// Use from 0 to 4. Higher number, more debugging messages and memory usage.
//#define _WIFIMGR_LOGLEVEL_  4
//#define DEBUG               1

#include <WiFi.h>
#include <WiFiManager.h>
#include "debug.h"
#include <Arduino.h>
#include <ESPmDNS.h>
#include <LiquidCrystal_I2C.h>
#include <looper.h>
#include <ESPDateTime.h>
#include <Time.h>
#include <DHT.h>
#include <esp_task_wdt.h>

#define MDNS_NAME             "wlanthermometer"
#define AP_SSID_CONFIG_NAME   "WLANTHERMOMETER-Config"
#define AP_CONFIG_PASSWORD    "wlanthermometer"
#define AP_DATA_RESET_PIN     25
#define TEMP_SENS_PIN         27
#define LCD_I2C_ADDR          0x3f
#define LCD_COL               20
#define LCD_ROW               4
#define KRATE_TEMP            5000
#define KRATE_TIME            500
#define KRATE_RESET_AP_DATA   5000
#define KRATE_CHECK_DATETIME  250000
#define ONBOARD_LED           2
#define NTP_TIMEOUT           30000
#define NTP_SERVER            "time.fu-berlin.de"
#define WIFI_CONNECT_TIMEOUT  30
#define CFG_PORTAL_TIMEOUT    90
#define DHTTYPE               DHT22
#define FIRST_MIN_MAX         300000  // = 5 min
#define HTML_RELOAD_PAGE_SECS 30
#define WDT_TIMEOUT           30

LiquidCrystal_I2C lcd(LCD_I2C_ADDR, LCD_COL, LCD_ROW);
looper sched;
float temp[3] = { NAN, NAN, NAN };
float hum[3] = { NAN, NAN, NAN };
float heat[3] = { NAN, NAN, NAN };
bool led_state;
String header;
WiFiServer server(80);
DHT dht(TEMP_SENS_PIN, DHTTYPE);
const uint8_t degree_sign[8] = { B00010, B00101, B00010, B00000, B00000, B00000, B00000, B00000 };
uint8_t add_summertime = 0;
bool last_reset_ap_check = false;
//bool minmax_enabled = false;
char date_string_old[9];

enum {
  ACT,
  MIN,
  MAX
};

void ConfigAPWeb(void);
void ConfigAPStarted(WiFiManager* wm);

void setup()
{
  bool ap_reset_last_state;

  esp_task_wdt_init(WDT_TIMEOUT, true);
  esp_task_wdt_add(NULL);

  pinMode(AP_DATA_RESET_PIN, INPUT_PULLDOWN);
  pinMode(ONBOARD_LED, OUTPUT);

  Serial.begin(115200);
  Serial.println(F("WLANThermometer (c)2020 H. Wirtz <wirtz@parasitstudio.de>"));
  delay(200);
  ap_reset_last_state = digitalRead(AP_DATA_RESET_PIN);

  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.noCursor();
  lcd.setCursor(2, 0);
  lcd.print(F("WLAN THERMOMETER"));
  lcd.setCursor(2, 1);
  lcd.print(F("(c)parasiTstudio"));

  if (digitalRead(AP_DATA_RESET_PIN) == HIGH && ap_reset_last_state == HIGH)
  {
    ap_data_reset();
  }

  WiFi.mode(WIFI_STA); // explicitly set mode, esp defaults to STA+AP

  WiFiManager wm;

  lcd.setCursor(0, 2);
  lcd.print(F("Connecting WiFi...  "));

  wm.setWebServerCallback(ConfigAPWeb);
  wm.setAPCallback(ConfigAPStarted);
  wm.setConnectTimeout(WIFI_CONNECT_TIMEOUT);
  wm.setConfigPortalTimeout(CFG_PORTAL_TIMEOUT);
  wm.setBreakAfterConfig(true);
  wm.setRemoveDuplicateAPs(true);
  wm.setWiFiAutoReconnect(false);
  wm.setEnableConfigPortal(false);

  if (!wm.autoConnect(AP_SSID_CONFIG_NAME, AP_CONFIG_PASSWORD))
  {
    lcd.setCursor(0, 2);
    lcd.print(F("Failed              "));
    DEBUG_MSG("Failed to connect\n");
    delay(1000);
    lcd.setCursor(7, 2);
    lcd.print(F("- restart"));
    delay(1000);
    ESP.restart();
  }
  else
  {
    DEBUG_MSG("Connected\n");

    if (!MDNS.begin(MDNS_NAME))
    {
      DEBUG_MSG("Error setting up MDNS responder!\n");
    }
    else
    {
      DEBUG_MSG("mDNS started.\n");
    }

    lcd.setCursor(0, 2);
    lcd.print(F("Mode WiFi client"));
    lcd.setCursor(0, 3);
    lcd.print(WiFi.localIP());

    delay(500);
  }

  lcd.setCursor(0, 3);
  lcd.print("Getting time...");
  DateTime.setTimeZone(1);
  DateTime.setServer(NTP_SERVER);
  DateTime.begin(NTP_TIMEOUT);
  /* while (!DateTime.isTimeValid())
    {
    DEBUG_MSG("Failed to get time from server.\n");
    DateTime.forceUpdate();
    }*/
  if (DateTime.isTimeValid())
  {
    if (is_wintertime(DateTime.getTime()) == false)
      add_summertime = 1;
    else
      add_summertime = 0;
  }

  // create a degree sign
  lcd.createChar(0, (uint8_t*)degree_sign);

  dht.begin();

  server.begin();

  sched.addJob(show_temperature, KRATE_TEMP);
  sched.addJob(show_time, KRATE_TIME);
  sched.addJob(check_reset_ap_data, KRATE_RESET_AP_DATA);
  sched.addJob(check_datetime, KRATE_CHECK_DATETIME);
  sched.addJob(watchdog_reset, WDT_TIMEOUT / 2);

  get_sensor_data();
  temp[MIN] = temp[ACT];
  temp[MAX] = temp[ACT];
  hum[MIN] = hum[ACT];
  hum[MAX] = hum[ACT];
  heat[MIN] = heat[ACT];
  heat[MAX] = heat[ACT];

  strcpy(date_string_old, "--:--:----");

  setup_screen();
  show_time();
  show_temperature();
}

void loop()
{
  static uint32_t next_time_check;

  sched.scheduler();

  if (!DateTime.isTimeValid() && millis() - 10000 > next_time_check)
  {
    next_time_check = millis();
    DateTime.setTimeZone(1);
    DateTime.forceUpdate();
    if (is_wintertime(DateTime.getTime()) == false)
      add_summertime = 1;
    else
      add_summertime = 0;
  }

  WiFiClient client = server.available(); // Listen for incoming clients

  if (client) { // If a new client connects,
    DEBUG_MSG("New Client.\n"); // print a message out in the serial port
    String currentLine = ""; // make a String to hold incoming data from the client
    while (client.connected())
    { // loop while the client's connected
      if (client.available())
      { // if there's bytes to read from the client,
        char c = client.read(); // read a byte, then
        Serial.write(c); // print it out the serial monitor
        header += c;
        if (c == '\n')
        { // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0)
          {
            // checking if header is valid
            // YWRtaW46c3RhYWdhcg== (user:pass) admin:staagar
            if (header.indexOf("YWRtaW46c3RhYWdhcg==") >= 0)
            {
              client.println("HTTP/1.1 200 OK");
              client.println("Content-type:text/html");
              client.println("Connection: close");
              client.println();
              client.println("<!DOCTYPE html>");
              client.println("<html>");
              client.println("<head>");
              client.println("<title>Temperatur</title>");
              client.print("<meta http-equiv=\"refresh\" content=\"");
              client.print(HTML_RELOAD_PAGE_SECS, DEC);
              client.println("\"/>");
              client.println("<meta http-equiv=\"cache-control\" content=\"no-cache\"/>");
              client.println("<meta name=\"robots\" content=\"noindex\"/>");
              client.println("</head>");
              client.println("<body>");
              client.println("<center>");
              client.println("<h1 style=\"color:green;\">Temperatur</h1>");
              client.print("<h2 style=\"color:green;\">Aktuell: ");
              if (!isnan(temp[ACT]))
                client.print(temp[ACT]);
              else
                client.print("--.--");
              client.println(" &deg;C</h2>");
              if (millis() > FIRST_MIN_MAX)
              {
                client.print("<h2 style=\"color:green;\">Minimum: ");
                if (!isnan(temp[MIN]))
                  client.print(temp[MIN]);
                else
                  client.print("--.--");
                client.print(" &deg;C");
                client.print("</h2>\n");
                client.print("<h2 style=\"color:green;\">Maximum: ");
                if (!isnan(temp[MAX]))
                  client.print(temp[MAX]);
                else
                  client.print("--.--");
                client.print(" &deg;C");
                client.println("</h2>");
              }
              client.println("<hr>");
              client.println("<h1 style=\"color:red;\">Gef&uuml;hlte Temperatur</h1>");
              client.print("<h2 style=\"color:red;\">Aktuell: ");
              if (!isnan(heat[ACT]))
                client.print(heat[ACT]);
              else
                client.print("--.--");
              client.println(" &deg;C</h2>");
              if (millis() > FIRST_MIN_MAX)
              {
                client.print("<h2 style=\"color:red;\">Minimum: ");
                if (!isnan(heat[MIN]))
                  client.print(heat[MIN]);
                else
                  client.print("--.--");
                client.print(" &deg;C");
                client.println("</h2>");
                client.print("<h2 style=\"color:red;\">Maximum: ");
                if (!isnan(heat[MAX]))
                  client.print(heat[MAX]);
                else
                  client.print("--.--");
                client.print(" &deg;C");
                client.println("</h2>");
              }
              client.println("<hr>");
              client.println("<h1 style=\"color:blue;\">Luftfeuchtigkeit</h1>");
              client.print("<h2 style=\"color:blue;\">Aktuell: ");
              if (!isnan(hum[ACT]))
                client.print(hum[ACT]);
              else
                client.print("--.--");
              client.println(" %</h2>");
              if (millis() > FIRST_MIN_MAX)
              {
                client.print("<h2 style=\"color:blue;\">Minimum: ");
                if (!isnan(hum[MIN]))
                  client.print(hum[MIN]);
                else
                  client.print("--.--");
                client.print(" %");
                client.println("</h2>");
                client.print("<h2 style=\"color:blue;\">Maximum: ");
                if (!isnan(hum[MAX]))
                  client.print(hum[MAX]);
                else
                  client.print("--.--");
                client.print(" %");
                client.println("</h2>");
              }

              if (DateTime.isTimeValid())
              {
                DateTimeParts p = DateTime.getParts();
                char dt[21];

                if (is_wintertime(DateTime.getTime()) == false)
                  add_summertime = 1;
                else
                  add_summertime = 0;

                client.println("<hr>");
                client.print("<h4 style=\"color:black;\">");

                sprintf(dt, "%02d.%02d.%4d  %02d:%02d:%02d", p.getMonthDay(), p.getMonth() + 1, p.getYear(), p.getHours() + add_summertime, p.getMinutes(), p.getSeconds());
                client.print(dt);
                if (add_summertime > 0)
                  client.print(" Sommerzeit");
                else
                  client.print(" Winterzeit");
                client.println("</h4>");
              }

              client.println("</center>");
              client.println("</body>");
              client.println("</html>");
              break;
            }
            // Wrong user or password, so HTTP request fails...
            else {
              client.println("HTTP/1.1 401 Unauthorized");
              client.println("WWW-Authenticate: Basic realm=\"Secure\"");
              client.println("Content-Type: text/html");
              client.println();
              client.println("<html>Authentification failed</html>");
              break;
            }
          } else { // if you got a newline, then clear currentLine
            currentLine = "";
          }
        } else if (c != '\r') { // if you got anything else but a carriage return character,
          currentLine += c; // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    DEBUG_MSG("Client disconnected.\n\n");
  }
}

void check_reset_ap_data(void)
{
  if (digitalRead(AP_DATA_RESET_PIN) == HIGH && last_reset_ap_check == true)
  {
    ap_data_reset();
  }
  else if (digitalRead(AP_DATA_RESET_PIN) == HIGH)
  {
    if (digitalRead(AP_DATA_RESET_PIN) == HIGH)
      DEBUG_MSG("Reset AP data pressed\n");
    last_reset_ap_check = true;
  }
  else
    last_reset_ap_check = false;
}

void show_time(void)
{
  char date_string[11];
  char time_string[9];

  if (DateTime.isTimeValid())
  {
    DateTimeParts p = DateTime.getParts();

    if (p.getHours() == 0 && p.getMinutes() == 0 && p.getSeconds() == 0)
      DateTime.forceUpdate();

    if ((p.getHours() == 2 || p.getHours() == 3) && p.getMinutes() == 0 && p.getSeconds() == 0)
    {
      if (is_wintertime(DateTime.getTime()) == false)
        add_summertime = 1;
      else
        add_summertime = 0;
    }

    sprintf(date_string, "%02d.%02d.%4d", p.getMonthDay(), p.getMonth() + 1, p.getYear());
    sprintf(time_string, "%02d:%02d:%02d", p.getHours() + add_summertime, p.getMinutes(), p.getSeconds());

    DEBUG_MSG("%s %s", date_string, time_string);
    if (add_summertime > 0)
      DEBUG_MSG(" Summertime\n");
    else
      DEBUG_MSG(" Wintertime\n");
  }
  else
  {
    strcpy(date_string, "--:--:----");
    strcpy(time_string, "--:--:--");
  }

  if (strcmp(date_string, date_string_old))
  {
    lcd.setCursor(0, 0);
    lcd.print(date_string);
    strcpy(date_string_old, date_string);
  }
  lcd.setCursor(12, 0);
  lcd.print(time_string);

  digitalWrite(ONBOARD_LED, led_state);
  led_state = !led_state;
}

void show_temperature(void)
{
  get_sensor_data();

  DEBUG_MSG("Temperature: %02.2f\n", temp[ACT]);

  lcd.setCursor(14, 1);
  if (isnan(temp[ACT]))
    lcd.print("--.-");
  else
    lcd.print(round_float(temp[ACT], 1), 1);

  if (millis() > FIRST_MIN_MAX)
  {
    lcd.setCursor(5, 2);
    if (isnan(temp[MIN]))
      lcd.print("--.-");
    else
      lcd.print(round_float(temp[MIN], 1), 1);
    lcd.setCursor(16, 2);
    if (isnan(temp[MAX]))
      lcd.print("--.-");
    else
      lcd.print(round_float(temp[MAX], 1), 1);
  }

  lcd.setCursor(5, 3);
  if (isnan(hum[ACT]))
    lcd.print("--.-");
  else
    lcd.print(round_float(hum[ACT], 1), 1);
  lcd.setCursor(16, 3);
  if (isnan(heat[ACT]))
    lcd.print("--.-");
  else
    lcd.print(round_float(heat[ACT], 1), 1);
}

void setup_screen(void)
{
  lcd.clear();
  lcd.setCursor(0, 1);
  lcd.print("Temperatur:");
  lcd.setCursor(18, 1);
  lcd.write(0);
  lcd.print("C");
  lcd.setCursor(0, 2);
  lcd.print("Min: --.-  Max: --.-");
  lcd.setCursor(0, 3);
  lcd.print("LF:     %  GT:");
}

bool is_wintertime(time_t t)
{
  // Sommerzeit/Winterzeit http://manfred.wilzeck.de/Datum_berechnen.html#Jahreszahl
  // Tag = 31 – ( 4 + Jahr*5 / 4) MOD 7  ' Datum Tag für Beginn Sommerzeit (Jahr 4-stellig)
  // Tag = 31 – ( 1 + Jahr*5 / 4) MOD 7  ' Datum Tag für Ende Sommerzeit (Jahr 4-stellig)
  tmElements_t tm;
  byte day_of_switch[2];
  time_t switch_secs[2];
  byte i;

  day_of_switch[0] = 31 - (4 + year(t) * 5 / 4) % 7; // winter->summer
  day_of_switch[1] = 31 - (1 + year(t) * 5 / 4) % 7; // summer->winter

  for (i = 0; i < 2; i++)
  {
    tm.Second = 0;
    if (i == 0)
      tm.Hour = 2;
    else
      tm.Hour = 3;
    tm.Minute = 0;
    tm.Day = day_of_switch[i];
    if (i == 0)
      tm.Month = 3;
    else
      tm.Month = 10;
    tm.Year = year(t) - 1970;

    switch_secs[i] = makeTime(tm);
  }

  if (t >= switch_secs[0] && t < switch_secs[1])
    return (false);
  else
    return (true);
}

void get_sensor_data(void)
{
  temp[ACT] = dht.readTemperature();
  hum[ACT] = dht.readHumidity();
  if (!isnan(temp[ACT]) && !isnan(hum[ACT]))
    heat[ACT] = dht.computeHeatIndex(temp[ACT], hum[ACT], false);
  else
    heat[ACT] = NAN;

  /*
    if (minmax_enabled == false && millis() > FIRST_MIN_MAX)
    minmax_enabled = true;

    if (minmax_enabled == false)
    {
      if (!isnan(temp[ACT]))
      {
        temp[MIN] = temp[ACT];
        temp[MAX] = temp[ACT];
      }

      if (!isnan(hum[ACT]))
      {
        hum[MIN] = hum[ACT];
        hum[MAX] = hum[ACT];
      }

      if (!isnan(heat[ACT]))
      {
        heat[MIN] = heat[ACT];
        heat[MIN] = heat[ACT];
      }
    }
    else
    {
  */
  if (!isnan(temp[ACT]))
  {
    if (isnan(temp[MIN]))
      temp[MIN] = temp[ACT];

    if (isnan(temp[MAX]))
      temp[MAX] = temp[ACT];

    if (temp[ACT] < temp[MIN])
      temp[MIN] = temp[ACT];
    else if (temp[ACT] > temp[MAX])
      temp[MAX] = temp[ACT];
  }

  if (!isnan(hum[ACT]))
  {
    if (isnan(hum[MIN]))
      hum[MIN] = hum[ACT];

    if (isnan(hum[MAX]))
      hum[MAX] = hum[ACT];

    if (hum[ACT] < hum[MIN])
      hum[MIN] = hum[ACT];
    else if (hum[ACT] > hum[MAX])
      hum[MAX] = hum[ACT];
  }

  if (!isnan(heat[ACT]))
  {
    if (isnan(heat[MIN]))
      heat[MIN] = heat[ACT];

    if (isnan(heat[MAX]))
      heat[MAX] = heat[ACT];

    if (heat[ACT] < heat[MIN])
      heat[MIN] = heat[ACT];
    else if (heat[ACT] > heat[MAX])
      heat[MAX] = heat[ACT];
  }
  //}
}

void ConfigAPWeb(void)
{
  lcd.setCursor(0, 2);
  lcd.print(F("Mode Config-AP      "));
  lcd.setCursor(0, 3);
  lcd.print(F("192.168.4.1"));
}

void ConfigAPStarted(WiFiManager * wm)
{
  DEBUG_MSG("Config-AP started\n");
}

float round_float(float num, uint8_t dec_place)
{
  return ((round(num * powf(10, dec_place))) / powf(10, dec_place));
}

void ap_data_reset(void)
{
  DEBUG_MSG("Reset AP data\n");

  WiFiManager wm;

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Resetting AP Data");
  delay(2000);
  wm.resetSettings();
  lcd.setCursor(0, 1);
  lcd.print("Done.");
  delay(1000);
  ESP.restart();
}

void check_datetime(void)
{
  if (!DateTime.isTimeValid())
  {
    lcd.setCursor(0, 0);
    lcd.print("  Time update   ");
    DateTime.forceUpdate();
    show_time();
  }
}

void watchdog_reset(void)
{
  esp_task_wdt_reset();
}