#include "skybox.h"

#include "shader.h"
#include "camera.h"
#include <string.h>

#include "openglrender.h"

static const float skyboxVertices[216] = {
    -1.0f, 1.0f, -1.0f,
    -1.0f, -1.0f, -1.0f,
    1.0f, -1.0f, -1.0f,
    1.0f, -1.0f, -1.0f,
    1.0f, 1.0f, -1.0f,
    -1.0f, 1.0f, -1.0f,

    -1.0f, -1.0f, 1.0f,
    -1.0f, -1.0f, -1.0f,
    -1.0f, 1.0f, -1.0f,
    -1.0f, 1.0f, -1.0f,
    -1.0f, 1.0f, 1.0f,
    -1.0f, -1.0f, 1.0f,

    1.0f, -1.0f, -1.0f,
    1.0f, -1.0f, 1.0f,
    1.0f, 1.0f, 1.0f,
    1.0f, 1.0f, 1.0f,
    1.0f, 1.0f, -1.0f,
    1.0f, -1.0f, -1.0f,

    -1.0f, -1.0f, 1.0f,
    -1.0f, 1.0f, 1.0f,
    1.0f, 1.0f, 1.0f,
    1.0f, 1.0f, 1.0f,
    1.0f, -1.0f, 1.0f,
    -1.0f, -1.0f, 1.0f,

    -1.0f, 1.0f, -1.0f,
    1.0f, 1.0f, -1.0f,
    1.0f, 1.0f, 1.0f,
    1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f, 1.0f,
    -1.0f, 1.0f, -1.0f,

    -1.0f, -1.0f, -1.0f,
    -1.0f, -1.0f, 1.0f,
    1.0f, -1.0f, -1.0f,
    1.0f, -1.0f, -1.0f,
    -1.0f, -1.0f, 1.0f,
    1.0f, -1.0f, 1.0f
};

struct mSkybox *MakeSkybox(const char *cubemap)
{
    struct mSkybox *newskybox =
	(struct mSkybox *) malloc(sizeof(struct mSkybox));

    newskybox->shader = MakeShader("skyvert.glsl", "skyfrag.glsl");
    shader_compile(newskybox->shader);

    glGenVertexArrays(1, &newskybox->VAO);
    glGenBuffers(1, &newskybox->VBO);
    glBindVertexArray(newskybox->VAO);
    glBindBuffer(GL_ARRAY_BUFFER, newskybox->VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(skyboxVertices), &skyboxVertices,
		 GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float),
			  (void *) 0);

    shader_use(newskybox->shader);
    shader_setint(newskybox->shader, "skybox", 0);

    const char *faces[6] =
	{ "right.jpg", "left.jpg", "top.jpg", "bottom.jpg", "front.jpg",
	"back.jpg"
    };

    glGenTextures(1, &newskybox->id);
    glBindTexture(GL_TEXTURE_CUBE_MAP, newskybox->id);
    char buf[100] = { '\0' };

    for (unsigned int i = 0; i < 6; i++) {
	buf[0] = '\0';
	strcat(buf, cubemap);
	strcat(buf, "/");
	strcat(buf, faces[i]);
	SDL_Surface *data = NULL;	//IMG_Load(buf);
	glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB, 2048,
		     2048, 0, GL_RGB, GL_UNSIGNED_BYTE, data->pixels);
	SDL_FreeSurface(data);
    }

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S,
		    GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T,
		    GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R,
		    GL_CLAMP_TO_EDGE);


    return newskybox;
}

void skybox_draw(const struct mSkybox *skybox,
		 const struct mCamera *camera)
{
    shader_use(skybox->shader);

    mfloat_t view[16] = { 0.f };
    getviewmatrix(view, camera);
    shader_setmat4(skybox->shader, "skyview", view);

    // skybox cube
    glBindVertexArray(skybox->VAO);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_CUBE_MAP, skybox->id);
    glDrawArrays(GL_TRIANGLES, 0, 36);
    glBindVertexArray(0);
}