#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);

	// Light
	GLfloat light0Pos[4] = { 0.0f, CHUNK_SIZE_Y, 0.0f, 1.0f };
	GLfloat light0Amb[4] = { 0.2f, 0.2f, 0.2f, 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);

	// 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_textureFloor, TEXTURE_PATH "grass.png");
	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 "dirt.png");
	TextureAtlas::TextureIndex texGrassIndex = m_textureAtlas.AddTexture(TEXTURE_PATH "grass.png");
	TextureAtlas::TextureIndex texMetalIndex = m_textureAtlas.AddTexture(TEXTURE_PATH "metal.png");

	if (!m_textureAtlas.Generate(128, 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
	glDisable(GL_LIGHTING);
	glColor4f(1.f, 1.f, 1.f, 1.f);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE);
	glEnable(GL_BLEND);
	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 << " 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();
	glEnable(GL_LIGHTING);
	glDisable(GL_BLEND);
	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);

	// 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!).
	glDisable(GL_LIGHT0);
	m_skybox.Render(skybox);

	// Génération/Update de Chunks.
	glEnable(GL_LIGHT0);
	m_textureAtlas.Bind();
	int cx = m_player.GetPosition().x;
	int cy = m_player.GetPosition().z;
	static int frameGenerate = 0;
	static int frameUpdate = 0;
	int side = 0;
	m_shader01.Use();
	m_renderCount = 0;

	if (frameGenerate > 0) --frameGenerate;
	if (frameUpdate > 0) --frameUpdate;

	if (!frameGenerate || !frameUpdate)
		while (side * CHUNK_SIZE_X <= VIEW_DISTANCE) {
			int tx = -side, ty = -side;

			for (; tx <= side; ++tx)
				UpdateWorld(frameGenerate, frameUpdate, cx + tx * CHUNK_SIZE_X, cy + ty * CHUNK_SIZE_Z);
			for (; ty <= side; ++ty)
				UpdateWorld(frameGenerate, frameUpdate, cx + tx * CHUNK_SIZE_X, cy + ty * CHUNK_SIZE_Z);
			for (; tx >= -side; --tx)
				UpdateWorld(frameGenerate, frameUpdate, cx + tx * CHUNK_SIZE_X, cy + ty * CHUNK_SIZE_Z);
			for (; ty >= -side; --ty)
				UpdateWorld(frameGenerate, frameUpdate, cx + tx * CHUNK_SIZE_X, cy + ty * CHUNK_SIZE_Z);

			++side;
		}

	// Rendering de Chunks.
	all.Use();
	if (m_renderer) { // Choix d'algorithme de rendu pour comparer.
		Vector3f direct = m_player.GetDirection();
		Vector3f renderpos = m_player.GetPosition();

		direct.y = 0;
		direct.Normalize();

		Vector3f viewL = renderpos - direct * CHUNK_SIZE_X * 2,
			viewR = viewL;

		viewL.Dot(direct);
		viewR.Dot(direct);

		for (int x = -3; x <= VIEW_DISTANCE / CHUNK_SIZE_X; ++x) {
			int chunkxL = -1, chunkyL = -1, chunkxR = -1, chunkyR = -1;

			if (m_world.ChunkAt(viewL)) {
				chunkxL = m_world.ChunkAt(viewL)->GetPosX();
				chunkyL = m_world.ChunkAt(viewL)->GetPosY();
			}
			if (m_world.ChunkAt(viewR)) {
				chunkxR = m_world.ChunkAt(viewR)->GetPosX();
				chunkyR = m_world.ChunkAt(viewR)->GetPosY();
			}

			if (chunkxL == chunkxR) {
				++chunkxR;
				--chunkxL;
			}
			if (chunkyL == chunkyR) {
				++chunkyR;
				--chunkyL;
			}

			if (chunkxL >= 0 && chunkyL >= 0 && chunkxR >= 0 && chunkyR >= 0)
				for (int rx = chunkxL; rx != chunkxR; chunkxL < chunkxR ? ++rx : --rx)
					for (int ry = chunkyL; ry != chunkyR; chunkyL < chunkyR ? ++ry : --ry) {
						all.ApplyTranslation(rx * CHUNK_SIZE_X, 0, ry * CHUNK_SIZE_Z);
						all.Use();
						if (m_world.GetChunks().Get(rx, ry)) {
							m_world.GetChunks().Get(rx, ry)->Render();
							++m_renderCount;
						}
						all.ApplyTranslation(-rx * CHUNK_SIZE_X, 0, -ry * CHUNK_SIZE_Z);
					}

			viewL.x += (direct.x + direct.z) * CHUNK_SIZE_X / 2;
			viewL.z += (direct.z - direct.x) * CHUNK_SIZE_X / 2;
			viewR.x += (direct.x - direct.z) * CHUNK_SIZE_X / 2;
			viewR.z += (direct.z + direct.x) * CHUNK_SIZE_X / 2;
		}
	}
	else {
		for (int chx = 0; chx < WORLD_SIZE_X; chx++)
			for (int chy = 0; chy < WORLD_SIZE_Y; chy++) {
				all.ApplyTranslation(chx * CHUNK_SIZE_X, 0, chy * CHUNK_SIZE_Z);
				all.Use();
				if (m_world.GetChunks().Get(chx, chy)) {
					m_world.GetChunks().Get(chx, chy)->Render();
					++m_renderCount;
				}
				all.ApplyTranslation(-chx * CHUNK_SIZE_X, 0, -chy * CHUNK_SIZE_Z);
			}
	}
	m_shader01.Disable();

	if (m_mouseL)
		GetBlockAtCursor(BTYPE_DIRT);
	else if (m_mouseR) GetBlockAtCursor(BTYPE_AIR);

	if (m_wireframe)
		glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
	DrawHud(elapsedTime);
	if (m_wireframe)
		glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

	
	if (m_player.GetPosition().y < -20.f)
		m_player = Player(Vector3f(CHUNK_SIZE_X * WORLD_SIZE_X / 2, CHUNK_SIZE_Y + 1.7f, CHUNK_SIZE_Z * WORLD_SIZE_X / 2)); // Respawn si le bonho- joueur tombe en bas du monde.
}

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
	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_renderer = !m_renderer;
		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;
}

bool Engine::GenerateChunk(int chx, int chy) {
	if (chx < WORLD_SIZE_X * CHUNK_SIZE_X && chy < WORLD_SIZE_Y * CHUNK_SIZE_Z &&
		chx >= 0 && chy >= 0)
		if (!m_world.ChunkAt(chx, 1, chy)) {
			m_world.GetChunks().Set(chx / CHUNK_SIZE_X, chy / CHUNK_SIZE_Z, new Chunk(chx / CHUNK_SIZE_X, chy / CHUNK_SIZE_Z));
			Chunk* chunk = m_world.GetChunks().Get(chx / CHUNK_SIZE_X, chy / CHUNK_SIZE_Z);

			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)
						chunk->SetBlock(x, y, z, (chx + chy) % (BTYPE_LAST - 1) + 1, &m_world);

			std::cout << "Chunk generated: " << chx / CHUNK_SIZE_X << ", " << chy / CHUNK_SIZE_Z << std::endl;


			return true;
		}
	return false;
}

void Engine::UpdateWorld(int& generates, int& updates, int chx, int chy) {
	if (generates == 0 && GenerateChunk(chx, chy)) generates = FRAMES_RENDER_CHUNKS;
	if (updates == 0 && m_world.ChunkAt(chx, 1, chy) &&
		m_world.ChunkAt(chx, 1, chy)->IsDirty()) {
		m_world.ChunkAt(chx, 1, chy)->Update(m_blockinfo, &m_world);
		updates = FRAMES_UPDATE_CHUNKS;
	}
}

void Engine::GetBlockAtCursor(BlockType blockType) {
	Vector3f currentPos = m_player.GetPosition();
	Vector3f currentBlock = currentPos;
	Vector3f ray = m_player.GetDirection();
	bool found = false;

	if (m_block) return;

	while ((currentPos - currentBlock).Length() <= MAX_SELECTION_DISTANCE && !found) {
		currentBlock += ray / 10.f;

		BlockType bt = m_world.BlockAt(currentBlock);
		
		if (bt != BTYPE_AIR)
			found = true;
	}

	if (found) {
		if (blockType != BTYPE_AIR) {
			found = false;
			while ((currentPos - currentBlock).Length() >= 1.7f && !found) {
				currentBlock -= ray / 10.f;

				BlockType bt = m_world.BlockAt(currentBlock);

				if (bt == BTYPE_AIR) {
					int Bx = (int)currentBlock.x;
					int By = (int)currentBlock.y;
					int Bz = (int)currentBlock.z;

					int Px = (int)currentPos.x;
					int PyA = (int)currentPos.y;
					int PyB = (int)(currentPos.y - .9f);
					int PyC = (int)(currentPos.y - 1.7f);
					int Pz = (int)currentPos.z;

					if (!(Bx == Px && 
						  (By == PyA || 
						   By == PyB ||
						   By == PyC) &&
						  Bz == Pz))
						found = true;			
				}
			}
		}
	}

	if (found && (int)currentBlock.y < CHUNK_SIZE_Y) {
		int bx = (int)currentBlock.x % CHUNK_SIZE_X;
		int by = (int)currentBlock.y % CHUNK_SIZE_Y;
		int bz = (int)currentBlock.z % CHUNK_SIZE_Z;

		m_world.ChunkAt(currentBlock)->SetBlock(bx, by, bz, blockType, &m_world);
		m_world.ChunkAt(currentBlock)->MakeModified();
		m_block = true;
	}
}