#include "doublyLinkedList.h"
#include <iostream>

DoublyLinkedList::DoublyLinkedList() {
  this->head = NULL;
  this->tail = NULL;
}

void DoublyLinkedList::insertAtStart(int key) {
  ExtendedListItem *temp = new ExtendedListItem(key);

  if (this->head == NULL) {
    this->head = temp;
    this->tail = temp;
  } else {
    temp->next = this->head;
    head->previous = temp;
    this->head = temp;
  }
}

void DoublyLinkedList::insertAtEnd(int key) {
  ExtendedListItem *temp = new ExtendedListItem(key);

  if (this->head == NULL) {
    this->head = temp;
    this->tail = temp;
  } else {
    this->tail->next = temp;
    temp->previous = this->tail;
    this->tail = temp;
    this->tail->next = NULL;
  }
}

void DoublyLinkedList::print() {
  ExtendedListItem *temp = this->head;

  if (temp == NULL) {
    std::cout << "<Empty List>" << std::endl;
    return;
  }

  while (temp != NULL) {
    std::cout << temp->toString();
    if (temp->next != NULL) {
      std::cout << " -> ";
    }
    temp = temp->next;
  }
  std::cout << std::endl;
}

void DoublyLinkedList::append(DoublyLinkedList *appendingList) {
  if (appendingList->head != NULL && appendingList->tail != NULL) {
    this->tail->next = appendingList->head;
    appendingList->head->previous = this->tail;
    this->tail = appendingList->tail;
    appendingList->head = NULL;
    appendingList->tail = NULL;
  }
}

void DoublyLinkedList::splice(DoublyLinkedList *insertingList, int position) {
  if (insertingList->head != NULL & insertingList->tail != NULL) {
    ExtendedListItem *prev = NULL;
    ExtendedListItem *current = NULL;
    current = this->head;
    // find the correct position to start spliceing
    for (int i = 0; i < position; i++) {
      prev = current;
      current = current->next;
    }
    // set the pointers correctly
    prev->next = insertingList->head;
    insertingList->head->previous = prev;
    insertingList->tail->next = current;
    current->previous = insertingList->tail;

    // clear the inserting list
    insertingList->head = NULL;
    insertingList->tail = NULL;
  }
}

void DoublyLinkedList::deleteItem(int key) {
  ExtendedListItem *prev = NULL;
  ExtendedListItem *current = NULL;
  // delete head?
  if (key == this->head->key) {
    ExtendedListItem *temp = this->head;
    this->head = this->head->next;
    this->head->previous = NULL;
    delete temp;
    return;
  }
  // set prev and current for the first time
  // (thx to Mr. Klingenschmid for bug spotting!)
  prev = this->head;
  current = prev->next;

  // searching the right key to delete
  bool deleted = false;
  while (deleted == false) {
    if (current->key == key) {
      deleted = true;
    } else {
      prev = current;
      current = current->next;
    }
    if (current == NULL) {
      return;
    }
  }
  // was element to be deleted the tail?
  if (current != this->tail) {
    prev->next = current->next;
    current->next->previous = prev;
  } else {
    this->tail = prev;
    prev->next = NULL;
  }

  delete current;
  return;
}