/*
 * Copyright (C) 2014 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.telecom;

import android.annotation.SystemApi;
import android.net.Uri;
import android.os.Bundle;

import java.lang.String;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.CopyOnWriteArrayList;

/**
 * Represents an ongoing phone call that the in-call app should present to the user.
 *
 * {@hide}
 */
@SystemApi
public final class Call {
    /**
     * The state of a {@code Call} when newly created.
     */
    public static final int STATE_NEW = 0;

    /**
     * The state of an outgoing {@code Call} when dialing the remote number, but not yet connected.
     */
    public static final int STATE_DIALING = 1;

    /**
     * The state of an incoming {@code Call} when ringing locally, but not yet connected.
     */
    public static final int STATE_RINGING = 2;

    /**
     * The state of a {@code Call} when in a holding state.
     */
    public static final int STATE_HOLDING = 3;

    /**
     * The state of a {@code Call} when actively supporting conversation.
     */
    public static final int STATE_ACTIVE = 4;

    /**
     * The state of a {@code Call} when no further voice or other communication is being
     * transmitted, the remote side has been or will inevitably be informed that the {@code Call}
     * is no longer active, and the local data transport has or inevitably will release resources
     * associated with this {@code Call}.
     */
    public static final int STATE_DISCONNECTED = 7;

    /**
     * The state of an outgoing {@code Call}, but waiting for user input before proceeding.
     */
    public static final int STATE_PRE_DIAL_WAIT = 8;

    /**
     * The initial state of an outgoing {@code Call}.
     * Common transitions are to {@link #STATE_DIALING} state for a successful call or
     * {@link #STATE_DISCONNECTED} if it failed.
     */
    public static final int STATE_CONNECTING = 9;

    /**
     * The state of a {@code Call} when the user has initiated a disconnection of the call, but the
     * call has not yet been disconnected by the underlying {@code ConnectionService}.  The next
     * state of the call is (potentially) {@link #STATE_DISCONNECTED}.
     */
    public static final int STATE_DISCONNECTING = 10;

    /**
     * The key to retrieve the optional {@code PhoneAccount}s Telecom can bundle with its Call
     * extras. Used to pass the phone accounts to display on the front end to the user in order to
     * select phone accounts to (for example) place a call.
     *
     * @hide
     */
    public static final String AVAILABLE_PHONE_ACCOUNTS = "selectPhoneAccountAccounts";

    public static class Details {

        /** Call can currently be put on hold or unheld. */
        public static final int CAPABILITY_HOLD = 0x00000001;

        /** Call supports the hold feature. */
        public static final int CAPABILITY_SUPPORT_HOLD = 0x00000002;

        /**
         * Calls within a conference can be merged. A {@link ConnectionService} has the option to
         * add a {@link Conference} call before the child {@link Connection}s are merged. This is how
         * CDMA-based {@link Connection}s are implemented. For these unmerged {@link Conference}s, this
         * capability allows a merge button to be shown while the conference call is in the foreground
         * of the in-call UI.
         * <p>
         * This is only intended for use by a {@link Conference}.
         */
        public static final int CAPABILITY_MERGE_CONFERENCE = 0x00000004;

        /**
         * Calls within a conference can be swapped between foreground and background.
         * See {@link #CAPABILITY_MERGE_CONFERENCE} for additional information.
         * <p>
         * This is only intended for use by a {@link Conference}.
         */
        public static final int CAPABILITY_SWAP_CONFERENCE = 0x00000008;

        /**
         * @hide
         */
        public static final int CAPABILITY_UNUSED = 0x00000010;

        /** Call supports responding via text option. */
        public static final int CAPABILITY_RESPOND_VIA_TEXT = 0x00000020;

        /** Call can be muted. */
        public static final int CAPABILITY_MUTE = 0x00000040;

        /**
         * Call supports conference call management. This capability only applies to {@link Conference}
         * calls which can have {@link Connection}s as children.
         */
        public static final int CAPABILITY_MANAGE_CONFERENCE = 0x00000080;

        /**
         * Local device supports video telephony.
         * @hide
         */
        public static final int CAPABILITY_SUPPORTS_VT_LOCAL = 0x00000100;

        /**
         * Remote device supports video telephony.
         * @hide
         */
        public static final int CAPABILITY_SUPPORTS_VT_REMOTE = 0x00000200;

        /**
         * Call is using high definition audio.
         * @hide
         */
        public static final int CAPABILITY_HIGH_DEF_AUDIO = 0x00000400;

        /**
         * Call is using voice over WIFI.
         * @hide
         */
        public static final int CAPABILITY_VoWIFI = 0x00000800;

        /**
         * Call is able to be separated from its parent {@code Conference}, if any.
         */
        public static final int CAPABILITY_SEPARATE_FROM_CONFERENCE = 0x00001000;

        /**
         * Call is able to be individually disconnected when in a {@code Conference}.
         */
        public static final int CAPABILITY_DISCONNECT_FROM_CONFERENCE = 0x00002000;

        /**
         * Whether the call is a generic conference, where we do not know the precise state of
         * participants in the conference (eg. on CDMA).
         *
         * @hide
         */
        public static final int CAPABILITY_GENERIC_CONFERENCE = 0x00004000;

        private final Uri mHandle;
        private final int mHandlePresentation;
        private final String mCallerDisplayName;
        private final int mCallerDisplayNamePresentation;
        private final PhoneAccountHandle mAccountHandle;
        private final int mCallCapabilities;
        private final int mCallProperties;
        private final DisconnectCause mDisconnectCause;
        private final long mConnectTimeMillis;
        private final GatewayInfo mGatewayInfo;
        private final int mVideoState;
        private final StatusHints mStatusHints;
        private final Bundle mExtras;

        /**
         * Whether the supplied capabilities  supports the specified capability.
         *
         * @param capabilities A bit field of capabilities.
         * @param capability The capability to check capabilities for.
         * @return Whether the specified capability is supported.
         * @hide
         */
        public static boolean can(int capabilities, int capability) {
            return (capabilities & capability) != 0;
        }

        /**
         * Whether the capabilities of this {@code Details} supports the specified capability.
         *
         * @param capability The capability to check capabilities for.
         * @return Whether the specified capability is supported.
         * @hide
         */
        public boolean can(int capability) {
            return can(mCallCapabilities, capability);
        }

        /**
         * Render a set of capability bits ({@code CAPABILITY_*}) as a human readable string.
         *
         * @param capabilities A capability bit field.
         * @return A human readable string representation.
         */
        public static String capabilitiesToString(int capabilities) {
            StringBuilder builder = new StringBuilder();
            builder.append("[Capabilities:");
            if (can(capabilities, CAPABILITY_HOLD)) {
                builder.append(" CAPABILITY_HOLD");
            }
            if (can(capabilities, CAPABILITY_SUPPORT_HOLD)) {
                builder.append(" CAPABILITY_SUPPORT_HOLD");
            }
            if (can(capabilities, CAPABILITY_MERGE_CONFERENCE)) {
                builder.append(" CAPABILITY_MERGE_CONFERENCE");
            }
            if (can(capabilities, CAPABILITY_SWAP_CONFERENCE)) {
                builder.append(" CAPABILITY_SWAP_CONFERENCE");
            }
            if (can(capabilities, CAPABILITY_RESPOND_VIA_TEXT)) {
                builder.append(" CAPABILITY_RESPOND_VIA_TEXT");
            }
            if (can(capabilities, CAPABILITY_MUTE)) {
                builder.append(" CAPABILITY_MUTE");
            }
            if (can(capabilities, CAPABILITY_MANAGE_CONFERENCE)) {
                builder.append(" CAPABILITY_MANAGE_CONFERENCE");
            }
            if (can(capabilities, CAPABILITY_SUPPORTS_VT_LOCAL)) {
                builder.append(" CAPABILITY_SUPPORTS_VT_LOCAL");
            }
            if (can(capabilities, CAPABILITY_SUPPORTS_VT_REMOTE)) {
                builder.append(" CAPABILITY_SUPPORTS_VT_REMOTE");
            }
            if (can(capabilities, CAPABILITY_HIGH_DEF_AUDIO)) {
                builder.append(" CAPABILITY_HIGH_DEF_AUDIO");
            }
            if (can(capabilities, CAPABILITY_VoWIFI)) {
                builder.append(" CAPABILITY_VoWIFI");
            }
            if (can(capabilities, CAPABILITY_GENERIC_CONFERENCE)) {
                builder.append(" CAPABILITY_GENERIC_CONFERENCE");
            }
            builder.append("]");
            return builder.toString();
        }

        /**
         * @return The handle (e.g., phone number) to which the {@code Call} is currently
         * connected.
         */
        public Uri getHandle() {
            return mHandle;
        }

        /**
         * @return The presentation requirements for the handle. See
         * {@link TelecomManager} for valid values.
         */
        public int getHandlePresentation() {
            return mHandlePresentation;
        }

        /**
         * @return The display name for the caller.
         */
        public String getCallerDisplayName() {
            return mCallerDisplayName;
        }

        /**
         * @return The presentation requirements for the caller display name. See
         * {@link TelecomManager} for valid values.
         */
        public int getCallerDisplayNamePresentation() {
            return mCallerDisplayNamePresentation;
        }

        /**
         * @return The {@code PhoneAccountHandle} whereby the {@code Call} is currently being
         * routed.
         */
        public PhoneAccountHandle getAccountHandle() {
            return mAccountHandle;
        }

        /**
         * @return A bitmask of the capabilities of the {@code Call}, as defined by the various
         *         {@code CAPABILITY_*} constants in this class.
         */
        public int getCallCapabilities() {
            return mCallCapabilities;
        }

        /**
         * @return A bitmask of the properties of the {@code Call}, as defined in
         *         {@link CallProperties}.
         */
        public int getCallProperties() {
            return mCallProperties;
        }

        /**
         * @return For a {@link #STATE_DISCONNECTED} {@code Call}, the disconnect cause expressed
         * by {@link android.telecom.DisconnectCause}.
         */
        public DisconnectCause getDisconnectCause() {
            return mDisconnectCause;
        }

        /**
         * @return The time the {@code Call} has been connected. This information is updated
         * periodically, but user interfaces should not rely on this to display any "call time
         * clock".
         */
        public long getConnectTimeMillis() {
            return mConnectTimeMillis;
        }

        /**
         * @return Information about any calling gateway the {@code Call} may be using.
         */
        public GatewayInfo getGatewayInfo() {
            return mGatewayInfo;
        }

        /**
         * @return The video state of the {@code Call}.
         */
        public int getVideoState() {
            return mVideoState;
        }

        /**
         * @return The current {@link android.telecom.StatusHints}, or {@code null} if none
         * have been set.
         */
        public StatusHints getStatusHints() {
            return mStatusHints;
        }

        /**
         * @return A bundle extras to pass with the call
         */
        public Bundle getExtras() {
            return mExtras;
        }

        @Override
        public boolean equals(Object o) {
            if (o instanceof Details) {
                Details d = (Details) o;
                return
                        Objects.equals(mHandle, d.mHandle) &&
                        Objects.equals(mHandlePresentation, d.mHandlePresentation) &&
                        Objects.equals(mCallerDisplayName, d.mCallerDisplayName) &&
                        Objects.equals(mCallerDisplayNamePresentation,
                                d.mCallerDisplayNamePresentation) &&
                        Objects.equals(mAccountHandle, d.mAccountHandle) &&
                        Objects.equals(mCallCapabilities, d.mCallCapabilities) &&
                        Objects.equals(mCallProperties, d.mCallProperties) &&
                        Objects.equals(mDisconnectCause, d.mDisconnectCause) &&
                        Objects.equals(mConnectTimeMillis, d.mConnectTimeMillis) &&
                        Objects.equals(mGatewayInfo, d.mGatewayInfo) &&
                        Objects.equals(mVideoState, d.mVideoState) &&
                        Objects.equals(mStatusHints, d.mStatusHints) &&
                        Objects.equals(mExtras, d.mExtras);
            }
            return false;
        }

        @Override
        public int hashCode() {
            return
                    Objects.hashCode(mHandle) +
                    Objects.hashCode(mHandlePresentation) +
                    Objects.hashCode(mCallerDisplayName) +
                    Objects.hashCode(mCallerDisplayNamePresentation) +
                    Objects.hashCode(mAccountHandle) +
                    Objects.hashCode(mCallCapabilities) +
                    Objects.hashCode(mCallProperties) +
                    Objects.hashCode(mDisconnectCause) +
                    Objects.hashCode(mConnectTimeMillis) +
                    Objects.hashCode(mGatewayInfo) +
                    Objects.hashCode(mVideoState) +
                    Objects.hashCode(mStatusHints) +
                    Objects.hashCode(mExtras);
        }

        /** {@hide} */
        public Details(
                Uri handle,
                int handlePresentation,
                String callerDisplayName,
                int callerDisplayNamePresentation,
                PhoneAccountHandle accountHandle,
                int capabilities,
                int properties,
                DisconnectCause disconnectCause,
                long connectTimeMillis,
                GatewayInfo gatewayInfo,
                int videoState,
                StatusHints statusHints,
                Bundle extras) {
            mHandle = handle;
            mHandlePresentation = handlePresentation;
            mCallerDisplayName = callerDisplayName;
            mCallerDisplayNamePresentation = callerDisplayNamePresentation;
            mAccountHandle = accountHandle;
            mCallCapabilities = capabilities;
            mCallProperties = properties;
            mDisconnectCause = disconnectCause;
            mConnectTimeMillis = connectTimeMillis;
            mGatewayInfo = gatewayInfo;
            mVideoState = videoState;
            mStatusHints = statusHints;
            mExtras = extras;
        }
    }

    public static abstract class Listener {
        /**
         * Invoked when the state of this {@code Call} has changed. See {@link #getState()}.
         *
         * @param call The {@code Call} invoking this method.
         * @param state The new state of the {@code Call}.
         */
        public void onStateChanged(Call call, int state) {}

        /**
         * Invoked when the parent of this {@code Call} has changed. See {@link #getParent()}.
         *
         * @param call The {@code Call} invoking this method.
         * @param parent The new parent of the {@code Call}.
         */
        public void onParentChanged(Call call, Call parent) {}

        /**
         * Invoked when the children of this {@code Call} have changed. See {@link #getChildren()}.
         *
         * @param call The {@code Call} invoking this method.
         * @param children The new children of the {@code Call}.
         */
        public void onChildrenChanged(Call call, List<Call> children) {}

        /**
         * Invoked when the details of this {@code Call} have changed. See {@link #getDetails()}.
         *
         * @param call The {@code Call} invoking this method.
         * @param details A {@code Details} object describing the {@code Call}.
         */
        public void onDetailsChanged(Call call, Details details) {}

        /**
         * Invoked when the text messages that can be used as responses to the incoming
         * {@code Call} are loaded from the relevant database.
         * See {@link #getCannedTextResponses()}.
         *
         * @param call The {@code Call} invoking this method.
         * @param cannedTextResponses The text messages useable as responses.
         */
        public void onCannedTextResponsesLoaded(Call call, List<String> cannedTextResponses) {}

        /**
         * Invoked when the post-dial sequence in the outgoing {@code Call} has reached a pause
         * character. This causes the post-dial signals to stop pending user confirmation. An
         * implementation should present this choice to the user and invoke
         * {@link #postDialContinue(boolean)} when the user makes the choice.
         *
         * @param call The {@code Call} invoking this method.
         * @param remainingPostDialSequence The post-dial characters that remain to be sent.
         */
        public void onPostDialWait(Call call, String remainingPostDialSequence) {}

        /**
         * Invoked when the {@code Call.VideoCall} of the {@code Call} has changed.
         *
         * @param call The {@code Call} invoking this method.
         * @param videoCall The {@code Call.VideoCall} associated with the {@code Call}.
         * @hide
         */
        public void onVideoCallChanged(Call call, InCallService.VideoCall videoCall) {}

        /**
         * Invoked when the {@code Call} is destroyed. Clients should refrain from cleaning
         * up their UI for the {@code Call} in response to state transitions. Specifically,
         * clients should not assume that a {@link #onStateChanged(Call, int)} with a state of
         * {@link #STATE_DISCONNECTED} is the final notification the {@code Call} will send. Rather,
         * clients should wait for this method to be invoked.
         *
         * @param call The {@code Call} being destroyed.
         */
        public void onCallDestroyed(Call call) {}

        /**
         * Invoked upon changes to the set of {@code Call}s with which this {@code Call} can be
         * conferenced.
         *
         * @param call The {@code Call} being updated.
         * @param conferenceableCalls The {@code Call}s with which this {@code Call} can be
         *          conferenced.
         */
        public void onConferenceableCallsChanged(Call call, List<Call> conferenceableCalls) {}
    }

    private final Phone mPhone;
    private final String mTelecomCallId;
    private final InCallAdapter mInCallAdapter;
    private final List<String> mChildrenIds = new ArrayList<>();
    private final List<Call> mChildren = new ArrayList<>();
    private final List<Call> mUnmodifiableChildren = Collections.unmodifiableList(mChildren);
    private final List<Listener> mListeners = new CopyOnWriteArrayList<>();
    private final List<Call> mConferenceableCalls = new ArrayList<>();
    private final List<Call> mUnmodifiableConferenceableCalls =
            Collections.unmodifiableList(mConferenceableCalls);

    private boolean mChildrenCached;
    private String mParentId = null;
    private int mState;
    private List<String> mCannedTextResponses = null;
    private String mRemainingPostDialSequence;
    private InCallService.VideoCall mVideoCall;
    private Details mDetails;

    /**
     * Obtains the post-dial sequence remaining to be emitted by this {@code Call}, if any.
     *
     * @return The remaining post-dial sequence, or {@code null} if there is no post-dial sequence
     * remaining or this {@code Call} is not in a post-dial state.
     */
    public String getRemainingPostDialSequence() {
        return mRemainingPostDialSequence;
    }

    /**
     * Instructs this {@link #STATE_RINGING} {@code Call} to answer.
     * @param videoState The video state in which to answer the call.
     */
    public void answer(int videoState) {
        mInCallAdapter.answerCall(mTelecomCallId, videoState);
    }

    /**
     * Instructs this {@link #STATE_RINGING} {@code Call} to reject.
     *
     * @param rejectWithMessage Whether to reject with a text message.
     * @param textMessage An optional text message with which to respond.
     */
    public void reject(boolean rejectWithMessage, String textMessage) {
        mInCallAdapter.rejectCall(mTelecomCallId, rejectWithMessage, textMessage);
    }

    /**
     * Instructs this {@code Call} to disconnect.
     */
    public void disconnect() {
        mInCallAdapter.disconnectCall(mTelecomCallId);
    }

    /**
     * Instructs this {@code Call} to go on hold.
     */
    public void hold() {
        mInCallAdapter.holdCall(mTelecomCallId);
    }

    /**
     * Instructs this {@link #STATE_HOLDING} call to release from hold.
     */
    public void unhold() {
        mInCallAdapter.unholdCall(mTelecomCallId);
    }

    /**
     * Instructs this {@code Call} to play a dual-tone multi-frequency signaling (DTMF) tone.
     *
     * Any other currently playing DTMF tone in the specified call is immediately stopped.
     *
     * @param digit A character representing the DTMF digit for which to play the tone. This
     *         value must be one of {@code '0'} through {@code '9'}, {@code '*'} or {@code '#'}.
     */
    public void playDtmfTone(char digit) {
        mInCallAdapter.playDtmfTone(mTelecomCallId, digit);
    }

    /**
     * Instructs this {@code Call} to stop any dual-tone multi-frequency signaling (DTMF) tone
     * currently playing.
     *
     * DTMF tones are played by calling {@link #playDtmfTone(char)}. If no DTMF tone is
     * currently playing, this method will do nothing.
     */
    public void stopDtmfTone() {
        mInCallAdapter.stopDtmfTone(mTelecomCallId);
    }

    /**
     * Instructs this {@code Call} to continue playing a post-dial DTMF string.
     *
     * A post-dial DTMF string is a string of digits entered after a phone number, when dialed,
     * that are immediately sent as DTMF tones to the recipient as soon as the connection is made.
     *
     * If the DTMF string contains a {@link TelecomManager#DTMF_CHARACTER_PAUSE} symbol, this
     * {@code Call} will temporarily pause playing the tones for a pre-defined period of time.
     *
     * If the DTMF string contains a {@link TelecomManager#DTMF_CHARACTER_WAIT} symbol, this
     * {@code Call} will pause playing the tones and notify listeners via
     * {@link Listener#onPostDialWait(Call, String)}. At this point, the in-call app
     * should display to the user an indication of this state and an affordance to continue
     * the postdial sequence. When the user decides to continue the postdial sequence, the in-call
     * app should invoke the {@link #postDialContinue(boolean)} method.
     *
     * @param proceed Whether or not to continue with the post-dial sequence.
     */
    public void postDialContinue(boolean proceed) {
        mInCallAdapter.postDialContinue(mTelecomCallId, proceed);
    }

    /**
     * Notifies this {@code Call} that an account has been selected and to proceed with placing
     * an outgoing call. Optionally sets this account as the default account.
     */
    public void phoneAccountSelected(PhoneAccountHandle accountHandle, boolean setDefault) {
        mInCallAdapter.phoneAccountSelected(mTelecomCallId, accountHandle, setDefault);

    }

    /**
     * Instructs this {@code Call} to enter a conference.
     *
     * @param callToConferenceWith The other call with which to conference.
     */
    public void conference(Call callToConferenceWith) {
        if (callToConferenceWith != null) {
            mInCallAdapter.conference(mTelecomCallId, callToConferenceWith.mTelecomCallId);
        }
    }

    /**
     * Instructs this {@code Call} to split from any conference call with which it may be
     * connected.
     */
    public void splitFromConference() {
        mInCallAdapter.splitFromConference(mTelecomCallId);
    }

    /**
     * Merges the calls within this conference. See {@link Details#CAPABILITY_MERGE_CONFERENCE}.
     */
    public void mergeConference() {
        mInCallAdapter.mergeConference(mTelecomCallId);
    }

    /**
     * Swaps the calls within this conference. See {@link Details#CAPABILITY_SWAP_CONFERENCE}.
     */
    public void swapConference() {
        mInCallAdapter.swapConference(mTelecomCallId);
    }

    /**
     * Obtains the parent of this {@code Call} in a conference, if any.
     *
     * @return The parent {@code Call}, or {@code null} if this {@code Call} is not a
     * child of any conference {@code Call}s.
     */
    public Call getParent() {
        if (mParentId != null) {
            return mPhone.internalGetCallByTelecomId(mParentId);
        }
        return null;
    }

    /**
     * Obtains the children of this conference {@code Call}, if any.
     *
     * @return The children of this {@code Call} if this {@code Call} is a conference, or an empty
     * {@code List} otherwise.
     */
    public List<Call> getChildren() {
        if (!mChildrenCached) {
            mChildrenCached = true;
            mChildren.clear();

            for(String id : mChildrenIds) {
                Call call = mPhone.internalGetCallByTelecomId(id);
                if (call == null) {
                    // At least one child was still not found, so do not save true for "cached"
                    mChildrenCached = false;
                } else {
                    mChildren.add(call);
                }
            }
        }

        return mUnmodifiableChildren;
    }

    /**
     * Returns the list of {@code Call}s with which this {@code Call} is allowed to conference.
     *
     * @return The list of conferenceable {@code Call}s.
     */
    public List<Call> getConferenceableCalls() {
        return mUnmodifiableConferenceableCalls;
    }

    /**
     * Obtains the state of this {@code Call}.
     *
     * @return A state value, chosen from the {@code STATE_*} constants.
     */
    public int getState() {
        return mState;
    }

    /**
     * Obtains a list of canned, pre-configured message responses to present to the user as
     * ways of rejecting this {@code Call} using via a text message.
     *
     * @see #reject(boolean, String)
     *
     * @return A list of canned text message responses.
     */
    public List<String> getCannedTextResponses() {
        return mCannedTextResponses;
    }

    /**
     * Obtains an object that can be used to display video from this {@code Call}.
     *
     * @return An {@code Call.VideoCall}.
     * @hide
     */
    public InCallService.VideoCall getVideoCall() {
        return mVideoCall;
    }

    /**
     * Obtains an object containing call details.
     *
     * @return A {@link Details} object. Depending on the state of the {@code Call}, the
     * result may be {@code null}.
     */
    public Details getDetails() {
        return mDetails;
    }

    /**
     * Adds a listener to this {@code Call}.
     *
     * @param listener A {@code Listener}.
     */
    public void addListener(Listener listener) {
        mListeners.add(listener);
    }

    /**
     * Removes a listener from this {@code Call}.
     *
     * @param listener A {@code Listener}.
     */
    public void removeListener(Listener listener) {
        if (listener != null) {
            mListeners.remove(listener);
        }
    }

    /** {@hide} */
    Call(Phone phone, String telecomCallId, InCallAdapter inCallAdapter) {
        mPhone = phone;
        mTelecomCallId = telecomCallId;
        mInCallAdapter = inCallAdapter;
        mState = STATE_NEW;
    }

    /** {@hide} */
    final String internalGetCallId() {
        return mTelecomCallId;
    }

    /** {@hide} */
    final void internalUpdate(ParcelableCall parcelableCall, Map<String, Call> callIdMap) {
        // First, we update the internal state as far as possible before firing any updates.
        Details details = new Details(
                parcelableCall.getHandle(),
                parcelableCall.getHandlePresentation(),
                parcelableCall.getCallerDisplayName(),
                parcelableCall.getCallerDisplayNamePresentation(),
                parcelableCall.getAccountHandle(),
                parcelableCall.getCapabilities(),
                parcelableCall.getProperties(),
                parcelableCall.getDisconnectCause(),
                parcelableCall.getConnectTimeMillis(),
                parcelableCall.getGatewayInfo(),
                parcelableCall.getVideoState(),
                parcelableCall.getStatusHints(),
                parcelableCall.getExtras());
        boolean detailsChanged = !Objects.equals(mDetails, details);
        if (detailsChanged) {
            mDetails = details;
        }

        boolean cannedTextResponsesChanged = false;
        if (mCannedTextResponses == null && parcelableCall.getCannedSmsResponses() != null
                && !parcelableCall.getCannedSmsResponses().isEmpty()) {
            mCannedTextResponses =
                    Collections.unmodifiableList(parcelableCall.getCannedSmsResponses());
        }

        boolean videoCallChanged = !Objects.equals(mVideoCall, parcelableCall.getVideoCall());
        if (videoCallChanged) {
            mVideoCall = parcelableCall.getVideoCall();
        }

        int state = stateFromParcelableCallState(parcelableCall.getState());
        boolean stateChanged = mState != state;
        if (stateChanged) {
            mState = state;
        }

        String parentId = parcelableCall.getParentCallId();
        boolean parentChanged = !Objects.equals(mParentId, parentId);
        if (parentChanged) {
            mParentId = parentId;
        }

        List<String> childCallIds = parcelableCall.getChildCallIds();
        boolean childrenChanged = !Objects.equals(childCallIds, mChildrenIds);
        if (childrenChanged) {
            mChildrenIds.clear();
            mChildrenIds.addAll(parcelableCall.getChildCallIds());
            mChildrenCached = false;
        }

        List<String> conferenceableCallIds = parcelableCall.getConferenceableCallIds();
        List<Call> conferenceableCalls = new ArrayList<Call>(conferenceableCallIds.size());
        for (String otherId : conferenceableCallIds) {
            if (callIdMap.containsKey(otherId)) {
                conferenceableCalls.add(callIdMap.get(otherId));
            }
        }

        if (!Objects.equals(mConferenceableCalls, conferenceableCalls)) {
            mConferenceableCalls.clear();
            mConferenceableCalls.addAll(conferenceableCalls);
            fireConferenceableCallsChanged();
        }

        // Now we fire updates, ensuring that any client who listens to any of these notifications
        // gets the most up-to-date state.

        if (stateChanged) {
            fireStateChanged(mState);
        }
        if (detailsChanged) {
            fireDetailsChanged(mDetails);
        }
        if (cannedTextResponsesChanged) {
            fireCannedTextResponsesLoaded(mCannedTextResponses);
        }
        if (videoCallChanged) {
            fireVideoCallChanged(mVideoCall);
        }
        if (parentChanged) {
            fireParentChanged(getParent());
        }
        if (childrenChanged) {
            fireChildrenChanged(getChildren());
        }

        // If we have transitioned to DISCONNECTED, that means we need to notify clients and
        // remove ourselves from the Phone. Note that we do this after completing all state updates
        // so a client can cleanly transition all their UI to the state appropriate for a
        // DISCONNECTED Call while still relying on the existence of that Call in the Phone's list.
        if (mState == STATE_DISCONNECTED) {
            fireCallDestroyed();
            mPhone.internalRemoveCall(this);
        }
    }

    /** {@hide} */
    final void internalSetPostDialWait(String remaining) {
        mRemainingPostDialSequence = remaining;
        firePostDialWait(mRemainingPostDialSequence);
    }

    /** {@hide} */
    final void internalSetDisconnected() {
        if (mState != Call.STATE_DISCONNECTED) {
            mState = Call.STATE_DISCONNECTED;
            fireStateChanged(mState);
            fireCallDestroyed();
            mPhone.internalRemoveCall(this);
        }
    }

    private void fireStateChanged(int newState) {
        for (Listener listener : mListeners) {
            listener.onStateChanged(this, newState);
        }
    }

    private void fireParentChanged(Call newParent) {
        for (Listener listener : mListeners) {
            listener.onParentChanged(this, newParent);
        }
    }

    private void fireChildrenChanged(List<Call> children) {
        for (Listener listener : mListeners) {
            listener.onChildrenChanged(this, children);
        }
    }

    private void fireDetailsChanged(Details details) {
        for (Listener listener : mListeners) {
            listener.onDetailsChanged(this, details);
        }
    }

    private void fireCannedTextResponsesLoaded(List<String> cannedTextResponses) {
        for (Listener listener : mListeners) {
            listener.onCannedTextResponsesLoaded(this, cannedTextResponses);
        }
    }

    private void fireVideoCallChanged(InCallService.VideoCall videoCall) {
        for (Listener listener : mListeners) {
            listener.onVideoCallChanged(this, videoCall);
        }
    }

    private void firePostDialWait(String remainingPostDialSequence) {
        for (Listener listener : mListeners) {
            listener.onPostDialWait(this, remainingPostDialSequence);
        }
    }

    private void fireCallDestroyed() {
        for (Listener listener : mListeners) {
            listener.onCallDestroyed(this);
        }
    }

    private void fireConferenceableCallsChanged() {
        for (Listener listener : mListeners) {
            listener.onConferenceableCallsChanged(this, mUnmodifiableConferenceableCalls);
        }
    }

    private int stateFromParcelableCallState(int parcelableCallState) {
        switch (parcelableCallState) {
            case CallState.NEW:
                return STATE_NEW;
            case CallState.CONNECTING:
                return STATE_CONNECTING;
            case CallState.PRE_DIAL_WAIT:
                return STATE_PRE_DIAL_WAIT;
            case CallState.DIALING:
                return STATE_DIALING;
            case CallState.RINGING:
                return STATE_RINGING;
            case CallState.ACTIVE:
                return STATE_ACTIVE;
            case CallState.ON_HOLD:
                return STATE_HOLDING;
            case CallState.DISCONNECTED:
                return STATE_DISCONNECTED;
            case CallState.ABORTED:
                return STATE_DISCONNECTED;
            case CallState.DISCONNECTING:
                return STATE_DISCONNECTING;
            default:
                Log.wtf(this, "Unrecognized CallState %s", parcelableCallState);
                return STATE_NEW;
        }
    }
}