/*
 * Copyright 2019 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 androidx.media2.common;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.annotation.SuppressLint;
import android.os.Binder;
import android.os.IBinder;
import android.os.Parcel;
import android.os.Parcelable;
import android.os.RemoteException;
import android.util.Log;

import androidx.annotation.NonNull;
import androidx.annotation.RestrictTo;
import androidx.versionedparcelable.ParcelImpl;

import java.util.ArrayList;
import java.util.List;

/**
 * Transfer a large list of {@link ParcelImpl} objects across an IPC. Splits into
 * multiple transactions if needed.
 *
 * Note: Using this class causes synchronous binder calls in the opposite direction regardless of
 * "oneway" property.
 *
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
@SuppressLint("BanParcelableUsage")
public class ParcelImplListSlice implements Parcelable {
    private static final String TAG = "ParcelImplListSlice";
    private static final boolean DEBUG = false;

    private static final int MAX_IPC_SIZE = 64 * 1024; // IBinder.MAX_IPC_SIZE
    private static final int INLINE_COUNT_LIMIT = 1;

    final List<ParcelImpl> mList;

    public ParcelImplListSlice(@NonNull List<ParcelImpl> list) {
        if (list == null) {
            throw new NullPointerException("list shouldn't be null");
        }
        mList = list;
    }

    ParcelImplListSlice(Parcel p) {
        final int itemCount = p.readInt();
        mList = new ArrayList<>(itemCount);
        if (DEBUG) {
            Log.d(TAG, "Retrieving " + itemCount + " items");
        }
        if (itemCount <= 0) {
            return;
        }

        int i = 0;
        while (i < itemCount) {
            if (p.readInt() == 0) {
                break;
            }

            final ParcelImpl parcelImpl = p.readParcelable(ParcelImpl.class.getClassLoader());
            mList.add(parcelImpl);

            if (DEBUG) {
                Log.d(TAG, "Read inline #" + i + ": " + mList.get(mList.size() - 1));
            }
            i++;
        }
        if (i >= itemCount) {
            return;
        }
        final IBinder retriever = p.readStrongBinder();
        while (i < itemCount) {
            if (DEBUG) {
                Log.d(TAG, "Reading more @" + i + " of " + itemCount + ": retriever=" + retriever);
            }
            Parcel data = Parcel.obtain();
            Parcel reply = Parcel.obtain();
            try {
                data.writeInt(i);
                try {
                    retriever.transact(IBinder.FIRST_CALL_TRANSACTION, data, reply, 0);
                } catch (RemoteException e) {
                    Log.w(TAG, "Failure retrieving array; only received " + i + " of " + itemCount,
                            e);
                    return;
                }
                while (i < itemCount && reply.readInt() != 0) {
                    final ParcelImpl parcelImpl = reply.readParcelable(
                            ParcelImpl.class.getClassLoader());
                    mList.add(parcelImpl);

                    if (DEBUG) {
                        Log.d(TAG, "Read extra #" + i + ": " + mList.get(mList.size() - 1));
                    }
                    i++;
                }
            } finally {
                reply.recycle();
                data.recycle();
            }
        }
    }

    public @NonNull List<ParcelImpl> getList() {
        return mList;
    }

    /**
     * Write this to another Parcel. Note that this discards the internal Parcel
     * and should not be used anymore. This is so we can pass this to a Binder
     * where we won't have a chance to call recycle on this.
     */
    @Override
    public void writeToParcel(Parcel dest, int flags) {
        final int itemCount = mList.size();
        dest.writeInt(itemCount);
        if (DEBUG) {
            Log.d(TAG, "Writing " + itemCount + " items");
        }
        if (itemCount > 0) {
            int i = 0;
            while (i < itemCount && i < INLINE_COUNT_LIMIT && dest.dataSize() < MAX_IPC_SIZE) {
                dest.writeInt(1);

                final ParcelImpl parcelable = mList.get(i);
                dest.writeParcelable(parcelable, flags);

                if (DEBUG) {
                    Log.d(TAG, "Wrote inline #" + i + ": " + mList.get(i));
                }
                i++;
            }
            if (i < itemCount) {
                dest.writeInt(0);
                Binder retriever = new Binder() {
                    @Override
                    protected boolean onTransact(int code, Parcel data, Parcel reply, int flags)
                            throws RemoteException {
                        if (code != FIRST_CALL_TRANSACTION) {
                            return super.onTransact(code, data, reply, flags);
                        }
                        int i = data.readInt();
                        if (DEBUG) {
                            Log.d(TAG, "Writing more @" + i + " of " + itemCount);
                        }
                        while (i < itemCount && reply.dataSize() < MAX_IPC_SIZE) {
                            reply.writeInt(1);

                            final ParcelImpl parcelable = mList.get(i);
                            reply.writeParcelable(parcelable, flags);

                            if (DEBUG) {
                                Log.d(TAG, "Wrote extra #" + i + ": " + mList.get(i));
                            }
                            i++;
                        }
                        if (i < itemCount) {
                            if (DEBUG) {
                                Log.d(TAG, "Breaking @" + i + " of " + itemCount);
                            }
                            reply.writeInt(0);
                        }
                        return true;
                    }
                };
                if (DEBUG) {
                    Log.d(TAG, "Breaking @" + i + " of " + itemCount + ": retriever=" + retriever);
                }
                dest.writeStrongBinder(retriever);
            }
        }
    }

    @Override
    public int describeContents() {
        return 0;
    }

    public static final Parcelable.Creator<ParcelImplListSlice> CREATOR =
            new Parcelable.Creator<ParcelImplListSlice>() {
        @Override
        public ParcelImplListSlice createFromParcel(Parcel in) {
            return new ParcelImplListSlice(in);
        }

        @Override
        public ParcelImplListSlice[] newArray(int size) {
            return new ParcelImplListSlice[size];
        }
    };
}