#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <WiFiClientSecure.h>

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

// ============ Google Apps Script ============
const char* SCRIPT_URL =
"https://script.google.com/macros/s/AKfycbxX9SU3DP1m9vcRi5rDnqEwG_OatYU3EWXHGgpUSkxh53KIXRwtOupyYdVM_UolxP5y/exec";

// ============ Retry & Timing Settings ============
const int MAX_RETRIES = 5;
const int retryDelayMs = 1000;

// Deep sleep time: 24 hours in microseconds
#define uS_TO_S_FACTOR   1000000ULL
#define TIME_TO_SLEEP_S  60 //(24ULL * 60ULL * 60ULL)          // 24 hours
#define TIME_TO_SLEEP_US (TIME_TO_SLEEP_S * uS_TO_S_FACTOR)

// Optional: keep track of boot count (useful for debugging)
RTC_DATA_ATTR int bootCount = 0;

// ================= Setup =================
void setup()
{
  esp_sleep_wakeup_cause_t cause = esp_sleep_get_wakeup_cause();
  Serial.print("Wakeup cause: ");
  Serial.println(cause);

  Serial.begin(115200);
  delay(100);           // give serial a moment

  bootCount++;
  Serial.println("\n----------------------------------");
  Serial.printf("Boot number: %d\n", bootCount);
  Serial.println("----------------------------------");

  // Connect to WiFi
  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password);

  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20)
  {
    delay(500);
    Serial.print(".");
    attempts++;
  }

  if (WiFi.status() != WL_CONNECTED)
  {
    Serial.println("\nWiFi connection failed → going back to sleep");
    goToDeepSleep();
    return; // not reached
  }

  Serial.println("\nWiFi connected");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());

  // Generate payload
  StaticJsonDocument<256> doc;
  doc["rmsACVoltage"]    = random(100, 200);
  doc["ChargingVoltage"] = random(10, 20);
  doc["BatteryVoltage"]  = random(12, 18);

  String payload;
  serializeJson(doc, payload);

  Serial.println("\nPayload:");
  Serial.println(payload);

  // ---------- POST + optional GET logic ----------
  bool success = sendDataWithRedirect(payload);

  if (!success)
  {
    Serial.println("Data send failed after retries.");
  }

  // Done → sleep again
  goToDeepSleep();
}

// ================= Deep Sleep Helper =================
void goToDeepSleep()
{
  Serial.println("Going to deep sleep for 1 minute...");
  Serial.flush();               // make sure message gets out

  esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP_US);
  esp_deep_sleep_start();       // → never returns
}

// ================= Send data (POST → 302 → GET) =================
bool sendDataWithRedirect(const String &payload)
{
  int postTries = 0;
  String redirectUrl = "";
  bool gotRedirect = false;

  while (!gotRedirect && postTries < MAX_RETRIES)
  {
    WiFiClientSecure client;
    client.setInsecure();
    client.setTimeout(15000);

    HTTPClient http;
    if (!http.begin(client, SCRIPT_URL))
    {
      postTries++;
      Serial.println("HTTP begin failed. Retry " + String(postTries));
      delay(retryDelayMs);
      continue;
    }

    http.addHeader("Content-Type", "application/json");
    const char* headerKeys[] = {"Location"};
    http.collectHeaders(headerKeys, 1);
    http.setFollowRedirects(HTTPC_DISABLE_FOLLOW_REDIRECTS);

    int httpCode = http.POST(payload);

    if (httpCode == 302)
    {
      redirectUrl = http.header("Location");
      if (redirectUrl.length() > 5)
      {
        gotRedirect = true;
        Serial.println("Redirect received: " + redirectUrl);
        http.end();
        break;
      }
    }

    postTries++;
    Serial.printf("POST failed (code %d). Retry %d/%d\n", httpCode, postTries, MAX_RETRIES);
    http.end();
    delay(retryDelayMs);
  }

  if (!gotRedirect)
  {
    Serial.println("No valid redirect after max retries.");
    return false;
  }

  // GET phase
  int getTries = 0;
  while (getTries < MAX_RETRIES)
  {
    WiFiClientSecure client;
    client.setInsecure();
    client.setTimeout(15000);

    HTTPClient httpGet;
    if (!httpGet.begin(client, redirectUrl))
    {
      getTries++;
      delay(retryDelayMs);
      continue;
    }

    int getCode = httpGet.GET();

    if (getCode == 200)
    {
      Serial.println("GET successful:");
      Serial.println(httpGet.getString());
      httpGet.end();
      return true;
    }

    Serial.printf("GET failed (code %d). Retry %d\n", getCode, getTries + 1);
    httpGet.end();
    getTries++;
    delay(retryDelayMs);
  }

  Serial.println("GET failed after max retries.");
  return false;
}

// ================= Loop =================
// (empty – everything happens in setup + deep sleep)
void loop()
{
  // Never reached when using deep sleep
}