/*
 * Copyright (C) 2010 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.hardware.usb;

import android.annotation.Nullable;
import android.os.Parcel;
import android.os.Parcelable;
import com.android.internal.util.Preconditions;

A class representing an interface on a UsbDevice. USB devices can have one or more interfaces, each one providing a different piece of functionality, separate from the other interfaces. An interface will have one or more UsbEndpoints, which are the channels by which the host transfers data with the device. 

Developer Guides
For more information about communicating with USB hardware, read the
USB developer guide.

/**
 * A class representing an interface on a {@link UsbDevice}.
 * USB devices can have one or more interfaces, each one providing a different
 * piece of functionality, separate from the other interfaces.
 * An interface will have one or more {@link UsbEndpoint}s, which are the
 * channels by which the host transfers data with the device.
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For more information about communicating with USB hardware, read the
 * <a href="{@docRoot}guide/topics/usb/index.html">USB</a> developer guide.</p>
 * </div>
 */
public class UsbInterface implements Parcelable {

    private final int mId;
    private final int mAlternateSetting;
    private @Nullable final String mName;
    private final int mClass;
    private final int mSubclass;
    private final int mProtocol;

    
All endpoints of this interface, only null during creation /** All endpoints of this interface, only null during creation */
    private Parcelable[] mEndpoints;

    
UsbInterface should only be instantiated by UsbService implementation
@hide
/**
     * UsbInterface should only be instantiated by UsbService implementation
     * @hide
     */
    public UsbInterface(int id, int alternateSetting, @Nullable String name,
            int Class, int subClass, int protocol) {
        mId = id;
        mAlternateSetting = alternateSetting;
        mName = name;
        mClass = Class;
        mSubclass = subClass;
        mProtocol = protocol;
    }

    
Returns the interface's bInterfaceNumber field.
This is an integer that along with the alternate setting uniquely identifies
the interface on the device.
Returns:
the interface's ID/**
     * Returns the interface's bInterfaceNumber field.
     * This is an integer that along with the alternate setting uniquely identifies
     * the interface on the device.
     *
     * @return the interface's ID
     */
    public int getId() {
        return mId;
    }

    
Returns the interface's bAlternateSetting field. This is an integer that along with the ID uniquely identifies the interface on the device. UsbDeviceConnection.setInterface can be used to switch between two interfaces with the same ID but different alternate setting. 
Returns:
the interface's alternate setting/**
     * Returns the interface's bAlternateSetting field.
     * This is an integer that along with the ID uniquely identifies
     * the interface on the device.
     * {@link UsbDeviceConnection#setInterface} can be used to switch between
     * two interfaces with the same ID but different alternate setting.
     *
     * @return the interface's alternate setting
     */
    public int getAlternateSetting() {
        return mAlternateSetting;
    }

    
Returns the interface's name.
Returns:
the interface's name, or null if the property could not be read/**
     * Returns the interface's name.
     *
     * @return the interface's name, or {@code null} if the property could not be read
     */
    public @Nullable String getName() {
        return mName;
    }

    
Returns the interface's class field. Some useful constants for USB classes can be found in UsbConstants 
Returns:
the interface's class/**
     * Returns the interface's class field.
     * Some useful constants for USB classes can be found in {@link UsbConstants}
     *
     * @return the interface's class
     */
    public int getInterfaceClass() {
        return mClass;
    }

    
Returns the interface's subclass field.
Returns:
the interface's subclass/**
     * Returns the interface's subclass field.
     *
     * @return the interface's subclass
     */
    public int getInterfaceSubclass() {
        return mSubclass;
    }

    
Returns the interface's protocol field.
Returns:
the interface's protocol/**
     * Returns the interface's protocol field.
     *
     * @return the interface's protocol
     */
    public int getInterfaceProtocol() {
        return mProtocol;
    }

    
Returns the number of UsbEndpoints this interface contains. 
Returns:
the number of endpoints/**
     * Returns the number of {@link android.hardware.usb.UsbEndpoint}s this interface contains.
     *
     * @return the number of endpoints
     */
    public int getEndpointCount() {
        return mEndpoints.length;
    }

    
Returns the UsbEndpoint at the given index. 
Returns:
the endpoint/**
     * Returns the {@link android.hardware.usb.UsbEndpoint} at the given index.
     *
     * @return the endpoint
     */
    public UsbEndpoint getEndpoint(int index) {
        return (UsbEndpoint)mEndpoints[index];
    }

    
Only used by UsbService implementation
@hide
/**
     * Only used by UsbService implementation
     * @hide
     */
    public void setEndpoints(Parcelable[] endpoints) {
        mEndpoints = Preconditions.checkArrayElementsNotNull(endpoints, "endpoints");
    }

    @Override
    public String toString() {
        StringBuilder builder = new StringBuilder("UsbInterface[mId=" + mId +
                ",mAlternateSetting=" + mAlternateSetting +
                ",mName=" + mName + ",mClass=" + mClass +
                ",mSubclass=" + mSubclass + ",mProtocol=" + mProtocol +
                ",mEndpoints=[");
        for (int i = 0; i < mEndpoints.length; i++) {
            builder.append("\n");
            builder.append(mEndpoints[i].toString());
        }
        builder.append("]");
        return builder.toString();
    }

    public static final Parcelable.Creator<UsbInterface> CREATOR =
        new Parcelable.Creator<UsbInterface>() {
        public UsbInterface createFromParcel(Parcel in) {
            int id = in.readInt();
            int alternateSetting = in.readInt();
            String name = in.readString();
            int Class = in.readInt();
            int subClass = in.readInt();
            int protocol = in.readInt();
            Parcelable[] endpoints = in.readParcelableArray(UsbEndpoint.class.getClassLoader());
            UsbInterface intf = new UsbInterface(id, alternateSetting, name, Class, subClass, protocol);
            intf.setEndpoints(endpoints);
            return intf;
        }

        public UsbInterface[] newArray(int size) {
            return new UsbInterface[size];
        }
    };

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel parcel, int flags) {
        parcel.writeInt(mId);
        parcel.writeInt(mAlternateSetting);
        parcel.writeString(mName);
        parcel.writeInt(mClass);
        parcel.writeInt(mSubclass);
        parcel.writeInt(mProtocol);
        parcel.writeParcelableArray(mEndpoints, 0);
   }
}