/* ESP drivers */
#include "esp_log.h"
#include "esp_system.h"
#include "esp_tls.h"

/* FreeRTOS */
#include "freertos/FreeRTOS.h"
#include "freertos/queue.h"
#include "freertos/task.h"

/* Cert bundle */
#include "esp_crt_bundle.h"

/* MQTT client */
#include "mqtt_client.h"

/* Private */
#include "app_wifi.h"

#define APP_LOG_TAG "APP_MQTT"

typedef struct {
    char *topic;
    char *payload;
} app_mqtt_queue_item_t;

extern const char mqtt_client_cert_start[] asm("_binary_client_crt_start");
extern const char mqtt_client_cert_end[] asm("_binary_client_crt_end");
extern const char mqtt_client_key_start[] asm("_binary_client_key_start");
extern const char mqtt_client_key_end[] asm("_binary_client_key_end");

static void app_mqtt_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data);
static void app_mqtt_task(void *pvParameters);

static QueueHandle_t s_app_mqtt_publish_queue;

int app_mqtt_init(void) {
    s_app_mqtt_publish_queue = xQueueCreate(4, sizeof(app_mqtt_queue_item_t));
    if(s_app_mqtt_publish_queue == NULL) {
        return -1;
    }

    if (xTaskCreate(app_mqtt_task, "MQ_TASK", 2048, NULL, 2U, NULL) != pdPASS) {
        return -2;
    }

    return 0;
}

int app_mqtt_publish(char *topic, char *payload) {
    app_mqtt_queue_item_t item;
    item.topic = malloc(strlen(topic) + 1);
    if(item.topic == NULL) return -1;

    item.payload = malloc(strlen(payload) + 1);
    if(item.payload == NULL) {
        free(item.topic);
        return -2;
    }

    strcpy(item.topic, topic);
    strcpy(item.payload, payload);

    if(xQueueSend(s_app_mqtt_publish_queue, &item, portMAX_DELAY) != pdPASS) {
        free(item.topic);
        free(item.payload);
        return -3;
    }

    return 0;
}

static void app_mqtt_task(void *pvParameters) {
    const esp_mqtt_client_config_t mqtt_cfg = {
        .uri                    = CONFIG_APP_MQTT_BROKER_ADDR,
        .client_cert_pem        = mqtt_client_cert_start,
        .client_key_pem         = mqtt_client_key_start,
        .clientkey_password     = CONFIG_APP_MQTT_TLS_CLIENT_PASSPHRASE,
        .clientkey_password_len = strlen(CONFIG_APP_MQTT_TLS_CLIENT_PASSPHRASE),
        .crt_bundle_attach      = esp_crt_bundle_attach,
    };

    esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg);
    esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, app_mqtt_event_handler, NULL);

    app_wifi_wait_ready(portMAX_DELAY);

    esp_mqtt_client_start(client);

    app_mqtt_queue_item_t item;

    for (;;) {
        if(xQueueReceive(s_app_mqtt_publish_queue, &item, portMAX_DELAY) == pdPASS) {
            esp_mqtt_client_publish(client, item.topic, item.payload, strlen(item.payload), 0, 0);

            /* This is alloc'ed by us. */
            free(item.topic);
            free(item.payload);
        }
    }
}

static void app_mqtt_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data) {
    /**/
}