#include "video_gr.h"

vbe_mode_info_t vmi_p;
static uint16_t x_resolution, y_resolution;// resolution of x and y in pixels --> resolution of the screen
static uint8_t bits_ppixel; //bits per pixel
static unsigned int vram_base, vram_size;
static uint8_t *video_mem;/* Process (virtual) address to which VRAM is mapped */

struct minix_mem_range mr;


void *(vg_init)(uint16_t mode){

  int r;
  struct reg86 r86;
  mmap_t mem_map;
  mem_map.phys = 0;
  mem_map.size = 1024 * 1024;
  lm_alloc(mem_map.size, &mem_map);

  if(vbe_get_mode_info(mode, &vmi_p )!=0){//Returns information on the input VBE mode, including screen dimensions, color depth and VRAM physical address.
    printf("It was detected an error in vbe_get_mode_info!\n");
    return NULL;
  }

  x_resolution = vmi_p.XResolution;
  y_resolution = vmi_p.YResolution;
  bits_ppixel  = vmi_p.BitsPerPixel;

  vram_base = vmi_p.PhysBasePtr;
  vram_size = (x_resolution*y_resolution)*(bits_ppixel/8);//the size of the buffer needs to be the resolution of the screen times the number of bytes per pixel

  mr.mr_base = (phys_bytes)vram_base;
  mr.mr_limit = vram_base + vram_size ;

  /*Section 4.1*/

  if(OK != (r= sys_privctl(SELF,SYS_PRIV_ADD_MEM,&mr))){//minix 3's kernel call
  /*
    The first argument specifies the process whose privileges will be affected, and the other two arguments depend on the privileges to change.

  */
    panic("sys_privctl(ADD_MEM) failed: %d\n",r);
  }
  /* MAP MEMORY*/
  video_mem = vm_map_phys(SELF, (void *)mr.mr_base, vram_size);

  if(video_mem == MAP_FAILED){
    panic("Couldn't map video memory");
  }

    /* Specify the appropriate register values */

  memset(&r86, 0, sizeof(r86));	  /* zero the structure */

  r86.intno = 0x10; /* BIOS video services */
   /*VBE call, function 02 -- Set VBE Mode */
  r86.ax = VBE_CALL;
  r86.bx = LINEAR_FRAME_BUFFER | mode;/* set bit 14: linear framebuffer */

  /* Make the BIOS call */

  if( sys_int86(&r86) != OK ) {
    printf("\tvg_exit(): sys_int86() failed \n");
    return NULL;
  }
  //check if al and ah are correct
  if(r86.ah != VBE_FUNCTION)
    return NULL;
  else if (r86.al != VBE_MODE)
    return NULL;


  return (void *)video_mem;
}


int vg_draw_hline(uint16_t x, uint16_t y, uint16_t len,uint32_t color){
    /*
    uint8_t addr;
    uint8_t *p_m;
    uint8_t bytes_ppixel = ceil((bits_ppixel+7)/8);
    addr =  (x + x_resolution*y)*(bytes_ppixel);

    p_m = addr + video_mem;//address of the VRAM location with the initial point

    /*if(bytes_ppixel ==1){
      if()
    }*/
    uint8_t aux_color=color & 0xFF;


  for(int j=0;j<len; j++){

    for(int k=0;k<bytes_ppixel;k++){
      *(p_m+k)=aux_color;
      aux_color=aux_color>>8;

    }
    x++;
  }*/

  return 0;
}



int vg_draw_retangle(uint16_t x, uint16_t y,uint16_t width, uint16_t height, uint32_t color){
  /*int i =0;
  while(i!=height){
    if(vg_draw_hline(x,y+i,width,color)!=0){
      return 1;
    }
    i++;
  }*/

  return 0;
}