/*
 * Copyright (c) 2018, Nordic Semiconductor
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package no.nordicsemi.android.ble;

import android.bluetooth.BluetoothGatt;
import android.os.Handler;

import androidx.annotation.IntRange;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.Deque;
import java.util.LinkedList;

import no.nordicsemi.android.ble.callback.BeforeCallback;
import no.nordicsemi.android.ble.callback.FailCallback;
import no.nordicsemi.android.ble.callback.InvalidRequestCallback;
import no.nordicsemi.android.ble.callback.SuccessCallback;
import no.nordicsemi.android.ble.exception.BluetoothDisabledException;
import no.nordicsemi.android.ble.exception.DeviceDisconnectedException;
import no.nordicsemi.android.ble.exception.InvalidRequestException;
import no.nordicsemi.android.ble.exception.RequestFailedException;

@SuppressWarnings("WeakerAccess")
public class RequestQueue extends Request {
	/**
	 * A list of operations that will be executed together.
	 */
	@NonNull
	private final Deque<Request> requests;

	RequestQueue() {
		super(Type.SET);
		requests = new LinkedList<>();
	}

	@NonNull
	@Override
	RequestQueue setRequestHandler(@NonNull final RequestHandler requestHandler) {
		super.setRequestHandler(requestHandler);
		return this;
	}

	@NonNull
	@Override
	public RequestQueue setHandler(@NonNull final Handler handler) {
		super.setHandler(handler);
		return this;
	}

	@Override
	@NonNull
	public RequestQueue done(@NonNull final SuccessCallback callback) {
		super.done(callback);
		return this;
	}

	@Override
	@NonNull
	public RequestQueue fail(@NonNull final FailCallback callback) {
		super.fail(callback);
		return this;
	}

	@NonNull
	@Override
	public RequestQueue invalid(@NonNull final InvalidRequestCallback callback) {
		super.invalid(callback);
		return this;
	}

	@Override
	@NonNull
	public RequestQueue before(@NonNull final BeforeCallback callback) {
		super.before(callback);
		return this;
	}

	/**
	 * Enqueues a new operation. All operations will be executed sequentially in order they were
	 * added.
	 *
	 * @param operation the new operation to be enqueued.
	 * @throws IllegalStateException    if the operation was enqueued before.
	 * @throws IllegalArgumentException if the operation is not a {@link Request}.
	 */
	@NonNull
	public RequestQueue add(@NonNull final Operation operation) {
		if (operation instanceof Request) {
			final Request request = (Request) operation;
			// Validate
			if (request.enqueued)
				throw new IllegalStateException("Request already enqueued");
			// Add
			request.internalFail(this::notifyFail);
			requests.add(request);
			// Mark
			request.enqueued = true;
			return this;
		} else {
			throw new IllegalArgumentException("Operation does not extend Request");
		}
	}

	/**
	 * Enqueues given request again in the request queue, putting it to the front of it.
	 *
	 * @param request the request to be enqueued.
	 */
	void addFirst(@NonNull final Request request) {
		requests.addFirst(request);
	}

	/**
	 * Returns number of enqueued operations.
	 *
	 * @return the size of the internal operations list.
	 */
	@IntRange(from = 0)
	public int size() {
		return requests.size();
	}

	/**
	 * Returns whether the set is empty, or not.
	 *
	 * @return true if the set is empty. Set gets emptied while it all enqueued operations
	 * are being executed.
	 */
	public boolean isEmpty() {
		return requests.isEmpty();
	}

	/**
	 * Cancels all the enqueued operations that were not executed yet.
	 * The one currently executed will be finished.
	 * <p>
	 * It is safe to call this method in {@link Request#done(SuccessCallback)} or
	 * {@link Request#fail(FailCallback)} callback;
	 */
	public void cancelQueue() {
		requests.clear();
	}

	/**
	 * Synchronously waits until all enqueued requests are done. The queue will fail if any of
	 * the enqueued requests fails. All following requests will be ignored.
	 * <p>
	 * Callbacks set using {@link #before(BeforeCallback)}, {@link #done(SuccessCallback)} and
	 * {@link #fail(FailCallback)} will be ignored.
	 * <p>
	 * This method may not be called from the main (UI) thread.
	 *
	 * @throws RequestFailedException      thrown when the BLE request finished with status other
	 *                                     than {@link BluetoothGatt#GATT_SUCCESS}.
	 * @throws IllegalStateException       thrown when you try to call this method from the main
	 *                                     (UI) thread.
	 * @throws DeviceDisconnectedException thrown when the device disconnected before the request
	 *                                     was completed.
	 * @throws BluetoothDisabledException  thrown when the Bluetooth adapter has been disabled.
	 * @throws InvalidRequestException     thrown when the request was called before the device was
	 *                                     connected at least once (unknown device).
	 * @throws InterruptedException        thrown when one of the request has failed with a timeout.
	 */
	public final void await() throws RequestFailedException, DeviceDisconnectedException,
			BluetoothDisabledException, InvalidRequestException, InterruptedException {
		assertNotMainThread();

		final BeforeCallback bc = beforeCallback;
		final SuccessCallback sc = successCallback;
		final FailCallback fc = failCallback;
		try {
			syncLock.close();
			final RequestCallback callback = new RequestCallback();
			beforeCallback = null;
			done(callback).fail(callback).invalid(callback).enqueue();

			syncLock.block();
			if (!callback.isSuccess()) {
				if (callback.status == FailCallback.REASON_DEVICE_DISCONNECTED) {
					throw new DeviceDisconnectedException();
				}
				if (callback.status == FailCallback.REASON_BLUETOOTH_DISABLED) {
					throw new BluetoothDisabledException();
				}
				if (callback.status == FailCallback.REASON_TIMEOUT) {
					throw new InterruptedException();
				}
				if (callback.status == RequestCallback.REASON_REQUEST_INVALID) {
					throw new InvalidRequestException(this);
				}
				throw new RequestFailedException(this, callback.status);
			}
		} finally {
			beforeCallback = bc;
			successCallback = sc;
			failCallback = fc;
		}
	}

	/**
	 * Returns the next {@link Request} to be enqueued.
	 *
	 * @return the next request.
	 */
	@Nullable
	Request getNext() {
		try {
			return requests.remove();
			// poll() may also throw an exception
			// See: https://github.com/NordicSemiconductor/Android-BLE-Library/issues/37
		} catch (final Exception e) {
			return null;
		}
	}

	/**
	 * Returns whether there are more operations to be executed.
	 *
	 * @return true, if not all operations were completed.
	 */
	boolean hasMore() {
		return !finished && !requests.isEmpty();
	}
}