/*
 * Copyright (C) 2017 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.media3.extractor.metadata.emsg;

import static androidx.media3.common.util.Util.castNonNull;

import android.os.Parcel;
import android.os.Parcelable;
import androidx.annotation.Nullable;
import androidx.annotation.VisibleForTesting;
import androidx.media3.common.Format;
import androidx.media3.common.Metadata;
import androidx.media3.common.MimeTypes;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import java.util.Arrays;

/** An Event Message (emsg) as defined in ISO 23009-1. */
@UnstableApi
public final class EventMessage implements Metadata.Entry {

  /**
   * emsg scheme_id_uri from the <a href="https://aomediacodec.github.io/av1-id3/#semantics">CMAF
   * spec</a>.
   */
  @VisibleForTesting public static final String ID3_SCHEME_ID_AOM = "https://aomedia.org/emsg/ID3";

  /**
   * The Apple-hosted scheme_id equivalent to {@code ID3_SCHEME_ID_AOM} - used before AOM adoption.
   */
  private static final String ID3_SCHEME_ID_APPLE =
      "https://developer.apple.com/streaming/emsg-id3";

  /**
   * scheme_id_uri from section 7.3.2 of <a
   * href="https://www.scte.org/SCTEDocs/Standards/ANSI_SCTE%20214-3%202015.pdf">SCTE 214-3
   * 2015</a>.
   */
  @VisibleForTesting public static final String SCTE35_SCHEME_ID = "urn:scte:scte35:2014:bin";

  private static final Format ID3_FORMAT =
      new Format.Builder().setSampleMimeType(MimeTypes.APPLICATION_ID3).build();
  private static final Format SCTE35_FORMAT =
      new Format.Builder().setSampleMimeType(MimeTypes.APPLICATION_SCTE35).build();

  /** The message scheme. */
  public final String schemeIdUri;

  /** The value for the event. */
  public final String value;

  /** The duration of the event in milliseconds. */
  public final long durationMs;

  /** The instance identifier. */
  public final long id;

  /** The body of the message. */
  public final byte[] messageData;

  // Lazily initialized hashcode.
  private int hashCode;

  /**
   * @param schemeIdUri The message scheme.
   * @param value The value for the event.
   * @param durationMs The duration of the event in milliseconds.
   * @param id The instance identifier.
   * @param messageData The body of the message.
   */
  public EventMessage(
      String schemeIdUri, String value, long durationMs, long id, byte[] messageData) {
    this.schemeIdUri = schemeIdUri;
    this.value = value;
    this.durationMs = durationMs;
    this.id = id;
    this.messageData = messageData;
  }

  /* package */ EventMessage(Parcel in) {
    schemeIdUri = castNonNull(in.readString());
    value = castNonNull(in.readString());
    durationMs = in.readLong();
    id = in.readLong();
    messageData = castNonNull(in.createByteArray());
  }

  @Override
  @Nullable
  public Format getWrappedMetadataFormat() {
    switch (schemeIdUri) {
      case ID3_SCHEME_ID_AOM:
      case ID3_SCHEME_ID_APPLE:
        return ID3_FORMAT;
      case SCTE35_SCHEME_ID:
        return SCTE35_FORMAT;
      default:
        return null;
    }
  }

  @Override
  @Nullable
  public byte[] getWrappedMetadataBytes() {
    return getWrappedMetadataFormat() != null ? messageData : null;
  }

  @Override
  public int hashCode() {
    if (hashCode == 0) {
      int result = 17;
      result = 31 * result + (schemeIdUri != null ? schemeIdUri.hashCode() : 0);
      result = 31 * result + (value != null ? value.hashCode() : 0);
      result = 31 * result + (int) (durationMs ^ (durationMs >>> 32));
      result = 31 * result + (int) (id ^ (id >>> 32));
      result = 31 * result + Arrays.hashCode(messageData);
      hashCode = result;
    }
    return hashCode;
  }

  @Override
  public boolean equals(@Nullable Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null || getClass() != obj.getClass()) {
      return false;
    }
    EventMessage other = (EventMessage) obj;
    return durationMs == other.durationMs
        && id == other.id
        && Util.areEqual(schemeIdUri, other.schemeIdUri)
        && Util.areEqual(value, other.value)
        && Arrays.equals(messageData, other.messageData);
  }

  @Override
  public String toString() {
    return "EMSG: scheme="
        + schemeIdUri
        + ", id="
        + id
        + ", durationMs="
        + durationMs
        + ", value="
        + value;
  }

  // Parcelable implementation.

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

  @Override
  public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(schemeIdUri);
    dest.writeString(value);
    dest.writeLong(durationMs);
    dest.writeLong(id);
    dest.writeByteArray(messageData);
  }

  public static final Parcelable.Creator<EventMessage> CREATOR =
      new Parcelable.Creator<EventMessage>() {

        @Override
        public EventMessage createFromParcel(Parcel in) {
          return new EventMessage(in);
        }

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