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/*
  This file is part of ct.

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with ct. If not, see <https://www.gnu.org/licenses/>.
*/

#include "lcdlib.h"

static char previous_lines[LCD_HEIGHT][LCD_WIDTH+1];
static const char* esc = "\x1B[L";
static FILE *lcd = NULL;
static int line_idx;

int
lcd_begin(void) {
  lcd = fopen("/dev/lcd", "w");
  if (lcd == NULL) return EXIT_FAILURE;
  lcd_clear();
  return EXIT_SUCCESS;
}

void
lcd_end(void) {
  fclose(lcd);
}

void
lcd_set_blink(void) {
  fprintf(lcd, "%sB", esc);
  fflush(lcd);
}

void
lcd_stop_blink(void) {
  fprintf(lcd, "%sb", esc);
  fflush(lcd);
}

void
lcd_clear(void) {
  line_idx = 0;
  for (int y = 0; y + 1 < LCD_HEIGHT; y++) {
    fprintf(lcd, "%sy%dx0;%sk", esc, y, esc);
    previous_lines[y][0] = 0;
  }
  fflush(lcd);
}

void
lcd_put_line(const enum LCD_WRITE_MODE mode, const char *line) {
  char last_line = 0;
  if (line_idx == LCD_HEIGHT) {
    if (mode == L_SCROLL) {
      // If we're at the bottom, ``shift'' everything up
      for (int y = 1; y < LCD_HEIGHT; y++) {
	// Go to the start of row y, clear the line, and print the
	// previous string there
	fprintf(lcd, "%sy%dx0;%sk%s", esc, y-1, esc, previous_lines[y]);
	// Overwrite the stored previous line with the next
	strncpy(previous_lines[y-1], previous_lines[y], LCD_WIDTH+1);
      }
    }
    last_line = 1;
  }
  // Go to the correct line, clear it, and write the input.
  fprintf(lcd, "%sy%dx0;%sk%s", esc, line_idx, esc, line);
  fflush(lcd);
  // Store this line, null-terminate!
  if (last_line) line_idx--;
  strncpy(previous_lines[line_idx], line, LCD_WIDTH+1);
  previous_lines[line_idx][LCD_WIDTH] = 0;
  if (mode == L_SCROLL && line_idx < LCD_HEIGHT) line_idx++;
}

void
lcd_printf_line(const enum LCD_WRITE_MODE mode,
		const char *format, ...) {
  char buf[LCD_WIDTH+1];

  va_list(args);
  va_start(args, format);
  vsnprintf(buf, LCD_WIDTH+1, format, args);
  va_end(args);

  lcd_put_line(mode, buf);
}