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

#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>

#include "vesa.h"

#define NPAR_START      1000
#define TERM_WIDTH      80
#define TERM_HEIGHT     24

// COLORS
#define SCR_BLACK           0x0
#define SCR_BLUE            0x1
#define SCR_GREEN           0x2
#define SCR_CYAN            0x3
#define SCR_RED             0x4
#define SCR_MAGENTA         0x5
#define SCR_BROWN           0x6
#define SCR_GRAY_LIGHT      0x7
#define SCR_GRAY_DARK       0x8
#define SCR_BLUE_LIGHT      0x9
#define SCR_GREEN_LIGHT     0xa
#define SCR_CYAN_LIGHT      0xb
#define SCR_RED_LIGHT       0xc
#define SCR_MAGENTA_LIGHT   0xd
#define SCR_YELLOW          0xe
#define SCR_WHITE           0xf
//

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_underscore_on, // set def color
    ecma48_underscore_off, // set def color

    ecma48_bg_black, //40
    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;

typedef struct term_out_struct
{
    void (*put_char)(uint8_t c,uint8_t color_fg, uint8_t color_bg, uint32_t x, uint32_t y);
    void (*update_cursor)(uint32_t col,uint32_t row);
}term_out;

typedef struct term_in_struct
{
    void (*put_char)(uint8_t c);
}term_in;

typedef struct terminal_tty_struct
{
    uint8_t     fg;
    uint8_t     bg;

    bool        set_buff;
    bool        set_lfnl;
    bool        set_echo;

    uint32_t    width;
    uint32_t    height;
    uint32_t    x;
    uint32_t    y;
    uint32_t    *data;      // screen data
    uint8_t     *command;   // command line / also holds npar for escape sequences somewhere
    int32_t     command_l;  // command line length

    uint8_t     escaping;   // escaping mode?
    uint8_t     npar;       // npar pos 

    term_out    *screen;
    term_in     *input;

    bool        reverse_video;

}terminal_tty;

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)
{
    uint8_t buf;

    switch(s)
    {
	case ecma48_null_mapping_2:
	    break;
	case ecma48_null_mapping_1:
	    break;
	case ecma48_reset_mapping:
	    break;
	case ecma48_blinkoff:
	    break;
	case ecma48_blink:
	    break;
	case ecma48_nounderline:
	    break;
	case ecma48_underscore_on:
	    break;
	case ecma48_underscore_off:
	    break;
	case ecma48_underscore:
	    break;
	case ecma48_halfbright:
	    break;
	case ecma48_normalbright_1:
	    break;
	case ecma48_normalbright_2:
	    break;
	case ecma48_bold:
	    break;
	case ecma48_reset:
	    tty->fg=SCR_WHITE;
	    tty->bg=SCR_BLACK;
	    break;
	
	case ecma48_reverse_video:

	    if(tty->reverse_video)break;
	    buf=tty->fg;
	    tty->fg=tty->bg;
	    tty->bg=buf;
	    break;

	case ecma48_reverse_video_off:

	    if(!tty->reverse_video)break;
	    buf=tty->fg;
	    tty->fg=tty->bg;
	    tty->bg=buf;
	    break;

	//fg 

	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;
	// bg

	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->bg=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=malloc(2*4096);

    tty.set_buff=true;
//    tty.set_buff=false;

    tty.set_lfnl=true;
//    tty.set_lfnl=false;


    tty.set_echo=true;
    tty.set_echo=false;

    tty.command=malloc(1*4096);
    tty.command_l=0;

    tty.escaping=0;

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

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

    tty.width=TERM_WIDTH;
    tty.height=TERM_HEIGHT;

    tty.reverse_video=false;

    reset(&tty);

    return tty;
}
term_out tout;
terminal_tty tty;
terminal_tty* terminal_init_vesa()
{

    tout.put_char=vesa_console_put_char;
    tout.update_cursor=vesa_update_cursor;

    tty=(terminal_init(&tout,NULL));
    return &tty;


}

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

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

    if(c==0x09)	// TAB
    {
	if(tty->x==tty->width-1)return;
	set_char(tty,tty->x,tty->y,' ',tty->fg,tty->bg);
	tty->x++;

	while(tty->x<tty->width-1&&tty->x%8!=0)
	{
	    set_char(tty,tty->x,tty->y,' ',tty->fg,tty->bg);
	    tty->x++;
	}
	tty->x--;
	c=' ';
    } 

    if(c==0x0E){return;} // G1 set (ignore)
    if(c==0x0F){return;} // G0 set (ignore)

    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)||!tty->set_echo)
	{
	    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(tty->set_lfnl)tty->x=0;	
    }
    else //
    { 
	// ESC- but not CSI-sequences
	if(tty->escaping==1)
	{
	    // FOOL-TERM: delchar
	    if(c=='x')
	    {
		set_char(tty, tty->x, tty->y, ' ', tty->fg, tty->bg);
	    } 
	    // FOOL-TERM: clear to end of line
	    if(c=='K')
	    {
                   for(uint32_t x=tty->x;x<tty->width;x++)
                   {
		       set_char(tty, x, tty->y, ' ', tty->fg, tty->bg);
                   }
	    }
	    // FOOL-TERM: clear to end of screen
	    if(c=='J')
	    {
                   for(uint32_t x=tty->x;x<tty->width;x++)
                   {
		       set_char(tty, x, tty->y, ' ', tty->fg, tty->bg);
                   }
                   for(uint32_t y=tty->y+1;y<tty->height;y++)
                   {
                       for(uint32_t x=0;x<tty->width;x++)
                       {
			    set_char(tty,x, y, ' ', tty->fg, tty->bg);
                       }
                   }
	    }

	    // FOOL-TERM: home
	    if(c=='H')
	    {
		tty->x=0;
		tty->y=0;
	    }
	    // FOOL-TERM: movement
	    if(c=='u')
	    {
		if(tty->y>0)
		    tty->y--;
	    }
	    
	    if(c=='d')
	    {
		if(tty->y+1<tty->height)
		    tty->y++;
	    }

	    if(c=='f')
	    {
		if(tty->x+1<tty->width)
		    tty->x++;
	    }

	    if(c=='b')
	    {
		if(tty->x>0)
		    tty->x--;
	    }

	    ///

	    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);
			}
		    }
		}
		else
		    tty->y--;
	    
	    } 

	    if(c=='Z'){// IDENTIFY: claim we are vt102
		
		if(tty->input!=NULL)
		{
		    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 (coord,attributes,G0/G1?)
	    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: OK
	    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
	    //
		//       ESC [ 1 ; n ]       Set color n as the underline color
		//       ESC [ 2 ; n ]       Set color n as the dim color
		//       ESC [ 8 ]           Make the current color pair the default attributes.
		//       ESC [ 9 ; n ]       Set screen blank timeout to n minutes.
		//       ESC [ 10 ; n ]      Set bell frequency in Hz.
		//       ESC [ 11 ; n ]      Set bell duration in msec.
		//       ESC [ 12 ; n ]      Bring specified console to the front.
		//       ESC [ 13 ]          Unblank the screen.
		//       ESC [ 14 ; n ]      Set the VESA powerdown interval in minutes.

	}
	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);
	    }
	}
    }

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