mock up for it

common/src/main/kotlin/com/cobblemon/mod/common/item/PokedexItem.kt

@@ -10,6 +10,8 @@ package com.cobblemon.mod.common.item
 
 import com.cobblemon.mod.common.client.CobblemonClient
 import com.cobblemon.mod.common.client.pokedex.PokedexTypes
+import com.cobblemon.mod.common.pokedex.scanner.PokedexController
+import com.cobblemon.mod.common.pokedex.scanner.PokemonScanner
 import net.minecraft.client.player.LocalPlayer
 import net.minecraft.server.level.ServerPlayer
 import net.minecraft.world.InteractionHand
@@ -53,6 +55,10 @@ class PokedexItem(val type: PokedexTypes): CobblemonItem(Item.Properties().stack
             val ticksInUse = getUseDuration(stack, user) - remainingUseTicks
             usageContext.useTick(user, ticksInUse, true)
         }
+        if (!world.isClientSide && user is ServerPlayer) {
+            val controller = PokedexController.getController(user)
+            controller.useTick(remainingUseTicks)
+        }
         super.onUseTick(world, user, stack, remainingUseTicks)
     }
 
@@ -67,6 +73,10 @@ class PokedexItem(val type: PokedexTypes): CobblemonItem(Item.Properties().stack
             val ticksInUse = getUseDuration(stack, user) - remainingUseTicks
             usageContext.stopUsing(user, ticksInUse)
         }
+        if (!world.isClientSide && user is ServerPlayer) {
+            val controller = PokedexController.getController(user)
+            controller.end()
+        }
 
         super.releaseUsing(stack, world, user, remainingUseTicks)
     }

common/src/main/kotlin/com/cobblemon/mod/common/pokedex/scanner/PokedexController.kt

@@ -0,0 +1,81 @@
+package com.cobblemon.mod.common.pokedex.scanner
+
+import com.cobblemon.mod.common.pokemon.Pokemon
+import net.minecraft.server.level.ServerPlayer
+import java.util.*
+
+enum class STATE {
+    IDLE,
+    SCANNING,
+    SCANNED
+}
+
+class PokedexController(val player: ServerPlayer) {
+    companion object {
+        private val controllers = mutableMapOf<UUID, PokedexController>()
+        fun getController(player: ServerPlayer): PokedexController {
+            val uuid = player.uuid
+            if (!controllers.containsKey(uuid)) controllers[uuid] = PokedexController(player)
+            return controllers[uuid]!!
+        }
+
+        const val GOAL_TICKS = 50
+    }
+
+    var zoom: Int = 10
+    var targetPokemon: Pokemon? = null
+    private var startTime: Int? = null
+
+    var state: STATE = STATE.IDLE
+
+    fun useTick(remainingUseTicks: Int) {
+        val target = PokemonScanner.findPokemon(player, zoom)
+        if (target === null) {
+            // Not pointed at anything.
+            startTime = null
+            targetPokemon = null
+            zoom = 10
+            state = STATE.IDLE
+            // TODO: Send IDLE update packet
+            /**
+             * {
+             *   state: "IDLE"
+             * }
+             */
+            return
+        }
+        val newTargetPokemon = target.pokemon
+        if (targetPokemon !== newTargetPokemon) {
+            // Pointed at a new thing.
+            startTime = remainingUseTicks
+            targetPokemon = newTargetPokemon
+            state = STATE.SCANNING
+            // TODO: Send SCANNING update packet
+            /**
+             * {
+             *   state: "SCANNING"
+             * }
+             */
+            return
+        }
+        if (state == STATE.SCANNING && startTime!! - remainingUseTicks >= GOAL_TICKS) {
+            state = STATE.SCANNED
+            // TODO: Send SCANNED update packet
+            /**
+             * {
+             *   state: "SCANNED",
+             *   pokemon: targetPokemon
+             * }
+             */
+        }
+    }
+
+    fun end() {
+        startTime = null
+        targetPokemon = null
+        if (state !== STATE.IDLE) {
+            // TODO: Send IDLE update packet (as above, so below)
+            state = STATE.IDLE
+        }
+    }
+}