// Copyright (c) 2015-2019 The HomeKit ADK Contributors
//
// Licensed under the Apache License, Version 2.0 (the “License”);
// you may not use this file except in compliance with the License.
// See [CONTRIBUTORS.md] for the list of HomeKit ADK project authors.

#ifndef HAP_PLATFORM_KEY_VALUE_STORE_INIT_H
#define HAP_PLATFORM_KEY_VALUE_STORE_INIT_H

#ifdef __cplusplus
extern "C" {
#endif

#include "HAPPlatform.h"

#if __has_feature(nullability)
#pragma clang assume_nonnull begin
#endif

/**@file
 * File system based key-value store.
 *
 * The implementation uses the filesystem to store data persistently.
 * Each `HAPPlatformKeyValueStoreKey` is mapped to a file within a configurable directory.
 *
 * Data writes and deletions are persisted in a blocking manner using `fsync`.
 * This guarantees atomicity in case of power failure.
 *
 * **Example**

   @code{.c}

   // Allocate key-value store.
   static HAPPlatformKeyValueStore keyValueStore;

   // Initialize key-value store.
   HAPPlatformKeyValueStoreCreate(&platform.keyValueStore,
       &(const HAPPlatformKeyValueStoreOptions) {
           .rootDirectory = ".HomeKitStore" // May be changed to store into a different directory.
       });

   @endcode
 */

/**
 * Key-value store initialization options.
 */
typedef struct {
    /**
     * Root directory into which the values will be stored as files.
     *
     * - This directory is relative to the directory from which the application is executing,
     *   i.e. not relative to the application binary.
     */
    const char* rootDirectory;
} HAPPlatformKeyValueStoreOptions;

/**
 * Key-value store.
 */
struct HAPPlatformKeyValueStore {
    // Opaque type. Do not access the instance fields directly.
    /**@cond */
    const char* rootDirectory;
    /**@endcond */
};

/**
 * Initializes the key-value store.
 *
 * @param[out] keyValueStore        Pointer to an allocated but uninitialized HAPPlatformKeyValueStore structure.
 * @param      options              Initialization options.
 */
void HAPPlatformKeyValueStoreCreate(
        HAPPlatformKeyValueStoreRef keyValueStore,
        const HAPPlatformKeyValueStoreOptions* options);

#if __has_feature(nullability)
#pragma clang assume_nonnull end
#endif

#ifdef __cplusplus
}
#endif

#endif