struct dll_node {
  struct dll_node *previous;
  struct dll_node *next;
  char *value;
};

typedef struct dll_node dll_node;

// TODO: I probably don't need a separate "list" type
typedef struct {
  struct dll_node *head;
} dll_list;

/**
 * Allocates a new (empty) doubly linked list
 */
dll_list *dll_list_new();

/**
 * Frees the memory used by a list, including all of its child nodes
 */
void dll_list_free(dll_list *list);

/**
 * Inserts a given node at the given index of the given list. If index is -1
*  or is greater than the size of the list, then the node will be inserted at the end of the list
 */
void dll_list_insert(dll_list *list, dll_node *node, int index);

/**
 * Appends a node to the end of a given list
 */
void dll_list_append(dll_list *list, dll_node *node) {
  dll_list_insert(list, node, -1);
}

/**
 * Searches the given list for a node with a given value
 * @returns a pointer to the node with the value or NULL if no nodes match the value
 */
dll_node *dll_list_find(dll_list *list, char *value);

/**
 * Removes the first node with the matching value in the given list
 * @returns a pointer to the node with the value or NULL if no nodes match the value
 */
dll_node *dll_list_delete(dll_list *list, char *value);

dll_node *dll_node_new(char *value);

/**
 * Frees the memory for a given node, returning a pointer to the next node, if any
 */
dll_node *dll_node_free(dll_node *node);