#include "engine.h"

// initialization:  Texture and vertices into memory
bool StoneBlock::init(){
	solid = true;
	hostile = true;
	GLfloat cube_vertices[] = {
		// front
		-0.25, -0.25,  0.25,
		0.25, -0.25,  0.25,
		0.25,  0.25,  0.25,
		-0.25,  0.25,  0.25,
		// top
		-0.25,  0.25,  0.25,
		0.25,  0.25,  0.25,
		0.25,  0.25, -0.25,
		-0.25,  0.25, -0.25,
		// back
		0.25, -0.25, -0.25,
		-0.25, -0.25, -0.25,
		-0.25,  0.25, -0.25,
		0.25,  0.25, -0.25,
		// bottom
		-0.25, -0.25, -0.25,
		0.25, -0.25, -0.25,
		0.25, -0.25,  0.25,
		-0.25, -0.25,  0.25,
		// left
		-0.25, -0.25, -0.25,
		-0.25, -0.25,  0.25,
		-0.25,  0.25,  0.25,
		-0.25,  0.25, -0.25,
		// right
		0.25, -0.25,  0.25,
		0.25, -0.25, -0.25,
		0.25,  0.25, -0.25,
		0.25,  0.25,  0.25,
	};
	for(float &n : cube_vertices)
		n *= cube_size;

	glGenBuffers(1, &vbuf);
	glBindBuffer(GL_SHADER_STORAGE_BUFFER, vbuf);
	glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(cube_vertices), cube_vertices, GL_STATIC_DRAW);

	GLushort cube_elements[] = {
		// front
		0,  1,  2,
		2,  3,  0,
		// top
		4,  5,  6,
		6,  7,  4,
		// back
		8,  9, 10,
		10, 11,  8,
		// bottom
		12, 13, 14,
		14, 15, 12,
		// left
		16, 17, 18,
		18, 19, 16,
		// right
		20, 21, 22,
		22, 23, 20,
	};
	element_count = sizeof(cube_elements) / sizeof(GLushort);
	glGenBuffers(1, &ebuf);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebuf);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(cube_elements), cube_elements, GL_STATIC_DRAW);

	GLfloat cube_texcoords[2*4*6] = {
		// front
		0.0, 0.0,
		1.0, 0.0,
		1.0, 1.0,
		0.0, 1.0,
	};
	for (int i = 1; i < 6; i++)
		memcpy(&cube_texcoords[i*4*2], &cube_texcoords[0], 2*4*sizeof(GLfloat));
	glGenBuffers(1, &tbuf);
	glBindBuffer(GL_ARRAY_BUFFER, tbuf);
	glBufferData(GL_ARRAY_BUFFER, sizeof(cube_texcoords), cube_texcoords, GL_STATIC_DRAW);

	setup_locations();
	setup_texture(texfile);
	setup_standard_shaders();

	return true;
}


bool StoneBlock::in_contact_location(float x, float y, float z, int i){
	const float margin = 0.25 * cube_size + 0.1;
	if(abs(x - locations[i].x) < margin && abs(y - locations[i].y) < margin && abs(z - locations[i].z) < margin){
		return true;
	}
	return false;
}

void StoneBlock::draw(mat4 vp)  {
	if(location_refresh){
		update_locations();
		location_refresh = false;
	}
	glUseProgram(program);
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, tex);
	glUniform1i(tex_uniform, 0);
	glUniformMatrix4fv(mvp_uniform, 1, 0, glm::value_ptr(vp));

	glEnableVertexAttribArray(vertex_attrib);
	glBindBuffer(GL_ARRAY_BUFFER, vbuf);
	glVertexAttribPointer(vertex_attrib, 3, GL_FLOAT, GL_FALSE, 0, 0);

	glEnableVertexAttribArray(tex_attrib);
	glBindBuffer(GL_ARRAY_BUFFER, tbuf);
	glVertexAttribPointer(tex_attrib, 2, GL_FLOAT, GL_FALSE, 0, 0);

	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebuf);
	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, lbuf);
	glDrawElementsInstanced(GL_TRIANGLES, element_count, GL_UNSIGNED_SHORT, 0, locations.size());
}

// movement:  for falling calculations
// Returns the effective floor level
float StoneBlock::find_floor(){
	float efloor = -1000;
	for(vec3 l : locations){
		if(abs(player_x - l.x) < 0.25 * cube_size && abs(player_z - l.z) < 0.25 * cube_size){
			if(l.y < player_y - 0.2 && l.y > efloor)
				efloor = l.y + 1;
		}
	}
	return efloor;
}

bool StoneBlock::dangerous_at(vec4 loc){
	for(int i = 0; i < locations.size(); i++) {
		vec4 mbl = locations[i];
		if(fabs(loc.x - mbl.x) < 0.5 * cube_size && fabs(loc.y - mbl.y) < 0.5 * cube_size && fabs(loc.z - mbl.z) < 0.5 * cube_size){
			locations[i] = locations[locations.size() - 1];
			locations.pop_back();
			location_refresh = true;
			return true;
		}
	}
	return false;
}

void StoneBlock::activate(float x, float y, float z){
	int i = in_contact(x, y, z);
	if(i != -1){
		locations[i].z += 10;
		location_refresh = true;
	}
}