/*
 * ESP8266 Environmental Sensor Node with SI7021 (Temp + Hum)
 * (to be build with Arduino or the supplied Makefile and makeEspArduino)
 *
 * copyright: Jannik Beyerstedt | https://jannikbeyerstedt.de | code@jannikbeyerstedt.de
 * license: http://www.gnu.org/licenses/gpl-3.0.txt GPLv3 License
 */

#include <Wire.h>
#include <Adafruit_Si7021.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>

#include "rtc-helpers.hpp"
rtcStore_t rtcStore;

#define BOARD_HUZZAH 1 /* Adafruit Feather HUZZAH */
#define BOARD_LOLIN 2  /* LoLin NodeMCU */
#define BOARD_ESP07S 3 /* standalone ESP07S */

/* DEBUG SETTINGS */
#define TEST       /* use test config and database */
#define PRINT_INFO /* enable Serial debugging */
// #define PRINT_DEBUG /* enable additional debug output */

/* CONFIGURATION OPTIONS */
#ifndef NODENAME
// #define NODENAME "env-huzzah-01" /* IMPORTANT: CHANGE FOR EACH DEVICE */
#define NODENAME "env-TODO" /* IMPORTANT: CHANGE FOR EACH DEVICE */
#endif

#ifndef BOARD
#define BOARD 0 /* IMPORTANT: select one of the BOARD_* types */
#endif

#define DB_HOSTNAME "ursaminor.fra80"
#define DB_PASSWD "c2Vuc29yczpTZW5zb3JzLXcuaW5mbHV4QGhvbWU"  // BasicAuth String

#if BOARD == BOARD_HUZZAH
#define BATT_FULL 3400
#define BATT_CUTOFF 2450 /* 2500=3,0V; 3080=4,0V (Battery Voltage!!!) */
#elif BOARD == BOARD_ESP07S
#define BATT_FULL 3600
#define BATT_CUTOFF 2450 /* 2450=2,7V; 3200=3,5V (VCC Voltage) */
#elif BOARD == BOARD_LOLIN
#define BATT_FULL 2812
#define BATT_CUTOFF 2280
#else
#error "unsupported board chosen"
#endif

#if BOARD == BOARD_ESP07S
String loggerId = "esp07-";  // UID = this prefix + last 3 octets of the MAC address
#endif
#if BOARD != BOARD_ESP07S
String loggerId = "esp12-";  // UID = this prefix + last 3 octets of the MAC address
#endif

/* SETTINGS */
float tempOffset = +0.0;
float humiOffset = +0.0;

const char* host     = "ursaminor.fra80";
const int   httpPort = 8086;

const char* wlan_ssid   = "WLAN-Bey-IoT";
const char* wlan_passwd = "IoT-Fra80";

#ifndef TEST
String         loggerName         = NODENAME;
const uint16_t sendInterval_sec   = 1800; /* 1800 sec (30 min) */
const uint8_t  sampleAvgNum       = 6;    /* 6 (every 5 minutes) */
const uint16_t sampleInterval_sec = sendInterval_sec / sampleAvgNum;
String         serviceUri         = "/write?db=sensors";
#else
String         loggerName         = "esp-test";
const uint16_t sendInterval_sec   = 180; /* 180 sec (3 min) */
const uint8_t  sampleAvgNum       = 6;   /* 3 (every 1 minute) */
const uint16_t sampleInterval_sec = sendInterval_sec / sampleAvgNum;
String         serviceUri         = "/write?db=test";
#endif

/* GLOBAL VARIABLES */
const uint16_t wlanConnectCheckInterval  = 250;   /* milli seconds: poll wifi.state after wifi.begin() */
const uint16_t wlanConnectTimeout        = 15000; /* milli seconds */
RTC_DATA_ATTR uint8_t wlanConnectFailCnt = 0;

Adafruit_Si7021 si7021 = Adafruit_Si7021();
float           temp   = 0.0;
float           humi   = 0.0;

uint16_t battLevel = 0;
float    battPerc  = 0.0;

RTC_DATA_ATTR uint8_t sampleCnt = 0;    // for average value
RTC_DATA_ATTR float   tempAccu  = 0.0;  // for average value
RTC_DATA_ATTR float   humiAccu  = 0.0;  // for average value

uint8_t chipid[6] = {0};  // WiFi MAC address

// setup the ADC for VCC measurement
ADC_MODE(ADC_VCC);

#ifdef PRINT_INFO
#define INFO_PRINT(x) Serial.print(x)
#define INFO_PRINTLN(x) Serial.println(x)
#else
#define INFO_PRINT(x)
#define INFO_PRINTLN(x)
#endif

#if defined(PRINT_INFO) && defined(PRINT_DEBUG)
#define DEBUG_PRINT(x) Serial.print(x)
#define DEBUG_PRINTLN(x) Serial.println(x)
#else
#define DEBUG_PRINT(x)
#define DEBUG_PRINTLN(x)
#endif

bool wlanConnect(void) {
  unsigned int cycles = 0;

  WiFi.forceSleepWake();
  INFO_PRINT("[INFO ] Connecting to WiFi");
  WiFi.mode(WIFI_STA);
  WiFi.begin(wlan_ssid, wlan_passwd);
  while (WiFi.status() != WL_CONNECTED) {
    delay(wlanConnectCheckInterval);
    INFO_PRINT(".");
    cycles++;
    if (cycles > wlanConnectTimeout / wlanConnectCheckInterval) {
      INFO_PRINTLN(" FAILED");
      return false;
    }
  }
  INFO_PRINT(" ok, IP: ");
  INFO_PRINTLN(WiFi.localIP());
  return true;
}

void doDeepSleep(uint16_t durationSec) {
  // store data to RTC user memory
  DEBUG_PRINTLN("[DEBUG] Persisting some values to RTC memory");
  rtcStore.sampleCnt          = sampleCnt;
  rtcStore.wlanConnectFailCnt = wlanConnectFailCnt;
  rtcStore.humiAccu           = humiAccu;
  rtcStore.tempAccu           = tempAccu;
#ifdef PRINT_DEBUG
  Serial.printf("[DEBUG] sample %3d  wlanFail %3d  HumiAccu %6.2f  TempAccu %6.2f\n", rtcStore.sampleCnt,
                rtcStore.wlanConnectFailCnt, rtcStore.humiAccu, rtcStore.tempAccu);
#endif
  rtcMemoryStore(&rtcStore);

#ifdef PRINT_DEBUG
  Serial.printf("[DEBUG] Going to deep sleep for %d seconds\n", durationSec);
#endif
#ifdef PRINT_INFO
  delay(100);  // time to send the messages via Serial
#endif
  ESP.deepSleep(durationSec * 1000000);
}

void setupRtcStore() {
  DEBUG_PRINTLN("[DEBUG] Loading persisted values from RTC memory");
  if (true == rtcMemoryLoad(&rtcStore)) {
    DEBUG_PRINTLN("[DEBUG] loaded data is valid");
    sampleCnt          = rtcStore.sampleCnt;
    wlanConnectFailCnt = rtcStore.wlanConnectFailCnt;
    humiAccu           = rtcStore.humiAccu;
    tempAccu           = rtcStore.tempAccu;
  } else {
    INFO_PRINTLN("[ERROR] Invalid data loaded from RTC memory -> clearing values");
    sampleCnt          = 0;
    wlanConnectFailCnt = 0;
    humiAccu           = 0.0;
    tempAccu           = 0.0;
  }
#ifdef PRINT_DEBUG
  Serial.printf("[DEBUG] sample %3d  wlanFail %3d  HumiAccu %6.2f  TempAccu %6.2f\n", rtcStore.sampleCnt,
                rtcStore.wlanConnectFailCnt, rtcStore.humiAccu, rtcStore.tempAccu);
#endif
}

void setup() {
  // set logger node unique ID with MAC address
  char macIdString[6] = {0};
  WiFi.macAddress(chipid);
  sprintf(macIdString, "%02x%02x%02x", chipid[3], chipid[4], chipid[5]);
  loggerId += macIdString;

#ifdef PRINT_INFO
  Serial.begin(115200);
  delay(100);
  Serial.println("");

  Serial.print("[INFO ] Node ");
  Serial.print(loggerId);
  Serial.print(", Name: ");
  Serial.print(loggerName);
  Serial.print(", BoardType: ");
  Serial.println(BOARD);
#endif

  // load data stored to RTC user memory
  setupRtcStore();

  // setup the wakeup pin
  pinMode(0, OUTPUT);

  // turn WiFi off for now
  WiFi.mode(WIFI_OFF);
  WiFi.forceSleepBegin();

  // setup the si7021 sensor
  if (false == si7021.begin()) {
    INFO_PRINTLN("[ERROR] SI7021 not set up properly");
  }

  /* GET VALUE SAMPLES */
  // measure environmental data from si7021
  humi = si7021.readHumidity() + humiOffset;
  temp = si7021.readTemperature() + tempOffset;

  // measure battery level
  uint16_t battLevel = ESP.getVcc();
  float    battPerc  = 100.0 * (battLevel - BATT_CUTOFF) / (BATT_FULL - BATT_CUTOFF);

#ifdef PRINT_INFO
  Serial.printf("[INFO ] > Humidity: %5.2f  Temperature: %5.2f", humi, temp);
  Serial.printf("  Battery Bat: %5.1f/100 (raw: %4d)\n", battPerc, battLevel);
#endif

  /* ---------- MAIN LOGIC START ---------- */
  // accumulate and average $sampleAvgNum samples before sending data
  sampleCnt++;
  tempAccu += temp;
  humiAccu += humi;

  // calculate average and send data, if $sampleAvgNum are reached
  if (sampleCnt >= sampleAvgNum) {

    INFO_PRINTLN("[INFO ] Enough samples collected -> send average to database");
    temp = tempAccu / (float)sampleCnt;
    humi = humiAccu / (float)sampleCnt;
#ifdef PRINT_INFO
    Serial.printf("[INFO ] < Humidity: %5.2f  Temperature: %5.2f\n", humi, temp);
#endif

    // turn wifi on again
    DEBUG_PRINTLN("[DEBUG] Turning wifi on again and connecting");
    if (wlanConnect()) {

      // send data to influxdb
      String influxDataLine = "weather,id=" + loggerId + ",sensor=" + loggerName + " temp=" + String(temp, 2);
      influxDataLine += ",hum=" + String(humi, 2);
      influxDataLine += ",batRaw=" + String(battLevel);
      influxDataLine += ",bat=" + String(battPerc);

      INFO_PRINT("[INFO ] connecting to ");
      INFO_PRINT(host);
      WiFiClient client;
      if (client.connect(host, httpPort)) {
        INFO_PRINTLN(" > success");

        String httpRequest = "POST " + serviceUri + " HTTP/1.1\r\n" + "Host: " + host + ":" + httpPort +
                             "\r\n" + "Content-Length: " + influxDataLine.length() + "\r\n" +
                             "Authorization: Basic " + DB_PASSWD + "=\r\n" + "Connection: close\r\n" +
                             "\r\n" + influxDataLine + "\r\n";
        client.print(httpRequest);
        delay(100);

        while (client.available()) {
          String line = client.readStringUntil('\n');
          if (line.indexOf("HTTP") != -1) {
            if (line.indexOf("204") == -1) {  // expect a HTTP 204 status code
              INFO_PRINTLN("[ERROR] invalid http status code");
              INFO_PRINTLN(line);
            } else {  // successful database submission
              // reset average after successful database submission
              sampleCnt = 0;
              tempAccu  = 0;
              humiAccu  = 0;

              wlanConnectFailCnt = 0;
            }
            break;
          } else {
            ;
          }
        }

      } else {
        INFO_PRINTLN(" > FAILED");
      }
      client.stop();
      WiFi.disconnect(true);
      // continue with deep sleep at end of main function

    } else {  // ELSE: !wlanConnect

      /* WIFI CONNECT FAILED, WAIT MAX 5 MINUTES IN DEEP SLEEP */
      wlanConnectFailCnt++;
#ifdef PRINT_INFO
      Serial.printf("[INFO ] WiFi connect failed %d time(s) -> wait %03d s and try again\n",
                    wlanConnectFailCnt, sampleInterval_sec);
#endif
      if (sampleInterval_sec > (5 * 60)) {
        doDeepSleep(5 * 60);
      } else {
        doDeepSleep(sampleInterval_sec);
      }
    }       // ENDIF: wlanConnect
  } else {  // ELSE: sampleCnt < sampleAvgNum

#ifdef PRINT_INFO
    Serial.printf("[INFO ] %d of %d samples collected -> sleep %4d s\n", sampleCnt, sampleAvgNum,
                  sampleInterval_sec);
    // continue with deep sleep at end of main function
#endif

  }  // ENDIF: sampleCnt
  /* ----------  MAIN LOGIC END  ---------- */

  /* SAVE ENERGY BY WAITING IN DEEP SLEEP */
  doDeepSleep(sampleInterval_sec);
}

void loop() {
  /* this should never be reached!!! */
  INFO_PRINTLN("[ERROR] the arduino loop should never be reached!!!");
  doDeepSleep(sampleInterval_sec);
}