#include <math.h>

#include "SDL.h"
#include "SDL_opengl.h"

#include "glpong3d.h"
#include "paddle.h"

static GLuint paddle_texture;

void
GLPong_PaddleDraw(const Paddle_t * paddle) {
	glLoadIdentity();
	glBindTexture(GL_TEXTURE_2D, paddle_texture);
	glEnable(GL_TEXTURE_2D);
	glColor3f(paddle->r, paddle->g, paddle->b);
	glTranslatef(paddle->x + (paddle->w / 2), paddle->y + (paddle->h / 2), paddle->z);
	glBegin(GL_QUADS);
		glTexCoord2f(0.168f, 1.0f); glVertex2f(paddle->w / 2, paddle->h / 2);	/* Upper Right */
		glTexCoord2f(0.832f, 1.0f); glVertex2f(-paddle->w / 2, paddle->h / 2);	/* Upper Left  */
		glTexCoord2f(0.832f, 0.0f); glVertex2f(-paddle->w / 2, -paddle->h / 2);	/* Lower Left */
		glTexCoord2f(0.168f, 0.0f); glVertex2f(paddle->w / 2, -paddle->h / 2);	/* Lower Right */
	glEnd();
	glDisable(GL_TEXTURE_2D);

#ifdef DEBUG
	/* Lower Left */
	glLoadIdentity();
	glColor3f(0.0f, 0.0f, 1.0f);
	glTranslatef(paddle->x, paddle->y, paddle->z);
	glBegin(GL_POINTS);
		glVertex3f(0.0f, 0.0f, 0.0f);
	glEnd();
	/* Lower Right */
	glLoadIdentity();
	glColor3f(1.0f, 0.0f, 0.0f);
	glTranslatef(paddle->x + paddle->w, paddle->y, paddle->z);
	glBegin(GL_POINTS);
		glVertex3f(0.0f, 0.0f, 0.0f);
	glEnd();
	/* Top Right */
	glLoadIdentity();
	glTranslatef(paddle->x + paddle->w, paddle->y + paddle->h, paddle->z);
	glBegin(GL_POINTS);
		glVertex3f(0.0f, 0.0f, 0.0f);
	glEnd();
	/* Top Left */
	glLoadIdentity();
	glTranslatef(paddle->x, paddle->y + paddle->h, paddle->z);
	glBegin(GL_POINTS);
		glVertex3f(0.0f, 0.0f, 0.0f);
	glEnd();
	/* Center */
	glLoadIdentity();
	glColor3f(0.0f, 1.0f, 0.0f);
	glTranslatef(paddle->x + paddle->w / 2.0f, paddle->y + paddle->h / 2.0f, paddle->z);
	glBegin(GL_POINTS);
		glVertex3f(0.0f, 0.0f, 0.0f);
	glEnd();
#endif
}

void
GLPong_PaddleInit(Paddle_t * paddle, GLfloat z, GLuint texture) {
	paddle->w = 0.66f;
	paddle->h = 0.5f;
	paddle->x = paddle->w / 2.0f;
	paddle->y = paddle->h / 2.0f;
	paddle->z = z;
	paddle->prev_x = paddle->x;
	paddle->prev_y = paddle->y;
	paddle->r = 1.0f;
	paddle->g = 1.0f;
	paddle->b = 1.0f;
	
	paddle_texture = texture;
}

void
GLPong_PaddleMove(Paddle_t * paddle, GLfloat x, GLfloat y) {
	GLfloat mouse_x;
	GLfloat mouse_y;
	paddle->prev_x = paddle->x;
	paddle->prev_y = paddle->y;

	/* clamp paddle to border */
	if (x <= -1.5f + (paddle->w / 2.0f)) {
		x = -1.5f + (paddle->w / 2.0f);
	} else if (x >= 1.5f - (paddle->w / 2.0f)) {
		x = 1.5f - (paddle->w / 2.0f);
	}

	if (y <= -1.0f + (paddle->h / 2.0f)) {
		y = -1.0f + (paddle->h / 2.0f);
	} else if (y >= 1.0f - (paddle->h / 2.0f)) {
		y = 1.0f - (paddle->h / 2.0f);
	}

	mouse_x = x - (paddle->w / 2.0f);
	mouse_y = -(y + (paddle->h / 2.0f));

#ifdef DEBUG
	printf("(mouse_x, mouse_y) = (%.3f, %.3f)\n", mouse_x, mouse_y);
	printf("x diff is %f\n", fabs(mouse_x - paddle->prev_x));
	printf("y diff is %f\n", fabs(mouse_y - paddle->prev_y));
#endif

	if (fabs(mouse_x - paddle->prev_x) > 0.33f / 2.0f) {
		if (mouse_x > paddle->prev_x) {
			paddle->x += 0.33f / 2.0f;
		} else {
			paddle->x -= 0.33f / 2.0f;
		}
	} else {
		paddle->x = mouse_x;
	}

	if (fabs(mouse_y - paddle->prev_y) > 0.25f / 2.0f) {
		if (mouse_y > paddle->prev_y) {
			paddle->y += 0.25f / 2.0f;
		} else {
			paddle->y -= 0.25f / 2.0f;
		}
	} else {
		paddle->y = mouse_y;
	}
}