//  Edit from https://randomnerdtutorials.com/esp32-plot-readings-charts-multiple/
//  https://chatgpt.com/share/69af1926-88f8-8006-bf28-2463ff38d7a2


#include <WiFi.h>
#include <WebServer.h>
#include <SPI.h>
#include <SD.h>
#include <time.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";

WebServer server(80);

#define SD_CS 32


const int analogPins[5] = {34, 35, 33, 25, 26};

String logfile = "/data.csv";

unsigned long lastLog = 0;
int logInterval = 5000; // 5000 = 0.5sec

const char* ntpServer = "pool.ntp.org";
const long  gmtOffset_sec = -21600;
const int   daylightOffset_sec = 3600;

//----------------------------------------------------------------------
//                       Get Timestamp
//----------------------------------------------------------------------

String getTimestamp(){
  struct tm timeinfo;

  if (!getLocalTime(&timeinfo))
    return "0000-00-00 00:00:00";

  char buffer[25];
  strftime(buffer, 25, "%Y-%m-%d %H:%M:%S", &timeinfo);

  return String(buffer);
}

//----------------------------------------------------------------------
//                            Log Data
//----------------------------------------------------------------------

void logData(){
  File file = SD.open(logfile, FILE_APPEND);

  if (!file) return;

  String line = getTimestamp();

  for (int i = 0; i < 5; i++)  {
    int value = analogRead(analogPins[i]);
    line += ",";
    line += String(value);
  }
  //Serial.println(line);
  file.println(line);
  file.close();
}

//----------------------------------------------------------------------
//                          Time Stamp Range
//----------------------------------------------------------------------

bool timestampInRange(String ts, String start, String end){
  if (start == "" || end == "") return true;

  if (ts >= start && ts <= end) return true;

  return false;
}

//----------------------------------------------------------------------
//                            Read Filtered CSV
//----------------------------------------------------------------------

String readFilteredCSV(String start, String end){
  File file = SD.open(logfile);

  if (!file) return "";

  String json = "{";
  json += "\"time\":[],\"p34\":[],\"p35\":[],\"p33\":[],\"p25\":[],\"p26\":[]";
  json += "}";

  String out = "";

  String timeArray = "";
  String p34 = "";
  String p35 = "";
  String p33 = "";
  String p25 = "";
  String p26 = "";

  while (file.available()){
    String line = file.readStringUntil('\n');

    if (line.length() < 10) continue;

    int idx1 = line.indexOf(',');
    String ts = line.substring(0, idx1);

    if (!timestampInRange(ts, start, end)) continue;

    int values[5];
    int last = idx1 + 1;

    for (int i = 0; i < 5; i++) {
      int next = line.indexOf(',', last);
      if (next == -1) next = line.length();

      values[i] = line.substring(last, next).toInt();

      last = next + 1;
    }

    timeArray += "\"" + ts + "\",";
    p34 += String(values[0]) + ",";
    p35 += String(values[1]) + ",";
    p33 += String(values[2]) + ",";
    p25 += String(values[3]) + ",";
    p26 += String(values[4]) + ",";
  }

  file.close();

  if (timeArray.endsWith(",")) timeArray.remove(timeArray.length() - 1);
  if (p34.endsWith(",")) p34.remove(p34.length() - 1);
  if (p35.endsWith(",")) p35.remove(p35.length() - 1);
  if (p33.endsWith(",")) p33.remove(p33.length() - 1);
  if (p25.endsWith(",")) p25.remove(p25.length() - 1);
  if (p26.endsWith(",")) p26.remove(p26.length() - 1);

  out = "{";
  out += "\"time\":[" + timeArray + "],";
  out += "\"p34\":[" + p34 + "],";
  out += "\"p35\":[" + p35 + "],";
  out += "\"p33\":[" + p33 + "],";
  out += "\"p25\":[" + p25 + "],";
  out += "\"p26\":[" + p26 + "]";
  out += "}";

  return out;
}

//----------------------------------------------------------------------
//                            Handle Data
//----------------------------------------------------------------------

void handleData(){
  String start = server.arg("start");
  String end = server.arg("end");

  start.replace("T", " ");
  end.replace("T", " ");

  String json = readFilteredCSV(start, end);

  server.send(200, "application/json", json);
}

//----------------------------------------------------------------------
//                            ROOT
//----------------------------------------------------------------------

void handleRoot()
{

  String page = R"rawliteral(

<!DOCTYPE html>
<html>
<head>
  <title>Plant Logger</title>
  <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
</head>
<body>
  <h2>Plant Moisture Log</h2>

  Start:
  <input type="datetime-local" id="start">
  End:
  <input type="datetime-local" id="end">
  <button onclick="loadData()">Load Chart</button>

  <br><br>

  <canvas id="chart" width="1200" height="400"></canvas>

  <script>
    let chart;

    function loadData() {
      let start = document.getElementById("start").value;
      let end = document.getElementById("end").value;

      fetch(`/data?start=${start}&end=${end}`)
        .then(response => response.json())
        .then(data => {
          let ctx = document.getElementById('chart').getContext('2d');

          if (chart) chart.destroy();

          chart = new Chart(ctx, {
            type: 'line',
            data: {
              labels: data.time,
              datasets: [
                { label: 'GPIO34', data: data.p34 },
                { label: 'GPIO35', data: data.p35 },
                { label: 'GPIO33', data: data.p33 },
                { label: 'GPIO25', data: data.p25 },
                { label: 'GPIO26', data: data.p26 }
              ]
            },
            options: {
              responsive: true,
              interaction: {
                mode: 'index',
                intersect: false
              },
              scales: {
                x: { display: true },
                y: { display: true }
              }
            }
          });
        });
    }
  </script>
</body>
</html>

)rawliteral";

  server.send(200,"text/html",page);
}

//----------------------------------------------------------------------
//                            SETUP
//----------------------------------------------------------------------

void setup()
{
  Serial.begin(115200);

  WiFi.begin(ssid,password,6);

  while(WiFi.status()!=WL_CONNECTED) {
    delay(500);
  }

  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);

  if(!SD.begin(SD_CS)) {
    Serial.println("SD failed");
    return;
  }

  if(!SD.exists(logfile)) {
    File file = SD.open(logfile, FILE_WRITE);
    file.println("timestamp,p34,p35,p33,p25,p26");
    file.close();
  }

  server.on("/",handleRoot);
  server.on("/data",handleData);

  server.begin();
}


//----------------------------------------------------------------------
//                            LOOP
//----------------------------------------------------------------------

void loop(){
  server.handleClient();

  if(millis()-lastLog > logInterval) {
    lastLog = millis();
    logData();
  }
}