/*
 * Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * Additions Copyright 2016 Espressif Systems (Shanghai) PTE LTD
 *
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.
 */
/**
 * @file thing_shadow_sample.c
 * @brief A simple connected window example demonstrating the use of Thing Shadow
 *
 * See example README for more details.
 */
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>
#include <limits.h>
#include <string.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event_loop.h"
#include "esp_log.h"
#include "esp_vfs_fat.h"
#include "driver/sdmmc_host.h"

#include "nvs.h"
#include "nvs_flash.h"

#include "aws_iot_config.h"
#include "aws_iot_log.h"
#include "aws_iot_version.h"
#include "aws_iot_mqtt_client_interface.h"
#include "aws_iot_shadow_interface.h"

/*!
 * The goal of this sample application is to demonstrate the capabilities of shadow.
 * This device(say Connected Window) will open the window of a room based on temperature
 * It can report to the Shadow the following parameters:
 *  1. temperature of the room (double)
 *  2. status of the window (open or close)
 * It can act on commands from the cloud. In this case it will open or close the window based on the json object "windowOpen" data[open/close]
 *
 * The two variables from a device's perspective are double temperature and bool windowOpen
 * The device needs to act on only on windowOpen variable, so we will create a primitiveJson_t object with callback
 The Json Document in the cloud will be
 {
 "reported": {
 "temperature": 0,
 "windowOpen": false
 },
 "desired": {
 "windowOpen": false
 }
 }
 */

static const char *TAG = "shadow";

#define ROOMTEMPERATURE_UPPERLIMIT 32.0f
#define ROOMTEMPERATURE_LOWERLIMIT 25.0f
#define STARTING_ROOMTEMPERATURE ROOMTEMPERATURE_LOWERLIMIT

#define MAX_LENGTH_OF_UPDATE_JSON_BUFFER 200

/* The examples use simple WiFi configuration that you can set via
   'make menuconfig'.

   If you'd rather not, just change the below entries to strings with
   the config you want - ie #define EXAMPLE_WIFI_SSID "mywifissid"
*/
#define EXAMPLE_WIFI_SSID CONFIG_WIFI_SSID
#define EXAMPLE_WIFI_PASS CONFIG_WIFI_PASSWORD


/* FreeRTOS event group to signal when we are connected & ready to make a request */
static EventGroupHandle_t wifi_event_group;

/* The event group allows multiple bits for each event,
   but we only care about one event - are we connected
   to the AP with an IP? */
const int CONNECTED_BIT = BIT0;


/* CA Root certificate, device ("Thing") certificate and device
 * ("Thing") key.

   Example can be configured one of two ways:

   "Embedded Certs" are loaded from files in "certs/" and embedded into the app binary.

   "Filesystem Certs" are loaded from the filesystem (SD card, etc.)

   See example README for more details.
*/
#if defined(CONFIG_EXAMPLE_EMBEDDED_CERTS)

extern const uint8_t aws_root_ca_pem_start[] asm("_binary_aws_root_ca_pem_start");
extern const uint8_t aws_root_ca_pem_end[] asm("_binary_aws_root_ca_pem_end");
extern const uint8_t certificate_pem_crt_start[] asm("_binary_certificate_pem_crt_start");
extern const uint8_t certificate_pem_crt_end[] asm("_binary_certificate_pem_crt_end");
extern const uint8_t private_pem_key_start[] asm("_binary_private_pem_key_start");
extern const uint8_t private_pem_key_end[] asm("_binary_private_pem_key_end");

#elif defined(CONFIG_EXAMPLE_FILESYSTEM_CERTS)

static const char * DEVICE_CERTIFICATE_PATH = CONFIG_EXAMPLE_CERTIFICATE_PATH;
static const char * DEVICE_PRIVATE_KEY_PATH = CONFIG_EXAMPLE_PRIVATE_KEY_PATH;
static const char * ROOT_CA_PATH = CONFIG_EXAMPLE_ROOT_CA_PATH;

#else
#error "Invalid method for loading certs"
#endif

static esp_err_t event_handler(void *ctx, system_event_t *event)
{
    switch(event->event_id) {
    case SYSTEM_EVENT_STA_START:
        esp_wifi_connect();
        break;
    case SYSTEM_EVENT_STA_GOT_IP:
        xEventGroupSetBits(wifi_event_group, CONNECTED_BIT);
        break;
    case SYSTEM_EVENT_STA_DISCONNECTED:
        /* This is a workaround as ESP32 WiFi libs don't currently
           auto-reassociate. */
        esp_wifi_connect();
        xEventGroupClearBits(wifi_event_group, CONNECTED_BIT);
        break;
    default:
        break;
    }
    return ESP_OK;
}

static void simulateRoomTemperature(float *pRoomTemperature) {
    static float deltaChange;

    if(*pRoomTemperature >= ROOMTEMPERATURE_UPPERLIMIT) {
        deltaChange = -0.5f;
    } else if(*pRoomTemperature <= ROOMTEMPERATURE_LOWERLIMIT) {
        deltaChange = 0.5f;
    }

    *pRoomTemperature += deltaChange;
}

static bool shadowUpdateInProgress;

void ShadowUpdateStatusCallback(const char *pThingName, ShadowActions_t action, Shadow_Ack_Status_t status,
                                const char *pReceivedJsonDocument, void *pContextData) {
    IOT_UNUSED(pThingName);
    IOT_UNUSED(action);
    IOT_UNUSED(pReceivedJsonDocument);
    IOT_UNUSED(pContextData);

    shadowUpdateInProgress = false;

    if(SHADOW_ACK_TIMEOUT == status) {
        ESP_LOGE(TAG, "Update timed out");
    } else if(SHADOW_ACK_REJECTED == status) {
        ESP_LOGE(TAG, "Update rejected");
    } else if(SHADOW_ACK_ACCEPTED == status) {
        ESP_LOGI(TAG, "Update accepted");
    }
}

void windowActuate_Callback(const char *pJsonString, uint32_t JsonStringDataLen, jsonStruct_t *pContext) {
    IOT_UNUSED(pJsonString);
    IOT_UNUSED(JsonStringDataLen);

    if(pContext != NULL) {
        ESP_LOGI(TAG, "Delta - Window state changed to %d", *(bool *) (pContext->pData));
    }
}

void aws_iot_task(void *param) {
    IoT_Error_t rc = FAILURE;

    char JsonDocumentBuffer[MAX_LENGTH_OF_UPDATE_JSON_BUFFER];
    size_t sizeOfJsonDocumentBuffer = sizeof(JsonDocumentBuffer) / sizeof(JsonDocumentBuffer[0]);
    float temperature = 0.0;

    bool windowOpen = false;
    jsonStruct_t windowActuator;
    windowActuator.cb = windowActuate_Callback;
    windowActuator.pData = &windowOpen;
    windowActuator.pKey = "windowOpen";
    windowActuator.type = SHADOW_JSON_BOOL;
    windowActuator.dataLength = sizeof(bool);

    jsonStruct_t temperatureHandler;
    temperatureHandler.cb = NULL;
    temperatureHandler.pKey = "temperature";
    temperatureHandler.pData = &temperature;
    temperatureHandler.type = SHADOW_JSON_FLOAT;
    temperatureHandler.dataLength = sizeof(float);

    ESP_LOGI(TAG, "AWS IoT SDK Version %d.%d.%d-%s", VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH, VERSION_TAG);

    // initialize the mqtt client
    AWS_IoT_Client mqttClient;

    ShadowInitParameters_t sp = ShadowInitParametersDefault;
    sp.pHost = AWS_IOT_MQTT_HOST;
    sp.port = AWS_IOT_MQTT_PORT;

#if defined(CONFIG_EXAMPLE_EMBEDDED_CERTS)
    sp.pClientCRT = (const char *)certificate_pem_crt_start;
    sp.pClientKey = (const char *)private_pem_key_start;
    sp.pRootCA = (const char *)aws_root_ca_pem_start;
#elif defined(CONFIG_EXAMPLE_FILESYSTEM_CERTS)
    sp.pClientCRT = DEVICE_CERTIFICATE_PATH;
    sp.pClientKey = DEVICE_PRIVATE_KEY_PATH;
    sp.pRootCA = ROOT_CA_PATH;
#endif
    sp.enableAutoReconnect = false;
    sp.disconnectHandler = NULL;

#ifdef CONFIG_EXAMPLE_SDCARD_CERTS
    ESP_LOGI(TAG, "Mounting SD card...");
    sdmmc_host_t host = SDMMC_HOST_DEFAULT();
    sdmmc_slot_config_t slot_config = SDMMC_SLOT_CONFIG_DEFAULT();
    esp_vfs_fat_sdmmc_mount_config_t mount_config = {
        .format_if_mount_failed = false,
        .max_files = 3,
    };
    sdmmc_card_t* card;
    esp_err_t ret = esp_vfs_fat_sdmmc_mount("/sdcard", &host, &slot_config, &mount_config, &card);
    if (ret != ESP_OK) {
        ESP_LOGE(TAG, "Failed to mount SD card VFAT filesystem. Error: %s", esp_err_to_name(ret));
        abort();
    }
#endif

    /* Wait for WiFI to show as connected */
    xEventGroupWaitBits(wifi_event_group, CONNECTED_BIT,
                        false, true, portMAX_DELAY);

    ESP_LOGI(TAG, "Shadow Init");
    rc = aws_iot_shadow_init(&mqttClient, &sp);
    if(SUCCESS != rc) {
        ESP_LOGE(TAG, "aws_iot_shadow_init returned error %d, aborting...", rc);
        abort();
    }

    ShadowConnectParameters_t scp = ShadowConnectParametersDefault;
    scp.pMyThingName = CONFIG_AWS_EXAMPLE_THING_NAME;
    scp.pMqttClientId = CONFIG_AWS_EXAMPLE_CLIENT_ID;
    scp.mqttClientIdLen = (uint16_t) strlen(CONFIG_AWS_EXAMPLE_CLIENT_ID);

    ESP_LOGI(TAG, "Shadow Connect");
    rc = aws_iot_shadow_connect(&mqttClient, &scp);
    if(SUCCESS != rc) {
        ESP_LOGE(TAG, "aws_iot_shadow_connect returned error %d, aborting...", rc);
        abort();
    }

    /*
     * Enable Auto Reconnect functionality. Minimum and Maximum time of Exponential backoff are set in aws_iot_config.h
     *  #AWS_IOT_MQTT_MIN_RECONNECT_WAIT_INTERVAL
     *  #AWS_IOT_MQTT_MAX_RECONNECT_WAIT_INTERVAL
     */
    rc = aws_iot_shadow_set_autoreconnect_status(&mqttClient, true);
    if(SUCCESS != rc) {
        ESP_LOGE(TAG, "Unable to set Auto Reconnect to true - %d, aborting...", rc);
        abort();
    }

    rc = aws_iot_shadow_register_delta(&mqttClient, &windowActuator);

    if(SUCCESS != rc) {
        ESP_LOGE(TAG, "Shadow Register Delta Error");
    }
    temperature = STARTING_ROOMTEMPERATURE;

    // loop and publish a change in temperature
    while(NETWORK_ATTEMPTING_RECONNECT == rc || NETWORK_RECONNECTED == rc || SUCCESS == rc) {
        rc = aws_iot_shadow_yield(&mqttClient, 200);
        if(NETWORK_ATTEMPTING_RECONNECT == rc || shadowUpdateInProgress) {
            rc = aws_iot_shadow_yield(&mqttClient, 1000);
            // If the client is attempting to reconnect, or already waiting on a shadow update,
            // we will skip the rest of the loop.
            continue;
        }
        ESP_LOGI(TAG, "=======================================================================================");
        ESP_LOGI(TAG, "On Device: window state %s", windowOpen ? "true" : "false");
        simulateRoomTemperature(&temperature);

        rc = aws_iot_shadow_init_json_document(JsonDocumentBuffer, sizeOfJsonDocumentBuffer);
        if(SUCCESS == rc) {
            rc = aws_iot_shadow_add_reported(JsonDocumentBuffer, sizeOfJsonDocumentBuffer, 2, &temperatureHandler,
                                             &windowActuator);
            if(SUCCESS == rc) {
                rc = aws_iot_finalize_json_document(JsonDocumentBuffer, sizeOfJsonDocumentBuffer);
                if(SUCCESS == rc) {
                    ESP_LOGI(TAG, "Update Shadow: %s", JsonDocumentBuffer);
                    rc = aws_iot_shadow_update(&mqttClient, CONFIG_AWS_EXAMPLE_THING_NAME, JsonDocumentBuffer,
                                               ShadowUpdateStatusCallback, NULL, 4, true);
                    shadowUpdateInProgress = true;
                }
            }
        }
        ESP_LOGI(TAG, "*****************************************************************************************");
        ESP_LOGI(TAG, "Stack remaining for task '%s' is %d bytes", pcTaskGetTaskName(NULL), uxTaskGetStackHighWaterMark(NULL));

        vTaskDelay(1000 / portTICK_RATE_MS);
    }

    if(SUCCESS != rc) {
        ESP_LOGE(TAG, "An error occurred in the loop %d", rc);
    }

    ESP_LOGI(TAG, "Disconnecting");
    rc = aws_iot_shadow_disconnect(&mqttClient);

    if(SUCCESS != rc) {
        ESP_LOGE(TAG, "Disconnect error %d", rc);
    }

    vTaskDelete(NULL);
}

static void initialise_wifi(void)
{
    tcpip_adapter_init();
    wifi_event_group = xEventGroupCreate();
    ESP_ERROR_CHECK( esp_event_loop_init(event_handler, NULL) );
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK( esp_wifi_init(&cfg) );
    ESP_ERROR_CHECK( esp_wifi_set_storage(WIFI_STORAGE_RAM) );
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = EXAMPLE_WIFI_SSID,
            .password = EXAMPLE_WIFI_PASS,
        },
    };
    ESP_LOGI(TAG, "Setting WiFi configuration SSID %s...", wifi_config.sta.ssid);
    ESP_ERROR_CHECK( esp_wifi_set_mode(WIFI_MODE_STA) );
    ESP_ERROR_CHECK( esp_wifi_set_config(WIFI_IF_STA, &wifi_config) );
    ESP_ERROR_CHECK( esp_wifi_start() );
}


void app_main()
{
    esp_err_t err = nvs_flash_init();
    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        err = nvs_flash_init();
    }
    ESP_ERROR_CHECK( err );

    initialise_wifi();
    /* Temporarily pin task to core, due to FPU uncertainty */
    xTaskCreatePinnedToCore(&aws_iot_task, "aws_iot_task", 9216, NULL, 5, NULL, 1);
}