#define WHITE_TXT 0x07 // white on black text

void k_clear_screen(); //the function to clear the screen
int k_printf(char *message, int line); //printf function
char test[58] = "This line is from a character datatype Defined in Globals!";
char inb(short); //read input from an address given by the short
void outb(short, char); //output to the address given by the short
int temp; //a temporary variable to hold the scancode
char current[1000]; //our current stuff typed in
int inparse=0; //a generic variable to move through current and place the latest keypress
int x; //generic variable for looping
int y; //generic variable for looping
char output[1000]; //our output (Stuff put out by echo, etc)
char lowercase[128] = "001234567890-=0 qwertyuiop[]00asdfghjkl;'~0|zxcvbnm,./0*0 0000000000000789-456+1230."; //our lookup table. We get our character based on the scancode given by the keyboard
void kmain() //main
{
   k_clear_screen(); //Clear the Screen

   k_printf("Welcome to '???' Operating System, v0.0.1", 0); //print a welcome message
   k_printf(test, 1); //print out a line from a globally defined char
   k_printf("Test Line\nThe previous endline used the slash-n character", 2); //testing printf functionality of \n
   k_printf("Beginning the actual Kernel......", 4); //tell the user we are starting the kernel
   /* and.... BEGIN!*/
   while(1==1) //endless loop
   {
      k_printf(current, 6); //print out what has been typed so far
      temp=(int)inb(0x60); //read in what is on the keyboard
      k_printchar(temp, 5, 0); //print out what is on the keyboard at line 5, row 0
      if(inparse<1000) //prevent an overflow
      {
          if(lowercase[temp] != 0) //if the input is SOMETHING besides the non-printing characters
          {
            current[inparse]=lowercase[temp]; //the location given by inparse is set to the character sent by keyboard
            inparse++; //increment inparse, so next time, we are loading to the next character
          }
            outb(0x60, 0xad); //disable //disable the keyboard, so it clears out what we just did
      }
      if(temp==0x1c) //if our scancode we just got is 'return'
      {
          if(current[0]==lowercase[18] && current[1]==lowercase[46] && current[2]==lowercase[35] && current[3]==lowercase[24]) //if it is e c h o
          {
             for(x=0; x<inparse; x++) //loop through all the characters we have put into current so far
             {
                output[x]=current[x+5];  //set output equal to current. (We skip 5 characters in current so we do not echo out the word echo)
             }
       k_printf(output, 10); //print out our output of echo
          }
          if(current[0]==lowercase[46] && current[1]==lowercase[38] && current[2]==lowercase[31]) //if it is c l s
          {
              k_clear_screen(); //clear the screen
          }
          if(current[0]==lowercase[35] && current[1]==lowercase[18] && current[2]==lowercase[38] && current[3]==lowercase[25]) // if it is h e l p
          {
              k_clear_screen();
              k_printf("HELP:\n   echo (Prints 'message' to screen): echo [message]\n   cls(Clears Screen): cls", 0); //print out the help
          }
         for(x=0; x<inparse+1; x++) //clear current to all 0's. We go over 1 just to make sure
         {
            current[x]=0;
         }
         inparse=0; //reset inparse for the next command
     }
   }
}

void k_clear_screen() // clear the entire text screen
{
	char *vidmem = (char *) 0xb8000; //the first location of video memory
	int i=0; //looping variable
	while(i < (80*25*2)) //we loop through all video memory
	{
		vidmem[i]=' '; //clear it
		i++;
		vidmem[i]=WHITE_TXT;
		i++;
	};
};

int k_printf(char *message, int line) // the message and then the line #
{
	char *vidmem = (char *) 0xb8000; //first video memory location
	int i=0;

	i=(line*80*2); //we start at the location given by 'line'

	while(*message!=0) //if it's not the end of the char
	{
		if(*message=='\n') // check for a new line
		{
			line++; //go to the next line if we have a newline
			i=(line*80*2);
			*message++;
		} else {
			vidmem[i]=*message; //set location in videomemory to what we have in the char
			*message++;
			i++;
			vidmem[i]=WHITE_TXT;
			i++;
		};
	};

	return(1);
};

void k_printchar(char message, int line, int location)
{
   char *vidmem = (char *) 0xb8000; //first vid memory locatoin
   int i = line*80*2; //get our line and such
   i += location; //move over in rows to location
   vidmem[i]=lowercase[(int)message]; //set videomemory given by the inputs to whatever message gives us
};
char inb (short port)
{
  char value;
  asm volatile ("inb    %w1, %0" : "=a" (value) : "Nd" (port));
  return value;
}
void outb (short port, char value)
{
asm volatile ("outb   %b0, %w1" : : "a" (value), "Nd" (port));
}