(dir, type + "_" + side + ".log");
+
+                // Rotate old log
+                if (file.exists()) {
+                    File backup = new File(dir, type + "_" + side + "-prev.log");
+                    if (backup.exists()) backup.delete();
+                    file.renameTo(backup);
+                }
+
+                Handler handler = new StreamHandler(new FileOutputStream(file), new Formatter() {
+                    @Override
+                    public String format(LogRecord record) {
+                        return record.getMessage();
+                    }
+                });
+                handler.setLevel(Level.ALL);
+                handlers.put(type, handler);
+
+                // Log header
+                String timestamp;
+                synchronized (DATE_FORMAT) {
+                    timestamp = DATE_FORMAT.format(new Date());
+                }
+                LogRecord header = new LogRecord(Level.INFO,
+                    "[" + timestamp + "][" + (client ? "CLIENT" : "SERVER") + "][DEBUG-" + type.toUpperCase() + "] Debug logging started" + System.lineSeparator());
+                handler.publish(header);
+                handler.flush();
+
+                return handler;
+            } catch (Exception e) {
+                e.printStackTrace();
+                return null;
+            }
+        }
+    }
+}

src/main/java/noppes/npcs/client/ClientProxy.java

@@ -6,6 +6,7 @@ import cpw.mods.fml.client.registry.RenderingRegistry;
 import cpw.mods.fml.common.FMLCommonHandler;
 import cpw.mods.fml.common.ObfuscationReflectionHelper;
 import kamkeel.npcs.addon.client.DBCClient;
+import kamkeel.npcs.client.command.CommandCNPCDebugger;
 import kamkeel.npcs.client.renderer.RenderAbilityBeam;
 import kamkeel.npcs.client.renderer.RenderAbilityDisc;
 import kamkeel.npcs.client.renderer.RenderAbilityLaser;
@@ -53,6 +54,7 @@ import net.minecraft.util.ChatComponentText;
 import net.minecraft.util.ReportedException;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.world.World;
+import net.minecraftforge.client.ClientCommandHandler;
 import net.minecraftforge.client.MinecraftForgeClient;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.common.util.FakePlayer;
@@ -360,6 +362,9 @@ public class ClientProxy extends CommonProxy {
         ClientTagMapController.Instance = new ClientTagMapController();
         MinecraftForge.EVENT_BUS.register(new ClientEventHandler());
 
+        // Debug commands
+        ClientCommandHandler.instance.registerCommand(new CommandCNPCDebugger());
+
         // Telegraph rendering system
         TelegraphManager.initClient();
         MinecraftForge.EVENT_BUS.register(new TelegraphRenderer());