/**

 * ShaderShark

 * Copyright © 2023 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 3 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

#pragma once

#include <iostream>

#include <iomanip>

#include <string>

#include <memory>

#include <functional>

#include <sstream>

#include <vector>

#include <chrono>

#include <unistd.h>

#include <sys/stat.h>

#include "Configuration.h"

#include "x11.h"

#include "opengl.h"

#include "EPoll.h"

#include "Logger.h"

#include "MappedFile.h"

#include "ImageLoader.h"

#include "Shader.h"

#include "Program.h"

class Shark {

private:

	struct {

		GLint aVertexXYZ = -2;

		GLint aTextureXY = -2;

		GLint fColor = -2;

		GLint uModel = -2;

		GLint uView = -2;

		GLint uProjection = -2;

		GLint uTexture = -2;

	} ProgAttr;

	struct {

		float yaw = -90.f;

		float pitch = 0.f;

		float roll = 0.f;

		float fov = 45.0f;

		glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);

		glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);

		glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);

		void adjustFov(float diff) {

			fov += diff;

			if (fov < 1.0f) fov = 1.0f;

			else if (fov > 120.0f) fov = 120.0f;

			std::cerr << "field of view: " << fov << " °" << std::endl;

		}

		void moveForward(const float cameraSpeed) {

			cameraPos += cameraSpeed * cameraFront;

		}

		void moveBackward(const float cameraSpeed) {

			cameraPos -= cameraSpeed * cameraFront;

		}

		void moveLeft(const float cameraSpeed) {

			cameraPos -= glm::normalize(

					glm::cross(cameraFront, cameraUp)) * cameraSpeed;

		}

		void moveRight(const float cameraSpeed) {

			cameraPos += glm::normalize(

					glm::cross(cameraFront, cameraUp)) * cameraSpeed;

		}

		void moveUp(const float cameraSpeed) {

			cameraPos += cameraSpeed * glm::normalize(cameraUp);

		}

		void moveDown(const float cameraSpeed) {

			cameraPos -= cameraSpeed * glm::normalize(cameraUp);

		}

		void updateCameraFrontAndUp() {

			std::cerr << "--- updateCameraFrontAndUp() --------" << std::endl;

			dump("pitch, yaw, roll", glm::vec3(pitch, yaw, roll));

			dump("cameraPos", cameraPos);

			dump("cameraFront", cameraFront);

			const auto pitchR = glm::radians(pitch); // around X axis

			const auto yawR = glm::radians(yaw); //     around Y axis

			const auto rollR = glm::radians(roll); //   around Z axis

			cameraFront.x = cos(pitchR) * cos(yawR);

			cameraFront.y = sin(pitchR);

			cameraFront.z = cos(pitchR) * sin(yawR);

			cameraFront = glm::normalize(cameraFront);

			dump("cameraFront", cameraFront);

			dump("cameraUp", cameraUp);

			// TODO: review ROLL rotation and default angle

			glm::mat4 rollMatrix = glm::rotate(

					glm::mat4(1.0f), rollR, cameraFront);

			cameraUp = glm::mat3(rollMatrix) * glm::vec3(0., 1., 0.);

			dump("cameraUp", cameraUp);

			std::cerr << "-------------------------------------" << std::endl;

		}

		void limitPitch() {

			if (pitch > +89.0f) pitch = +89.0f;

			if (pitch < -89.0f) pitch = -89.0f;

		}

		void turnLeft(const float angleSpeed) {

			yaw -= angleSpeed;

			updateCameraFrontAndUp();

		}

		void turnRight(const float angleSpeed) {

			yaw += angleSpeed;

			updateCameraFrontAndUp();

		}

		void turnUp(const float angleSpeed) {

			pitch += angleSpeed;

			limitPitch();

			updateCameraFrontAndUp();

		}

		void turnDown(const float angleSpeed) {

			pitch -= angleSpeed;

			limitPitch();

			updateCameraFrontAndUp();

		}

		void rollLeft(const float angleSpeed) {

			roll += angleSpeed;

			updateCameraFrontAndUp();

		}

		void rollRight(const float angleSpeed) {

			roll -= angleSpeed;

			updateCameraFrontAndUp();

		}

	} initialCtx, ctx;

	class Texture {

	public:

		GLuint id;

		std::string fileName;

		int width;

		int height;

		GLfloat getRatio() const {

			return (GLfloat) width / (GLfloat) height;

		}

	};

	Display* dpy;

	Window win;

	XVisualInfo* vi;

	GLXContext glc;

	ImageLoader imageLoader;

	std::vector<std::shared_ptr<Shader>> shaders;

	std::shared_ptr<Program> shaderProgram;

	std::vector<Texture> textures;

	Configuration cfg;

	std::ostream& logOutput = std::cerr;

	void clear();

	void runShaders();

	Window getRootWindow(Window defaultValue);

	void log(LogLevel level, std::string message);

	int setNonBlocking(int fd);

	void loadVertices();

	Texture loadTexture(const std::string& fileName);

	void loadTextures();

	std::shared_ptr<Program> loadShaders();

public:

	Shark(const Configuration& cfg);

	virtual ~Shark();

	Shark(const Shark&) = delete;

	Shark& operator=(const Shark&) = delete;

	void run();

};