#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();
	}

	glDisable(GL_FRAMEBUFFER_SRGB);
	glClearColor(0.f, 0.f, 0.f, 1.f);
	glEnable(GL_TEXTURE_2D);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0f, (float)Width() / (float)Height(), 0.1f, VIEW_DISTANCE);
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_STENCIL_TEST);
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
	glShadeModel(GL_SMOOTH);
	
	glEnable(GL_POINT_SMOOTH);
	glEnable(GL_CULL_FACE);

	glEnable(GL_BLEND);
	glBlendFunc(GL_CONSTANT_COLOR, GL_ONE_MINUS_CONSTANT_COLOR); // , GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glBlendEquation(GL_FUNC_SUBTRACT);// , GL_FUNC_ADD);

	// Objet de skybox avec sa propre texture et son propre shader!
	m_skybox.Init(0.2f);

	// Objet de musique!
	m_audio.ToggleMusicState();

	// Init Chunks
	m_world.GetChunks().Reset(nullptr);

	// Gestion de souris.
	CenterMouse();
	HideCursor();
}

void Engine::DeInit() { }

void Engine::LoadResource() {
	LoadTexture(m_skybox.GetTexture(), TEXTURE_PATH "skybox.png");
	LoadTexture(m_textureCrosshair, TEXTURE_PATH "cross.bmp");
	LoadTexture(m_textureFont, TEXTURE_PATH "font.bmp");
	TextureAtlas::TextureIndex texDirtIndex = m_textureAtlas.AddTexture(TEXTURE_PATH "metal3.png");
	TextureAtlas::TextureIndex texIceIndex = m_textureAtlas.AddTexture(TEXTURE_PATH "metal2.png");
	TextureAtlas::TextureIndex texGrassIndex = m_textureAtlas.AddTexture(TEXTURE_PATH "grass.png");
	TextureAtlas::TextureIndex texMetalIndex = m_textureAtlas.AddTexture(TEXTURE_PATH "dirt.png");

	if (!m_textureAtlas.Generate(TEXTURE_SIZE, false)) {
		std::cout << " Unable to generate texture atlas ..." << std::endl;
		abort();
	}

	float u, v, s;
	m_textureAtlas.TextureIndexToCoord(texDirtIndex, u, v, s, s);
	m_blockinfo[BTYPE_DIRT] = new BlockInfo(BTYPE_DIRT, "Dirt", u, v, s, 1);
	m_textureAtlas.TextureIndexToCoord(texGrassIndex, u, v, s, s);
	m_blockinfo[BTYPE_GRASS] = new BlockInfo(BTYPE_GRASS, "Grass", u, v, s, 1);
	m_textureAtlas.TextureIndexToCoord(texMetalIndex, u, v, s, s);
	m_blockinfo[BTYPE_METAL] = new BlockInfo(BTYPE_METAL, "Metal", u, v, s, 1);
	m_textureAtlas.TextureIndexToCoord(texIceIndex, u, v, s, s);
	m_blockinfo[BTYPE_ICE] = new BlockInfo(BTYPE_ICE, "Ice", u, v, s, 1);

	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::DrawHud(float elapsedTime) {
	// Setter le blend function , tout ce qui sera noir sera transparent
	glColor4f(1.f, 1.f, 1.f, 1.f);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE);
	glBlendEquation(GL_FUNC_ADD);
	glDisable(GL_DEPTH_TEST);
	glMatrixMode(GL_PROJECTION);
	glPushMatrix();
	glLoadIdentity();
	glOrtho(0, Width(), 0, Height(), -1, 1);
	glMatrixMode(GL_MODELVIEW);
	glPushMatrix();

	// Bind de la texture pour le font
	m_textureFont.Bind();
	std::ostringstream ss;
	ss << " Fps : " << GetFps(elapsedTime);
	PrintText(10, Height() - 25, ss.str());
	ss.str("");
	ss << " Rendered Chunks : " << m_renderCount;
	PrintText(10, Height() - 35, ss.str());
	ss.str("");
	ss << " Bad Hits on Chunks : " << m_badHitCount;
	PrintText(10, Height() - 45, ss.str());
	ss.str("");
	ss << " Velocity  : " << m_player.GetVelocity(); // IMPORTANT : on utilise l ’ operateur << pour afficher la position
	PrintText(10, 10, ss.str());
	ss.str("");
	ss << " Direction : " << m_player.GetDirection();
	PrintText(10, 20, ss.str());
	ss.str("");
	ss << " Position  : " << m_player.GetPosition();
	PrintText(10, 30, ss.str());
	ss.str("");
	ss << " CamPos  : " << m_player.GetPOV();
	PrintText(10, 40, ss.str());
	// Affichage du crosshair
	m_textureCrosshair.Bind();
	static const int crossSize = 32;
	glLoadIdentity();
	glTranslated(Width() / 2 - crossSize / 2, Height() / 2 - crossSize / 2, 0);
	glBegin(GL_QUADS);
	glTexCoord2f(0, 0);
	glVertex2i(0, 0);
	glTexCoord2f(1, 0);
	glVertex2i(crossSize, 0);
	glTexCoord2f(1, 1);
	glVertex2i(crossSize, crossSize);
	glTexCoord2f(0, 1);
	glVertex2i(0, crossSize);
	glEnd();
	glBlendFunc(GL_CONSTANT_COLOR, GL_ONE_MINUS_CONSTANT_COLOR); // , GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glBlendEquation(GL_FUNC_SUBTRACT);// , GL_FUNC_ADD);
	glEnable(GL_DEPTH_TEST);
	glMatrixMode(GL_PROJECTION);
	glPopMatrix();
	glMatrixMode(GL_MODELVIEW);
	glPopMatrix();
}

void Engine::PrintText(unsigned int x, unsigned int y, const std::string& t) {
	glLoadIdentity();
	glTranslated(x, y, 0);
	for (unsigned int i = 0; i < t.length(); ++i) {
		float left = (float)((t[i] - 32) % 16) / 16.f;
		float top = (float)((t[i] - 32) / 16) / 16.f;
		top += .5f;
		glBegin(GL_QUADS);
		glTexCoord2f(left, 1.f - top - .0625f);
		glVertex2f(0, 0);
		glTexCoord2f(left + .0625f, 1.f - top - .0625f);
		glVertex2f(12, 0);
		glTexCoord2f(left + .0625f, 1.f - top);
		glVertex2f(12, 12);
		glTexCoord2f(left, 1.f - top);
		glVertex2f(0, 12);
		glEnd();
		glTranslated(8, 0, 0);
	}
}

int Engine::GetFps(float elapsedTime) const { return 1 / elapsedTime; }

void Engine::Render(float elapsedTime) {
	static float gameTime = elapsedTime;
	if (elapsedTime > 0.1f) return;

	gameTime += elapsedTime;

	Transformation all;
	Transformation skybox;
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

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

	m_player.ApplyPhysics(m_player.GetInput(m_keyW, m_keyS, m_keyA, m_keyD, m_keySpace, m_keylshift, elapsedTime), m_world, elapsedTime);
	m_audio.Update3DAudio(m_player.GetPOV(), m_player.GetDirection(), m_player.GetVelocity()); // Ajustement du positionnement 3D avec les coordonnées du joueur et
																									// son vecteur de vélocité (pour l'effet Doppler)
	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!).
	
	if (m_mouseL)
		m_world.ChangeBlockAtCursor(BTYPE_DIRT, m_player, m_block);
	else if (m_mouseR)
		m_world.ChangeBlockAtCursor(BTYPE_AIR, m_player, m_block);

	glStencilFunc(GL_EQUAL, 1, 0x00);
	glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
	m_world.Update(m_renderCount, m_badHitCount, m_player, all, m_shader01, m_textureAtlas, m_perlin, m_blockinfo);

	glStencilFunc(GL_GREATER, 1, 0xFF);
	if (m_isSkybox) m_skybox.Render(skybox);
	
	if (m_wireframe)
		glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
	glDisable(GL_STENCIL_TEST);
	DrawHud(elapsedTime);
	glEnable(GL_STENCIL_TEST);
	if (m_wireframe)
		glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

	if (m_player.GetPosition().y < -20.f)
		m_player = Player(Vector3f(0, CHUNK_SIZE_Y + 1.8f, 0)); // Respawn si le bonho- joueur tombe en bas du monde.
}

void Engine::KeyPressEvent(unsigned char key) {
	switch (key) {
	case 36: // ESC
		m_world.CleanUpWorld(m_renderCount, true);
		for (int x = 0; x < WORLD_SIZE_X; ++x) // Les destructeurs de Chunks ont de la misère je les aide un peu!
			for (int y = 0; y < WORLD_SIZE_Y; ++y)
				if (m_world.GetChunks().Get(x,y)) 
					m_world.GetChunks().Get(x, y)->~Chunk();
		m_world.GetChunks().Reset(nullptr); // Hack cheap qui empêche d'avoir une exception en sortant du jeu
		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
	case 12: // M - Ignorer
	case 17: // R - Ignorer
		break;
	default:
		std::cout << "Unhandled key: " << (int)key << std::endl;
	}
}

void Engine::KeyReleaseEvent(unsigned char key) {
	switch (key) {
	case 12:
		m_audio.ToggleMusicState();
		break;
	case 17:
		m_isSkybox = !m_isSkybox;
		break;
	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) {
	switch (button) {
	case MOUSE_BUTTON_LEFT:
		m_mouseL = true;
		break;
	case MOUSE_BUTTON_RIGHT:
		m_mouseR = true;
		break;
	case MOUSE_BUTTON_MIDDLE:
		m_mouseC = true;
		break;
	case MOUSE_BUTTON_WHEEL_UP:
		m_mouseWU = true;
		break;
	case MOUSE_BUTTON_WHEEL_DOWN:
		m_mouseWD = true;
		break;
	case MOUSE_BUTTON_NONE: break;
	}
}

void Engine::MouseReleaseEvent(const MOUSE_BUTTON& button, int x, int y) {
	switch (button) {
	case MOUSE_BUTTON_LEFT:
		m_mouseL = false;
		m_block = false;
		break;
	case MOUSE_BUTTON_RIGHT:
		m_mouseR = false;
		m_block = false;
		break;
	case MOUSE_BUTTON_MIDDLE:
		m_mouseC = false;
		break;
	case MOUSE_BUTTON_WHEEL_UP:
		m_mouseWU = false;
		break;
	case MOUSE_BUTTON_WHEEL_DOWN:
		m_mouseWD = false;
		break;
	case MOUSE_BUTTON_NONE: break;
	}
}

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;
}