#include <stdlib.h> // srand, rand
#include <time.h> // time
#include <math.h> // sin, cos, M_PI
#include "ball.h"
#include "racket.h"

Ball*
Ball_init(int screen_width, int screen_height, int posX_start)
{
  srand(time(NULL));
  Ball *b = malloc(sizeof(Ball));
  *(int *)&b->BALL_POSX_START = posX_start;
  *(int *)&b->SCREEN_WIDTH = screen_width;
  *(int *)&b->SCREEN_HEIGHT = screen_height;
  Ball_reset(b, 1);
  return b;
}

void
Ball_reset(Ball *b, int direction) {
  // 120 deg angle with norm horizontal vector
  int angle;
  do {
    angle = rand() % BALL_ANGLE_MAX_OFFSET*2 + BALL_ANGLE_MAX_OFFSET/2 - 90;
  } while (-BALL_ANGLE_MIN_OFFSET <= angle && angle <= BALL_ANGLE_MIN_OFFSET);
  if (direction < 0) {
    b->posX = b->BALL_POSX_START;
  }
  else {
    b->posX = b->SCREEN_WIDTH - b->BALL_POSX_START;
  }
  b->posY = b->SCREEN_HEIGHT/2;
  b->velX = -direction * BALL_VELOCITY * cos(angle * M_PI / 180);
  b->velY = BALL_VELOCITY * sin(angle * M_PI / 180);
}

void
Ball_free(Ball *b)
{
  free(b);
}

int
Ball_collision(const Ball *b, const Racket *r) {
  const int leftB = b->posX;
  const int rightB = leftB + BALL_WIDTH;
  const int upB = b->posY;
  const int downB = upB + BALL_HEIGHT;
  
  const int leftR = r->posX;
  const int rightR = leftR + RACKET_WIDTH;
  const int upR = r->posY;
  const int downR = upR + RACKET_HEIGHT;

  if(downB <= upR
     || upB >= downR
     || rightB <= leftR
     || leftB >= rightR)
    {
        return false;
    }
  return true;
}

int
Ball_render(const Ball *b, SDL_Renderer *renderer) {
  SDL_Rect rect = { b->posX, b->posY, BALL_WIDTH, BALL_HEIGHT };
  if (SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255) < 0) {
    printf("SDL_SetRenderDrawColor failed! SDL_Error: %s\n", SDL_GetError());
    return 1;
  }
  SDL_RenderFillRect(renderer, &rect);
  return 0;
  //SDL_RenderCopy(renderer, b->texture, NULL, &rect);
}