package main

import (
	"fmt"
	"runtime"

	"git.tek.govt.hu/dowerx/opengl-deferred/types/gbuffer"
	"git.tek.govt.hu/dowerx/opengl-deferred/types/geometry"
	"git.tek.govt.hu/dowerx/opengl-deferred/types/light"
	"git.tek.govt.hu/dowerx/opengl-deferred/types/shader"
	"git.tek.govt.hu/dowerx/opengl-deferred/types/texture"
	"git.tek.govt.hu/dowerx/opengl-deferred/utils/assetmanager"
	"git.tek.govt.hu/dowerx/opengl-deferred/utils/fpscontrols"
	"github.com/go-gl/gl/v4.6-core/gl"
	"github.com/go-gl/glfw/v3.3/glfw"
	"github.com/go-gl/mathgl/mgl32"
)

const (
	WIDTH  = 1600
	HEIGHT = 900
	TITLE  = "opengl-deferred"
	FOV    = 45.0
)

func main() {
	// init glfw
	runtime.LockOSThread()
	if err := glfw.Init(); err != nil {
		panic(err)
	}
	defer glfw.Terminate()

	glfw.WindowHint(glfw.Resizable, glfw.False)
	glfw.WindowHint(glfw.ContextVersionMajor, 4)
	glfw.WindowHint(glfw.ContextVersionMinor, 6)
	glfw.WindowHint(glfw.OpenGLProfile, glfw.OpenGLCoreProfile)
	glfw.WindowHint(glfw.OpenGLForwardCompatible, glfw.True)

	window, err := glfw.CreateWindow(WIDTH, HEIGHT, TITLE, nil, nil)
	if err != nil {
		panic(err)
	}
	window.MakeContextCurrent()

	// init gl
	if err := gl.Init(); err != nil {
		panic(err)
	}

	gl.Enable(gl.CULL_FACE)
	gl.DepthFunc(gl.LESS)
	gl.ClearColor(0, 0, 0, 1)

	fmt.Println("OpenGL version:", gl.GoStr(gl.GetString(gl.VERSION)))

	// load assets
	assetManager := assetmanager.Get()
	defer assetManager.Delete()

	// shader
	tmpShader, err := shader.FromFiles("assets/shader/deferred/deferred.vs", "assets/shader/deferred/deferred.fs")
	if err != nil {
		panic(err)
	}
	assetManager.Add("deferred", tmpShader)

	tmpShader, err = shader.FromFiles("assets/shader/pbr/pbr.vs", "assets/shader/pbr/pbr.fs")
	if err != nil {
		panic(err)
	}
	assetManager.Add("pbr", tmpShader)

	tmpShader, err = shader.FromFiles("assets/shader/screen/screen.vs", "assets/shader/screen/screen.fs")
	if err != nil {
		panic(err)
	}
	assetManager.Add("screen", tmpShader)

	deferredShader := assetManager.Shadres["deferred"]
	screenShader := assetManager.Shadres["pbr"]

	// geometry
	tmpGeometry, err := geometry.LoadOBJ("assets/geometries/20.obj")
	if err != nil {
		panic(err)
	}
	assetManager.Add("teapot", tmpGeometry)

	// tmpGeometry, err = geometry.LoadOBJ("assets/geometries/plane.obj")
	// if err != nil {
	// 	panic(err)
	// }
	// assetManager.Add("plane", tmpGeometry)

	screen, err := geometry.Screen()
	if err != nil {
		panic(err)
	}
	defer screen.Delete()

	// textures
	tmpTexture, err := texture.Load("assets/textures/TCom_Pavement_PaintedConcrete3_512_albedo.tif")
	if err != nil {
		panic(err)
	}
	assetManager.Add("albedo", tmpTexture)

	tmpTexture, err = texture.Load("assets/textures/TCom_Pavement_PaintedConcrete3_512_normal.tif")
	if err != nil {
		panic(err)
	}
	assetManager.Add("normal", tmpTexture)

	tmpTexture, err = texture.Load("assets/textures/TCom_Pavement_PaintedConcrete3_512_roughness.tif")
	if err != nil {
		panic(err)
	}
	assetManager.Add("roughness", tmpTexture)

	tmpTexture, err = texture.Load("assets/textures/white.png")
	if err != nil {
		panic(err)
	}
	assetManager.Add("white", tmpTexture)

	tmpTexture, err = texture.Load("assets/textures/black.png")
	if err != nil {
		panic(err)
	}
	assetManager.Add("black", tmpTexture)

	// lights
	lights := []light.Light{
		{Color: [3]float32{1, 1, 1}, Position: mgl32.Vec3{0, 10, 0}, Intensity: 40, Type: light.POINT},
		{Color: [3]float32{1, 0, 0}, Position: mgl32.Vec3{5, 5, 5}, Intensity: 30, Type: light.POINT},
		{Color: [3]float32{0, 0, 1}, Position: mgl32.Vec3{-5, 5, -5}, Intensity: 30, Type: light.POINT},
	}

	// gbuffer
	gbuff, err := gbuffer.New(WIDTH, HEIGHT)
	if err != nil {
		panic(err)
	}
	defer gbuff.Delete()
	gbuff.Bind()

	// transformations
	projection := mgl32.Perspective(mgl32.DegToRad(FOV), float32(WIDTH)/HEIGHT, 0.1, 1000)
	model := mgl32.Ident4()
	controls := fpscontrols.Get(10, 10, mgl32.Vec3{0, 0, -10}, mgl32.Vec2{0, 0}, window)

	for !window.ShouldClose() {
		glfw.PollEvents()
		controls.Update()

		// first pass
		gl.Enable(gl.DEPTH_TEST)

		gbuff.Bind()

		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

		assetManager.Textures["albedo"].Bind(gl.TEXTURE0)
		assetManager.Textures["normal"].Bind(gl.TEXTURE1)
		assetManager.Textures["roughness"].Bind(gl.TEXTURE2)
		assetManager.Textures["roughness"].Bind(gl.TEXTURE3)
		assetManager.Textures["roughness"].Bind(gl.TEXTURE4)

		// transfer uniforms
		deferredShader.Use()
		deferredShader.Mat4("projection", projection)
		deferredShader.Mat4("view", controls.View())
		deferredShader.Mat4("model", model)

		deferredShader.Int("s_albedo", 0)
		deferredShader.Int("s_normal", 1)
		deferredShader.Int("s_specular", 2)
		deferredShader.Int("s_roughness", 3)
		deferredShader.Int("s_metalic", 4)
		for _, g := range assetManager.Geometries {
			g.Draw()
		}

		// second pass
		gl.Disable(gl.DEPTH_TEST)
		gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
		gl.Clear(gl.COLOR_BUFFER_BIT)

		gbuff.BindTextures()

		screenShader.Use()
		screenShader.Int("s_albedo", 0)
		screenShader.Int("s_depth", 1)
		screenShader.Int("s_normal", 2)
		screenShader.Int("s_material", 3)
		screenShader.Int("s_position", 4)

		pos := controls.Position()
		screenShader.Vec3("view_pos", &pos[0])

		for _, light := range lights {
			screenShader.Light(&light)
		}

		screen.Draw()

		window.SwapBuffers()
	}

	defer fmt.Println("exiting...")
}