#define _XOPEN_SOURCE 600
#define _XOPEN_SOURCE_EXTENDED

#include <ncursesw/ncurses.h>
#include <ncursesw/form.h>

#include <locale.h>
#include <stdio.h>


#define TRY_MULTIBYTE 1


int main() {
  FIELD * fields[2];
  FORM * form;
  WINDOW * outer;
  WINDOW * inner;
  int rows;
  int cols;
  int done;

  setlocale(LC_ALL, "");

  initscr();
  keypad(stdscr, TRUE);
  nonl();
  cbreak();
  noecho();

  fields[0] = new_field(1, 20, 0, 1, 0, 0);
  fields[1] = NULL;

  form = new_form(fields);
  scale_form(form, &rows, &cols);

  outer = newwin(rows + 2, cols + 2, (LINES - rows) / 2, (COLS - cols) / 2);
  inner = derwin(outer, rows, cols, 1, 1);

  box(outer, 0, 0);
  keypad(outer, TRUE);

  set_form_win(form, outer);
  set_form_sub(form, inner);

  post_form(form);

  wrefresh(outer);

  done = 0;
  while (done == 0) {
    int i;
    wint_t ch = 0;
    char buf[20];
#if TRY_MULTIBYTE
    int n;
    int j;
#endif

    i = get_wch(&ch);

    snprintf(buf, sizeof(buf), "i: %d; ch: %lu        ", i, (unsigned long) ch);
    mvaddstr(LINES - 1, 0, buf);
    refresh();

    switch (i) {
    case OK:
      switch (ch) {
      case '\r':
      case '\n':
        form_driver(form, REQ_VALIDATION);
        done = KEY_ENTER;
        break;

      case '\x03':        /* Ctrl + C */
      case '\x1b':        /* Esc */
        done = KEY_CANCEL;
        break;

      case '\x08':        /* Ctrl + H */
        if (form_driver(form, REQ_PREV_CHAR) == E_OK) {
          form_driver(form, REQ_DEL_CHAR);
        }
        break;

      case '\x15':        /* Ctrl + U */
        while (form_driver(form, REQ_PREV_CHAR) == E_OK) {
          form_driver(form, REQ_DEL_CHAR);
        }
        break;

      case 0:
        beep();
        break;

      default:
#if TRY_MULTIBYTE
        n = wctomb(buf, ch);
        for (j = 0; j < n; ++j) {
          if ((i = form_driver(form, buf[j])) != E_OK) {
            snprintf(buf, sizeof(buf), "driver: %d (%d/%d)", i, j, n);
            break;
          }
        }
#else
        i = form_driver(form, ch);
        snprintf(buf, sizeof(buf), "driver: %d", i);
#endif
        mvaddstr(LINES - 1, 40, buf);
        refresh();
        break;
      }
      break;

    case KEY_CODE_YES:
      switch (ch) {
      case KEY_ENTER:
        form_driver(form, REQ_VALIDATION);
        done = KEY_ENTER;
        break;

      case KEY_CANCEL:
      case KEY_BREAK:
      case KEY_EXIT:
        done = KEY_CANCEL;
        break;

      case KEY_DC:
        form_driver(form, REQ_DEL_CHAR);
        break;

      case KEY_BACKSPACE:
        if (form_driver(form, REQ_PREV_CHAR) == E_OK) {
          form_driver(form, REQ_DEL_CHAR);
        }
        break;

      case KEY_LEFT:
        form_driver(form, REQ_PREV_CHAR);
        break;

      case KEY_RIGHT:
        form_driver(form, REQ_NEXT_CHAR);
        break;

      case KEY_HOME:
        form_driver(form, REQ_BEG_FIELD);
        break;

      case KEY_END:
        form_driver(form, REQ_END_FIELD);
        break;

      default:
        form_driver(form, ch);
        break;
      }
      break;

    case ERR:
      done = KEY_CANCEL;
      break;
    }

    wrefresh(outer);
  }

  delwin(inner);
  delwin(outer);
  free_form(form);
  free_field(fields[0]);

  endwin();

  return 0;
}