package unit2.slist;



public class SList implements IList {

	public SNode first; 
	public SNode last;  
	int size; 
	
	
	
	//checks if the list is empty
	public boolean isEmpty() {
		//return (last==null); is also right
		return (first == null);
	}

	public int getSize() {
		return size;
	}

	//adds an element at the beginning of the list
	public void addFirst(String newElem) {
		//creates the new node
		SNode newNode = new SNode(newElem);
		//we have link it to the list
		//newNode will be the new first node, 
		//so it should be before the current first node
		newNode.next = first;
		//If list is empty, last is also the newnode
		if (isEmpty()) last=newNode;
		//finally, we update first to the new node
		first = newNode;
		size++;
	}

	//removes the first node of the list
	public void removeFirst() {
		if (!isEmpty()) {
			first = first.next;
			if (first==null) {
				//this means, the list only had a node
				//so, we must set last to null
				last=null;
			}
			size--;
		} else {
			//if the list is already empty, we do nothing
		}
	}
	
	//adds a new element at the end of the list
	public void addLast(String newElem) {
		//if the list is empty, we can use the addFirst method
		if (isEmpty()) addFirst(newElem);
		else {
			//creates the node
			SNode node = new SNode(newElem);
			//we have to link to the list.
			//the next node of the current last should be the new node
			last.next=node;
			//finally, we set last to the new last node
			last=node;
			//increases size
			size++;
		}	
		
	}
	
	//remove the last element
	public void removeLast() {
		if (!isEmpty()) {
			//if the list only has an element,
			//you can use the method removeFirst
			if (size==1) removeFirst();
			else {
				//if the list has several nodes,
				//we must find the penultimate node of the list
				SNode penult=first;
				while (penult.next!=last) {
					penult=penult.next;
				}
				//here, penult is the penultimate
				penult.next=null;
				//sets last to penult, the new last
				last=penult;
				//decrease size
				size--;
			}
		} else {
			//if the list is empty, we do nothing
		}
	}

	//checks if elem exists in the list
	public boolean contains(String elem) {
		boolean found=false;
		for (SNode nodeIt=first;nodeIt!=null&&!found;nodeIt=nodeIt.next) {
			if (nodeIt.elem.equals(elem)) found=true;
		}
		return found;
	}
	
//	//version using a for int i
//	public boolean contains(String elem) {
//		boolean found=false;
//		SNode nodeIt=first;
//		for (int i=0; i<size && !found; i++) {
//			if (nodeIt.elem.equals(elem)) found=true;
//			nodeIt=nodeIt.next;
//		}
//		return found;
//	}
	
	public String getAt(int index) {
		String result=null;
		if (index<0 || index>=size) {
			System.out.println("Index out of range");
		} else {
			int i=0; 
			for (SNode nodeIt=first; nodeIt!=null && result==null; nodeIt=nodeIt.next) {
				if (i==index) result= nodeIt.elem;
				i++;
			}
		}
		return result;
	}

	//version with for i
//	public String getAt(int index) {
//		String result=null;
//		if (index<0 || index>=size) {
//			System.out.println("Index out of range");
//		} else {
//			SNode nodeIt=first;
//			for (int i=1; i<=index; i++) {
//				nodeIt=nodeIt.next;
//			}
//			result= nodeIt.elem;
//		}
//		return result;
//		
//	}
	
	//return the first 
//	public int getIndexOf(String elem) {
//		int index=0;
//		boolean found=false;
//		for (SNode nodeIt=first; nodeIt!=null && !found; nodeIt=nodeIt.next) {
//			if (nodeIt.elem.equals(elem)) found=true;
//			else index++;
//		}
//		if (!found) {
//			System.out.println(elem + " is not in the list");
//			index=-1;
//		}  
//		return index;
//	}
	
	public int getIndexOf(String elem) {
		int index=-1;
		SNode nodeIt=first; 
		for (int i=0;i<size&&index<0;i++) {
			if (nodeIt.elem.equals(elem)) index=i;
			nodeIt=nodeIt.next;
		}
		return index;
	}
	
	public void insertAt(int index, String newElem) {
		
		if (index<0 ||index>size) 
			System.out.println("index out of range");
		else if (index==0) addFirst(newElem);
		else if (index==size) addLast(newElem);
		else {
			//we have to reach the previous node
			SNode previous=first;
			for (int i=1; i<index; i++) {
				previous=previous.next;
			}
			SNode newNode=new SNode(newElem);
			newNode.next=previous.next;
			previous.next=newNode;
			size++;
		}


	}

	



	

	

	public void removeAll(String elem) {
		int index=getIndexOf(elem);
		while (index>=0) {
			removeAt(index);
			index=getIndexOf(elem);
		}
	}

//	public void removeAll(String elem) {
//		
//		for (SNode nodeIt=first, prev=null;nodeIt!=null; 
//				prev=nodeIt, nodeIt=nodeIt.next) {
//			if (nodeIt.elem.equals(elem)) {
//				if (nodeIt==first) removeFirst();
//				else if (nodeIt==last) removeLast();
//				else {
//					prev.next=nodeIt.next;
//					size--;
//				} 
//			}
//		}
//	}

	@Override
	public void removeAt(int index) {
		if (index<0||index>=size) 
			System.out.println("Index out of range");
		else if (index==0) removeFirst();
		else if (index==size-1) removeLast();
		else {
			//we have to reach the previous node
			SNode previous=first;
			for (int i=1; i<index; i++) {
				previous=previous.next;
			}
			previous.next=previous.next.next;
			size--;
		}
		
	}

	
	

	@Override
	public String getFirst() {
		if (isEmpty()) return null;
		return first.elem;
	}

	@Override
	public String getLast() {
		if (isEmpty()) return null;

		return last.elem;

	}

	

	public String toString() {
		String result = null;
		for (SNode nodeIt = first; nodeIt != null; nodeIt = nodeIt.next) {
			if (result == null) {
				result = nodeIt.elem.toString();
			} else {
				result += "," + nodeIt.elem.toString();
			}
		}
		return result == null ? "empty" : result;
	}

	

	public static void main(String[] args) {
		// incomplete test
		SList list = new SList();
		list.addLast("Ana");
//		System.out.println("list.addLast(Ana):"+list.toString());
//		
//		list.addLast("Bea");
//		System.out.println("list.addLast(Bea):"+list.toString());
//		
//		list.addFirst("Paco");
//		System.out.println("list.addFirst(Paco)"+list.toString());
//		list.removeFirst();
//		System.out.println("list.removeFirst()"+list.toString());
//		
//		list.addFirst("Juan");
//		System.out.println("list.addFirst(Juan)"+list.toString());
//
//		System.out.println(list.contains("Beaa"));
//		for (int i=0; i<list.getSize(); i++) {
//			System.out.println(list.getAt(i));
//		}
//		list.getAt(-1);
//		list.getAt(list.getSize());
//		System.out.println(list.getIndexOf("Bea"));
//		System.out.println(list.getIndexOf("Juan"));
//		System.out.println(list.getIndexOf("Ana"));
//		System.out.println(list.getIndexOf("Beadd"));

		for (int i=0; i<=10; i++) {
			list.insertAt(i, String.valueOf(i));
			System.out.println(list.toString());
		}
		list.insertAt(list.getSize(), "fin");
		System.out.println(list.toString());
		while(list.getSize()>2) {
			list.removeAt(2);
			System.out.println(list.toString());

		}
		list.insertAt(2, "1");
		list.addLast("0");
		list.addLast("c");
		list.addLast("1");
		System.out.println(list.toString());
		list.removeAll("0");
		System.out.println(list.toString());
		list.removeAll("1");
		System.out.println(list.toString());



	}
}