#include <glm/glm.hpp>
#include <glm/gtc/constants.hpp>

#include "../graphics/Mesh.hpp"
#include "../graphics/Vertex.hpp"
#include "objects.hpp"

using namespace glm;

const int cube_num_v = 8;
Vertex cube_vertices[cube_num_v] = {
	// first 4 - up edge
	{ vec3(-1.0f, -1.0f, -1.0f), vec2(0.0f, 0.0f) },
	{ vec3(1.0f, -1.0f, -1.0f), vec2(0.0f, 0.0f) },
	{ vec3(1.0f, 1.0f, -1.0f), vec2(0.0f, 0.0f) },
	{ vec3(-1.0f, 1.0f, -1.0f), vec2(0.0f, 0.0f) },
	{ vec3(1.0f, 1.0f, 1.0f), vec2(0.0f, 0.0f) },
	{ vec3(-1.0f, 1.0f, 1.0f), vec2(0.0f, 0.0f) },
	{ vec3(-1.0f, -1.0f, 1.0f), vec2(0.0f, 0.0f) },
	{ vec3(1.0f, -1.0f, 1.0f), vec2(0.0f, 0.0f) }
};

const int cube_num_i = 12 * 3;
GLuint cube_indices[cube_num_i] = {
	0, 1, 2, // up edge
 	0, 2, 3,
	2, 3, 4, // far edge
	3, 4, 5,
	0, 3, 5, // left edge
	0, 5, 6,
	0, 6, 7, // near edge
	0, 1, 7,
	1, 4, 7, // right edge
	1, 2, 4,
	4, 5, 6, // down edge
	4, 6, 7
};

Mesh *form_cube()
{
	return new Mesh(GL_TRIANGLES, cube_vertices, cube_num_v, cube_indices, cube_num_i);
}

Mesh *form_sphere(int longitude_count, int latitude_count)
{
	/* The points on the sphere with radius r > 0 and center (x0, y0, z0)...
		...can be parameterized via:
	{
		x = x0 + R * sin(tetta) * cos(phi)
		y = y0 + R * sin(tetta) * sin(phi)
		z = z0 + R * cos(tetta)
		tetta : [0, PI];  phi : [0, 2PI]
	}
	or:
	{
		x = x0 + R * cos(phi) * cos(tetta)
		y = y0 + R * cos(phi) * sin(tetta)
		z = z0 + R * sin(phi)
	}
	our x0, y0, z0 = 0 */
	int i, j, idx, k1, k2;
	float x, y, z;
	float s, t;
	float radius = 1.0;

	// sectors
	float longitude_step = pi<float>() / longitude_count;
	float longitude_angle;

	// stacks
	float latitude_step = 2 * pi<float>() / latitude_count;
	float latitude_angle;

	int sphere_num_v = (longitude_count + 1) * (latitude_count + 1);
	Vertex *sphere_vertices = new Vertex[sphere_num_v];
	for(i = 0, idx = 0; i <= longitude_count; i++) {
		longitude_angle = i * longitude_step;
		z = radius * cos(longitude_angle);

		for(j = 0; j <= latitude_count; j++) {
			latitude_angle = j * latitude_step;

			x = radius * sinf(longitude_angle) * cosf(latitude_angle);
			y = radius * sinf(longitude_angle) * sinf(latitude_angle);
			sphere_vertices[idx].pos_coords = glm::vec3(x, y, z);

			s = (float)j / longitude_count;
			t = (float)i / latitude_count;
			sphere_vertices[idx].tex_coords = glm::vec2(s, t);
			idx++;
		}
	}

	int sphere_num_i = (longitude_count - 1) * latitude_count * 6;
	GLuint *sphere_indices = new GLuint[sphere_num_i];
	for(i = 0, idx = 0; i < longitude_count; i++) {
		k1 = i * (latitude_count+1);
		k2 = k1 + (latitude_count+1);

		for(j = 0; j < latitude_count; j++, k1++, k2++) {
			if(i != 0)
			{
				sphere_indices[idx++] = k1;
				sphere_indices[idx++] = k2;
				sphere_indices[idx++] = k1 + 1;
			}
			if(i != (longitude_count-1))
			{
				sphere_indices[idx++] = k1 + 1;
				sphere_indices[idx++] = k2;
				sphere_indices[idx++] = k2 + 1;
			}
		}
	}

	Mesh *sphere = new Mesh(GL_TRIANGLES, sphere_vertices, sphere_num_v,
		sphere_indices, sphere_num_i);

	delete[] sphere_vertices;
	delete[] sphere_indices;
	return sphere;
}

Mesh *form_circle(int angle_count)
{
	int i, idx, idy;
	float x, y, z;
	float radius = 1.0f;
	float angle_step = 2 * pi<float>() / angle_count;
	float angle;

	Vertex *circle_vertices = new Vertex[angle_count];
	GLuint *circle_indices = new GLuint[angle_count * 2];
	for(i = 0, idx = 0, idy = 0; i < angle_count; i++) {
		angle = i * angle_step;
		x = radius * cosf(angle);
		y = 0;
		z = radius * sinf(angle);
		circle_vertices[idx].pos_coords = glm::vec3(x, y, z);
		circle_vertices[idx].tex_coords = glm::vec2(0, 0);
		idx++;

		if(i != 0) {
			circle_indices[idy++] = i-1;
			circle_indices[idy++] = i;
		}
	}
	circle_indices[idy++] = i-1;
	circle_indices[idy] = 0;

	Mesh *circle = new Mesh(GL_LINES, circle_vertices, angle_count,
		circle_indices, angle_count * 2);

	delete[] circle_vertices;
	delete[] circle_indices;
	return circle;
}