/*
 * Copyright 2020 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.camera.video;

import android.media.AudioFormat;
import android.media.MediaRecorder;
import android.util.Range;

import androidx.annotation.IntDef;
import androidx.annotation.NonNull;
import androidx.annotation.RestrictTo;
import androidx.annotation.RestrictTo.Scope;

import com.google.auto.value.AutoValue;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * Audio specification that is options to config audio source and encoding.
 */
@RestrictTo(Scope.LIBRARY)
@AutoValue
public abstract class AudioSpec {

    /**
     * The audio source format representing no preference for audio source format.
     */
    public static final int SOURCE_FORMAT_AUTO = -1;
    /**
     * The PCM 16 bit per sample audio source format. Guaranteed to be supported by all devices.
     */
    public static final int SOURCE_FORMAT_PCM_16BIT = AudioFormat.ENCODING_PCM_16BIT;

    @IntDef({SOURCE_FORMAT_AUTO, SOURCE_FORMAT_PCM_16BIT})
    @Retention(RetentionPolicy.SOURCE)
    @interface SourceFormat {
    }

    /**
     * Allows the audio source to choose the appropriate number of channels.
     */
    public static final int CHANNEL_COUNT_AUTO = -1;
    /**
     * A channel count which is equivalent to no audio.
     */
    public static final int CHANNEL_COUNT_NONE = 0;
    /**
     * A channel count corresponding to a single audio channel.
     */
    public static final int CHANNEL_COUNT_MONO = 1;
    /**
     * A channel count corresponding to two audio channels.
     */
    public static final int CHANNEL_COUNT_STEREO = 2;

    @IntDef(open = true,
            value = {CHANNEL_COUNT_AUTO, CHANNEL_COUNT_NONE, CHANNEL_COUNT_MONO,
                    CHANNEL_COUNT_STEREO})
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(RestrictTo.Scope.LIBRARY)
    public @interface ChannelCount {
    }

    /**
     * The audio source representing no preference for audio source.
     */
    public static final int SOURCE_AUTO = -1;
    /**
     * Microphone audio source tuned for video recording, with the same orientation as the camera
     * if available.
     */
    public static final int SOURCE_CAMCORDER = MediaRecorder.AudioSource.CAMCORDER;

    @IntDef({SOURCE_AUTO, SOURCE_CAMCORDER})
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(RestrictTo.Scope.LIBRARY)
    public @interface Source {
    }

    /**
     * Bitrate range representing no preference for bitrate.
     *
     * <p>Using this value with {@link AudioSpec.Builder#setBitrate(Range)} informs the device it
     * should choose any appropriate bitrate given the device and codec constraints.
     */
    @NonNull
    public static final Range<Integer> BITRATE_RANGE_AUTO = new Range<>(0,
            Integer.MAX_VALUE);

    /**
     * Sample rate range representing no preference for sample rate.
     *
     * <p>Using this value with {@link AudioSpec.Builder#setSampleRate(Range)} informs the device it
     * should choose any appropriate sample rate given the device and codec constraints.
     */
    @NonNull
    public static final Range<Integer> SAMPLE_RATE_RANGE_AUTO = new Range<>(0,
            Integer.MAX_VALUE);

    // Restrict constructor to same package
    AudioSpec() {
    }

    /** Returns a build for this config. */
    @NonNull
    public static Builder builder() {
        return new AutoValue_AudioSpec.Builder()
                .setSourceFormat(SOURCE_FORMAT_AUTO)
                .setSource(SOURCE_AUTO)
                .setChannelCount(CHANNEL_COUNT_AUTO)
                .setBitrate(BITRATE_RANGE_AUTO)
                .setSampleRate(SAMPLE_RATE_RANGE_AUTO);
    }

    /** Gets the bitrate. */
    @NonNull
    public abstract Range<Integer> getBitrate();

    // Configurations for AudioRecord.
    // *********************************************************************************************

    /** Gets the audio format. */
    @SourceFormat
    public abstract int getSourceFormat();

    /** Gets the audio source. */
    @Source
    public abstract int getSource();

    /** Gets the sample bitrate. */
    @NonNull
    public abstract Range<Integer> getSampleRate();

    /** Gets the channel count. */
    @ChannelCount
    public abstract int getChannelCount();

    // *********************************************************************************************

    /**
     * Returns a {@link Builder} instance with the same property values as this instance.
     */
    @NonNull
    public abstract Builder toBuilder();

    /**
     * The builder of the {@link AudioSpec}.
     */
    @RestrictTo(Scope.LIBRARY)
    @SuppressWarnings("StaticFinalBuilder")
    @AutoValue.Builder
    public abstract static class Builder {
        // Restrict construction to same package
        Builder() {
        }

        /**
         * Sets the desired range of bitrates to be used by the encoder.
         *
         * <p>If not set, defaults to {@link #BITRATE_RANGE_AUTO}.
         */
        @NonNull
        public abstract Builder setBitrate(@NonNull Range<Integer> bitrate);

        // Configurations for AudioRecord.
        // *****************************************************************************************

        /**
         * Sets the audio source format.
         *
         * <p>Available values for source format are {@link #SOURCE_FORMAT_AUTO} and
         * {@link #SOURCE_FORMAT_PCM_16BIT}.
         *
         * <p>If not set, defaults to {@link #SOURCE_FORMAT_AUTO}.
         */
        @NonNull
        public abstract Builder setSourceFormat(@SourceFormat int audioFormat);

        /**
         * Sets the audio source.
         *
         * <p>Available values for source are {@link #SOURCE_AUTO} and {@link #SOURCE_CAMCORDER}.
         *
         * <p>If not set, defaults to {@link #SOURCE_AUTO}.
         */
        @NonNull
        public abstract Builder setSource(@Source int source);

        /**
         * Sets the desired range of sample rates to be used by the encoder.
         *
         * <p>If not set, defaults to {@link #SAMPLE_RATE_RANGE_AUTO}.
         */
        @NonNull
        public abstract Builder setSampleRate(@NonNull Range<Integer> sampleRate);

        /**
         * Sets the desired number of audio channels.
         *
         * <p>If not set, defaults to {@link #CHANNEL_COUNT_AUTO}. Other common channel counts
         * include {@link #CHANNEL_COUNT_MONO} or {@link #CHANNEL_COUNT_STEREO}.
         *
         * <p>Setting to {@link #CHANNEL_COUNT_NONE} is equivalent to requesting that no audio
         * should be present.
         */
        @NonNull
        public abstract Builder setChannelCount(@ChannelCount int channelCount);

        // *****************************************************************************************

        /** Builds the AudioSpec instance. */
        @NonNull
        public abstract AudioSpec build();
    }

    /**
     * An audio specification that corresponds to no audio.
     *
     * <p>This is equivalent to creating an {@link AudioSpec} with channel count set to
     * {@link #CHANNEL_COUNT_NONE}.
     */
    public static final AudioSpec NO_AUDIO = builder().setChannelCount(CHANNEL_COUNT_NONE).build();
}