#include <libconfig.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <MQTTClient.h>
#include <pthread.h>
#include <stdio.h>
#include <stdbool.h>
#include "handleType.h"
#include "ringbuffer.h"


const char MQTT_BROKER_KEY[] = "mqttBroker";
const char DEFAULT_MQTT_BROKER[] = "127.0.0.1:1883";
const char MQTT_CLIENTID_KEY[] = "mqttClientId";
const char *generatedMqttClientId = NULL;
const char MQTT_STATUS_TOPIC_KEY[] = "mqttStatusTopic";
const char DEFAULT_MQTT_STATUS_TOPIC[] = "Iot/MqttAuditing/Status";
const char MQTT_HEARTBEAT_TOPIC_KEY[] = "mqttHeartbeatTopic";
const char DEFAULT_MQTT_HEARTBEAT_TOPIC[] = "Iot/MqttAuditing/Heartbeat";
const char MQTT_COMMAND_TOPIC_KEY[] = "mqttCommandTopic";
const char DEFAULT_MQTT_COMMAND_TOPIC[] = "Iot/MqttAuditing/Command";
const char MQTT_AUDIT_TOPIC_KEY[] = "mqttAuditTopic";
const char DEFAULT_MQTT_AUDIT_TOPIC[] = "Iot/MqttAuditing/Audit";
const char MQTT_WATCHDOG_TOPIC_KEY[] = "mqttWatchdogTopic";
const char DEFAULT_MQTT_WATCHDOG_TOPIC[] = "Iot/MqttAuditing/Watchdog";
const char MQTT_WATCHDOG_GRACE_TIME_KEY[] = "mqttWatchdogGraceTime";
const int DEFAULT_MQTT_WATCHDOG_GRACE_TIME = 15;

typedef struct {
    const char *broker;
    const char *clientId;
    const char *statusTopic;
    const char *watchdogTopic;
    const char *heartbeatTopic;
    const char *commandTopic;
    const char *auditTopic;
    int watchdogGraceTime;
    bool stopSignal;
    uint32_t watchdogCounter;
} mqttThreadContext_t;




int on_message(void *kontext, char *topicName, int topicLen, MQTTClient_message *message) {
    commonThreadHandle_t *handle = (commonThreadHandle_t*)kontext;
    mqttThreadContext_t *context = (mqttThreadContext_t*)handle->context;

    printf("Topic: %s, TopicLen: %d\n", topicName, topicLen);
    char* payload = message->payload;
    printf("Received operation: %s\n", payload);

    int curTopicLen = (topicLen == 0) ? strlen(topicName) : topicLen;
    if (strncmp(topicName, context->watchdogTopic, curTopicLen) == 0) {
        printf("Watchdog signal received\n");
        context->watchdogCounter += 1;
    } else if (strncmp(topicName, context->commandTopic, curTopicLen) == 0) {
        printf("Command received\n");
        if (strcmp(payload, "stop") == 0) {
            context->stopSignal = true;
            printf("Stop command received\n");
        }
    } else if (strncmp(topicName, context->auditTopic, curTopicLen) == 0) {
        printf("Audit message received\n");        
    }

    MQTTClient_freeMessage(&message);
    MQTTClient_free(topicName);
    return 1;
}





void *mqttreceiver(void *ptr) {

    fprintf(stderr, "mqttreceiver entered\n");

    commonThreadHandle_t *handle = (commonThreadHandle_t*)ptr;
    mqttThreadContext_t *context = (mqttThreadContext_t*) malloc(sizeof(mqttThreadContext_t));
    handle->context = (void*)context;
    context->stopSignal = false;
    context->watchdogCounter = 0;

    char *generatedMqttClientId;

    if (! config_lookup_string(handle->config, MQTT_BROKER_KEY, &(context->broker))) {
        context->broker = DEFAULT_MQTT_BROKER;
    }

    if (! config_lookup_string(handle->config, MQTT_CLIENTID_KEY, &(context->clientId))) {
        const uint32_t sizeOfGeneratedMqttClientId = 32;
        generatedMqttClientId = (char*) malloc(sizeOfGeneratedMqttClientId);
        memset(generatedMqttClientId, 0, sizeOfGeneratedMqttClientId);
        char myHostname[8];
        gethostname(myHostname, sizeof(myHostname));
        pid_t myPid = getpid();
        snprintf(generatedMqttClientId, sizeOfGeneratedMqttClientId-1, "%s-%u", myHostname, myPid);
        context->clientId = generatedMqttClientId;
    }

    if (! config_lookup_string(handle->config, MQTT_STATUS_TOPIC_KEY, &(context->statusTopic))) {
        context->statusTopic = DEFAULT_MQTT_STATUS_TOPIC;
    }

    if (! config_lookup_string(handle->config, MQTT_HEARTBEAT_TOPIC_KEY, &(context->heartbeatTopic))) {
        context->heartbeatTopic = DEFAULT_MQTT_HEARTBEAT_TOPIC;
    }

    if (! config_lookup_string(handle->config, MQTT_COMMAND_TOPIC_KEY, &(context->commandTopic))) {
        context->commandTopic = DEFAULT_MQTT_COMMAND_TOPIC;
    }

    if (! config_lookup_string(handle->config, MQTT_AUDIT_TOPIC_KEY, &(context->auditTopic))) {
        context->auditTopic = DEFAULT_MQTT_AUDIT_TOPIC;
    }

    if (! config_lookup_string(handle->config, MQTT_WATCHDOG_TOPIC_KEY, &(context->watchdogTopic))) {
        context->watchdogTopic = DEFAULT_MQTT_WATCHDOG_TOPIC;
    }

    if (! config_lookup_int(handle->config, MQTT_WATCHDOG_GRACE_TIME_KEY, &(context->watchdogGraceTime))) {
        context->watchdogGraceTime = DEFAULT_MQTT_WATCHDOG_GRACE_TIME;
    }

    MQTTClient client;
    MQTTClient_create(&client, context->broker, context->clientId, MQTTCLIENT_PERSISTENCE_NONE, NULL);
    MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
    //conn_opts.username = "<<tenant_ID>>/<<username>>";
    //conn_opts.password = "<<password>>";

    MQTTClient_setCallbacks(client, (void*)handle, NULL, on_message, NULL);

    int rc;
    if ((rc = MQTTClient_connect(client, &conn_opts)) == MQTTCLIENT_SUCCESS) {
        fprintf(stderr, "Connected to MQTT broker\n");
        if (MQTTClient_subscribe(client, context->watchdogTopic, 0) == MQTTCLIENT_SUCCESS) {
            fprintf(stderr, "Subscribed to %s\n", context->watchdogTopic);
        };

        if (MQTTClient_subscribe(client, context->commandTopic, 0) == MQTTCLIENT_SUCCESS) {
            fprintf(stderr, "Subscribed to %s\n", context->commandTopic);
        }

        if (MQTTClient_subscribe(client, context->auditTopic, 0) == MQTTCLIENT_SUCCESS) {
            fprintf(stderr, "Subscribed to %s\n", context->auditTopic);
        }

        uint32_t loopCounter = 0;
        while (! context->stopSignal) {
            loopCounter++;
            if (loopCounter > context->watchdogGraceTime) {
                if (context->watchdogCounter == 0) {
                    fprintf(stderr, "missing watchdog signals for too longer, terminating\n");
                    context->stopSignal = true;
                } else {
                    fprintf(stderr, "Watchdog fine: %d\n", context->watchdogCounter);
                }
                loopCounter = 0;
                context->watchdogCounter = 0;
            }

            MQTTClient_yield();
            sleep(1);
        }
        fprintf(stderr, "mqtt receiver thread stopped\n");
    } else {
        fprintf(stderr, "Failed to connect to MQTT broker, return code %d\n", rc);
    }

    MQTTClient_disconnect(client, 1000);
    MQTTClient_destroy(&client);

    if (generatedMqttClientId != NULL) {
        free(generatedMqttClientId);
        generatedMqttClientId = NULL;
    }
    if (context != NULL) {
        free(context);
        context = NULL;
    }

    return NULL;
}