/*
 * Copyright 2021 HIMSA II K/S - www.himsa.com.
 * Represented by EHIMA - www.ehima.com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.bluetooth;

import static android.bluetooth.BluetoothUtils.getSyncTimeout;

import android.Manifest;
import android.annotation.CallbackExecutor;
import android.annotation.IntRange;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.RequiresPermission;
import android.annotation.SdkConstant;
import android.annotation.SdkConstant.SdkConstantType;
import android.annotation.SuppressLint;
import android.annotation.SystemApi;
import android.bluetooth.annotations.RequiresBluetoothConnectPermission;
import android.content.AttributionSource;
import android.content.Context;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.CloseGuard;
import android.util.Log;

import com.android.modules.utils.SynchronousResultReceiver;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeoutException;

/**
 * This class provides the public APIs to control the Bluetooth Volume Control service.
 *
 * <p>BluetoothVolumeControl is a proxy object for controlling the Bluetooth VC
 * Service via IPC. Use {@link BluetoothAdapter#getProfileProxy} to get
 * the BluetoothVolumeControl proxy object.
 * @hide
 */
@SystemApi
public final class BluetoothVolumeControl implements BluetoothProfile, AutoCloseable {
    private static final String TAG = "BluetoothVolumeControl";
    private static final boolean DBG = true;
    private static final boolean VDBG = false;

    private CloseGuard mCloseGuard;
    private final Map<Callback, Executor> mCallbackExecutorMap = new HashMap<>();

    /**
     * This class provides a callback that is invoked when volume offset value changes on
     * the remote device.
     *
     * <p> In order to balance volume on the group of Le Audio devices,
     * Volume Offset Control Service (VOCS) shall be used. User can verify
     * if the remote device supports VOCS by calling {@link #isVolumeOffsetAvailable(device)}.
     *
     * @hide
     */
    @SystemApi
    public interface Callback {
        /**
         * Callback invoked when callback is registered and when volume offset
         * changes on the remote device. Change can be triggered autonomously by the remote device
         * or after volume offset change on the user request done by calling
         * {@link #setVolumeOffset(device, volumeOffset)}
         *
         * @param device remote device whose volume offset changed
         * @param volumeOffset latest volume offset for this device
         * @hide
         */
        @SystemApi
        void onVolumeOffsetChanged(@NonNull BluetoothDevice device,
                                   @IntRange(from = -255, to = 255) int volumeOffset);
    }

    @SuppressLint("AndroidFrameworkBluetoothPermission")
    private final IBluetoothVolumeControlCallback mCallback =
            new IBluetoothVolumeControlCallback.Stub() {
        @Override
        public void onVolumeOffsetChanged(@NonNull BluetoothDevice device, int volumeOffset) {
            Attributable.setAttributionSource(device, mAttributionSource);
            for (Map.Entry<BluetoothVolumeControl.Callback, Executor> callbackExecutorEntry:
                    mCallbackExecutorMap.entrySet()) {
                        BluetoothVolumeControl.Callback callback = callbackExecutorEntry.getKey();
                Executor executor = callbackExecutorEntry.getValue();
                executor.execute(() -> callback.onVolumeOffsetChanged(device, volumeOffset));
            }
        }
    };

    /**
     * Intent used to broadcast the change in connection state of the Volume Control
     * profile.
     *
     * <p>This intent will have 3 extras:
     * <ul>
     * <li> {@link #EXTRA_STATE} - The current state of the profile. </li>
     * <li> {@link #EXTRA_PREVIOUS_STATE}- The previous state of the profile.</li>
     * <li> {@link BluetoothDevice#EXTRA_DEVICE} - The remote device. </li>
     * </ul>
     *
     * <p>{@link #EXTRA_STATE} or {@link #EXTRA_PREVIOUS_STATE} can be any of
     * {@link #STATE_DISCONNECTED}, {@link #STATE_CONNECTING},
     * {@link #STATE_CONNECTED}, {@link #STATE_DISCONNECTING}.
     *
     * @hide
     */
    @SystemApi
    @SuppressLint("ActionValue")
    @RequiresBluetoothConnectPermission
    @RequiresPermission(Manifest.permission.BLUETOOTH_CONNECT)
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_CONNECTION_STATE_CHANGED =
            "android.bluetooth.volume-control.profile.action.CONNECTION_STATE_CHANGED";

    private BluetoothAdapter mAdapter;
    private final AttributionSource mAttributionSource;
    private final BluetoothProfileConnector<IBluetoothVolumeControl> mProfileConnector =
            new BluetoothProfileConnector(this, BluetoothProfile.VOLUME_CONTROL, TAG,
                    IBluetoothVolumeControl.class.getName()) {
                @Override
                public IBluetoothVolumeControl getServiceInterface(IBinder service) {
                    return IBluetoothVolumeControl.Stub.asInterface(service);
                }
            };

    @SuppressLint("AndroidFrameworkBluetoothPermission")
    private final IBluetoothStateChangeCallback mBluetoothStateChangeCallback =
            new IBluetoothStateChangeCallback.Stub() {
                public void onBluetoothStateChange(boolean up) {
                    if (DBG) Log.d(TAG, "onBluetoothStateChange: up=" + up);
                    if (!up) {
                        return;
                    }
                    // re-register the service-to-app callback
                    synchronized (mCallbackExecutorMap) {
                        if (!mCallbackExecutorMap.isEmpty()) {
                            try {
                                final IBluetoothVolumeControl service = getService();
                                if (service != null) {
                                    final SynchronousResultReceiver<Integer> recv =
                                                    SynchronousResultReceiver.get();
                                    service.registerCallback(mCallback, mAttributionSource, recv);
                                    recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
                                }
                            } catch (RemoteException e) {
                                Log.e(TAG, "onBluetoothServiceUp: Failed to register"
                                        + "Volume Control callback", e);
                            } catch (TimeoutException e) {
                                Log.e(TAG, e.toString() + "\n"
                                        + Log.getStackTraceString(new Throwable()));
                            }
                        }
                    }
                }
            };

    /**
     * Create a BluetoothVolumeControl proxy object for interacting with the local
     * Bluetooth Volume Control service.
     */
    /*package*/ BluetoothVolumeControl(Context context, ServiceListener listener,
            BluetoothAdapter adapter) {
        mAdapter = adapter;
        mAttributionSource = adapter.getAttributionSource();
        mProfileConnector.connect(context, listener);

        IBluetoothManager mgr = mAdapter.getBluetoothManager();
        if (mgr != null) {
            try {
                mgr.registerStateChangeCallback(mBluetoothStateChangeCallback);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
                throw e.rethrowFromSystemServer();
            }
        }

        mCloseGuard = new CloseGuard();
        mCloseGuard.open("close");
    }

    @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
    protected void finalize() {
        if (mCloseGuard != null) {
            mCloseGuard.warnIfOpen();
        }
        close();
    }

    /**
     * Close this VolumeControl server instance.
     *
     * <p>Application should call this method as early as possible after it is done with this
     * VolumeControl server.
     */
    @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
    @Override
    public void close() {
        if (VDBG) log("close()");

        IBluetoothManager mgr = mAdapter.getBluetoothManager();
        if (mgr != null) {
            try {
                mgr.unregisterStateChangeCallback(mBluetoothStateChangeCallback);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        mProfileConnector.disconnect();
    }

    private IBluetoothVolumeControl getService() {
        return mProfileConnector.getService();
    }

    /**
     * Get the list of connected devices. Currently at most one.
     *
     * @return list of connected devices
     *
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public @NonNull List<BluetoothDevice> getConnectedDevices() {
        if (DBG) log("getConnectedDevices()");
        final IBluetoothVolumeControl service = getService();
        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
                        SynchronousResultReceiver.get();
                service.getConnectedDevices(mAttributionSource, recv);
                return Attributable.setAttributionSource(
                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                        mAttributionSource);
            } catch (RemoteException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return defaultValue;
    }

    /**
     * Get the list of devices matching specified states. Currently at most one.
     *
     * @return list of matching devices
     *
     * @hide
     */
    @RequiresBluetoothConnectPermission
    @RequiresPermission(Manifest.permission.BLUETOOTH_CONNECT)
    public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
        if (DBG) log("getDevicesMatchingStates()");
        final IBluetoothVolumeControl service = getService();
        final List<BluetoothDevice> defaultValue = new ArrayList<BluetoothDevice>();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                final SynchronousResultReceiver<List<BluetoothDevice>> recv =
                        SynchronousResultReceiver.get();
                service.getDevicesMatchingConnectionStates(states, mAttributionSource, recv);
                return Attributable.setAttributionSource(
                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue),
                        mAttributionSource);
            } catch (RemoteException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return defaultValue;
    }

    /**
     * Get connection state of device
     *
     * @return device connection state
     *
     * @hide
     */
    @RequiresBluetoothConnectPermission
    @RequiresPermission(Manifest.permission.BLUETOOTH_CONNECT)
    public int getConnectionState(BluetoothDevice device) {
        if (DBG) log("getConnectionState(" + device + ")");
        final IBluetoothVolumeControl service = getService();
        final int defaultValue = BluetoothProfile.STATE_DISCONNECTED;
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled() && isValidDevice(device)) {
            try {
                final SynchronousResultReceiver<Integer> recv = SynchronousResultReceiver.get();
                service.getConnectionState(device, mAttributionSource, recv);
                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
            } catch (RemoteException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return defaultValue;
    }

    /**
     * Register a {@link Callback} that will be invoked during the
     * operation of this profile.
     *
     * Repeated registration of the same <var>callback</var> object will have no effect after
     * the first call to this method, even when the <var>executor</var> is different. API caller
     * would have to call {@link #unregisterCallback(Callback)} with
     * the same callback object before registering it again.
     *
     * @param executor an {@link Executor} to execute given callback
     * @param callback user implementation of the {@link Callback}
     * @throws IllegalArgumentException if a null executor, sink, or callback is given
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public void registerCallback(@NonNull @CallbackExecutor Executor executor,
            @NonNull Callback callback) {
        Objects.requireNonNull(executor, "executor cannot be null");
        Objects.requireNonNull(callback, "callback cannot be null");
        if (DBG) log("registerCallback");
        synchronized (mCallbackExecutorMap) {
            // If the callback map is empty, we register the service-to-app callback
            if (mCallbackExecutorMap.isEmpty()) {
                if (!mAdapter.isEnabled()) {
                    /* If Bluetooth is off, just store callback and it will be registered
                     * when Bluetooth is on
                     */
                    mCallbackExecutorMap.put(callback, executor);
                    return;
                }
                try {
                    final IBluetoothVolumeControl service = getService();
                    if (service != null) {
                        final SynchronousResultReceiver<Integer> recv =
                                                        SynchronousResultReceiver.get();
                        service.registerCallback(mCallback, mAttributionSource, recv);
                        recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
                    }
                } catch (RemoteException e) {
                    Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
                    throw e.rethrowFromSystemServer();
                } catch (TimeoutException e) {
                    Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
                }
            }

            // Adds the passed in callback to our map of callbacks to executors
            if (mCallbackExecutorMap.containsKey(callback)) {
                throw new IllegalArgumentException("This callback has already been registered");
            }
            mCallbackExecutorMap.put(callback, executor);
        }
    }

    /**
     * Unregister the specified {@link Callback}.
     * <p>The same {@link Callback} object used when calling
     * {@link #registerCallback(Executor, Callback)} must be used.
     *
     * <p>Callbacks are automatically unregistered when application process goes away
     *
     * @param callback user implementation of the {@link Callback}
     * @throws IllegalArgumentException when callback is null or when no callback is registered
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public void unregisterCallback(@NonNull Callback callback) {
        Objects.requireNonNull(callback, "callback cannot be null");
        if (DBG) log("unregisterCallback");
        synchronized (mCallbackExecutorMap) {
            if (mCallbackExecutorMap.remove(callback) == null) {
                throw new IllegalArgumentException("This callback has not been registered");
            }
        }

        // If the callback map is empty, we unregister the service-to-app callback
        if (mCallbackExecutorMap.isEmpty()) {
            try {
                final IBluetoothVolumeControl service = getService();
                if (service != null) {
                    final SynchronousResultReceiver<Integer> recv = SynchronousResultReceiver.get();
                    service.unregisterCallback(mCallback, mAttributionSource, recv);
                    recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
                }
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
                throw e.rethrowFromSystemServer();
            } catch (IllegalStateException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
    }

    /**
     * Tells the remote device to set a volume offset to the absolute volume.
     *
     * @param device {@link BluetoothDevice} representing the remote device
     * @param volumeOffset volume offset to be set on the remote device
     *
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public void setVolumeOffset(@NonNull BluetoothDevice device,
            @IntRange(from = -255, to = 255) int volumeOffset) {
        if (DBG) log("setVolumeOffset(" + device  + " volumeOffset: " + volumeOffset + ")");
        final IBluetoothVolumeControl service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                final SynchronousResultReceiver recv = SynchronousResultReceiver.get();
                service.setVolumeOffset(device, volumeOffset, mAttributionSource, recv);
                recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(null);
            } catch (RemoteException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
    }

    /**
     * Provides information about the possibility to set volume offset on the remote device.
     * If the remote device supports Volume Offset Control Service, it is automatically
     * connected.
     *
     * @param device {@link BluetoothDevice} representing the remote device
     * @return {@code true} if volume offset function is supported and available to use on the
     *         remote device. When Bluetooth is off, the return value should always be
     *         {@code false}.
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public boolean isVolumeOffsetAvailable(@NonNull BluetoothDevice device) {
        if (DBG) log("isVolumeOffsetAvailable(" + device + ")");
        final IBluetoothVolumeControl service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
            return false;
        }

        if (!isEnabled()) {
            return false;
        }

        final boolean defaultValue = false;
        try {
            final SynchronousResultReceiver recv = SynchronousResultReceiver.get();
            service.isVolumeOffsetAvailable(device, mAttributionSource, recv);
            recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
        } catch (RemoteException | TimeoutException e) {
            Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
        }

        return defaultValue;
    }

    /**
     * Set connection policy of the profile
     *
     * <p> The device should already be paired.
     * Connection policy can be one of {@link #CONNECTION_POLICY_ALLOWED},
     * {@link #CONNECTION_POLICY_FORBIDDEN}, {@link #CONNECTION_POLICY_UNKNOWN}
     *
     * @param device Paired bluetooth device
     * @param connectionPolicy is the connection policy to set to for this profile
     * @return true if connectionPolicy is set, false on error
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public boolean setConnectionPolicy(@NonNull BluetoothDevice device,
            @ConnectionPolicy int connectionPolicy) {
        if (DBG) log("setConnectionPolicy(" + device + ", " + connectionPolicy + ")");
        final IBluetoothVolumeControl service = getService();
        final boolean defaultValue = false;
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled() && isValidDevice(device)
                && (connectionPolicy == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN
                    || connectionPolicy == BluetoothProfile.CONNECTION_POLICY_ALLOWED)) {
            try {
                final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
                service.setConnectionPolicy(device, connectionPolicy, mAttributionSource, recv);
                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
            } catch (RemoteException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return defaultValue;
    }

    /**
     * Get the connection policy of the profile.
     *
     * <p> The connection policy can be any of:
     * {@link #CONNECTION_POLICY_ALLOWED}, {@link #CONNECTION_POLICY_FORBIDDEN},
     * {@link #CONNECTION_POLICY_UNKNOWN}
     *
     * @param device Bluetooth device
     * @return connection policy of the device
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(allOf = {
            android.Manifest.permission.BLUETOOTH_CONNECT,
            android.Manifest.permission.BLUETOOTH_PRIVILEGED,
    })
    public @ConnectionPolicy int getConnectionPolicy(@NonNull BluetoothDevice device) {
        if (VDBG) log("getConnectionPolicy(" + device + ")");
        final IBluetoothVolumeControl service = getService();
        final int defaultValue = BluetoothProfile.CONNECTION_POLICY_FORBIDDEN;
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled() && isValidDevice(device)) {
            try {
                final SynchronousResultReceiver<Integer> recv = SynchronousResultReceiver.get();
                service.getConnectionPolicy(device, mAttributionSource, recv);
                return recv.awaitResultNoInterrupt(getSyncTimeout()).getValue(defaultValue);
            } catch (RemoteException | TimeoutException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return defaultValue;
    }

    private boolean isEnabled() {
        return mAdapter.getState() == BluetoothAdapter.STATE_ON;
    }

    private static boolean isValidDevice(@Nullable BluetoothDevice device) {
        return device != null && BluetoothAdapter.checkBluetoothAddress(device.getAddress());
    }

    private static void log(String msg) {
        Log.d(TAG, msg);
    }
}