/*--------------------------------------------------------------------------*/
/*     MEN.C       a point and shoot menu function                          */
/*--------------------------------------------------------------------------*/
is_select(
          struct key_in *nkey,
          int pass_backsp_q /*LG_YES treats backspace as a printable char */
         )
{
 if(nkey->mou_chng_q == LG_YES)
 {
  if(nkey->mou_l_bt == LG_YES) return(LG_YES);
  else return(R_ERR);
 }
 else if(nkey->have_char_q == LG_YES)
 {
  if(nkey->is_ext_q == LG_YES) return(R_ERR);
  else if(nkey->charin == '\r') return(LG_YES);
  else if(nkey->charin == '\b')
  {
   if(pass_backsp_q == LG_YES) return(LG_NO);
   else return(R_ERR);
  }
  else if(isprint(nkey->charin)) return(LG_NO);
  else return(R_ERR);
 }
 else return(LG_NO); /*if no nonmovement key or button at all pressed */
}
/*----------------------------------*/
struct menu_dat
{
 char *men_line[]  /*see p 231, 237*/
 int  num_lines;
 int first_option; /*position of first selectable line, or equal to */
                   /* num_lines if none                             */
 int last option;
 enum {choose_upcase, choose_any} valid_option; 
}

/*----------------------------------*/
x_menu(
       struct menu_dat *curr_menu
      )
{
 char c;
 struct key_in *nkey;
 int a, i, men_width, curr_line, new_line;
 /* 1. set up the menu    */
 men_width = max_strlen_in_arr_ptrstr(curr_menu->men_line, 
                                             curr_menu->num_lines);
 menu_border(cur_menu->num_lines,men_width);  /* set up the menu space   */
 for(i=0; i < num_lines; i++) /* c. write the lines into it, marking one */
 {
  if(i == first_option) v_attr = NORMAL_VIDEO; else v_attr = REVERSE_VIDEO;
  put_a_line(curr_menu, i, v_attr, men_width);
 }
 cursoff();
 curr_line=curr_menu->first_option;
 /* 2. get in a response  */
 for(;;)
 {
  get_mov_ch(nkey, 8, 24); 
  if(nkey->have_move_q)      
  {  /* if its a move, make it, clamping the new position within the menu */
   new_line=iclamp( (curr_line+nkey->down_move),   
                    curr_menu->first_option,  
                    curr_menu->last_option );
   cur_line=shift_highlited_line(cur_menu, curr_line, new_line, men_width);
  }
  a=is_select(
              nkey,
              LG_NO
             )
  if(a == R_ERR) return(R_ERR);  /*invalid response */
  else if(a == LG_NO)
  {
   if(nkey->have_char_q) 
   {
    if(curr_menu->valid_option == choose_upcase) 
     return(toupper(nkey->charin));
    else return(nkey->charin);
   } 
   else continue;
  }
  else if(a == LG_YES) /* parse selection under the cursor, and return that */
  {
   if(curr_menu->valid_option == choose_any) /*if it can be lowercase */
    b=opt_str_parse(curr_menu->men_line[curr_line], LG_YES);
   else
    b=opt_str_parse(curr_menu->men_line[curr_line], LG_NO);
   return(b);
  }
 }
}
/*-----------------------------------------------------*/
put_a_line(
           struct menu_dat *curr_menu,
           int i, 
           char v_attr,
           int width
          )
{
 scrnputs(
          i,0,                    /* on the left edge of screen */
          curr_menu->men_line[i],
          ' ', v_attr,          /* select attribute and fill with spaces */
          men_width,
          LG_NO     /*don't restore cursor pos */
         );
}
/*----------------------------------------------------------------------*/
int shift_highlited_line(struct menu_dat *menu, 
                          int o_line, int n_line, int men_width)
{
 put_a_line(menu, o_line, REVERSE_VIDEO, men_width); /*unmark the old line */
 put_a_line(menu, n_line, NORMAL_VIDEO, men_width); /* and set the new one */
 return(n_line);
}
/*------------------------------------------------------------*/
int opt_str_parse(char *opt_str, int take_lowcase_q)
{
 int c,i;
 for(i=0;;i++)
 {
  c=opt_str[i];
  if(c == NULL_BYTE) return(R_ERR);/*end of string: report failure */
  else if(isspace(c)) continue;  /* ignore spaces, tabs, etc.      */
  else if(islower(c))
  {
   if(take_lowcase_q == LG_YES) /*it can be lowercase */
       return(c);                          
   else continue
  }
  else return(c);       /* if it isn't any of those, it must be an  */
                          /*  uppercase, numeral, or punctuation mark */
                          /* which are always acceptable              */
 }
}
/*-----------------------------------------------------*/
menu_border(int rows, int cols)  /* use (0,0) to reset, else the number of */
{                                /*  rows and cols to be enclosed          */
 static int old_rows;
 static int old_cols;
 if((rows == 0) && (cols == 0)) /*reset*/
   old_rows=old_cols=0;
 else
 {
  /* 1. if the new menu does not cover the old one, blank the old one */
  if((old_rows > rows) || (old_cols > cols))
   w_roll(0,old_rows, 0, old_cols, old_rows, REVERSE_VIDEO);
  /* 2. if room, place the botton border */
  if( rows < screen_size.rows)
  {
   poscurs(rows,0);
   writechs(E_ASC_LN_DRW_2_HOR, REVERSE_VIDEO, cols);
  }
  /* 3. if room, place the right border */
  if( cols < screen_size.cols)
   for(i=0; ((i < rows) && (i < screensize.rows)); i++)
   {
    poscurs(i,cols);
    writechs(E_ASC_LN_DRW_2_VERT, REVERSE_VIDEO, 1);
   }
  /* 4. and likewise the bottom corner */
  if(
     (rows < screen_size.rows)
    &&
     (cols < screen_size.cols)
    )
  {
   poscurs(rows, cols);
   writechs(E_ASC_LN_DRW_2_LW_RT, HIGHLIGHT, 1);
  }
 }
}