/****************   A window for a menu ********************/

#include <curses.h>
#include <signal.h>

#define TOP_MARGIN 4
#define BOT_MARGIN 2
#define INSTR_LINES 2
#define MAXITEMS  LINES - INSTR_LINES - TOP_MARGIN - BOT_MARGIN
#define SIDE_MARGIN 6
#define LABEL_WIDTH 5
#define bell() printf("\007")
#define MIN(a,b) ((a) > (b) ? b : a)
#define MAX(a,b) ((a) < (b) ? b : a)

typedef char *String;
static int y_0 = 3;
static int x_0;

void clean_up()
{   clear();
    refresh();
    fflush(stdin);
    fflush(stdout);
}

/* Exit program properly  */
void normal_end()
{  mvcur(0, COLS-1, LINES-1, 0); /* position cursor */
   clean_up();
   endwin();                     /* finish curses */
   putchar('\n');                /* position cursor */
}

void abnormal_end()
{   normal_end();
    exit(1);
}
/* items -- array of menu items
   title -- title of menu
   dim -- number of items on menu  */

   WINDOW *setup_menu(int, String items[], String, String);
   void display_choice(WINDOW *scr, int choice, int old_choice); 

int menu_select(int dim, String items[], String title, String cook)
{   int choice, old_choice = 1;
    char c;
    WINDOW *menu_scr;
    if (dim > MAXITEMS) 
    {   fprintf(stderr, "too many items on menu\n");
        exit(1);
    }
    menu_scr = setup_menu(dim, items, title, cook); /* set up menu */
    for (;;)
    {   choice = retrieve_choice(dim, old_choice);
        if ( choice < 0 ) return(old_choice); /* done */
        if ( choice != old_choice )
        {    display_choice(menu_scr, choice, old_choice);
             old_choice = choice;
        }
    }
}

int retrieve_choice(int total_items, int old_choice)
{   char c;
    int choice;

    while (c = getchar())
    {   if (c == '\n') return(-1);  /* final choice */
        if (c == ' ' || c == '+')   /* next item */
        {   choice = old_choice + 1;
            if (choice > total_items) choice = 1;
            return(choice);
        }
        if (c == '-')   /* previous item */
        {   choice = old_choice - 1;
            if (choice == 0) choice = total_items;
            return(choice);
        }
        choice = c - '0';            /* 1 thru 9 */
        if (choice > total_items || choice > 9)
            bell();                  /* no such choice */
        else 
            return(choice);
    }
}

void init()
{   fflush(stdin);
    fflush(stdout);
    noecho();              /* terminal will not echo input characters */
    crmode();              /* set to cbreak mode */
}

int max_length(int dim, String items[])
{   int max = 0, len;
    while (dim-- > 0)
    {   len = strlen(items[dim]);
        if (len > max)  max = len;
    }
    return(max);
}

labeling(WINDOW *scr, int no, int y, int x, int standout_flag)
{   char label[LABEL_WIDTH];

    if (standout_flag) wstandout(scr);  /* standout mode begin */
    sprintf(label, "(%d)\0", no);       /* highlight label */
    mvwaddstr(scr, y, x, label);
    if (standout_flag) wstandend(scr);  /* standout mode end */
}

void display_choice(WINDOW *scr, int choice, int old_choice)
{   labeling(scr, old_choice, y_0 + old_choice, x_0, 0);
    labeling(scr, choice, y_0 + choice, x_0, 1);
    refresh();
}

/* set up menu_scr */

WINDOW *setup_menu(int dim, String items[], String title, String cook)
{   int tlen, maxlen, i, tx, mid_x, menu_lines, menu_cols;
    WINDOW *menu_scr;
	 WINDOW *cook_scr;
/* compute menu dimensions */
    tlen = strlen(title);
    maxlen = max_length(dim,items) + LABEL_WIDTH;
    menu_cols = MAX(tlen, maxlen) + 2*SIDE_MARGIN;
    if (menu_cols > COLS) 
    {   fprintf(stderr, "menu items too long.\n");
        exit(1);
    }
    menu_lines = dim + TOP_MARGIN + BOT_MARGIN;
/* establish cook window */
	 cook_scr = subwin(stdscr,3,menu_cols,0,0);
	 box(cook_scr,'*','*'); /* draw box to form a window */
/* establish menu window */
    menu_scr = subwin(stdscr,menu_lines,menu_cols, 4, 0);
    box(menu_scr,'*','*'); /* draw box to form a window */
/* display title */
    mid_x = menu_cols/2;
    tx = mid_x - (tlen/2);
	 mvwaddstr(cook_scr,1,tx,cook);
    wstandout(menu_scr);   /* standout mode begin */
    mvwaddstr(menu_scr,2,tx,title);
    wstandend(menu_scr);   /* standout mode end */
    y_0 = 3;
/* display all items */
    x_0 = MIN(mid_x - maxlen/2, tx);    /* x-position for each item */
    for(i=1 ; i <= dim ; i++)
    {   labeling(menu_scr, i, y_0+i, x_0, i == 1 );
        mvwaddstr(menu_scr, y_0+i, x_0+LABEL_WIDTH, items[i-1]);
    }
/* display fixed instructions */
    mvaddstr(LINES-INSTR_LINES, 0,
           "TYPE A DIGIT, +, - OR <SPACE BAR> TO REACH AN ITEM,");
    mvaddstr(LINES-INSTR_LINES+1, 0, "<RETURN> TO FINALIZE CHOICE.");
    refresh();  
    return(menu_scr);
}

main(int argc, String argv[])
{       void abnormal_end(void);
        int choice;

        initscr();         /* initialize curses */
        init();            /* other initializations */
        signal(SIGINT, abnormal_end); /* trap signal */
        choice = menu_select(argc - 3, argv+3, argv[2], argv[1]);
        normal_end();
        printf("(%d) selected\n", choice);
}