listbox.h

/*
========================================================================
- HEADER -
Module to implement a listBox integrated with LYNX.
@author : Velorek
@version : 1.0
Last modified: 26/12/2022
========================================================================
*/

#ifndef _LISTBOX_H_
#define _LISTBOX_H_

/*====================================================================*/
/* COMPILER DIRECTIVES AND INCLUDES                                   */
/*====================================================================*/

#include <stdio.h>
#include "scbuf.h"
/*====================================================================*/
/* CONSTANTS */
/*====================================================================*/
//Scroll Control values.
#define SCROLL_ACTIVE 1
#define SCROLL_INACTIVE 0
#define CONTINUE_SCROLL -1
#define DOWN_SCROLL 1
#define UP_SCROLL 0
#define SELECT_ITEM 1
#define UNSELECT_ITEM 0
#define CIRCULAR_ACTIVE 1
#define CIRCULAR_INACTIVE 0
#define LOCKED 1
#define NOT_LOCKED 0
/*====================================================================*/
/* TYPEDEF STRUCTS DEFINITIONS */
/*====================================================================*/

typedef struct _listchoice {
	unsigned index;		// Item number
	char *item;		// Item string
	struct _listchoice *next;	// Pointer to next item
	struct _listchoice *back;	// Pointer to previous item
} LISTCHOICE;

typedef struct _scrolldata {
	unsigned scrollActive;	//To know whether scroll is active or not.
	unsigned scrollLimit;	//Last index for scroll.
	unsigned listLength;	//Total no. of items in the list
	unsigned currentListIndex;	//Pointer to new sublist of items when scrolling.
	unsigned displayLimit;	//No. of elements to be displayed.
	unsigned selectorLimit;	//how many items of string item can be displayed
	unsigned scrollDirection;	//To keep track of scrolling Direction.
	unsigned wherex;
	unsigned wherey;
	unsigned selector;	//Y++
	unsigned backColor0;	//0 unselected; 1 selected
	unsigned foreColor0;
	unsigned backColor1;
	unsigned foreColor1;
	unsigned displayMetrics;	//to show metrics on screen/reuse code for text viewing
	char *item;
	int itemIndex;		//-1 means ESC was pressed
	LISTCHOICE *head;	//store head of the list
} SCROLLDATA;

/*====================================================================*/
/* GLOBAL VARIABLES */
/*====================================================================*/
extern LISTCHOICE *listBox1;	//Head pointer.

/*====================================================================*/
/* PROTOTYPES OF FUNCTIONS                                            */
/*====================================================================*/

//DYNAMIC LINKED LIST FUNCTIONS
void removeList(LISTCHOICE ** head);
LISTCHOICE *addatend(LISTCHOICE * head, LISTCHOICE * newp);
LISTCHOICE *newitem(char *text);

//LISTBOX FUNCTIONS
//void    addItems(LISTCHOICE ** listBox1);
char listBox(LISTCHOICE * selector, unsigned whereX, unsigned whereY,
	     SCROLLDATA * scrollData, unsigned bColor0,
	     unsigned fColor0, unsigned bColor1, unsigned fColor1,
	     unsigned displayLimit, unsigned locked);
void loadlist(LISTCHOICE * head, SCROLLDATA * scrollData, unsigned indexAt);

void printlist(LISTCHOICE * head, SCROLLDATA * scrollData,
	       unsigned displayLimit);

void gotoIndex(LISTCHOICE ** aux, SCROLLDATA * scrollData, unsigned indexAt);
int query_length(LISTCHOICE ** head);
int move_selector(LISTCHOICE ** head, SCROLLDATA * scrollData);
char selectorMenu(LISTCHOICE * aux, SCROLLDATA * scrollData);
void displayItem(LISTCHOICE * aux, SCROLLDATA * scrollData, int select);

/*====================================================================*/
/* FUNCTION PROTOTYPES                                                */
/*====================================================================*/

#endif