BetterFoliage/src/main/kotlin/mods/betterfoliage/render/EntityFallingLeavesFX.kt

package mods.betterfoliage.render

import mods.betterfoliage.config.Config
import mods.betterfoliage.render.old.AbstractEntityFX
import mods.betterfoliage.render.old.HSB
import mods.betterfoliage.util.Double3
import mods.betterfoliage.util.PI2
import mods.betterfoliage.util.minmax
import mods.betterfoliage.util.randomD
import net.minecraft.client.Minecraft
import net.minecraft.client.renderer.BufferBuilder
import net.minecraft.util.math.BlockPos
import net.minecraft.util.math.MathHelper
import net.minecraft.world.World
import net.minecraftforge.common.MinecraftForge
import net.minecraftforge.event.TickEvent
import net.minecraftforge.event.world.WorldEvent
import net.minecraftforge.eventbus.api.SubscribeEvent
import java.util.Random
import kotlin.math.abs
import kotlin.math.cos
import kotlin.math.sin

const val rotationFactor = PI2.toFloat() / 64.0f

class EntityFallingLeavesFX(
    world: World, pos: BlockPos
) : AbstractEntityFX(
    world, pos.x.toDouble() + 0.5, pos.y.toDouble(), pos.z.toDouble() + 0.5
) {

    companion object {
        @JvmStatic val biomeBrightnessMultiplier = 0.5f
    }

    var particleRot = rand.nextInt(64)
    var rotPositive = true
    val isMirrored = (rand.nextInt() and 1) == 1
    var wasCollided = false

    init {
        maxAge = MathHelper.floor(randomD(0.6, 1.0) * Config.fallingLeaves.lifetime * 20.0)
        motionY = -Config.fallingLeaves.speed

        particleScale = Config.fallingLeaves.size.toFloat() * 0.1f

        val state = world.getBlockState(pos)
//        val leafInfo = LeafRegistry[state, world, pos]
        val blockColor = Minecraft.getInstance().blockColors.getColor(state, world, pos, 0)
//        if (leafInfo != null) {
//            sprite = leafInfo.particleTextures[rand.nextInt(1024)]
//            calculateParticleColor(leafInfo.averageColor, blockColor)
//        } else {
//            sprite = LeafParticleRegistry["default"][rand.nextInt(1024)]
//            setColor(blockColor)
//        }
    }

    override val isValid: Boolean get() = (sprite != null)

    override fun update() {
        if (rand.nextFloat() > 0.95f) rotPositive = !rotPositive
        if (age > maxAge - 20) particleAlpha = 0.05f * (maxAge - age)

        if (onGround || wasCollided) {
            velocity.setTo(0.0, 0.0, 0.0)
            if (!wasCollided) {
                age = age.coerceAtLeast(maxAge - 20)
                wasCollided = true
            }
        } else {
            velocity.setTo(cos[particleRot], 0.0, sin[particleRot]).mul(Config.fallingLeaves.perturb)
                    .add(LeafWindTracker.current).add(0.0, -1.0, 0.0).mul(Config.fallingLeaves.speed)
            particleRot = (particleRot + (if (rotPositive) 1 else -1)) and 63
            particleAngle = rotationFactor * particleRot.toFloat()
        }
    }

    override fun render(worldRenderer: BufferBuilder, partialTickTime: Float) {
//        if (Config.fallingLeaves.opacityHack) GL11.glDepthMask(true)
//        renderParticleQuad(worldRenderer, partialTickTime, rotation = particleRot, isMirrored = isMirrored)
    }

    fun calculateParticleColor(textureAvgColor: Int, blockColor: Int) {
        val texture = HSB.fromColor(textureAvgColor)
        val block = HSB.fromColor(blockColor)

        val weightTex = texture.saturation / (texture.saturation + block.saturation)
        val weightBlock = 1.0f - weightTex

        // avoid circular average for hue for performance reasons
        // one of the color components should dominate anyway
        val particle = HSB(
            weightTex * texture.hue + weightBlock * block.hue,
            weightTex * texture.saturation + weightBlock * block.saturation,
            weightTex * texture.brightness + weightBlock * block.brightness * biomeBrightnessMultiplier
        )
        setColor(particle.asColor)
    }
}

object LeafWindTracker {
    var random = Random()
    val target = Double3.zero
    val current = Double3.zero
    var nextChange: Long = 0

    init {
        MinecraftForge.EVENT_BUS.register(this)
    }

    fun changeWind(world: World) {
        nextChange = world.worldInfo.gameTime + 120 + random.nextInt(80)
        val direction = PI2 * random.nextDouble()
        val speed = abs(random.nextGaussian()) * Config.fallingLeaves.windStrength +
            (if (!world.isRaining) 0.0 else abs(random.nextGaussian()) * Config.fallingLeaves.stormStrength)
        target.setTo(cos(direction) * speed, 0.0, sin(direction) * speed)
    }

    @SubscribeEvent
    fun handleWorldTick(event: TickEvent.ClientTickEvent) {
        if (event.phase == TickEvent.Phase.START) Minecraft.getInstance().world?.let { world ->
            // change target wind speed
            if (world.worldInfo.dayTime >= nextChange) changeWind(world)

            // change current wind speed
            val changeRate = if (world.isRaining) 0.015 else 0.005
            current.add(
                (target.x - current.x).minmax(-changeRate, changeRate),
                0.0,
                (target.z - current.z).minmax(-changeRate, changeRate)
            )
        }
    }

    @SubscribeEvent
    fun handleWorldLoad(event: WorldEvent.Load) { if (event.world.isRemote) changeWind(event.world.world) }
}