package org.warp.commonutils.type;

import it.unimi.dsi.fastutil.objects.Object2FloatMap;
import it.unimi.dsi.fastutil.objects.Object2FloatOpenHashMap;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Iterator;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.function.Consumer;
import java.util.function.IntFunction;
import java.util.stream.Stream;
import org.jetbrains.annotations.NotNull;

public class FloatPriorityQueue<T> implements Queue<T> {

	private final Object2FloatMap<T> contentValues;
	private final Queue<ScoredValue<T>> internalQueue;

	public static <T> FloatPriorityQueue<T> of() {
		return new FloatPriorityQueue<>(0);
	}

	public static <T> FloatPriorityQueue<T> of(T value, float score) {
		var pq = new FloatPriorityQueue<T>(1);
		pq.offer(value);
		return pq;
	}

	public static <T> FloatPriorityQueue<T> of(ScoredValue<T> value) {
		var pq = new FloatPriorityQueue<T>(1);
		pq.offer(value);
		return pq;
	}

	@SafeVarargs
	public static <T> FloatPriorityQueue<T> of(ScoredValue<T>... values) {
		var pq = new FloatPriorityQueue<T>(values.length);
		for (ScoredValue<T> value : values) {
			pq.offer(value);
		}
		return pq;
	}

	public FloatPriorityQueue(PriorityQueue<ScoredValue<T>> internalQueue) {
		this(internalQueue.size());
		for (ScoredValue<T> tScoredValue : internalQueue) {
			add(tScoredValue.getValue(), tScoredValue.getScore());
		}
	}

	private FloatPriorityQueue(Object2FloatMap<T> contentValues, Queue<ScoredValue<T>> internalQueue) {
		this.contentValues = contentValues;
		this.internalQueue = internalQueue;
	}

	public FloatPriorityQueue() {
		this.contentValues = new Object2FloatOpenHashMap<>();
		internalQueue = new PriorityQueue<>();
	}

	public FloatPriorityQueue(int initialCapacity) {
		this.contentValues = new Object2FloatOpenHashMap<>(initialCapacity);
		internalQueue = new PriorityQueue<>(Math.max(1, initialCapacity));
	}

	public static <T> FloatPriorityQueue<T> synchronize(FloatPriorityQueue<T> queue) {
		return new SynchronizedFloatPriorityQueue<>(queue.contentValues, queue.internalQueue);
	}

	public static <T> FloatPriorityQueue<T> synchronizedPq(int initialCapacity) {
		var pq = new FloatPriorityQueue<T>(initialCapacity);
		return new SynchronizedFloatPriorityQueue<>(pq.contentValues, pq.internalQueue);
	}

	@Override
	public int size() {
		assert contentValues.size() == internalQueue.size();
		return internalQueue.size();
	}

	@Override
	public boolean isEmpty() {
		assert contentValues.size() == internalQueue.size();
		return internalQueue.isEmpty();
	}

	@Override
	public boolean contains(Object o) {
		assert contentValues.size() == internalQueue.size();
		return internalQueue.contains(ScoredValue.of(0, o));
	}

	@NotNull
	@Override
	public Iterator<T> iterator() {
		assert contentValues.size() == internalQueue.size();
		var it = internalQueue.iterator();
		return new Iterator<>() {
			@Override
			public boolean hasNext() {
				assert contentValues.size() == internalQueue.size();
				return it.hasNext();
			}

			@Override
			public T next() {
				assert contentValues.size() == internalQueue.size();
				return getValueOrNull(it.next());
			}
		};
	}

	private static <T> T getValueOrNull(ScoredValue<T> scoredValue) {
		if (scoredValue == null) {
			return null;
		} else {
			return scoredValue.getValue();
		}
	}

	@NotNull
	@Override
	public Object @NotNull [] toArray() {
		assert contentValues.size() == internalQueue.size();
		return internalQueue.stream().map(FloatPriorityQueue::getValueOrNull).toArray(Object[]::new);
	}

	@SuppressWarnings({"SuspiciousToArrayCall", "unchecked"})
	@NotNull
	@Override
	public <T1> T1 @NotNull [] toArray(@NotNull T1 @NotNull [] a) {
		assert contentValues.size() == internalQueue.size();
		return internalQueue
				.stream()
				.map(FloatPriorityQueue::getValueOrNull)
				.toArray(i -> (T1[]) Array.newInstance(a.getClass().getComponentType(), i));
	}

	@Deprecated
	@Override
	public boolean add(T t) {
		assert contentValues.size() == internalQueue.size();
		return offer(t, 0);
	}

	public boolean addTop(T t) {
		assert contentValues.size() == internalQueue.size();
		if (contentValues.getFloat(t) == Integer.MAX_VALUE) {
			return false;
		} else {
			if (contentValues.containsKey(t)) {
				internalQueue.remove(ScoredValue.of(0, t));
			}
			contentValues.put(t, Integer.MAX_VALUE);
			return internalQueue.add(ScoredValue.of(Integer.MAX_VALUE, t));
		}
	}

	public boolean add(T t, float score) {
		assert contentValues.size() == internalQueue.size();
		return offer(t, score);
	}

	@Override
	public boolean remove(Object o) {
		assert contentValues.size() == internalQueue.size();
		contentValues.removeFloat(o);
		return internalQueue.remove(ScoredValue.of(0, o));
	}

	@Override
	public boolean containsAll(@NotNull Collection<?> c) {
		assert contentValues.size() == internalQueue.size();
		for (Object o : c) {
			//noinspection SuspiciousMethodCalls
			if (!contentValues.containsKey(o)) {
				return false;
			}
		}
		return true;
	}

	@Override
	public boolean addAll(@NotNull Collection<? extends T> c) {
		assert contentValues.size() == internalQueue.size();
		boolean added = false;
		for (T t : c) {
			added |= add(t);
		}
		return added;
	}

	@Override
	public boolean removeAll(@NotNull Collection<?> c) {
		assert contentValues.size() == internalQueue.size();
		boolean removed = false;
		for (Object o : c) {
			removed |= remove(o);
		}
		return removed;
	}

	@Override
	public boolean retainAll(@NotNull Collection<?> c) {
		assert contentValues.size() == internalQueue.size();
		return removeIf(item -> !c.contains(item));
	}

	@Override
	public void clear() {
		assert contentValues.size() == internalQueue.size();
		contentValues.clear();
		internalQueue.clear();
	}

	@Override
	public boolean offer(T t) {
		assert contentValues.size() == internalQueue.size();
		return offer(ScoredValue.of(0, t));
	}

	public boolean offer(T t, float score) {
		assert contentValues.size() == internalQueue.size();
		return offer(ScoredValue.of(score, t));
	}

	public boolean offer(ScoredValue<T> value) {
		int contentValuesSize = contentValues.size();
		int internalQueueSize = internalQueue.size();
		assert contentValuesSize == internalQueueSize;

		boolean added = true;
		float oldValue;
		if (contentValues.containsKey(value.getValue())) {
			internalQueue.remove(value);
			oldValue = contentValues.getFloat(value.getValue());
			added = false;
		} else {
			oldValue = 0f;
		}
		contentValues.put(value.getValue(), oldValue + value.getScore());
		internalQueue.add(value);
		return added;
	}

	@Override
	public T remove() {
		assert contentValues.size() == internalQueue.size();
		var val = internalQueue.remove();
		if (val != null) {
			contentValues.removeFloat(val.getValue());
		}
		return getValueOrNull(val);
	}

	@Override
	public T poll() {
		assert contentValues.size() == internalQueue.size();
		var val = internalQueue.poll();

		if (val != null) {
			contentValues.removeFloat(val.getValue());
		}
		return getValueOrNull(val);
	}

	@Override
	public T element() {
		assert contentValues.size() == internalQueue.size();
		return getValueOrNull(internalQueue.element());
	}

	@Override
	public T peek() {
		assert contentValues.size() == internalQueue.size();
		return getValueOrNull(internalQueue.peek());
	}

	public void forEachItem(Consumer<ScoredValue<T>> action) {
		assert contentValues.size() == internalQueue.size();
		internalQueue.forEach(action);
	}

	public Stream<ScoredValue<T>> streamItems() {
		assert contentValues.size() == internalQueue.size();
		return internalQueue.stream();
	}

	public <U extends T> FloatPriorityQueueView<U> view() {
		return new FloatPriorityQueueView<>(this);
	}

	private static class SynchronizedFloatPriorityQueue<T> extends FloatPriorityQueue<T> {

		public SynchronizedFloatPriorityQueue(Object2FloatMap<T> contentValues, Queue<ScoredValue<T>> internalQueue) {
			super(contentValues, internalQueue);
		}

		@Override
		public synchronized int size() {
			return super.size();
		}

		@Override
		public synchronized boolean isEmpty() {
			return super.isEmpty();
		}

		@Override
		public synchronized boolean contains(Object o) {
			return super.contains(o);
		}

		@Override
		public synchronized @NotNull Iterator<T> iterator() {
			var it = super.iterator();
			return new Iterator<>() {
				@Override
				public boolean hasNext() {
					synchronized (SynchronizedFloatPriorityQueue.this) {
						return it.hasNext();
					}
				}

				@Override
				public T next() {
					synchronized (SynchronizedFloatPriorityQueue.this) {
						return it.next();
					}
				}
			};
		}

		@Override
		public synchronized @NotNull Object @NotNull [] toArray() {
			return super.toArray();
		}

		@SuppressWarnings("SuspiciousToArrayCall")
		@Override
		public synchronized <T1> @NotNull T1 @NotNull [] toArray(@NotNull T1 @NotNull [] a) {
			return super.toArray(a);
		}

		@Override
		public synchronized <T1> T1[] toArray(IntFunction<T1[]> generator) {
			//noinspection SuspiciousToArrayCall
			return super.toArray(generator);
		}

		@Override
		public synchronized boolean add(T t, float score) {
			return super.add(t, score);
		}

		@Override
		public synchronized boolean addTop(T t) {
			return super.addTop(t);
		}

		@Deprecated
		@Override
		public synchronized boolean add(T t) {
			return super.add(t);
		}

		@Override
		public synchronized boolean addAll(@NotNull Collection<? extends T> c) {
			return super.addAll(c);
		}

		@Override
		public synchronized boolean remove(Object o) {
			return super.remove(o);
		}

		@Override
		public synchronized boolean removeAll(@NotNull Collection<?> c) {
			return super.removeAll(c);
		}

		@Override
		public synchronized boolean containsAll(@NotNull Collection<?> c) {
			return super.containsAll(c);
		}

		@Override
		public synchronized boolean retainAll(@NotNull Collection<?> c) {
			return super.retainAll(c);
		}

		@Override
		public synchronized void clear() {
			super.clear();
		}

		@Override
		public synchronized boolean offer(T t) {
			return super.offer(t);
		}

		@Override
		public synchronized boolean offer(T t, float score) {
			return super.offer(t, score);
		}

		@Override
		public synchronized boolean offer(ScoredValue<T> value) {
			return super.offer(value);
		}

		@Override
		public synchronized T remove() {
			return super.remove();
		}

		@Override
		public synchronized T poll() {
			return super.poll();
		}

		@Override
		public synchronized T element() {
			return super.element();
		}

		@Override
		public synchronized T peek() {
			return super.peek();
		}

		@Override
		public synchronized void forEachItem(Consumer<ScoredValue<T>> action) {
			super.forEachItem(action);
		}

		@Override
		public synchronized Stream<ScoredValue<T>> streamItems() {
			return super.streamItems();
		}
	}
}