// 
// http://en.wikipedia.org/wiki/VT52
// http://vt100.net/docs/vt520-rm/
// man 4 console_codes
//

#include "terminal.h"
#include "kernel/kmalloc.h"
#include "driver/screen.h"

#define SET_LFNL true
#define SET_BUFF false
#define SET_ECHO true


typedef enum {

    ecma48_reset,
    ecma48_bold,
    ecma48_halfbright,
    ecma48_underscore,
    ecma48_blink,
    ecma48_reverse_video,
    ecma48_reset_mapping,
    ecma48_null_mapping_1,
    ecma48_null_mapping_2,
    ecma48_normalbright_1,
    ecma48_normalbright_2,
    ecma48_nounderline,
    ecma48_blinkoff,
    ecma48_reverse_video_off,

    ecma48_fg_black =30,
    ecma48_fg_red,
    ecma48_fg_green,
    ecma48_fg_brown,
    ecma48_fg_blue,
    ecma48_fg_magenta,
    ecma48_fg_cyan,
    ecma48_fg_white,
    ecma48_undersore_on, // set def color
    ecma48_undersore_off, // set def color

    ecma48_bg_black,
    ecma48_bg_red,
    ecma48_bg_green,
    ecma48_bg_brown,
    ecma48_bg_blue,
    ecma48_bg_magenta,
    ecma48_bg_cyan,
    ecma48_bg_white,

    ecma48_bg_default =49,

}terminal_settings;


// deprecated
#define VT52_WIDTH 75
#define VT52_HEIGHT 24

#define VT52_ESC_1 0x1b  //ESC

#define VT52_UP 'A'
#define VT52_DOWN 'B'
#define VT52_RIGHT 'C'
#define VT52_LEFT 'D'
#define VT52_GRAPH_ON 'F'
#define VT52_GRAPH_OFF 'G'
#define VT52_HOME 'H'
#define VT52_REV_FEED 'I'
#define VT52_ERASE_SCR 'J'
#define VT52_ERASE_LINE 'K'
#define VT52_KEYPAD_ON '='
#define VT52_KEYPAD_OFF '>'

#define VT52_EXIT '<'

#define VT52_ENTER_AUTOPRINT '^'
#define VT52_EXIT_AUTOPRINT '_'

#define VT52_PRINT_LINE 'W'
#define VT52_ENTER_PRINT 'W'
#define VT52_EXIT_PRINT 'X'
#define VT52_PRINT ']'
#define VT52_JUMP 'Y' // followed by LINE COL (subtr -32 from val)
#define VT52_IDENTIFY 'Z'
#define VT52_IDENTIFY_TO_HOST "/Z"
//

#define NPAR_START 1000

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

static void set_char(terminal_tty *tty, uint32_t x, uint32_t y, uint8_t c, uint8_t fg, uint8_t bg)
{
    tty->data[index(tty,x,y)]=c;
    tty->data[index(tty,x,y)]|=fg<<8;
    tty->data[index(tty,x,y)]|=bg<<16;
    tty->screen->put_char(c,fg,bg,x,y);
}

static void process_graphic_npar(terminal_tty *tty, terminal_settings s)
{
    switch(s)
    {
	case ecma48_fg_black:
	    tty->fg=SCR_BLACK;
	    break;

	case ecma48_fg_red:
	    tty->fg=SCR_RED;
	    break;

	case ecma48_fg_green:
	    tty->fg=SCR_GREEN;
	    break;

	case ecma48_fg_brown:
	    tty->fg=SCR_BROWN;
	    break;

	case ecma48_fg_blue:
	    tty->fg=SCR_BLUE;
	    break;

	case ecma48_fg_magenta:
	    tty->fg=SCR_MAGENTA;
	    break;

	case ecma48_fg_cyan:
	    tty->fg=SCR_CYAN;
	    break;

	case ecma48_fg_white:
	    tty->fg=SCR_WHITE;
	    break;



	case ecma48_bg_black:
	    tty->bg=SCR_BLACK;
	    break;

	case ecma48_bg_red:
	    tty->bg=SCR_RED;
	    break;

	case ecma48_bg_green:
	    tty->bg=SCR_GREEN;
	    break;

	case ecma48_bg_brown:
	    tty->bg=SCR_BROWN;
	    break;

	case ecma48_bg_blue:
	    tty->bg=SCR_BLUE;
	    break;

	case ecma48_bg_magenta:
	    tty->bg=SCR_MAGENTA;
	    break;

	case ecma48_bg_cyan:
	    tty->bg=SCR_CYAN;
	    break;

	case ecma48_bg_white:
	    tty->bg=SCR_WHITE;
	    break;







	case ecma48_bg_default:
	    tty->fg=SCR_BLACK;
	    break;

    }
}


static void process_graphic_npars(terminal_tty *tty)
{

	char buf[4];
	int b=0;

	tty->escaping=0;

	for(int i=0;i<tty->npar+1;i++)
	{
	    char c=tty->command[NPAR_START+i];
	    buf[b++]=c;

	    if(i==tty->npar||c==';')
	    {
		if(b==2)process_graphic_npar(tty,buf[0]-'0');
		if(b==3)process_graphic_npar(tty,(buf[0]-'0')*10+(buf[1]-'0'));
		b=0;
	    }
	   //terminal_put(tty,tty->command[NPAR_START+i]);
	}

	tty->npar=0;




}

static void reset(terminal_tty *tty)
{
    tty->bg=SCR_BLACK;
    tty->fg=SCR_WHITE;

    for(int x=0;x<tty->width;x++)
	for(int y=0;y<tty->height;y++)
	{
	    set_char(tty,x,y,' ',tty->fg,tty->bg);
	}

    tty->x=0;
    tty->y=0;
    tty->command_l=0;
}

terminal_tty terminal_init(term_out *screen,term_in *input)
{
    terminal_tty tty;

    tty.data=kballoc(2);

    tty.command=kballoc(1);
    tty.command_l=0;

    tty.escaping=0;

    tty.screen=screen;
    tty.input=input;

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

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

    reset(&tty);

    return tty;
}



void terminal_kb(terminal_tty *tty, uint8_t c)
{

    if(SET_ECHO)terminal_put(tty,c);

    if(SET_BUFF)
    {
	tty->command[tty->command_l]=c;
	(tty->command_l)++;
	
	if(c==0x08)
	{
	    tty->command_l-=2;
	    if(tty->command_l<0)tty->command_l=0;
	}
	else if(c=='\n')
	{
	    // write command to ringbuff
	    for(int i=0;i<tty->command_l;i++)
		tty->input->put_char(tty->command[i]);

	    tty->command_l=0;
	}
    }
    else
    {
	tty->input->put_char(c);
    }

}

// send one ASCII character to the terminal
bool terminal_put(terminal_tty *tty, uint8_t c)
{

    // CONTROL CHARACTERS
    if(c==0x07){return;} // BEL
    if(c==0x7F){return;} // nothing

    if(c==0x09){return;} // TAB TODO!
    if(c==0x0E){return;} // G1 set
    if(c==0x0F){return;} // G0 set

    if(c==0x18||c==0x1A){tty->escaping=0;return;}  // cancel escaping
    if(c==0x1B){tty->escaping=1;return;} // ESC
    if(c==0x9B){tty->escaping=2;tty->npar=0;return;} // CSI = ESC [

    if(c==0x08)	//BACKSPACE
    {
	if(tty->x>0&&tty->command_l>0)
	{
	    set_char(tty,tty->x-1,tty->y,' ',tty->fg,tty->bg);
	    tty->x--;
	}
    }

    else if(c==0x0D) // CR
    {
	tty->x=0;
	return;
    }
    
    else if(c==0x0A||c==0x0B||c==0x0C) // \n NEXTLINE
    {
	for(uint32_t x=tty->x;x<tty->width;x++)
	{
	    set_char(tty,x,tty->y,' ',tty->fg,tty->bg);
	}
	tty->y++;
	if(SET_LFNL)tty->x=0;	
    }
    else //
    { 
	// ESC- but not CSI-sequences
	if(tty->escaping==1)
	{
	    if(c=='c'){reset(tty);} // RESET
	    if(c=='D'){tty->y++;} // LINEFEED
	    if(c=='E'){tty->y++;tty->x=0;} //NEWLINE
	    if(c=='H'){} // SET TABSTOP: TODO
	    if(c=='M'){ // REVERSE LINEFEED

		if(tty->y==0)
		{
		    for(int32_t y=tty->height-1;y>=0;y--)
		    {
			for(uint32_t x=0;x<tty->width;x++)
			{
			    uint32_t c=' '|tty->fg<<8|tty->bg<<16;
			    if(y!=0) c=tty->data[index(tty,x,y-1)];
			    tty->data[index(tty,x,y)] = c;

			    tty->screen->put_char(c&0xff,(c>>8)&0xff,c>>16,x,y); //TODO: get from buffer
			}
		    }
		}
		else
		    tty->y--;
	    
	    } 

	    if(c=='Z'){// IDENTIFY: claim we are vt102
		
		tty->input->put_char(0x1B); //ESC
		tty->input->put_char('['); 
		tty->input->put_char('?'); 
		tty->input->put_char('6'); 
		tty->input->put_char('c'); 

	    return;} 

	    if(c=='7'){}//   SAVE STATE
	    if(c=='8'){}//   RESTORE STATE
	    if(c=='['){tty->escaping=2;tty->npar=0;return;} // CONTROL SEQ INTRODUCER


	    // TODO 
	    // %, %@, %G, %8, #8, (, (B, (O, (U, (K
	    // ), >, =, ] (???)
	    //
	    //

	    tty->escaping=0; // DONE
	}	    
	// CSI SEQEUENCES (AFTER ESC [..)
	else if(tty->escaping==2)
	{
	    //ECMA-48: TODO
	    //ECMA-48 GRAPHIC RENDITION: TODO
	    if(c!='m')
	    {
		tty->command[NPAR_START+(tty->npar++)]=c;
	    }
	    else
	    {
		process_graphic_npars(tty);
	    }
	    
	    //ECMA-48 MODE SWITCHES: TODO
	    //ECMA-48 STATUS REPORT: TODO
	    
	    //DEC PRIVATE MODE: TODO
	    //LINUX CONSOLE PRIVATE CSI: TODO

	}
	else //PROBABLY (AND HOPEFULLY) JUST A NORMAL CHAR
	{
	    set_char(tty,tty->x,tty->y,c,tty->fg,tty->bg);
	    tty->x++;
	}

    }





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

    //autoscroll
    if(tty->y>=tty->height)
    {
	tty->y--;
	for(uint32_t y=0;y<tty->height;y++)
	{
	    for(uint32_t x=0;x<tty->width;x++)
	    {
		uint32_t c=tty->data[index(tty,x,y+1)];
		if(y==tty->height-1)c=' '|tty->fg<<8|tty->bg<<16;
		tty->data[index(tty,x,y)] = c;
		tty->screen->put_char(c&0xff,(c>>8)&0xff,c>>16,x,y); //TODO: get from buffer
	    }
	}
    }

    //cusor pos
    tty->screen->update_cursor(tty->x,tty->y);
    return true;
}

//deprecated
/*
bool vt52_put(terminal_tty *tty, uint8_t c)
{   
    if(c==VT52_ESC_1){tty->escaping=1;return;}
    if(c=='['){if(tty->escaping==1)escaping=2;return;}

    if(escaping==3){tty->x=c-32; escaping++;return;} //TODO: check for overflow?
    if(escaping==4){tty->y=c-32; escaping=0;return;}

     // does this really need to be escaped with ESC [ not JUST ESC?? TODO; check?
    if(escaping==2) // two last characters are escape seq: ^[
    {
	if(c==VT52_JUMP)escaping++;

	else
	{
	    switch('c')
	    {
		case VT52_UP:
		    if(tty->y>0)tty->y--;
		break;

		case VT52_DOWN:
		    if(tty->y+1<tty->height)tty->y++;
		break;

		case VT52_LEFT:
		    if(tty->x+1<tty->width)tty->x++;
		break;

		case VT52_RIGHT:
		    if(tty->x>0)tty->x--;
		break;

		case VT52_HOME:
		    tty->x=tty->y=0;
		break;

		case VT52_REV_FEED:

		break;

		case VT52_ERASE_SCR:
		    for(uint32_t y=tty->y+1;y<tty->height;y++)
		    {
			for(uint32_t x=0;x<tty->width;x++)
			{
			    uint32_t c=tty->data[index(tty,x,y+1)];
			    tty->data[index(tty,x,y)] = c;
			    tty->screen->put_char(c,0xf,x,y);
			}
		    }
		case VT52_ERASE_LINE:

		    for(uint32_t x=tty->x;x<tty->width;x++)
		    {
			uint32_t c=tty->data[index(tty,x,tty->y)];
			tty->data[index(tty,x,tty->y)] = c;
			tty->screen->put_char(c,0xf,x,tty->y);
		    }

		break;

	    }

	    escaping=0;
	}

	return;

    }

    if(c!='\n')
    {
        tty->data[index(tty,tty->x,tty->y)]=c;
	tty->screen->put_char(c,0xf,tty->x,tty->y);
    }
    else
    {
	tty->y++;
	tty->x=-1;

    }

    tty->x++;

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

    }

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

    tty->screen->update_cursor(tty->x,tty->y);
    return true;
}
*/