#include <cassert>
#include <cstdlib>

#include "linkedlist_bigthree.h"
#include "node.h"

// Constructs an empty linked list
LinkedList::LinkedList() {
  head = NULL;
}

// Destructs (frees memory) the linked list
LinkedList::~LinkedList() {
  clear();
}

// Constructs a new linked list given an existing list
LinkedList::LinkedList(const LinkedList &rhs) {
  head = NULL;
  if(rhs.head != NULL) {
    head = new Node(rhs.head->value(), NULL);
    Node* rhs_curr = rhs.head->next();
    Node* this_curr = head;
    while(rhs_curr != NULL) {
      this_curr->setNext(new Node(rhs_curr->value(), NULL));
      this_curr = this_curr->next();
      rhs_curr = rhs_curr->next();
    }
  }
}

// Does a deep copy of one list to another
LinkedList & LinkedList::operator=(const LinkedList& rhs) {
  if(this != &rhs) {
    clear();
    if(rhs.head != NULL) {
      head = new Node(rhs.head->value(), NULL);
      Node* rhs_curr = rhs.head->next();
      Node* this_curr = head;
      while(rhs_curr != NULL) {
	this_curr->setNext(new Node(rhs_curr->value(), NULL));
	this_curr = this_curr->next();
	rhs_curr = rhs_curr->next();
      }
    }
  }
  return *this;
}

// Adds a node to the head of the list
void LinkedList::addFirst(int value) {
  head = new Node(value, head);
}

// Removes node from head of list
int LinkedList::removeFirst() {
  assert(head != NULL);
  
  int return_val = head->value();
  Node* old_head = head;

  head = head->next();  // advance the head pointer
  delete old_head;      // free the memory for the old head
  
  return return_val;
}


// Return integer value of head node
int LinkedList::getFirst() const {
  return head->value();
}

// Checks if list contains value
bool LinkedList::contains(int value) const {
  Node* finger = head;
  
  while( finger != NULL && finger->value() != value ){
    finger = finger->next();
  }
  
  return finger != NULL;
}

// Clears the linked list
void LinkedList::clear() {
  if(!isEmpty()) {
    Node* prev = NULL;
    Node* curr = head;
    while(curr->next() != NULL) {
      prev = curr;
      curr = curr->next();
      delete prev;
    }
    delete curr;
    head = NULL;
  }
}

// Sets the node at position index to value
void LinkedList::set(int index, int value) {
  Node* finger = head;
  
  for( int i = 0; i < index && head != NULL; i++ ){
    finger = finger->next();
  }
  
  if( finger != NULL ){
    finger->setValue(value);
  }
}

// Checks if list is empty
bool LinkedList::isEmpty() {
  return head == NULL;
}