/*
 * Copyright (C) 2018 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.telephony.ims.compat.feature;

import android.annotation.IntDef;
import android.annotation.UnsupportedAppUsage;
import android.content.Context;
import android.os.IInterface;
import android.os.RemoteException;
import android.telephony.SubscriptionManager;
import android.util.Log;

import com.android.ims.internal.IImsFeatureStatusCallback;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import java.util.WeakHashMap;

/**
 * Base class for all IMS features that are supported by the framework.
 * @hide
 */
public abstract class ImsFeature {

    private static final String LOG_TAG = "ImsFeature";

    // Invalid feature value
    public static final int INVALID = -1;
    // ImsFeatures that are defined in the Manifests. Ensure that these values match the previously
    // defined values in ImsServiceClass for compatibility purposes.
    public static final int EMERGENCY_MMTEL = 0;
    public static final int MMTEL = 1;
    public static final int RCS = 2;
    // Total number of features defined
    public static final int MAX = 3;

    // Integer values defining the state of the ImsFeature at any time.
    @IntDef(flag = true,
            value = {
                    STATE_NOT_AVAILABLE,
                    STATE_INITIALIZING,
                    STATE_READY,
            })
    @Retention(RetentionPolicy.SOURCE)
    public @interface ImsState {}
    public static final int STATE_NOT_AVAILABLE = 0;
    public static final int STATE_INITIALIZING = 1;
    public static final int STATE_READY = 2;

    private final Set<IImsFeatureStatusCallback> mStatusCallbacks = Collections.newSetFromMap(
            new WeakHashMap<IImsFeatureStatusCallback, Boolean>());
    private @ImsState int mState = STATE_NOT_AVAILABLE;
    private int mSlotId = SubscriptionManager.INVALID_SIM_SLOT_INDEX;
    protected Context mContext;

    public void setContext(Context context) {
        mContext = context;
    }

    public void setSlotId(int slotId) {
        mSlotId = slotId;
    }

    @UnsupportedAppUsage
    public int getFeatureState() {
        return mState;
    }

    @UnsupportedAppUsage
    protected final void setFeatureState(@ImsState int state) {
        if (mState != state) {
            mState = state;
            notifyFeatureState(state);
        }
    }

    public void addImsFeatureStatusCallback(IImsFeatureStatusCallback c) {
        if (c == null) {
            return;
        }
        try {
            // If we have just connected, send queued status.
            c.notifyImsFeatureStatus(mState);
            // Add the callback if the callback completes successfully without a RemoteException.
            synchronized (mStatusCallbacks) {
                mStatusCallbacks.add(c);
            }
        } catch (RemoteException e) {
            Log.w(LOG_TAG, "Couldn't notify feature state: " + e.getMessage());
        }
    }

    public void removeImsFeatureStatusCallback(IImsFeatureStatusCallback c) {
        if (c == null) {
            return;
        }
        synchronized (mStatusCallbacks) {
            mStatusCallbacks.remove(c);
        }
    }

    /**
     * Internal method called by ImsFeature when setFeatureState has changed.
     * @param state
     */
    private void notifyFeatureState(@ImsState int state) {
        synchronized (mStatusCallbacks) {
            for (Iterator<IImsFeatureStatusCallback> iter = mStatusCallbacks.iterator();
                 iter.hasNext(); ) {
                IImsFeatureStatusCallback callback = iter.next();
                try {
                    Log.i(LOG_TAG, "notifying ImsFeatureState=" + state);
                    callback.notifyImsFeatureStatus(state);
                } catch (RemoteException e) {
                    // remove if the callback is no longer alive.
                    iter.remove();
                    Log.w(LOG_TAG, "Couldn't notify feature state: " + e.getMessage());
                }
            }
        }
    }

    /**
     * Called when the feature is ready to use.
     */
    public abstract void onFeatureReady();

    /**
     * Called when the feature is being removed and must be cleaned up.
     */
    public abstract void onFeatureRemoved();

    /**
     * @return Binder instance
     */
    public abstract IInterface getBinder();
}