#include <ncurses.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>      // for isspace()

int barmenu(const char const **array, int row, int col,
        int arraylength, int width, int menulength, int selection);

// Removes whitespace from the end of strings
void chomp(char *str)
{
        int len=strlen(str);

        if(len>0)
        while((len>0) && isspace(str[len-1]))
                str[--len]='\0';
}

int main(void)
{
        char buf[128];
        int selection,row=1,col=10,arraylength=0,width=5, menulength=5;

        char **testarray=NULL;
        FILE *fp=fopen("filename","r");

        while(fgets(buf,128,fp) != NULL)
        {
                chomp(buf); // Remove \n from end of line
                if(strlen(buf) > width) width=strlen(buf);
                if(!buf[0]) continue; // Ignore blank lines

                arraylength++;
                // Room for n+1 elements of char * size.
                testarray=realloc(testarray, sizeof(char *)*(arraylength+1));
                // strdup is an easy str=malloc(strlen(s)+1); strcpy(str,s);
                testarray[arraylength-1]=strdup(buf);
        }

        // The +1 gives us room for a NULL on the end.  Makes it easier to find crashes.
        testarray[arraylength]=NULL;
        fclose(fp);

        // If no elements were loaded, it will still be NULL
        if(testarray == NULL)
        {
                fprintf(stderr, "Unable to load options\n");
                exit(1);
        }

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

        selection=barmenu((const char const **)testarray,row,col,arraylength,width,menulength,0);

        mvprintw(15,0,"Selection= %d",selection);
        refresh();
        getch();
        endwin();

        // Add another option to file
        fp=fopen("filename","a");
        fputs("whatever\n", fp);
        fclose(fp);

        // We allocated all this stuff, so free it.
        for(col=0; col<arraylength; col++) if(testarray[col]) free(testarray[col]);
        free(testarray);

        // Cannot return -1 to commandline.  127 is the maximum we should return.
        if(selection < 0) return(127);
        // 0 has special meaning, return n+1
        return selection+1;
}

int barmenu(const char const **array, int row, int col,
        int arraylength, int width, int menulength, int selection)
{
        int counter,offset=0,ky=0;
         char formatstring[7];
         curs_set(0);

         if (arraylength < menulength)
                 menulength=arraylength;

         if (selection > menulength)
                 offset=selection-menulength+1;

         sprintf(formatstring,"%%-%ds",width); // remove - sign to right-justify the menu items

         while(ky != 27)
                 {
                 for (counter=0; counter < menulength; counter++)
                         {
                         if (counter+offset==selection)
                                 attron(A_REVERSE);
                         mvprintw(row+counter,col,formatstring,array[counter+offset]);
                         attroff(A_REVERSE);
                         }

                 ky=getch();

                 switch(ky)
                         {
                         case KEY_UP:
                                 if (selection)
                                         {
                                         selection--;
                                         if (selection < offset)
                                                 offset--;
                                         }
                                 break;
                         case KEY_DOWN:
                                 if (selection < arraylength-1)
                                         {
                                         selection++;
                                         if (selection > offset+menulength-1)
                                                 offset++;
                                         }
                                 break;
                         case KEY_HOME:
                                 selection=0;
                                 offset=0;
                                 break;
                         case KEY_END:
                                 selection=arraylength-1;
                                 offset=arraylength-menulength;
                                 break;
                         case KEY_PPAGE:
                                 selection-=menulength;
                                 if (selection < 0)
                                         selection=0;
                                 offset-=menulength;
                                 if (offset < 0)
                                         offset=0;
                                 break;
                         case KEY_NPAGE:
                                 selection+=menulength;
                                 if (selection > arraylength-1)
                                         selection=arraylength-1;
                                 offset+=menulength;
                                 if (offset > arraylength-menulength)
                                         offset=arraylength-menulength;
                                 break;

                         case 10: //enter
                                 return selection;
                                 break;
                         case KEY_F(1): // function key 1
                                 return -1;
                         case 27: //esc
                                 // esc twice to get out, otherwise eat the chars that don't work
                                 //from home or end on the keypad
                                 ky=getch();
                                 if (ky == 27)
                                         {
                                         curs_set(0);
                                         mvaddstr(9,77,"   ");
                                         return -1;
                                         }
                                 else
                                         if (ky=='[')
                                                 {
                                                 getch();
                                                 getch();
                                                 }
                                         else
                                                 ungetch(ky);
                         }
                 }
         return -1;
}