#include "engine.h"
#include <algorithm>
#include <cmath>
#include "transformation.h"
#include "player.h"

Engine::Engine() { }

Engine::~Engine() { }

void Engine::Init()
{
	GLenum glewErr = glewInit();
	if (glewErr != GLEW_OK) {
		std::cerr << " ERREUR GLEW : " << glewGetErrorString(glewErr) << std::endl;
		abort();
	}

	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glEnable(GL_TEXTURE_2D);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0f, (float)Width() / (float)Height(), 0.0001f, 1000.0f);
	glEnable(GL_DEPTH_TEST);
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
	glShadeModel(GL_SMOOTH);
	glEnable(GL_LIGHTING);
	glEnable(GL_LINE_SMOOTH);
	glEnable(GL_CULL_FACE);
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	// Light
	GLfloat light0Pos[4] = { 0.0f, CHUNK_SIZE_Y, 0.0f, 1.0f };
	GLfloat light0Amb[4] = { 0.9f, 0.9f, 0.9f, 1.f };
	GLfloat light0Diff[4] = { 1.f, 1.f, 1.f, 1.f };
	GLfloat light0Spec[4] = { 0.2f, 0.2f, 0.2f, 1.0f };

	glEnable(GL_LIGHT0);
	glLightfv(GL_LIGHT0, GL_POSITION, light0Pos);
	glLightfv(GL_LIGHT0, GL_AMBIENT, light0Amb);
	glLightfv(GL_LIGHT0, GL_DIFFUSE, light0Diff);
	glLightfv(GL_LIGHT0, GL_SPECULAR, light0Spec);

	// Objet de skybox avec sa propre texture et son propre shader!
	m_skybox.Init(0.00013f);

	// Init testChunk
	for (int x = 0; x < CHUNK_SIZE_X; ++x) {
		for (int z = 0; z < CHUNK_SIZE_Z; ++z) {
			for (int y = 0; y < 32; ++y) {
				if (x % 2 == 0 && y % 2 == 0 && z % 2 == 0)
					m_testChunk.SetBlock(x, y, z, BTYPE_DIRT);
			}
		}
	}

	CenterMouse();
	HideCursor();
}

void Engine::DeInit() { }

void Engine::LoadResource() {
	LoadTexture(m_textureFloor, TEXTURE_PATH "grass.png");
	LoadTexture(m_skybox.GetTexture(), TEXTURE_PATH "skybox.png");
	LoadTexture(m_textureCube1, TEXTURE_PATH "metal1.png");
	LoadTexture(m_textureCube2, TEXTURE_PATH "metal2.png");
	LoadTexture(m_textureCube3, TEXTURE_PATH "metal3.png");
	LoadTexture(m_textureCube4, TEXTURE_PATH "metal4.png");

	std::cout << " Loading and compiling shaders ..." << std::endl;
	if (!m_shader01.Load(SHADER_PATH "shader01.vert", SHADER_PATH "shader01.frag", true)) {
		std::cout << " Failed to load shader " << std::endl;
		exit(1);
	}

	if (!m_skybox.GetShader().Load(SHADER_PATH "skybox.vert", SHADER_PATH "skybox.frag", true)) {
		std::cout << " Failed to load shader " << std::endl;
		exit(1);
	}
}

void Engine::UnloadResource(){}

void Engine::Render(float elapsedTime)
{
	static float gameTime = elapsedTime;

	gameTime += elapsedTime;

	Transformation all;
	Transformation skybox;

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// Transformations initiales
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();

	m_player.Move(m_keyW, m_keyS, m_keyA, m_keyD, m_keySpace, m_keylshift, elapsedTime);
	m_player.ApplyTransformation(all);
	m_player.ApplyTransformation(skybox, false); // Version d'ApplyTransformation qui ne tient compte que de la rotation 
												// (donc l'objet ne bouge pas relativement au joueur, ce qui est pratique pour une skybox!).
							
	m_skybox.Render(skybox);
	
	// Plancher
	// Les vertex doivent etre affiches dans le sens anti-horaire (CCW)
	all.Use();
	m_shader01.Use();
	m_textureFloor.Bind();
	float nbRep = 5.f;
	glBegin(GL_QUADS);
	glNormal3f(0, 1, 0); // Normal vector
	glTexCoord2f(0, 0);
	glVertex3f(-100.f, -2.f, 100.f);
	glTexCoord2f(nbRep, 0);
	glVertex3f(100.f, -2.f, 100.f);
	glTexCoord2f(nbRep, nbRep);
	glVertex3f(100.f, -2.f, -100.f);
	glTexCoord2f(0, nbRep);
	glVertex3f(-100.f, -2.f, -100.f);
	glEnd();

	// Chunk
	switch ((int)(gameTime * 5) % 4) {
	case 0: m_textureCube1.Bind();
		break;
	case 1: m_textureCube2.Bind();
		break;
	case 2: m_textureCube3.Bind();
		break;
	case 3: m_textureCube4.Bind();
		break;
	}
	if (m_testChunk.IsDirty())
		m_testChunk.Update();
	
	m_testChunk.Render();
	//Shader::Disable();

}

void Engine::KeyPressEvent(unsigned char key)
{
	switch (key) {
	case 36: // ESC
		Stop();
		break;
	case 94: // F10
		SetFullscreen(!IsFullscreen());
		break;
	case 22: // W
		if (!m_keyW) {
			std::cout << "W " << std::endl;
			m_keyW = true;
		}
		break;
	case 0: // A
		if (!m_keyA) {
			std::cout << "A " << std::endl;
			m_keyA = true;
		}
		break;
	case 18: // S
		if (!m_keyS) {
			std::cout << "S " << std::endl;
			m_keyS = true;
		}
		break;
	case 3: // D
		if (!m_keyD) {
			std::cout << "D " << std::endl;
			m_keyD = true;
		}
		break;
	case 38: // Left Shift
		if (!m_keylshift) {
			std::cout << "Dash!" << std::endl;
			m_keylshift = true;
		}
		break;
	case 57: // Space
		if (!m_keySpace) {
			std::cout << "Jump! " << std::endl;
			m_keySpace = true;
		}
		break;
	case 24: // Y - Ignorer
	case 255: // Fn - Ignorer
		break;
	default:
		std::cout << "Unhandled key: " << (int)key << std::endl;
	}
}

void Engine::KeyReleaseEvent(unsigned char key)
{
	switch (key) {
	case 24: // Y
		m_wireframe = !m_wireframe;
		if (m_wireframe)
			glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
		else
			glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
		break;
	case 22: // W
		std::cout << "rW " << std::endl;
		m_keyW = false;
		break;
	case 0: // A
		std::cout << "rA " << std::endl;
		m_keyA = false;
		break;
	case 18: // S
		std::cout << "rS " << std::endl;
		m_keyS = false;
		break;
	case 3: // D
		std::cout << "rD " << std::endl;
		m_keyD = false;
		break;
	case 38: // Left Shift
		std::cout << "rLS " << std::endl;
		m_keylshift = false;
	case 57: // Espace
		std::cout << "rSpace " << std::endl;
		m_keySpace = false;
		break;
	}
}

void Engine::MouseMoveEvent(int x, int y)
{
	m_player.TurnLeftRight(x - (Width() / 2));
	m_player.TurnTopBottom(y - (Height() / 2));

	// Centrer la souris seulement si elle n'est pas déjà centrée
	// Il est nécessaire de faire la vérification pour éviter de tomber
	// dans une boucle infinie où l'appel à CenterMouse génère un
	// MouseMoveEvent, qui rapelle CenterMouse qui rapelle un autre
	// MouseMoveEvent, etc
	if (x == (Width() / 2) && y == (Height() / 2))
		return;

	CenterMouse();
}

void Engine::MousePressEvent(const MOUSE_BUTTON& button, int x, int y)
{
}

void Engine::MouseReleaseEvent(const MOUSE_BUTTON& button, int x, int y)
{
}

bool Engine::LoadTexture(Texture& texture, const std::string& filename, bool stopOnError)
{
	texture.Load(filename);
	if (!texture.IsValid())
	{
		std::cerr << "Unable to load texture (" << filename << ")" << std::endl;
		if (stopOnError)
			Stop();

		return false;
	}

	return true;
}