package ru.dbotthepony.kstarbound.client.gl

import org.apache.logging.log4j.LogManager
import org.lwjgl.opengl.GL46.*
import org.lwjgl.stb.STBImage
import ru.dbotthepony.kstarbound.defs.image.Image
import ru.dbotthepony.kvector.vector.Vector2i
import java.io.File
import java.io.FileNotFoundException
import java.nio.ByteBuffer
import kotlin.reflect.KProperty

class TextureLoadingException(message: String) : Throwable(message)

data class UVCoord(val u: Float, val v: Float)

private class GLTexturePropertyTracker(private val flag: Int, private var value: Int) {
	operator fun getValue(thisRef: GLTexture2D, property: KProperty<*>): Int {
		return value
	}

	operator fun setValue(thisRef: GLTexture2D, property: KProperty<*>, value: Int) {
		thisRef.state.ensureSameThread()
		if (this.value == value) return
		this.value = value
		glTextureParameteri(thisRef.pointer, flag, value)
		checkForGLError()
	}
}

@Suppress("SameParameterValue")
class GLTexture2D(val state: GLStateTracker, val name: String = "<unknown>") {
	init {
		state.ensureSameThread()
	}

	val pointer = glGenTextures()

	init {
		checkForGLError()
		state.registerCleanable(this, ::glDeleteTextures, pointer)
	}

	var width = 0
		private set

	var height = 0
		private set

	var uploaded = false
		private set

	val aspectRatioWH: Float get() {
		if (height == 0) {
			return 1f
		}

		return width.toFloat() / height.toFloat()
	}

	val aspectRatioHW: Float get() {
		if (width == 0) {
			return 1f
		}

		return height.toFloat() / width.toFloat()
	}

	var textureMinFilter by GLTexturePropertyTracker(GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_LINEAR)
	var textureMagFilter by GLTexturePropertyTracker(GL_TEXTURE_MAG_FILTER, GL_LINEAR)
	var maxLevel by GLTexturePropertyTracker(GL_TEXTURE_MAX_LEVEL, 1000)

	var textureWrapS by GLTexturePropertyTracker(GL_TEXTURE_WRAP_S, GL_REPEAT)
	var textureWrapT by GLTexturePropertyTracker(GL_TEXTURE_WRAP_T, GL_REPEAT)

	fun bind(): GLTexture2D {
		state.texture2D = this
		return this
	}

	fun generateMips(): GLTexture2D {
		state.ensureSameThread()
		glGenerateTextureMipmap(pointer)
		checkForGLError("Generating texture mipmaps")
		return this
	}

	fun pixelToUV(x: Float, y: Float): UVCoord {
		check(uploaded) { "Texture is not uploaded to be used" }
		return UVCoord(x / width, y / height)
	}

	fun pixelToUV(x: Int, y: Int): UVCoord {
		check(uploaded) { "Texture is not uploaded to be used" }
		return UVCoord(x.toFloat() / width, y.toFloat() / height)
	}

	fun pixelToUV(pos: Vector2i) = pixelToUV(pos.x, pos.y)

	fun allocate(mipmap: Int, loadedFormat: Int, width: Int, height: Int): GLTexture2D {
		bind()

		require(width > 0) { "Invalid width $width" }
		require(height > 0) { "Invalid height $height" }
		this.width = width
		this.height = height
		glTexImage2D(GL_TEXTURE_2D, mipmap, loadedFormat, width, height, 0, loadedFormat, GL_UNSIGNED_BYTE, 0L)
		checkForGLError()
		uploaded = true
		return this
	}

	fun allocate(loadedFormat: Int, width: Int, height: Int): GLTexture2D {
		return allocate(0, loadedFormat, width, height)
	}

	private fun upload(mipmap: Int, loadedFormat: Int, width: Int, height: Int, bufferFormat: Int, dataFormat: Int, data: IntArray): GLTexture2D {
		bind()

		require(width > 0) { "Invalid width $width" }
		require(height > 0) { "Invalid height $height" }
		this.width = width
		this.height = height
		glTexImage2D(GL_TEXTURE_2D, mipmap, loadedFormat, width, height, 0, bufferFormat, dataFormat, data)
		checkForGLError()
		uploaded = true
		return this
	}

	private fun upload(mipmap: Int, memoryFormat: Int, width: Int, height: Int, bufferFormat: Int, dataFormat: Int, data: ByteBuffer): GLTexture2D {
		bind()

		require(width > 0) { "Invalid width $width" }
		require(height > 0) { "Invalid height $height" }

		this.width = width
		this.height = height
		glTexImage2D(GL_TEXTURE_2D, mipmap, memoryFormat, width, height, 0, bufferFormat, dataFormat, data)
		checkForGLError()
		uploaded = true
		return this
	}

	fun upload(memoryFormat: Int, width: Int, height: Int, bufferFormat: Int, dataFormat: Int, data: IntArray): GLTexture2D {
		return upload(0, memoryFormat, width, height, bufferFormat, dataFormat, data)
	}

	fun upload(memoryFormat: Int, width: Int, height: Int, bufferFormat: Int, dataFormat: Int, data: ByteBuffer): GLTexture2D {
		return upload(0, memoryFormat, width, height, bufferFormat, dataFormat, data)
	}

	fun upload(path: File, memoryFormat: Int, bufferFormat: Int): GLTexture2D {
		state.ensureSameThread()

		if (!path.exists()) {
			throw FileNotFoundException("${path.absolutePath} does not exist")
		}

		if (!path.isFile) {
			throw FileNotFoundException("${path.absolutePath} is not a file")
		}

		val getwidth = intArrayOf(0)
		val getheight = intArrayOf(0)
		val getchannels = intArrayOf(0)

		val bytes = STBImage.stbi_load(path.absolutePath, getwidth, getheight, getchannels, 0) ?: throw TextureLoadingException("Unable to load ${path.absolutePath}. Is it a valid image?")

		require(getwidth[0] > 0) { "Image ${path.absolutePath} has bad width of ${getwidth[0]}" }
		require(getheight[0] > 0) { "Image ${path.absolutePath} has bad height of ${getheight[0]}" }

		upload(memoryFormat, getwidth[0], getheight[0], bufferFormat, GL_UNSIGNED_BYTE, bytes)
		STBImage.stbi_image_free(bytes)

		return this
	}

	fun upload(path: File): GLTexture2D {
		state.ensureSameThread()

		if (!path.exists()) {
			throw FileNotFoundException("${path.absolutePath} does not exist")
		}

		if (!path.isFile) {
			throw FileNotFoundException("${path.absolutePath} is not a file")
		}

		val getwidth = intArrayOf(0)
		val getheight = intArrayOf(0)
		val getchannels = intArrayOf(0)

		val bytes = STBImage.stbi_load(path.absolutePath, getwidth, getheight, getchannels, 0) ?: throw TextureLoadingException("Unable to load ${path.absolutePath}. Is it a valid image?")

		require(getwidth[0] > 0) { "Image ${path.absolutePath} has bad width of ${getwidth[0]}" }
		require(getheight[0] > 0) { "Image ${path.absolutePath} has bad height of ${getheight[0]}" }

		val bufferFormat = when (val numChannels = getchannels[0]) {
			1 -> GL_R
			2 -> GL_RG
			3 -> GL_RGB
			4 -> GL_RGBA
			else -> throw IllegalArgumentException("Weird amount of channels in file: $numChannels")
		}

		upload(bufferFormat, getwidth[0], getheight[0], bufferFormat, GL_UNSIGNED_BYTE, bytes)
		STBImage.stbi_image_free(bytes)

		return this
	}

	fun upload(buff: ByteBuffer, memoryFormat: Int, bufferFormat: Int): GLTexture2D {
		state.ensureSameThread()

		val getwidth = intArrayOf(0)
		val getheight = intArrayOf(0)
		val getchannels = intArrayOf(0)

		val bytes = STBImage.stbi_load_from_memory(buff, getwidth, getheight, getchannels, 0) ?: throw TextureLoadingException("Unable to load ${buff}. Is it a valid image?")

		require(getwidth[0] > 0) { "Image '$name' has bad width of ${getwidth[0]}" }
		require(getheight[0] > 0) { "Image '$name' has bad height of ${getheight[0]}" }

		upload(memoryFormat, getwidth[0], getheight[0], bufferFormat, GL_UNSIGNED_BYTE, bytes)
		STBImage.stbi_image_free(bytes)

		return this
	}

	fun upload(buff: ByteBuffer): GLTexture2D {
		state.ensureSameThread()

		val getwidth = intArrayOf(0)
		val getheight = intArrayOf(0)
		val getchannels = intArrayOf(0)

		val bytes = STBImage.stbi_load_from_memory(buff, getwidth, getheight, getchannels, 0) ?: throw TextureLoadingException("Unable to load ${buff}. Is it a valid image?")

		require(getwidth[0] > 0) { "Image '$name' has bad width of ${getwidth[0]}" }
		require(getheight[0] > 0) { "Image '$name' has bad height of ${getheight[0]}" }

		val bufferFormat = when (val numChannels = getchannels[0]) {
			1 -> GL_R
			2 -> GL_RG
			3 -> GL_RGB
			4 -> GL_RGBA
			else -> throw IllegalArgumentException("Weird amount of channels in file: $numChannels")
		}

		upload(bufferFormat, getwidth[0], getheight[0], bufferFormat, GL_UNSIGNED_BYTE, bytes)
		STBImage.stbi_image_free(bytes)

		return this
	}

	fun upload(data: Image): GLTexture2D {
		state.ensureSameThread()

		val bufferFormat = when (val numChannels = data.amountOfChannels) {
			1 -> GL_R
			2 -> GL_RG
			3 -> GL_RGB
			4 -> GL_RGBA
			else -> throw IllegalArgumentException("Weird amount of channels in file: $numChannels")
		}

		upload(bufferFormat, data.width, data.height, bufferFormat, GL_UNSIGNED_BYTE, data.data)

		return this
	}

	companion object {
		private val LOGGER = LogManager.getLogger()
	}
}