/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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.annotation.SystemApi.Client.MODULE_LIBRARIES;

import android.annotation.IntDef;
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.bluetooth.annotations.RequiresLegacyBluetoothPermission;
import android.compat.annotation.UnsupportedAppUsage;
import android.content.AttributionSource;
import android.content.Context;
import android.net.TetheringManager.TetheredInterfaceCallback;
import android.net.TetheringManager.TetheredInterfaceRequest;
import android.os.Build;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Log;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.Executor;

/**
 * This class provides the APIs to control the Bluetooth Pan Profile.
 *
 * <p>BluetoothPan is a proxy object for controlling the Bluetooth Service via IPC. Use {@link
 * BluetoothAdapter#getProfileProxy} to get the BluetoothPan proxy object.
 *
 * <p>Each method is protected with its appropriate permission.
 *
 * @hide
 */
@SystemApi
public final class BluetoothPan implements BluetoothProfile {
    private static final String TAG = "BluetoothPan";
    private static final boolean DBG = true;
    private static final boolean VDBG = false;

    /**
     * Intent used to broadcast the change in connection state of the Pan profile.
     *
     * <p>This intent will have 4 extras:
     *
     * <ul>
     *   <li>{@link #EXTRA_STATE} - The current state of the profile.
     *   <li>{@link #EXTRA_PREVIOUS_STATE}- The previous state of the profile.
     *   <li>{@link BluetoothDevice#EXTRA_DEVICE} - The remote device.
     *   <li>{@link #EXTRA_LOCAL_ROLE} - Which local role the remote device is bound to.
     * </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}.
     *
     * <p>{@link #EXTRA_LOCAL_ROLE} can be one of {@link #LOCAL_NAP_ROLE} or {@link
     * #LOCAL_PANU_ROLE}
     */
    @SuppressLint("ActionValue")
    @RequiresLegacyBluetoothPermission
    @RequiresBluetoothConnectPermission
    @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_CONNECTION_STATE_CHANGED =
            "android.bluetooth.pan.profile.action.CONNECTION_STATE_CHANGED";

    /**
     * Extra for {@link #ACTION_CONNECTION_STATE_CHANGED} intent The local role of the PAN profile
     * that the remote device is bound to. It can be one of {@link #LOCAL_NAP_ROLE} or {@link
     * #LOCAL_PANU_ROLE}.
     */
    @SuppressLint("ActionValue")
    public static final String EXTRA_LOCAL_ROLE = "android.bluetooth.pan.extra.LOCAL_ROLE";

    /**
     * Intent used to broadcast the change in tethering state of the Pan Profile
     *
     * <p>This intent will have 1 extra:
     *
     * <ul>
     *   <li>{@link #EXTRA_TETHERING_STATE} - The current state of Bluetooth tethering.
     * </ul>
     *
     * <p>{@link #EXTRA_TETHERING_STATE} can be any of {@link #TETHERING_STATE_OFF} or {@link
     * #TETHERING_STATE_ON}
     */
    @RequiresLegacyBluetoothPermission
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_TETHERING_STATE_CHANGED =
            "android.bluetooth.action.TETHERING_STATE_CHANGED";

    /**
     * Extra for {@link #ACTION_TETHERING_STATE_CHANGED} intent The tethering state of the PAN
     * profile. It can be one of {@link #TETHERING_STATE_OFF} or {@link #TETHERING_STATE_ON}.
     */
    public static final String EXTRA_TETHERING_STATE = "android.bluetooth.extra.TETHERING_STATE";

    /** @hide */
    @IntDef({PAN_ROLE_NONE, LOCAL_NAP_ROLE, LOCAL_PANU_ROLE})
    @Retention(RetentionPolicy.SOURCE)
    public @interface LocalPanRole {}

    public static final int PAN_ROLE_NONE = 0;

    /** The local device is acting as a Network Access Point. */
    public static final int LOCAL_NAP_ROLE = 1;

    /** The local device is acting as a PAN User. */
    public static final int LOCAL_PANU_ROLE = 2;

    /** @hide */
    @IntDef({PAN_ROLE_NONE, REMOTE_NAP_ROLE, REMOTE_PANU_ROLE})
    @Retention(RetentionPolicy.SOURCE)
    public @interface RemotePanRole {}

    public static final int REMOTE_NAP_ROLE = 1;

    public static final int REMOTE_PANU_ROLE = 2;

    /**
     * @hide *
     */
    @IntDef({TETHERING_STATE_OFF, TETHERING_STATE_ON})
    @Retention(RetentionPolicy.SOURCE)
    public @interface TetheringState {}

    public static final int TETHERING_STATE_OFF = 1;

    public static final int TETHERING_STATE_ON = 2;

    /**
     * Return codes for the connect and disconnect Bluez / Dbus calls.
     *
     * @hide
     */
    public static final int PAN_DISCONNECT_FAILED_NOT_CONNECTED = 1000;

    /** @hide */
    public static final int PAN_CONNECT_FAILED_ALREADY_CONNECTED = 1001;

    /** @hide */
    public static final int PAN_CONNECT_FAILED_ATTEMPT_FAILED = 1002;

    /** @hide */
    public static final int PAN_OPERATION_GENERIC_FAILURE = 1003;

    /** @hide */
    public static final int PAN_OPERATION_SUCCESS = 1004;

    /**
     * Request class used by Tethering to notify that the interface is closed.
     *
     * @see #requestTetheredInterface
     * @hide
     */
    public class BluetoothTetheredInterfaceRequest implements TetheredInterfaceRequest {
        private IBluetoothPan mService;
        private final IBluetoothPanCallback mPanCallback;
        private final int mId;

        private BluetoothTetheredInterfaceRequest(
                @NonNull IBluetoothPan service,
                @NonNull IBluetoothPanCallback panCallback,
                int id) {
            this.mService = service;
            this.mPanCallback = panCallback;
            this.mId = id;
        }

        /** Called when the Tethering interface has been released. */
        @RequiresPermission(
                allOf = {
                    android.Manifest.permission.BLUETOOTH_CONNECT,
                    android.Manifest.permission.BLUETOOTH_PRIVILEGED,
                    android.Manifest.permission.TETHER_PRIVILEGED,
                })
        @Override
        public void release() {
            if (mService == null) {
                throw new IllegalStateException(
                        "The tethered interface has already been released.");
            }
            try {
                mService.setBluetoothTethering(mPanCallback, mId, false, mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            } finally {
                mService = null;
            }
        }
    }

    private final Context mContext;

    private final BluetoothAdapter mAdapter;
    private final AttributionSource mAttributionSource;

    private IBluetoothPan mService;

    /**
     * Create a BluetoothPan proxy object for interacting with the local Bluetooth Service which
     * handles the Pan profile
     *
     * @hide
     */
    @UnsupportedAppUsage
    /* package */ BluetoothPan(Context context, BluetoothAdapter adapter) {
        mAdapter = adapter;
        mAttributionSource = adapter.getAttributionSource();
        mContext = context;
        mService = null;
    }

    /**
     * Closes the connection to the service and unregisters callbacks
     *
     * @hide
     */
    @UnsupportedAppUsage
    public void close() {
        if (VDBG) log("close()");
        mAdapter.closeProfileProxy(this);
    }

    /** @hide */
    @Override
    public void onServiceConnected(IBinder service) {
        mService = IBluetoothPan.Stub.asInterface(service);
    }

    /** @hide */
    @Override
    public void onServiceDisconnected() {
        mService = null;
    }

    private IBluetoothPan getService() {
        return mService;
    }

    /** @hide */
    @Override
    public BluetoothAdapter getAdapter() {
        return mAdapter;
    }

    /** @hide */
    @SuppressWarnings("Finalize") // TODO(b/314811467)
    protected void finalize() {
        close();
    }

    /**
     * Initiate connection to a profile of the remote bluetooth device.
     *
     * <p>This API returns false in scenarios like the profile on the device is already connected or
     * Bluetooth is not turned on. When this API returns true, it is guaranteed that connection
     * state intent for the profile will be broadcasted with the state. Users can get the connection
     * state of the profile from this intent.
     *
     * @param device Remote Bluetooth Device
     * @return false on immediate error, true otherwise
     * @hide
     */
    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
    @RequiresBluetoothConnectPermission
    @RequiresPermission(
            allOf = {
                android.Manifest.permission.BLUETOOTH_CONNECT,
                android.Manifest.permission.BLUETOOTH_PRIVILEGED,
            })
    public boolean connect(BluetoothDevice device) {
        if (DBG) log("connect(" + device + ")");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled() && isValidDevice(device)) {
            try {
                return service.connect(device, mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return false;
    }

    /**
     * Initiate disconnection from a profile
     *
     * <p>This API will return false in scenarios like the profile on the Bluetooth device is not in
     * connected state etc. When this API returns, true, it is guaranteed that the connection state
     * change intent will be broadcasted with the state. Users can get the disconnection state of
     * the profile from this intent.
     *
     * <p>If the disconnection is initiated by a remote device, the state will transition from
     * {@link #STATE_CONNECTED} to {@link #STATE_DISCONNECTED}. If the disconnect is initiated by
     * the host (local) device the state will transition from {@link #STATE_CONNECTED} to state
     * {@link #STATE_DISCONNECTING} to state {@link #STATE_DISCONNECTED}. The transition to {@link
     * #STATE_DISCONNECTING} can be used to distinguish between the two scenarios.
     *
     * @param device Remote Bluetooth Device
     * @return false on immediate error, true otherwise
     * @hide
     */
    @UnsupportedAppUsage
    @RequiresBluetoothConnectPermission
    @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
    public boolean disconnect(BluetoothDevice device) {
        if (DBG) log("disconnect(" + device + ")");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled() && isValidDevice(device)) {
            try {
                return service.disconnect(device, mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return false;
    }

    /**
     * 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 IBluetoothPan service = getService();
        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 {
                return service.setConnectionPolicy(device, connectionPolicy, mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return false;
    }

    /**
     * {@inheritDoc}
     *
     * @hide
     */
    @SystemApi
    @Override
    @RequiresBluetoothConnectPermission
    @RequiresPermission(
            allOf = {
                android.Manifest.permission.BLUETOOTH_CONNECT,
                android.Manifest.permission.BLUETOOTH_PRIVILEGED,
            })
    public @NonNull List<BluetoothDevice> getConnectedDevices() {
        if (VDBG) log("getConnectedDevices()");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                return Attributable.setAttributionSource(
                        service.getConnectedDevices(mAttributionSource), mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return Collections.emptyList();
    }

    /**
     * {@inheritDoc}
     *
     * @hide
     */
    @Override
    @RequiresLegacyBluetoothPermission
    @RequiresBluetoothConnectPermission
    @RequiresPermission(
            allOf = {
                android.Manifest.permission.BLUETOOTH_CONNECT,
                android.Manifest.permission.BLUETOOTH_PRIVILEGED,
            })
    public List<BluetoothDevice> getDevicesMatchingConnectionStates(int[] states) {
        if (VDBG) log("getDevicesMatchingStates()");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                return Attributable.setAttributionSource(
                        service.getDevicesMatchingConnectionStates(states, mAttributionSource),
                        mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return Collections.emptyList();
    }

    /**
     * {@inheritDoc}
     *
     * @hide
     */
    @SystemApi
    @Override
    @RequiresBluetoothConnectPermission
    @RequiresPermission(
            allOf = {
                android.Manifest.permission.BLUETOOTH_CONNECT,
                android.Manifest.permission.BLUETOOTH_PRIVILEGED,
            })
    public int getConnectionState(@NonNull BluetoothDevice device) {
        if (VDBG) log("getState(" + device + ")");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled() && isValidDevice(device)) {
            try {
                return service.getConnectionState(device, mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return BluetoothProfile.STATE_DISCONNECTED;
    }

    /**
     * Turns on/off bluetooth tethering.
     *
     * @param value is whether to enable or disable bluetooth tethering
     * @deprecated Use {@link #requestTetheredInterface} with {@link TetheredInterfaceCallback}
     *     instead.
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(
            allOf = {
                android.Manifest.permission.BLUETOOTH_CONNECT,
                android.Manifest.permission.BLUETOOTH_PRIVILEGED,
                android.Manifest.permission.TETHER_PRIVILEGED,
            })
    @Deprecated
    public void setBluetoothTethering(boolean value) {
        String pkgName = mContext.getOpPackageName();
        if (DBG) log("setBluetoothTethering(" + value + "), calling package:" + pkgName);
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                service.setBluetoothTethering(null, 0, value, mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
    }

    /**
     * Turns on Bluetooth tethering.
     *
     * <p>When one or more devices are connected, the PAN service will trigger {@link
     * TetheredInterfaceCallback#onAvailable} to inform the caller that it is ready to tether. On
     * the contrary, when all devices have been disconnected, the PAN service will trigger {@link
     * TetheredInterfaceCallback#onUnavailable}.
     *
     * <p>To turn off Bluetooth tethering, the caller must use {@link
     * TetheredInterfaceRequest#release} method.
     *
     * @param executor thread to execute callback methods
     * @param callback is the tethering callback to indicate PAN service is ready or not to tether
     *     to one or more devices
     * @return new instance of {@link TetheredInterfaceRequest} which can be used to turn off
     *     Bluetooth tethering or {@code null} if service is not enabled
     * @hide
     */
    @SystemApi(client = MODULE_LIBRARIES)
    @RequiresBluetoothConnectPermission
    @RequiresPermission(
            allOf = {
                android.Manifest.permission.BLUETOOTH_CONNECT,
                android.Manifest.permission.BLUETOOTH_PRIVILEGED,
                android.Manifest.permission.TETHER_PRIVILEGED,
            })
    @Nullable
    public TetheredInterfaceRequest requestTetheredInterface(
            @NonNull final Executor executor, @NonNull final TetheredInterfaceCallback callback) {
        Objects.requireNonNull(callback, "Callback must be non-null");
        Objects.requireNonNull(executor, "Executor must be non-null");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            final IBluetoothPanCallback panCallback =
                    new IBluetoothPanCallback.Stub() {
                        @Override
                        public void onAvailable(String iface) {
                            executor.execute(() -> callback.onAvailable(iface));
                        }

                        @Override
                        public void onUnavailable() {
                            executor.execute(() -> callback.onUnavailable());
                        }
                    };
            try {
                service.setBluetoothTethering(
                        panCallback, callback.hashCode(), true, mAttributionSource);
                return new BluetoothTetheredInterfaceRequest(
                        service, panCallback, callback.hashCode());
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return null;
    }

    /**
     * Determines whether tethering is enabled
     *
     * @return true if tethering is on, false if not or some error occurred
     * @hide
     */
    @SystemApi
    @RequiresBluetoothConnectPermission
    @RequiresPermission(android.Manifest.permission.BLUETOOTH_CONNECT)
    public boolean isTetheringOn() {
        if (VDBG) log("isTetheringOn()");
        final IBluetoothPan service = getService();
        if (service == null) {
            Log.w(TAG, "Proxy not attached to service");
            if (DBG) log(Log.getStackTraceString(new Throwable()));
        } else if (isEnabled()) {
            try {
                return service.isTetheringOn(mAttributionSource);
            } catch (RemoteException e) {
                Log.e(TAG, e.toString() + "\n" + Log.getStackTraceString(new Throwable()));
            }
        }
        return false;
    }

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

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

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