#include "term.h"

void redraw(struct terminal *term)
{
	lcd.noCursor();
	lcd.clear();
	lcd.home();
	for (byte i = 0; i < COLS * ROWS; i++) {
		if (i % COLS == 0)
			lcd.setCursor(i % COLS, i / COLS);
		lcd.write(term->contents[i]);
	}
	lcd.cursor();
}

void scroll_up(struct terminal *term)
{
	for (byte i = 0; i < COLS * (ROWS - 1); i++)
		term->contents[i] = term->contents[i + COLS];
	for (byte i = COLS * (ROWS - 1); i < COLS * ROWS; i++)
		term->contents[i] = ' ';
	redraw(term);
}

/**
 * Special character meanings are defined here.
 */
void write(struct terminal *term, char ch)
{
	switch (ch) {
		case '\r':
			term->x = 0;
			lcd.setCursor(term->x, term->y);
			break;
		case '\n':
			if (++term->y >= ROWS) {
				term->y--;
				scroll_up(term);
			}
			lcd.setCursor(term->x, term->y);
			break;
		case 0x7f:
			if (term->x != 0) {
				term->x--;
				term->contents[term->x + term->y * COLS] = 0x00;
				lcd.setCursor(term->x, term->y);
				lcd.write(' ');
				lcd.setCursor(term->x, term->y);
			}
			break;
		default:
			term->contents[term->x + term->y * COLS] = ch;
			lcd.write(ch);
			if (++term->x >= COLS) {
				term->x = 0;
				if (++term->y >= ROWS) {
					term->y--;
					scroll_up(term);
				}
				lcd.setCursor(term->x, term->y);
			}
	}
}