package speiger.src.collections.shorts.lists;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.RandomAccess;

import speiger.src.collections.shorts.collections.AbstractShortCollection;
import speiger.src.collections.shorts.collections.ShortCollection;
import speiger.src.collections.shorts.collections.ShortIterator;
import speiger.src.collections.shorts.collections.ShortSplititerator;
import speiger.src.collections.ints.lists.IntList;
import speiger.src.collections.shorts.utils.ShortSplititerators;
import speiger.src.collections.utils.SanityChecks;

/**
 * Abstract implementation of the {@link ShortList} interface.
 */
public abstract class AbstractShortList extends AbstractShortCollection implements ShortList 
{
	/**
	 * A Type-Specific implementation of add function that delegates to {@link List#add(int, Object)}
	 */
	@Override
	public boolean add(short e) {
		add(size(), e);
		return true;
	}
	
	/** {@inheritDoc}
	 * <p>This default implementation delegates to the corresponding type-specific function.
	 * @deprecated Please use the corresponding type-specific function instead. 
	 */
	@Override
	@Deprecated
	public void add(int index, Short element) {
		add(index, element.shortValue());
	}
	
	/**
	 * A Type-Specific implementation that iterates over the elements and adds them.
	 * @param c the elements that wants to be added
	 * @return true if the list was modified
	 */
	@Override
	public boolean addAll(ShortCollection c) {
		return addAll(size(), c);
	}
	
	/**
	 * A Type-Specific implementation that iterates over the elements and adds them.
	 * @param c the elements that wants to be added
	 * @return true if the list was modified
	 */
	@Override
	public boolean addAll(ShortList c) {
		return addAll(size(), c);
	}
	
	/** {@inheritDoc}
	 * <p>This default implementation delegates to the corresponding type-specific function.
	 * @deprecated Please use the corresponding type-specific function instead. 
	 */
	@Override
	@Deprecated
	public boolean addAll(Collection<? extends Short> c) {
		return c instanceof ShortCollection ? addAll((ShortCollection)c) : addAll(size(), c);
	}
	
	/**
	 * The IndexOf implementation iterates over all elements and compares them to the search value.
	 * @param o the value that the index is searched for.
	 * @return index of the value that was searched for. -1 if not found
	 * @note it is highly suggested not to use this with Primitives because of boxing. But it is still supported because of ObjectComparason that are custom objects and allow to find the contents.
	 */
	@Override
	@Deprecated
	public int indexOf(Object o) {
		ShortListIterator iter = listIterator();
		if(o == null) return -1;
		while(iter.hasNext()) {
			if(Objects.equals(o, Short.valueOf(iter.nextShort())))
				return iter.previousIndex();
		}
		return -1;
	}
	
	/**
	 * The lastIndexOf implementation iterates over all elements and compares them to the search value.
	 * @param o the value that the index is searched for.
	 * @return the last index of the value that was searched for. -1 if not found
	 * @note it is highly suggested not to use this with Primitives because of boxing. But it is still supported because of ObjectComparason that are custom objects and allow to find the contents.
	 */
	@Override
	@Deprecated
	public int lastIndexOf(Object o) {
		ShortListIterator iter = listIterator(size());
		if(o == null) return -1;
		while(iter.hasPrevious()) {
			if(Objects.equals(o, Short.valueOf(iter.previousShort())))
				return iter.nextIndex();
		}
		return -1;
	}
	
	/**
	 * The indexOf implementation iterates over all elements and compares them to the search value.
	 * @param e the value that the index is searched for.
	 * @return index of the value that was searched for. -1 if not found
	 */
	@Override
	public int indexOf(short e) {
		ShortListIterator iter = listIterator();
		while(iter.hasNext()) {
			if(iter.nextShort() == e)
				return iter.previousIndex();
		}
		return -1;
	}
	
	/**
	 * The lastIndexOf implementation iterates over all elements and compares them to the search value.
	 * @param e the value that the index is searched for.
	 * @return the last index of the value that was searched for. -1 if not found
	 */
	@Override
	public int lastIndexOf(short e) {
		ShortListIterator iter = listIterator(size());
		while(iter.hasPrevious()) {
			if(iter.previousShort() == e)
				return iter.nextIndex();
		}
		return -1;
	}
	
	@Override
	public boolean swapRemoveShort(short e) {
		int index = indexOf(e);
		if(index == -1) return false;
		swapRemove(index);
		return true;
	}
	
	/**
	 * Compares if the list are the same.
	 */
	@Override
	public boolean equals(Object o) {
		if (o == this)
			return true;
		if (!(o instanceof List))
			return false;
		List<?> l = (List<?>)o;
		if(l.size() != size()) return false;
		if(l instanceof ShortList)
		{
			ShortListIterator e1 = listIterator();
			ShortListIterator e2 = ((ShortList)l).listIterator();
			while (e1.hasNext() && e2.hasNext()) {
				if(!(e1.nextShort() == e2.nextShort()))
					return false;
			}
			return !(e1.hasNext() || e2.hasNext());
		}
		ListIterator<Short> e1 = listIterator();
		ListIterator<?> e2 = l.listIterator();
		while (e1.hasNext() && e2.hasNext()) {
			if(!Objects.equals(e1.next(), e2.next()))
				return false;
		}
		return !(e1.hasNext() || e2.hasNext());
	}
	
	/**
	 * Generates the hashcode based on the values stored in the list.
	 */
	@Override
	public int hashCode() {
		int hashCode = 1;
		ShortListIterator i = listIterator();
		while(i.hasNext())
			hashCode = 31 * hashCode + Short.hashCode(i.nextShort());
		return hashCode;
	}
	
	@Override
	public ShortList subList(int fromIndex, int toIndex) {
		SanityChecks.checkArrayCapacity(size(), fromIndex, toIndex-fromIndex);
		return new SubList(this, 0, fromIndex, toIndex);
	}
	
	@Override
	public ShortList reversed() {
		return new ReversedList(this);
	}
	
	@Override
	public ShortIterator iterator() {
		return listIterator(0);
	}
	
	@Override
	public ShortListIterator listIterator() {
		return listIterator(0);
	}
		
	@Override
	public ShortListIterator listIterator(int index) {
		if(index < 0 || index > size()) throw new IndexOutOfBoundsException();
		return new ShortListIter(index);
	}
	
	@Override
	public ShortListIterator indexedIterator(int...indecies) {
		return new IndexedIterator(indecies);
	}
	
	@Override
	public ShortListIterator indexedIterator(IntList indecies) {
		return new ListIndexedIterator(indecies);
	}
	
	@Override
	public void size(int size) {
		while(size > size()) add((short)0);
		while(size < size()) removeShort(size() - 1);
	}
	
	public AbstractShortList copy() { throw new UnsupportedOperationException(); }
	
	private class ReversedList extends AbstractShortList
	{
		final AbstractShortList list;
		
		public ReversedList(AbstractShortList list) {
			this.list = list;
		}

		@Override
		public void add(int index, short e) {
			list.add(list.size() - index - 1, e);
		}
		
		@Override
		public boolean addAll(int index, ShortCollection c) {
			return addCollection(index, c);
		}
		
		@Override
		public boolean addAll(int index, ShortList c) {
			if(c instanceof RandomAccess) {
				for(int i = 0,m=c.size();i<m;i++) {
					list.add(list.size() - index - i - 1, c.getShort(i));
				}
				return true;
			}
			return addCollection(index, c);
		}
		
		private boolean addCollection(int index, ShortCollection c) {
			int i = 0;
			for(ShortIterator iter = c.iterator();iter.hasNext();i++) {
				list.add(list.size() - index - i - 1, iter.nextShort());
			}
			return true;
		}
		
		@Override
		public boolean addAll(int index, Collection<? extends Short> c) {
			int i = 0;
			for(Iterator<? extends Short> iter = c.iterator();iter.hasNext();i++) {
				list.add(list.size() - index - i - 1, iter.next());
			}
			return true;
		}
		
		@Override
		public short getShort(int index) {
			return list.getShort(list.size() - index - 1);
		}

		@Override
		public short set(int index, short e) {
			return list.set(list.size() - index - 1, e);
		}

		@Override
		public short removeShort(int index) {
			return list.removeShort(list.size() - index - 1);
		}
		
		@Override
		public void addElements(int from, short[] a, int offset, int length) {
			for(int i = 0,m=length;i<m;i++) {
				list.add(list.size() - from - i - 1, a[i+offset]);
			}
		}
		
		@Override
		public short[] getElements(int from, short[] a, int offset, int length) {
			return reverse(list.getElements(list.size() - from - 1, a, offset, length));
		}

		@Override
		public void removeElements(int from, int to) {
			list.removeElements(list.size() - to - 1, list.size() - from - 1);
		}

		@Override
		public short swapRemove(int index) {
			return list.swapRemove(list.size() - index - 1);
		}
		@Override
		public short[] extractElements(int from, int to) {
			return reverse(list.extractElements(list.size() - to - 1, list.size() - from - 1));
		}
		
		@Override
		public int size() {
			return list.size();
		}
		
		@Override
		public void clear() {
			list.clear();
		}
		
		@Override
		public ShortList reversed() {
			return list;
		}
		
		private short[] reverse(short[] data) {
			for (int i = 0, mid = data.length >> 1, j = data.length - 1; i < mid; i++, j--) {
				short t = data[i];
				data[i] = data[j];
				data[j] = t;
			}
			return data;
		}
	
	}
	
	private class SubList extends AbstractShortList
	{
		final AbstractShortList list;
		final int parentOffset;
		final int offset;
		int size;
		
		public SubList(AbstractShortList list, int offset, int from, int to) {
			this.list = list;
			this.parentOffset = from;
			this.offset = offset + from;
			this.size = to - from;
		}
		
		@Override
		public void add(int index, short element) {
			checkAddSubRange(index);
			list.add(parentOffset+index, element);
			size++;
		}
		
		@Override
		public boolean addAll(int index, Collection<? extends Short> c) {
			checkAddSubRange(index);
			int add = c.size();
			if(add <= 0) return false;
			list.addAll(parentOffset+index, c);
			this.size += add;
			return true;
		}
		
		@Override
		public boolean addAll(int index, ShortCollection c) {
			checkAddSubRange(index);
			int add = c.size();
			if(add <= 0) return false;
			list.addAll(parentOffset+index, c);
			this.size += add;
			return true;
		}

		@Override
		public boolean addAll(int index, ShortList c) {
			checkAddSubRange(index);
			int add = c.size();
			if(add <= 0) return false;
			list.addAll(parentOffset+index, c);
			this.size += add;
			return true;
		}
		
		@Override
		public void addElements(int from, short[] a, int offset, int length) {
			checkAddSubRange(from);
			if(length <= 0) return;
			list.addElements(parentOffset+from, a, offset, length);
			this.size += length;
		}
		
		@Override
		public short[] getElements(int from, short[] a, int offset, int length) {
			SanityChecks.checkArrayCapacity(size, from, length);
			SanityChecks.checkArrayCapacity(a.length, offset, length);
			return list.getElements(from+parentOffset, a, offset, length);
		}
		
		@Override
		public void removeElements(int from, int to) {
			if(to-from <= 0) return;
			checkSubRange(from);
			checkAddSubRange(to);
			list.removeElements(from+parentOffset, to+parentOffset);
			size -= to - from;
		}
		
		@Override
		public short[] extractElements(int from, int to) {
			checkSubRange(from);
			checkAddSubRange(to);
			short[] result = list.extractElements(from+parentOffset, to+parentOffset);
			size -= result.length;
			return result;
		}
		
		@Override
		public short getShort(int index) {
			checkSubRange(index);
			return list.getShort(parentOffset+index);
		}

		@Override
		public short set(int index, short element) {
			checkSubRange(index);
			return list.set(parentOffset+index, element);
		}
		
		@Override
		public short swapRemove(int index) {
			checkSubRange(index);
			if(index == size-1) {
				short result = list.removeShort(parentOffset+size-1);
				size--;
				return result;
			}
			short result = list.set(index+parentOffset, list.getShort(parentOffset+size-1));
			list.removeShort(parentOffset+size-1);
			size--;
			return result;
		}
		
		@Override
		public short removeShort(int index) {
			checkSubRange(index);
			short result = list.removeShort(index+parentOffset);
			size--;
			return result;
		}
		
		@Override
		public int size() {
			return size;
		}
		@Override
		public ShortSplititerator spliterator() { return ShortSplititerators.createSplititerator(this, 16464); }
		
		@Override
		public ShortListIterator listIterator(int index) {
			if(index < 0 || index > size()) throw new IndexOutOfBoundsException();
			return new SubListIterator(this, index);
		}
		
		@Override
		public ShortList subList(int fromIndex, int toIndex) {
			SanityChecks.checkArrayCapacity(size, fromIndex, toIndex-fromIndex);
			return new SubList(this, offset, fromIndex, toIndex);
		}
		
		protected void checkSubRange(int index) {
			if (index < 0 || index >= size)
				throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
		}
		
		protected void checkAddSubRange(int index) {
			if (index < 0 || index > size)
				throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
		}
		
		private class SubListIterator implements ShortListIterator
		{
			AbstractShortList list;
			int index;
			int lastReturned = -1;
			
			SubListIterator(AbstractShortList list, int index) {
				this.list = list;
				this.index = index;
			}
			
			@Override
			public boolean hasNext() {
				return index < list.size();
			}
			
			@Override
			public short nextShort() {
				if(!hasNext()) throw new NoSuchElementException();
				int i = index++;
				return list.getShort((lastReturned = i));
			}
			
			@Override
			public boolean hasPrevious() {
				return index > 0;
			}
			
			@Override
			public short previousShort() {
				if(!hasPrevious()) throw new NoSuchElementException();
				index--;
				return list.getShort((lastReturned = index));
			}
			
			@Override
			public int nextIndex() {
				return index;
			}
			
			@Override
			public int previousIndex() {
				return index-1;
			}
			
			@Override
			public void remove() {
				if(lastReturned == -1) throw new IllegalStateException();
				list.removeShort(lastReturned);
				index = lastReturned;
				lastReturned = -1;
			}
			
			@Override
			public void set(short e) {
				if(lastReturned == -1) throw new IllegalStateException();
				list.set(lastReturned, e);
			}
			
			@Override
			public void add(short e) {
				list.add(index, e);
				index++;
				lastReturned = -1;
			}
			
			@Override
			public int skip(int amount) {
				if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
				int steps = Math.min(amount, size() - index);
				index += steps;
				if(steps > 0) lastReturned = Math.min(index-1, size()-1);
				return steps;
			}
			
			@Override
			public int back(int amount) {
				if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
				int steps = Math.min(amount, index);
				index -= steps;
				if(steps > 0) lastReturned = Math.min(index, size()-1);
				return steps;
			}
		}
	}
	
	private class ListIndexedIterator implements ShortListIterator {
		IntList indecies;
		int index;
		int lastReturned = -1;
		
		ListIndexedIterator(IntList indecies) {
			this.indecies = indecies;
		}
		
		@Override
		public boolean hasNext() {
			return index < indecies.size();
		}
		
		@Override
		public short nextShort() {
			if(!hasNext()) throw new NoSuchElementException();
			int i = index++;
			return getShort((lastReturned = indecies.getInt(i)));
		}
		
		@Override
		public boolean hasPrevious() {
			return index > 0;
		}
		
		@Override
		public short previousShort() {
			if(!hasPrevious()) throw new NoSuchElementException();
			index--;
			return getShort((lastReturned = indecies.getInt(index)));
		}
		
		@Override
		public int nextIndex() {
			return index;
		}
		
		@Override
		public int previousIndex() {
			return index-1;
		}
		
		@Override
		public void remove() { throw new UnsupportedOperationException(); }
		@Override
		public void add(short e) { throw new UnsupportedOperationException(); }
		
		@Override
		public void set(short e) {
			if(lastReturned == -1) throw new IllegalStateException();
			AbstractShortList.this.set(lastReturned, e);
		}
		
		@Override
		public int skip(int amount) {
			if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
			int steps = Math.min(amount, indecies.size() - index);
			index += steps;
			if(steps > 0) lastReturned = Math.min(index-1, indecies.size()-1);
			return steps;
		}
		
		@Override
		public int back(int amount) {
			if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
			int steps = Math.min(amount, index);
			index -= steps;
			if(steps > 0) lastReturned = Math.max(index, 0);
			return steps;
		}
	}
	
	private class IndexedIterator implements ShortListIterator {
		int[] indecies;
		int index;
		int lastReturned = -1;
		
		IndexedIterator(int[] indecies) {
			this.indecies = indecies;
		}
		
		@Override
		public boolean hasNext() {
			return index < indecies.length;
		}
		
		@Override
		public short nextShort() {
			if(!hasNext()) throw new NoSuchElementException();
			int i = index++;
			return getShort((lastReturned = indecies[i]));
		}
		
		@Override
		public boolean hasPrevious() {
			return index > 0;
		}
		
		@Override
		public short previousShort() {
			if(!hasPrevious()) throw new NoSuchElementException();
			index--;
			return getShort((lastReturned = indecies[index]));
		}
		
		@Override
		public int nextIndex() {
			return index;
		}
		
		@Override
		public int previousIndex() {
			return index-1;
		}
		
		@Override
		public void remove() { throw new UnsupportedOperationException(); }
		@Override
		public void add(short e) { throw new UnsupportedOperationException(); }
		
		@Override
		public void set(short e) {
			if(lastReturned == -1) throw new IllegalStateException();
			AbstractShortList.this.set(lastReturned, e);
		}
		
		@Override
		public int skip(int amount) {
			if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
			int steps = Math.min(amount, indecies.length - index);
			index += steps;
			if(steps > 0) lastReturned = Math.min(index-1, indecies.length-1);
			return steps;
		}
		
		@Override
		public int back(int amount) {
			if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
			int steps = Math.min(amount, index);
			index -= steps;
			if(steps > 0) lastReturned = Math.max(index, 0);
			return steps;
		}
	}
	
	private class ShortListIter implements ShortListIterator {
		int index;
		int lastReturned = -1;
		
		ShortListIter(int index) {
			this.index = index;
		}
		
		@Override
		public boolean hasNext() {
			return index < size();
		}
		
		@Override
		public short nextShort() {
			if(!hasNext()) throw new NoSuchElementException();
			int i = index++;
			return getShort((lastReturned = i));
		}
		
		@Override
		public boolean hasPrevious() {
			return index > 0;
		}
		
		@Override
		public short previousShort() {
			if(!hasPrevious()) throw new NoSuchElementException();
			index--;
			return getShort((lastReturned = index));
		}
		
		@Override
		public int nextIndex() {
			return index;
		}
		
		@Override
		public int previousIndex() {
			return index-1;
		}
		
		@Override
		public void remove() {
			if(lastReturned == -1) throw new IllegalStateException();
			AbstractShortList.this.removeShort(lastReturned);
			index = lastReturned;
			lastReturned = -1;
		}
		
		@Override
		public void set(short e) {
			if(lastReturned == -1) throw new IllegalStateException();
			AbstractShortList.this.set(lastReturned, e);
		}
		
		@Override
		public void add(short e) {
			AbstractShortList.this.add(index, e);
			index++;
			lastReturned = -1;
		}
		
		@Override
		public int skip(int amount) {
			if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
			int steps = Math.min(amount, size() - index);
			index += steps;
			if(steps > 0) lastReturned = Math.min(index-1, size()-1);
			return steps;
		}
		
		@Override
		public int back(int amount) {
			if(amount < 0) throw new IllegalStateException("Negative Numbers are not allowed");
			int steps = Math.min(amount, index);
			index -= steps;
			if(steps > 0) lastReturned = Math.max(index, 0);
			return steps;
		}
	}
}