// 
// http://en.wikipedia.org/wiki/VT52
//
//
//
//              ------------
// PROG <--->   |  VT 52   |  <---  Keyboard
//              |          |   ---> Screen
//              ------------

// Interface:
//
// struct vt52_tty_struct;  // TODO: check what is better to put in header!
// vt52_tty vt52_init();
// put(vt52_tty *tty, uint8_t c);
//
//


// REQUIREMENTS
// * kballoc // block wise in-kernel allocation

#include <stdint.h>
#include "kernel/kmalloc.h"

//TODO: check?
#define VT52_WIDTH 80
#define VT52_HEIGHT 24
#define VT52_ESC 0x33 

typedef struct vt52_tty_struct
{

    uint32_t width;
    uint32_t height;
    uint32_t x;
    uint32_t y;
    uint32_t *data; // screen data

}vt52_tty;


vt52_tty vt52_init()
{
    vt52_tty tty;

    tty.data=kballoc(1);

    tty.x=0;
    tty.y=0;

    tty.width=VT52_WIDTH;
    tty.height=VT52_HEIGHT;

    return tty;
}

uint32_t index(vt52_tty *tty, uint32_t x, uint32_t y)
{
    return tty->width*y+x;
}

void set_char(vt52_tty *tty, uint32_t x, uint32_t y, uint32_t c)
{
    tty->data[index(tty,x,y)]=c;
}

// send one ASCII character to the terminal
void put(vt52_tty *tty, uint8_t c)
{
    set_char(tty,tty->x,tty->y,c);

    if(tty->x>tty->width)
    {
	tty->x=0;
	tty->y++;
    }

    //autoscroll
    if(tty->y>=tty->height)
    {
	tty->y--;
	for(uint32_t l=tty->y; l>0; l--)
	{
	    for(uint32_t x=0;x<tty->width;x++)
	    {
		tty->data[index(tty,x,l-1)] = tty->data[index(tty,x,l)];
	    }
	}
    }
}