// Reworked sample code from OSDev! Stripped down some of the extra stuff to leave as an exercise.
//Headers provided by GCC :). No need for libs! We don't even have those yet.
#include <stddef.h>
#include <stdint.h>


//VGA buffer is the easiest way to write to the screen at this stage. it's just a massive array with two datapoints: what color, and what character?
//array starts at the absolute address 0xB8000
volatile uint16_t* vga_buffer = (uint16_t*)0xB8000;
//the VGA buffer is 80x25 to represent the screen.
const int GRID_COLS = 80;
const int GRID_ROWS = 25;


//grid is top left origin. This is our cursor!
int cursor_col = 0;
int cursor_row = 0;
uint16_t term_color = 0x0F00; // Black background, White foreground


//wipe the screen
void term_clear() {
	for (int col = 0; col < GRID_COLS; col ++) {
		for (int row = 0; row < GRID_ROWS; row ++) {
            //works out to iterating every cell
			const size_t index = (GRID_COLS * row) + col;
            //vga buffer looks something like xxxxyyyyzzzzzzzz
            //x=bg color
            //y=fg color
            //c=character to use
            //Therefore, to write, we just take our color data and tack on the character to the end.
			vga_buffer[index] = term_color | ' '; //blank out
		}
	}
}

// 
void term_printc(char c)
{
		const size_t index = (GRID_COLS * cursor_row) + cursor_col; //where am i puttin it
		vga_buffer[index] = term_color | c; //put it there by putting color+char into that spot in the array
		cursor_col++; //next time put it in the next spot.
}	

//print a string!
void term_println(const char* out)
{
	for (int i = 0; out[i] != '\0'; i++) 
		term_printc(out[i]);
    //go to the next line for a println func.
    cursor_col = 0;
    cursor_row++;
}


//finally, main.
void kern_main()
{

    //wipe the screen
	term_clear();

	//IT IS TIME. TO PRINT.
	term_println("hello my chungus world");
    term_println(":100:");
}