/*
  Pi Pico W WiFi Station Demo
  picow-wifi-station.ino
  Use WiFi library to connect Pico W to WiFi in Station mode

  DroneBot Workshop 2022
  https://dronebotworkshop.com
*/

// Include the WiFi Library
#include <WiFi.h>
#include <HTTPClient.h>

// Inclusions for GPS
#include "TinyGPSPlus.h"
#include "SoftwareSerial.h"
#include "LittleFS.h"
#include "Arduino.h"

SoftwareSerial serial_connection (1, 0);
TinyGPSPlus gps; // GPS object
#define button_pin 14

// set up logfile and memory handling
File logFile;
unsigned long lastWriteFlushMs = 0;
unsigned long lastLoggedSecond = 99999;

// Network credentials
const char* ssid = "Fen House";
const char* password = "Wetlands6";
const char* serverUrl = "http://192.168.68.51:5001/api/log";  // change this

// Variable to store onboard LED state
String picoLEDState = "off";

// set up time tracking for GPS
String isoTimeUTC()
{
  if (gps.date.isValid() && gps.time.isValid())
  {
    char buf[25];
    // YYYY-MM-DDThh:mm:ssZ
    snprintf(buf, sizeof(buf), "%04d-%02d-%02dT%02d:%02d:%02dZ",
             (int)gps.date.year(),
             (int)gps.date.month(),
             (int)gps.date.day(),
             (int)gps.time.hour(),
             (int)gps.time.minute(),
             (int)gps.time.second());
    return String(buf);
  }
  return String(""); // unknown yet
}

// set up header for CSV
void writeCSVHeader()
{
  if (!logFile) return;
  logFile.println(F("time_utc,lat,lon"));
}

// dump flash memory into CSV and print it to serial monitor
void dumpFile() {
  Serial.println(F("\n----- BEGIN walk.csv -----"));
  File f = LittleFS.open("/walk.csv", "r");
  if (!f) {
    Serial.println(F("No /walk.csv file found."));
    return;
  }
  while (f.available()) {
    Serial.write(f.read());
  }
  f.close();
  Serial.println(F("\n----- END walk.csv -----\n"));
}

void setup() {

  // Start the Serial Monitor
  Serial.begin(115200);
  serial_connection.begin(115200); 
  Serial.println("GPS Start"); // sketch starting

  // Operate in WiFi Station mode
  WiFi.mode(WIFI_STA);
  // Start WiFi with supplied parameters
  WiFi.begin(ssid, password);

  // Print ... on monitor while establishing connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    delay(500);
  }

  // Connection established
  Serial.println("");
  Serial.print("Pico W is connected to WiFi network ");
  Serial.println(WiFi.SSID());

  // init LED
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);

  // init flash memory
  if (!LittleFS.begin())
  {
    Serial.println(F("LittleFS mount failed. Did you select a Flash Size with FS? (Tools > Flash Size)"));
    // You can still run, but logging won't work.
  }

  // Open /walk.csv for write (overwrite each run)
  logFile = LittleFS.open("/walk.csv", "w");

  if (!logFile) {
    Serial.println(F("Failed to open /walk.csv for writing"));
  }
  else {
    writeCSVHeader();
    Serial.println(F("Logging to /walk.csv"));
  }

}

bool button_up = true;

void loop() {

  // while connection is available, encode GPS feedback
  while(serial_connection.available())
  {
    gps.encode(serial_connection.read());
  }

  // sense if button is down, and record + print full GPS Message
  if ((digitalRead(button_pin) == LOW) && button_up) {
        digitalWrite(led_pin,HIGH);
        Serial.println("BUTTON DOWN_______________ RECORDING");

        // if we get a valid location, print it:
        if (gps.location.isValid()) {

          double lat = gps.location.lat();
          double lon = gps.location.lng();
          String tiso = isoTimeUTC();

          // print the location to serial
          Serial.println("Latitude:");
          Serial.println(lat, 6);
          Serial.println("Longitude");
          Serial.println(lon, 6);

          // if the log file is there, print data to the log file
          if (logFile) {
            Serial.println("writing to walk.csv");
            // CSV: time_utc,lat,lon,
            logFile.print(tiso);           logFile.print(',');
            logFile.print(lat, 6);         logFile.print(',');
            logFile.print(lon, 6);         logFile.print(',');
            logFile.println();
          }
          else {
            Serial.println("did not find logfile");
          }
      }
      else {
        // print error to serial
        Serial.println("GPS Location Invalid");
      }
        button_up = false;
    }

  // when the button goes back up, flush the log file data and turn off the LED
  else if ((digitalRead(button_pin) == HIGH) && !button_up) {
      digitalWrite(led_pin,LOW);
      button_up = true;
      logFile.flush();
  }

// IF THERE IS WIFI, send whatever you have in walk csv
  if (WiFi.status() == WL_CONNECTED) {

    Serial.print("WiFi status: ");
    Serial.println(WiFi.status());
    //Serial.print("Pico IP: ");
    //Serial.println(WiFi.localIP());
    //Serial.print("Server URL: ");
    //Serial.println(serverUrl);

    HTTPClient http;
    http.begin(serverUrl);
    http.addHeader("Content-Type", "application/json");

    File f = LittleFS.open("/walk.csv", "r");
    if (!f) {
      Serial.println(F("No /walk.csv file found."));
      return;
    }

    while (f.available()) {
      String line = f.readStringUntil('\n');
      line.trim();
      if (line.length() == 0) continue;

      // parse CSV: lat, long, time
      int i1 = line.indexOf(',');
      int i2 = line.indexOf(',', i1 + 1);
      int i3 = line.indexOf(',', i2 + 1);

      if (i1 < 0 || i2 < 0 || i3 < 0) {
        Serial.print("Bad line: ");
        Serial.println(line);
        continue;
      }

      String lat_string  = line.substring(0, i1);
      String lon_string = line.substring(i1 + 1, i2);
      String t_string = line.substring(i2 + 1, i3);

      // build JSON payload
      String payload = "{";
      payload += "\"timestamp\":" + t_string;
      payload += ",\"lat\":" + lat_string;
      payload += ",\"lon\":" + lon_string;
      payload += "}";

      Serial.print("Sending: ");
      Serial.println(payload);

      int httpCode = http.POST(payload);

      Serial.printf("POST code: %d\n", httpCode);
      String response = http.getString();
      Serial.println(response);

      http.end();
    }

    // String payload = "{\"temperature\": 23.5, \"humidity\": 45}";
  }

  delay(10000); // send every 10 seconds

}