#include "wled.h"

/*
 * MQTT communication protocol for home automation
 */

#ifdef WLED_ENABLE_MQTT
#define MQTT_KEEP_ALIVE_TIME 60    // contact the MQTT broker every 60 seconds

void parseMQTTBriPayload(char* payload)
{
  if      (strstr(payload, "ON") || strstr(payload, "on") || strstr(payload, "true")) {bri = briLast; stateUpdated(CALL_MODE_DIRECT_CHANGE);}
  else if (strstr(payload, "T" ) || strstr(payload, "t" )) {toggleOnOff(); stateUpdated(CALL_MODE_DIRECT_CHANGE);}
  else {
    uint8_t in = strtoul(payload, NULL, 10);
    if (in == 0 && bri > 0) briLast = bri;
    bri = in;
    stateUpdated(CALL_MODE_DIRECT_CHANGE);
  }
}


void onMqttConnect(bool sessionPresent)
{
  //(re)subscribe to required topics
  char subuf[38];

  if (mqttDeviceTopic[0] != 0) {
    strlcpy(subuf, mqttDeviceTopic, 33);
    mqtt->subscribe(subuf, 0);
    strcat_P(subuf, PSTR("/col"));
    mqtt->subscribe(subuf, 0);
    strlcpy(subuf, mqttDeviceTopic, 33);
    strcat_P(subuf, PSTR("/api"));
    mqtt->subscribe(subuf, 0);
  }

  if (mqttGroupTopic[0] != 0) {
    strlcpy(subuf, mqttGroupTopic, 33);
    mqtt->subscribe(subuf, 0);
    strcat_P(subuf, PSTR("/col"));
    mqtt->subscribe(subuf, 0);
    strlcpy(subuf, mqttGroupTopic, 33);
    strcat_P(subuf, PSTR("/api"));
    mqtt->subscribe(subuf, 0);
  }

  usermods.onMqttConnect(sessionPresent);

  doPublishMqtt = true;
  DEBUG_PRINTLN(F("MQTT ready"));
}


void onMqttMessage(char* topic, char* payload, AsyncMqttClientMessageProperties properties, size_t len, size_t index, size_t total) {
  static char *payloadStr;

  DEBUG_PRINT(F("MQTT msg: "));
  DEBUG_PRINTLN(topic);

  // paranoia check to avoid npe if no payload
  if (payload==nullptr) {
    DEBUG_PRINTLN(F("no payload -> leave"));
    return;
  }

  if (index == 0) {                       // start (1st partial packet or the only packet)
    if (payloadStr) delete[] payloadStr;  // fail-safe: release buffer
    payloadStr = new char[total+1];       // allocate new buffer
  }
  if (payloadStr == nullptr) return;      // buffer not allocated

  // copy (partial) packet to buffer and 0-terminate it if it is last packet
  char* buff = payloadStr + index;
  memcpy(buff, payload, len);
  if (index + len >= total) { // at end
    payloadStr[total] = '\0'; // terminate c style string
  } else {
    DEBUG_PRINTLN(F("Partial packet received."));
    return; // process next packet
  }
  DEBUG_PRINTLN(payloadStr);

  size_t topicPrefixLen = strlen(mqttDeviceTopic);
  if (strncmp(topic, mqttDeviceTopic, topicPrefixLen) == 0) {
    topic += topicPrefixLen;
  } else {
    topicPrefixLen = strlen(mqttGroupTopic);
    if (strncmp(topic, mqttGroupTopic, topicPrefixLen) == 0) {
      topic += topicPrefixLen;
    } else {
      // Non-Wled Topic used here. Probably a usermod subscribed to this topic.
      usermods.onMqttMessage(topic, payloadStr);
      delete[] payloadStr;
      payloadStr = nullptr;
      return;
    }
  }

  //Prefix is stripped from the topic at this point

  if (strcmp_P(topic, PSTR("/col")) == 0) {
    colorFromDecOrHexString(col, payloadStr);
    colorUpdated(CALL_MODE_DIRECT_CHANGE);
  } else if (strcmp_P(topic, PSTR("/api")) == 0) {
    if (!requestJSONBufferLock(15)) {
      delete[] payloadStr;
      payloadStr = nullptr;
      return;
    }
    if (payloadStr[0] == '{') { //JSON API
      deserializeJson(doc, payloadStr);
      deserializeState(doc.as<JsonObject>());
    } else { //HTTP API
      String apireq = "win"; apireq += '&'; // reduce flash string usage
      apireq += payloadStr;
      handleSet(nullptr, apireq);
    }
    releaseJSONBufferLock();
  } else if (strlen(topic) != 0) {
    // non standard topic, check with usermods
    usermods.onMqttMessage(topic, payloadStr);
  } else {
    // topmost topic (just wled/MAC)
    parseMQTTBriPayload(payloadStr);
  }
  delete[] payloadStr;
  payloadStr = nullptr;
}


void publishMqtt()
{
  doPublishMqtt = false;
  if (!WLED_MQTT_CONNECTED) return;
  DEBUG_PRINTLN(F("Publish MQTT"));

  #ifndef USERMOD_SMARTNEST
  char s[10];
  char subuf[38];

  sprintf_P(s, PSTR("%u"), bri);
  strlcpy(subuf, mqttDeviceTopic, 33);
  strcat_P(subuf, PSTR("/g"));
  mqtt->publish(subuf, 0, retainMqttMsg, s);         // optionally retain message (#2263)

  sprintf_P(s, PSTR("#%06X"), (col[3] << 24) | (col[0] << 16) | (col[1] << 8) | (col[2]));
  strlcpy(subuf, mqttDeviceTopic, 33);
  strcat_P(subuf, PSTR("/c"));
  mqtt->publish(subuf, 0, retainMqttMsg, s);         // optionally retain message (#2263)

  strlcpy(subuf, mqttDeviceTopic, 33);
  strcat_P(subuf, PSTR("/status"));
  mqtt->publish(subuf, 0, true, "online");          // retain message for a LWT

  char apires[1024];                                // allocating 1024 bytes from stack can be risky
  XML_response(nullptr, apires);
  strlcpy(subuf, mqttDeviceTopic, 33);
  strcat_P(subuf, PSTR("/v"));
  mqtt->publish(subuf, 0, retainMqttMsg, apires);   // optionally retain message (#2263)
  #endif
}


//HA autodiscovery was removed in favor of the native integration in HA v0.102.0

bool initMqtt()
{
  if (!mqttEnabled || mqttServer[0] == 0 || !WLED_CONNECTED) return false;

  if (mqtt == nullptr) {
    mqtt = new AsyncMqttClient();
    mqtt->onMessage(onMqttMessage);
    mqtt->onConnect(onMqttConnect);
  }
  if (mqtt->connected()) return true;

  DEBUG_PRINTLN(F("Reconnecting MQTT"));
  IPAddress mqttIP;
  if (mqttIP.fromString(mqttServer)) //see if server is IP or domain
  {
    mqtt->setServer(mqttIP, mqttPort);
  } else {
    mqtt->setServer(mqttServer, mqttPort);
  }
  mqtt->setClientId(mqttClientID);
  if (mqttUser[0] && mqttPass[0]) mqtt->setCredentials(mqttUser, mqttPass);

  #ifndef USERMOD_SMARTNEST
  strlcpy(mqttStatusTopic, mqttDeviceTopic, 33);
  strcat_P(mqttStatusTopic, PSTR("/status"));
  mqtt->setWill(mqttStatusTopic, 0, true, "offline"); // LWT message
  #endif
  mqtt->setKeepAlive(MQTT_KEEP_ALIVE_TIME);
  mqtt->connect();
  return true;
}
#endif
