cobblemon-survival-pack/mod/src/main/kotlin/dev/cobblesurvival/machine/MachineDisplay.kt

package dev.cobblesurvival.machine

import com.cobblemon.mod.common.api.Priority
import com.cobblemon.mod.common.api.events.CobblemonEvents
import com.cobblemon.mod.common.api.events.battles.BattleStartedEvent
import com.cobblemon.mod.common.entity.pokemon.PokemonEntity
import com.cobblemon.mod.common.pokemon.Pokemon
import com.cobblemon.mod.common.pokemon.properties.UncatchableProperty
import net.minecraft.core.BlockPos
import net.minecraft.core.Direction
import net.minecraft.core.Holder
import net.minecraft.resources.ResourceLocation
import net.minecraft.sounds.SoundEvent
import net.minecraft.sounds.SoundSource
import net.minecraft.nbt.CompoundTag
import net.minecraft.server.level.ServerLevel
import net.minecraft.world.entity.Entity
import net.neoforged.neoforge.common.NeoForge
import net.neoforged.neoforge.event.entity.EntityJoinLevelEvent
import net.neoforged.neoforge.event.entity.player.AttackEntityEvent
import net.neoforged.neoforge.event.entity.player.PlayerInteractEvent
import net.neoforged.neoforge.event.tick.ServerTickEvent
import java.util.UUID

/**
 * The Pokémon a machine shows in its chamber (roadmap Phase 6: a real Cobblemon entity, so its own model and
 * animations are used). It's a copy of the Pokémon kept in the core, with its own id, scaled to fit the chamber,
 * without AI, invulnerable, silent, uncatchable, and it can't be used, hit or battled. It's never meant to be in the
 * world save: one that comes back from disk is dropped, and the core puts a fresh one there.
 */
object MachineDisplay {
    /** Key in the copy's persistent data; its value is the core's position. */
    const val TAG = "cobblesurvival_machine"
    /** The chamber is one block; leave a little room. */
    private const val FIT = 0.9f
    /** A fainting Pokémon's cry is played lower, as in the games. */
    private const val FAINT_PITCH = 0.6f
    const val FAINT_TICKS = 40L

    private class Fading(val entity: PokemonEntity, val until: Long)
    private val fading = ArrayList<Fading>()

    fun register() {
        NeoForge.EVENT_BUS.addListener(::onJoin)
        NeoForge.EVENT_BUS.addListener<PlayerInteractEvent.EntityInteract> { if (isDisplay(it.target)) it.isCanceled = true }
        NeoForge.EVENT_BUS.addListener<PlayerInteractEvent.EntityInteractSpecific> { if (isDisplay(it.target)) it.isCanceled = true }
        NeoForge.EVENT_BUS.addListener<AttackEntityEvent> { if (isDisplay(it.target)) it.isCanceled = true }
        CobblemonEvents.BATTLE_STARTED_PRE.subscribe(Priority.HIGHEST, ::onBattle)
        NeoForge.EVENT_BUS.addListener<ServerTickEvent.Post> { event ->
            if (fading.isEmpty()) return@addListener
            val now = event.server.overworld().gameTime
            fading.removeIf { f -> (f.until <= now || f.entity.isRemoved).also { if (it) f.entity.discard() } }
        }
    }

    /**
     * The shown Pokémon dies (a sacrifice, or the old form at the end of a rebirth; Adrian, 2026-11-02): its cry,
     * pitched down as for a fainting Pokémon, and Cobblemon's faint animation; then it's gone after [FAINT_TICKS].
     */
    fun faint(level: ServerLevel, entity: PokemonEntity) {
        val species = entity.pokemon.species.resourceIdentifier
        val cry = SoundEvent.createVariableRangeEvent(ResourceLocation.fromNamespaceAndPath(species.namespace, "pokemon.${species.path}.cry"))
        level.playSeededSound(null, entity.x, entity.y, entity.z, Holder.direct(cry), SoundSource.NEUTRAL, 1f, FAINT_PITCH, level.random.nextLong())
        entity.playAnimation("faint")
        fading += Fading(entity, level.gameTime + FAINT_TICKS)
    }

    fun isDisplay(entity: Entity?): Boolean = entity is PokemonEntity && entity.pokemon.persistentData.contains(TAG)

    fun spawn(level: ServerLevel, pokemon: Pokemon, core: BlockPos, chamber: BlockPos, facing: Direction): PokemonEntity {
        val copy = Pokemon().loadFromNBT(level.registryAccess(), pokemon.saveToNBT(level.registryAccess(), CompoundTag()))
        copy.uuid = UUID.randomUUID()
        copy.persistentData.putLong(TAG, core.asLong())
        UncatchableProperty.uncatchable().apply(copy)
        val entity = PokemonEntity(level, copy)
        val size = maxOf(entity.bbWidth, entity.bbHeight)
        if (size > FIT) {
            copy.scaleModifier = copy.scaleModifier * FIT / size
            entity.refreshDimensions()
        }
        entity.setNoAi(true)
        entity.setNoGravity(true)
        entity.isInvulnerable = true
        entity.isSilent = true
        entity.setPersistenceRequired()
        entity.busyLocks.add(this)
        entity.moveTo(chamber.x + 0.5, chamber.y.toDouble(), chamber.z + 0.5, facing.toYRot(), 0f)
        entity.yHeadRot = facing.toYRot()
        entity.yBodyRot = facing.toYRot()
        level.addFreshEntity(entity)
        return entity
    }

    /** A copy saved with its chunk comes back without its core knowing it: drop it. */
    private fun onJoin(event: EntityJoinLevelEvent) {
        if (event.loadedFromDisk() && isDisplay(event.entity)) event.isCanceled = true
    }

    private fun onBattle(event: BattleStartedEvent.Pre) {
        if (event.battle.actors.any { actor -> actor.pokemonList.any { isDisplay(it.entity) } }) event.cancel()
    }
}