package com.suno.android.common_ui.components.aura

import android.graphics.RuntimeShader
import android.os.Build
import androidx.annotation.RequiresApi
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.toArgb
import androidx.compose.ui.util.lerp

@RequiresApi(Build.VERSION_CODES.TIRAMISU)
internal class AuraShader(
    style: AuraStyle,
) : RuntimeShader(AURA_FRAGMENT_SHADER) {

    init {
        setColorUniform("iBackgroundColor", 0x0)
        setColorUniform("iColorA", style.colors.a.toArgb())
        setColorUniform("iColorB", style.colors.b.toArgb())
        setColorUniform("iColorC", style.colors.c.toArgb())

        setFloatUniform("mixPointStart", style.points.start)
        setFloatUniform("mixPointBackground", style.points.background)
        setFloatUniform("mixPointBackgroundA", style.points.backgroundA)
        setFloatUniform("mixPointAB", style.points.ab)
        setFloatUniform("mixPointBC", style.points.bc)
        setFloatUniform("mixPointEnd", style.points.end)

        // todo move these hardcoded values to AuraStyle
        setFloatUniform("iFractalScale", style.scales.fractal)
        setFloatUniform("iGrainScale", style.scales.grain)
    }

    fun setResolution(
        size: Size,
    ) {
        setFloatUniform("iResolution", size.width, size.height)
    }

    // store uniform name to color so we can perform general operations
    private val colors by lazy {
        listOf(
            "A" to style.colors.a.toArgb(),
            "B" to style.colors.b.toArgb(),
            "C" to style.colors.c.toArgb(),
        )
    }

    val floatBuffer = FloatArray(3)

    fun update(
        state: AuraState,
    ) = update(
        time = state.time,
        enabledScalar = state.enabledScalar.value,
    )

    fun update(
        time: Float,
        enabledScalar: Float,
    ) {
        // accessing the `time` mutable state here causes a recomposition which will
        // trigger a redraw as time changes
        setFloatUniform("iTime", time)

        // generalized logic to fade colors out when disabling
        // by interpolating saturation and value to 0% and 30%
        // can change the specific gray color by changing value bound (plug gray rgb into hsv converted and use that v)
        colors.forEach {
            if (enabledScalar == 1f) return@forEach
            val (id, color) = it
            android.graphics.Color.colorToHSV(color, floatBuffer)
            floatBuffer[1] = lerp(0f, floatBuffer[1], enabledScalar)
            floatBuffer[2] = lerp(.3f, floatBuffer[2], enabledScalar)
            val newColor = android.graphics.Color.HSVToColor(floatBuffer)
            setColorUniform("iColor$id", newColor)
        }
    }
}