Example Curses Login Form

/*
 * CRM LOGIN
 *
 * Main login page for a generic CRM.
 */

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <ncurses.h>
#include <form.h>

#include "common_util.h"
#include "date_time_util.h"

enum {
    FORM_LOGIN_USER,
    FORM_LOGIN_PASS,
    FORM_LOGIN_PROG,
    FORM_LOGIN_DATE,
    FORM_LOGIN_TIME,
    FORM_LOGIN_FMSG,
    FORM_LOGIN_LINE,
    FORM_LOGIN_FIELD_COUNT
};

static void driver(FORM *form, int ch)
{
    FIELD **fields, **field;
    char *buffer;
    char *text;

    fields = form->field;
    field = NULL;

    switch (ch) {
        case KEY_F(2):
        case KEY_ENTER:
        case '\n':
            /* Force a form buffer refresh with some key movement: */
            form_driver(form, REQ_NEXT_FIELD);
            form_driver(form, REQ_PREV_FIELD);

            if (
                strcmp(trim_whitespace(field_buffer(fields[FORM_LOGIN_USER], 0)), "u/green_boy") == 0 &&
                strcmp(trim_whitespace(field_buffer(fields[FORM_LOGIN_PASS], 0)), "pass") == 0
            ) {
                set_field_buffer(fields[FORM_LOGIN_FMSG], 0, "Login succeeded");

            }
            else {
                set_field_buffer(fields[FORM_LOGIN_FMSG], 0, "Login failed");
            }

            switch(field_just(fields[FORM_LOGIN_FMSG])) {
                case JUSTIFY_RIGHT:
                    text = "DEBUG: Right justified requested for form message";
                    break;
                case JUSTIFY_LEFT:
                    text = "DEBUG: Left justified requested for form message";
                    break;
                case JUSTIFY_CENTER:
                    text = "DEBUG: Centered requested for form message";
                    break;
                case NO_JUSTIFICATION:
                    text = "DEBUG: Floating requested for form message";
                    break;
                default:
                    text = "DEBUG: Not set requested for form message";
                    break;
            }
            set_field_buffer(fields[FORM_LOGIN_LINE], 0, text);

            /* Reload field values, clearing blanking fields */
            for (field = fields; *field != NULL; field++) {
                buffer = trim_whitespace(field_buffer(*field, 0));
                if (field_opts(*field) & O_BLANK) {
                    set_field_buffer(*field, 0, "");
                }
                else if (field_opts(*field) & O_EDIT) {
                    set_field_buffer(*field, 0, buffer);
                }
            }

            refresh();
            pos_form_cursor(form);
            break;

        case KEY_DOWN:
        case '\t':
            form_driver(form, REQ_NEXT_FIELD);
            form_driver(form, REQ_END_LINE);
            break;

        case KEY_UP:
        case KEY_BTAB:
            form_driver(form, REQ_PREV_FIELD);
            form_driver(form, REQ_END_LINE);
            break;

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

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

        /* Perform a backspace-delete: */
        case KEY_BACKSPACE:
        case 127:
            form_driver(form, REQ_DEL_PREV);
            break;

        /* Perform a forward-delete: */
        case KEY_DC:
            form_driver(form, REQ_DEL_CHAR);
            break;

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

    wrefresh(form->sub);
}

void login_form(void)
{
    static FIELD *fields[FORM_LOGIN_FIELD_COUNT];
    char date[CUR_DATE_MAX_SZ];
    char time[CUR_TIME_MAX_SZ];

    WINDOW *win_body, *win_form;
    FORM *form;
    int ch, i;

    ch = '\0';

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

    /* Establish the needed fields with a null terminator: */
    assert_not_null(fields[FORM_LOGIN_USER] = new_field(1, 18, 10, 39, 0, 0));
    assert_not_null(fields[FORM_LOGIN_PASS] = new_field(1, 18, 12, 39, 0, 0));
    assert_not_null(fields[FORM_LOGIN_PROG] = new_field(1, 18, 14, 39, 0, 0));

    assert_not_null(fields[FORM_LOGIN_DATE] = new_field(1, 12, 23,  3, 0, 0));
    assert_not_null(fields[FORM_LOGIN_TIME] = new_field(1,  5, 23, 74, 0, 0));

    assert_not_null(fields[FORM_LOGIN_FMSG] = new_field(1, 32, 16, 25, 0, 0));
    assert_not_null(fields[FORM_LOGIN_LINE] = new_field(1, 76, 22,  3, 0, 0));

    fields[FORM_LOGIN_FIELD_COUNT] = NULL;

    /* Set up form field options and formatting: */
    set_field_opts(fields[FORM_LOGIN_USER], O_VISIBLE | O_EDIT | O_ACTIVE | O_PUBLIC);
    set_field_opts(fields[FORM_LOGIN_PASS], O_VISIBLE | O_EDIT | O_ACTIVE | O_BLANK);
    set_field_opts(fields[FORM_LOGIN_PROG], O_VISIBLE | O_EDIT | O_ACTIVE | O_PUBLIC);
    set_field_opts(fields[FORM_LOGIN_DATE], O_VISIBLE | O_PUBLIC);
    set_field_opts(fields[FORM_LOGIN_TIME], O_VISIBLE | O_PUBLIC);
    set_field_opts(fields[FORM_LOGIN_FMSG], O_VISIBLE | O_PUBLIC);
    set_field_opts(fields[FORM_LOGIN_LINE], O_VISIBLE | O_PUBLIC);

    set_field_back(fields[FORM_LOGIN_USER], A_UNDERLINE);
    set_field_back(fields[FORM_LOGIN_PASS], A_UNDERLINE);
    set_field_back(fields[FORM_LOGIN_PROG], A_UNDERLINE);
    set_field_back(fields[FORM_LOGIN_LINE], A_UNDERLINE);
    set_field_back(fields[FORM_LOGIN_FMSG], A_UNDERLINE);

    set_field_just(fields[FORM_LOGIN_FMSG], JUSTIFY_CENTER);
    set_field_just(fields[FORM_LOGIN_DATE], JUSTIFY_LEFT);
    set_field_just(fields[FORM_LOGIN_TIME], JUSTIFY_RIGHT);
    set_field_just(fields[FORM_LOGIN_LINE], JUSTIFY_CENTER);

    /* Set a default application: */
    /* TODO: this is hokey, parameterise field initialisation! */
    set_field_buffer(fields[FORM_LOGIN_PROG], 0, "CRMMAIN");

    /*
     * Wire up a form with two windows:
     * - Main window is for labels.
     * - Form window is for the form itself and its fields.
     */
    assert_not_null(form = new_form(fields));
    assert_not_null(win_body = newwin(24, 80, 0, 0));
    assert_not_null(win_form = derwin(win_body, 24, 80, 0, 0));
    set_form_win(form, win_body);
    set_form_sub(form, win_form);
    pos_form_cursor(form);
    post_form(form);

    /* Draw out the labels: */
    mvwprintw(win_body,  3, 33, "COMPANY NAME HERE");
    mvwprintw(win_body,  5, 34, "SYSTEM SIGN ON");
    mvwprintw(win_body, 10, 28, "Username :");
    mvwprintw(win_body, 12, 28, "Password :");
    mvwprintw(win_body, 14, 25, "Application :");

    get_cur_date(date, sizeof(date));
    get_cur_time(time, sizeof(time));
    set_field_buffer(fields[FORM_LOGIN_DATE], 0, date);
    set_field_buffer(fields[FORM_LOGIN_TIME], 0, time);
    wrefresh(form->sub);

    /* Refresh and display: */
    refresh();
    wrefresh(win_body);
    wrefresh(win_form);

    while ((ch = getch()) != KEY_F(1))
        driver(form, ch);

    unpost_form(form);
    for (i = 0; i < FORM_LOGIN_FIELD_COUNT; i++) {
        free_field(fields[i]);
    }
    free_form(form);
    delwin(win_form);
    delwin(win_body);
    endwin();
}