#include <stdio.h>
#include <avr/io.h>

#define BAUD 57600
#include <util/setbaud.h>

#include "display.h"

/* WIDTH+1 for string terminator */
static char display[LCD_HEIGHT][LCD_WIDTH+1];
static int cursor_x;
static int cursor_y;

/* Slightly icky hack to use first avaialable USART */
#ifdef UDR0
#  define UBRRx  UBRR0
#  define UCSRxA UCSR0A
#  define UCSRxB UCSR0B
#  define UCSRxC UCSR0C
#  define UCSZx0 UCSZ00
#  define UCSZx1 UCSZ01
#  define RXENx  RXEN0
#  define TXENx  TXEN0
#  define UDREx  UDRE0
#  define UDRx   UDR0
#  define U2Xx   U2X0
#else
#  define UBRRx  UBRR1
#  define UCSRxA UCSR1A
#  define UCSRxB UCSR1B
#  define UCSRxC UCSR1C
#  define UCSZx0 UCSZ10
#  define UCSZx1 UCSZ11
#  define RXENx  RXEN1
#  define TXENx  TXEN1
#  define UDREx  UDRE1
#  define UDRx   UDR1
#  define U2Xx   U2X1
#endif

static void uart_init(void)
{
	UBRRx = UBRR_VALUE;
#if USE_2X
	UCSRxA |= (1 << U2Xx);
#else
	UCSRxA &= ~(1 << U2Xx);
#endif
    UCSRxB = _BV(RXENx) | _BV(TXENx);
    UCSRxC = _BV(UCSZx1) | _BV(UCSZx0);
}

static int uart_putc(char c, FILE *unused)
{
	(void)unused;
	UDRx = c;
	loop_until_bit_is_set(UCSRxA, UDREx);
	return 1;
}

/* uart_out is plopped on stdout so that prints go to it by default */
static FILE uart_out = FDEV_SETUP_STREAM(uart_putc, NULL, _FDEV_SETUP_WRITE);

/* internal function to dump the display contents to stdout, since there
 * is no background thread for doing this constantly */
void display_display(void)
{
	int y = 0;
	printf("\033[6A"); // hack: raw ANSI escape sequence to move up 6
	printf(",--------------------.\n");
	for (y = 0; y < LCD_HEIGHT; y++) {
		printf("|%s|\n", display[y]);
	}
	printf("`--------------------'\n");
}

void display_clear(void)
{
	int x = 0;
	int y = 0;
	for (y = 0; y < LCD_HEIGHT; y++) {
		for (x = 0; x < LCD_WIDTH; x++) {
			display[y][x] = ' ';
		}
		display[y][x] = '\0';
	}

	display_display();
}

void display_init(void)
{
	uart_init();
	/* FIXME hack: stdout not guaranteed to be assignable */
	stdout = &uart_out;
	display_clear();
	cursor_x = cursor_y = 0;
}

void display_write(const char *text)
{
	char c = '\0';
	while (cursor_x < LCD_WIDTH && *text) {
		c = *(text++);
		/* 0-7 are custom chars in CGRAM on real LCD */
		if (c < 8)
			c = '_';
		display[cursor_y][cursor_x++] = c;
	}
	display_display();
}

void display_set_cursor(int x, int y)
{
	cursor_x = x;
	cursor_y = y;
}