/*
 * Copyright (C) 2016 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.contexthub@1.0;

import IContexthubCallback;

/**
 * The Context Hub HAL provides an interface to a separate low-power processing
 * domain that has direct access to contextual information, such as sensors.
 * Native applications that run within a context hub are known as nanoapps, and
 * they execute within the Context Hub Runtime Environment (CHRE), which is
 * standardized via the CHRE API, defined elsewhere.
 */
interface IContexthub {
    /**
     * Enumerate all available context hubs on the system.
     *
     * @return hubs list of hubs on this system.
     */
    getHubs() generates (vec<ContextHub> hubs);

    /**
     * Register a callback for the HAL implementation to send asynchronous
     * messages to the service from a context hub. There can be a maximum of
     * one callback registered with the HAL. A call to this function when a
     * callback has already been registered must override the previous
     * registration.
     *
     * @param hubId    identifier for the hub
     * @param callback an implementation of the IContextHubCallbacks
     *
     * @return result OK on success
     *                BAD_VALUE if parameters are not sane
     *
     */
     registerCallback(uint32_t hubId, IContexthubCallback cb) generates (Result result);

    /**
     * Send a message to a hub
     *
     * @param hubId identifier for hub to send message to
     * @param msg   message to be sent
     *
     * @return result OK if successful, error code otherwise
     *                BAD_VALUE if parameters are not sane
     *                TRANSACTION_FAILED if message send failed
     */
    sendMessageToHub(uint32_t hubId, ContextHubMsg msg)
            generates (Result result);

    /**
     * Loads a nanoApp. After loading, the nanoApp's init method must be called.
     * After the init method for nanoApp returns success, this must be indicated
     * to the service by an asynchronous call to handleTxnResult.
     *
     * Loading a nanoapp must not take more than 30 seconds.
     *
     * Depending on the implementation, nanoApps loaded via this API may or may
     * not persist across reboots of the hub. If they do persist, the
     * implementation must initially place nanoApps in the disabled state upon a
     * reboot, and not start them until a call is made to enableNanoApp(). In
     * this case, the app must also be unloaded upon a factory reset of the
     * device.
     *
     * @param hubId identifer of the contextHub
     * @param appBinary contains the binary representation of the nanoApp, plus
     *                  metadata
     * @param transactionId transactionId for this call
     *
     * @return result OK if transation started
     *                BAD_VALUE if parameters are not sane
     *                TRANSACTION_PENDING if hub is busy with another
     *                                    load/unload transaction
     *                TRANSACTION_FAILED if load failed synchronously
     *
     */
    loadNanoApp(uint32_t hubId,
                NanoAppBinary appBinary,
                uint32_t transactionId)
            generates (Result result);

    /**
     * Unloads a nanoApp. Before the unload, the apps deinit method is called.
     * After this, success must be indicated to the service through an
     * asynchronous call to handleTxnResult.
     *
     * Unloading a nanoapp must not take more than 5 seconds.
     *
     * @param hubId identifer of the contextHub
     * @param appId appIdentifier returned by the HAL
     * @param msg   message to be sent
     *
     * @return result OK if transation started
     *                BAD_VALUE if parameters are not sane
     *                TRANSACTION_PENDING if hub is busy with another
     *                                    load/unload transaction
     *                TRANSACTION_FAILED if unload failed synchronously
     *
     */
    unloadNanoApp(uint32_t hubId, uint64_t appId, uint32_t transactionId)
            generates (Result result);

    /**
     * Enables a nanoApp. The app's init method is called.
     * After this, success must be indicated to the service through an
     * asynchronous message.
     *
     * Enabling a nanoapp must not take more than 5 seconds.
     *
     * @param hubId identifer of the contextHub
     * @param appId appIdentifier returned by the HAL
     * @param msg   message to be sent
     *
     * @return result OK if transation started
     *                BAD_VALUE if parameters are not sane
     *                TRANSACTION_PENDING if hub is busy with another
     *                                    load/unload transaction
     *                FAILED_TRANSACTION if load fails immediately
     *
     */
    enableNanoApp(uint32_t hubId, uint64_t appId, uint32_t transactionId)
            generates (Result result);

    /**
     * Disables a nanoApp. The app's deinit method is called.
     * After this, success must be indicated to the service through an
     * asynchronous message.
     *
     * Disabling a nanoapp must not take more than 5 seconds.
     *
     * @param hubId identifer of the contextHub
     * @param appId appIdentifier returned by the HAL
     * @param msg   message to be sent
     *
     * @return result OK if transation started
     *                BAD_VALUE if parameters are not sane
     *                TRANSACTION_PENDING if hub is busy with another
     *                                    load/unload transaction
     *                FAILED_TRANSACTION if load fails immediately
     *
     */
    disableNanoApp(uint32_t hubId, uint64_t appId, uint32_t transactionId)
            generates (Result result);

    /**
     * Queries for Loaded apps on the hub
     *
     * @param hubId identifer of the contextHub
     *
     * @return apps all nanoApps on the hub.
     *              All nanoApps that can be modified by the service must
     *              be returned. A non-modifiable nanoapps must not be
     *              returned. A modifiable nanoApp is one that can be
     *              unloaded/disabled/enabled by the service.
     *
     */
    queryApps(uint32_t hubId) generates (Result result);
};
