#ifndef __INT_LIST_H
#define __INT_LIST_H

#include <stdbool.h>
#include "util.h"

/*
 * Declaration of a undirected list for storing integers for the
 * "Datastructures and algorithms" courses at the Department of
 * Computing Science, Umea University. The implementation uses a
 * dynamic, linked structure. After use, the function list_kill must
 * be called to de-allocate the dynamic memory used by the list
 * itself. The implementation is a written a code copy specialization
 * of the generic list to provide a simpler starting data structure
 * than the generic list.
 *
 * Authors: Niclas Borlin (niclas@cs.umu.se)
 *
 * Version information:
 *   v1.0  2018-01-28: First public version.
 *   v1.1  2023-01-19: Added list_pos_equal and list_pos_is_valid functions.
 *   v1.2  2023-01-20: Renamed list_pos_equal to list_pos_are_equal.
 *   v1.3  2023-03-23: Renamed list_pos_are_equal to list_pos_is_equal.
 *   v1.4  2024-05-10: Added print_internal.
 */

// ==========PUBLIC DATA TYPES============

// List type.
typedef struct list list;

// List position type.
typedef struct cell *list_pos;

// ==========DATA STRUCTURE INTERFACE==========

/**
 * list_empty() - Create an empty list.
 *
 * Returns: A pointer to the new list.
 */
list *list_empty(void);

/**
 * list_is_empty() - Check if a list is empty.
 * @l: List to check.
 *
 * Returns: True if the list is empty, otherwise false.
 */
bool list_is_empty(const list *l);

/**
 * list_first() - Return the first position of a list, i.e. the
 *                position of the first element in the list.
 * @l: List to inspect.
 *
 * Returns: The first position in the given list.
 */
list_pos list_first(const list *l);

/**
 * list_end() - Return the last position of a list, i.e. the position
 *              after the last element in the list.
 * @l: List to inspect.
 *
 * Returns: The last position in the given list.
 */
list_pos list_end(const list *l);

/**
 * list_next() - Return the next position in a list.
 * @l: List to inspect.
 * @p: Any valid position except the last in the list.
 *
 * Returns: The position in the list after the given position.
 *          NOTE: The return value is undefined for the last position.
 */
list_pos list_next(const list *l, const list_pos p);

/**
 * list_prev() - Return the previous position in a list.
 * @l: List to inspect.
 * @p: Any valid position except the first in the list.
 *
 * Returns: The position in the list before the given position.
 *          NOTE: The return value is undefined for the first position.
 */
list_pos list_prev(const list *l, const list_pos p);

/**
 * list_inspect() - Return the value of the element at a given
 *                  position in a list.
 * @l: List to inspect.
 * @p: Any valid position in the list, except the last.
 *
 * Returns: The integer value stored in the element at postiion pos.
 *          NOTE: The return value is undefined for the last position.
 */
int list_inspect(const list *l, const list_pos p);

/**
 * list_insert() - Insert a new element with a given value into a list.
 * @l: List to manipulate.
 * @data: Integer value to be inserted into the list.
 * @p: Position in the list before which the value should be inserted.
 *
 * Creates a new element and inserts it into the list before p.
 * Stores data in the new element.
 *
 * Returns: The position of the newly created element.
 */
list_pos list_insert(list *l, int data, const list_pos p);

/**
 * list_remove() - Remove an element from a list.
 * @l: List to manipulate.
 * @p: Position in the list of the element to remove.
 *
 * Removes the element at position p from the list.
 *
 * Returns: The position after the removed element.
 */
list_pos list_remove(list *l, const list_pos p);

/**
 * list_kill() - Destroy a given list.
 * @l: List to destroy.
 *
 * Returns all dynamic memory used by the list.
 *
 * Returns: Nothing.
 */
void list_kill(list *l);

/**
 * list_print() - Iterate over the list elements and print their values.
 * @l: List to inspect.
 *
 * Iterates over the list and prints each stored integer.
 *
 * Returns: Nothing.
 */
void list_print(const list *l);

/**
 * list_pos_is_valid() - Return true for a valid position in a list
 * @l: List to inspect.
 * @p: Any position.
 *
 * Returns: True if p is a valid position in the list, otherwise false.
 */
bool list_pos_is_valid(const list *l, const list_pos p);

/**
 * list_pos_is_equal() - Return true if two positions in a list are equal.
 * @l: List to inspect.
 * @p1: First position to compare.
 * @p2: Second position to compare.
 *
 * Returns: True if p1 and p2 refer to the same position in l, otherwise False.
 *          NOTE: The result is defined only if p1 and p2 are valid positions in l.
 *          p1 and p2 are assumed to be valid positions in l, no check is performed.
 */
bool list_pos_is_equal(const list *l, const list_pos p1, const list_pos p2);

/**
 * list_print_internal() - Print the lists internal structure in dot format.
 * @l: List to inspect.
 * @desc: String with a description/state of the list, or NULL for no description.
 * @indent_level: Indentation level, 0 for outermost
 *
 * Iterates over the list and outputs dot code that shows the internal
 * structure of the list.  The dot code can be visualized by
 * Graphviz.
 *
 * On linux system, the output can be parsed by the dot program, e.g.
 *
 *   <list_program> | dot -Tsvg > /tmp/dot.svg; firefox /tmp/dot.svg
 *
 * where <list_program> is the name of the executable
 *
 * The output may also be possible to visualize online on
 * https://dreampuf.github.io/GraphvizOnline/ or google "graphviz
 * online".
 *
 * For documention of the dot language, see graphviz.org.
 *
 * Returns: Nothing.
 */
void list_print_internal(const list *l, const char *desc, int indent_level);

#endif