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

// ============== CONFIGURATION ==============
const char* ssid = "iot-2GHz";
const char* password = "lesson-greater";

// TOPIC URLS — short poll (no ?poll=1) for ESP32 HTTP client compatibility
const char* COMMAND_POLL_URL = "http://ntfy.sh/ALERT_klubhaus_topic/json";
const char* SILENCE_POLL_URL = "http://ntfy.sh/SILENCE_klubhaus_topic/json";
const char* STATUS_POST_URL = "http://ntfy.sh/STATUS_klubhaus_topic";

const unsigned long COMMAND_POLL_INTERVAL = 30000;
const unsigned long SILENCE_POLL_INTERVAL = 5000;
const unsigned long BLINK_DURATION = 180000;
const unsigned long BLINK_PERIOD = 1000;
const unsigned long ERROR_BACKOFF = 60000;

#define BACKLIGHT_PIN 22
#define BUTTON_PIN     9

// ============== COCAINE CHIC PALETTE ==============
#define COLOR_BLACK     0x0000
#define COLOR_COCAINE   0xFFFE
#define COLOR_TEAL      0x05F5
#define COLOR_FUCHSIA   0xFC6E
#define COLOR_MINT      0x674D

#define ALERT_BG_1      COLOR_TEAL
#define ALERT_TEXT_1    COLOR_COCAINE
#define ALERT_BG_2      COLOR_FUCHSIA
#define ALERT_TEXT_2    COLOR_COCAINE

// ============== DISPLAY SETUP ==============
#define SCREEN_WIDTH  320
#define SCREEN_HEIGHT 172

Arduino_DataBus *bus = new Arduino_HWSPI(15, 14, 7, 6, -1);
Arduino_GFX *gfx = new Arduino_ST7789(bus, 21, 1, true, 172, 320, 34, 0, 34, 0);

// ============== STATE MANAGEMENT ==============
enum State { STATE_SILENT, STATE_ALERT };

State currentState = STATE_SILENT;
State lastPublishedState = STATE_SILENT;

unsigned long lastCommandPoll = 0;
unsigned long lastSilencePoll = 0;
unsigned long nextPollTime = 0;
unsigned long blinkStartTime = 0;
bool blinkPhase = false;

String lastCommandId = "";
String lastSilenceId = "";
bool lastButtonState = false;
String alertMessage = "";

void setup() {
  Serial.begin(115200);
  delay(3000);
  Serial.println("\n=== KLUBHAUS DOORBELL v3.5 ===");
  Serial.println("Fix: Arduino String.trim() in-place modification");

  pinMode(BACKLIGHT_PIN, OUTPUT);
  digitalWrite(BACKLIGHT_PIN, LOW);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  gfx->begin();
  digitalWrite(BACKLIGHT_PIN, HIGH);
  testDisplay();
  delay(300);

  transitionTo(STATE_SILENT);

  WiFi.begin(ssid, password);
  int timeout = 0;
  while (WiFi.status() != WL_CONNECTED && timeout < 40) {
    delay(500);
    Serial.print(".");
    timeout++;
  }

  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("\nWiFi FAILED");
    showFatalError("OFFLINE");
  } else {
    Serial.println("\nWiFi OK: " + WiFi.localIP().toString());
    publishStatus();
  }

  Serial.println("=== READY ===");
}

void loop() {
  unsigned long now = millis();

  if (now < nextPollTime) {
    delay(100);
    return;
  }

  handleButton();

  switch (currentState) {
    case STATE_SILENT:
      if (now - lastSilencePoll >= SILENCE_POLL_INTERVAL) {
        lastSilencePoll = now;
        checkSilenceTopic();
      }
      if (now - lastCommandPoll >= COMMAND_POLL_INTERVAL) {
        lastCommandPoll = now;
        checkCommandTopic();
      }
      break;

    case STATE_ALERT:
      if (now - lastSilencePoll >= SILENCE_POLL_INTERVAL) {
        lastSilencePoll = now;
        checkSilenceTopic();
      }
      updateBlink(now);
      if (now - blinkStartTime >= BLINK_DURATION) {
        Serial.println("ALERT TIMEOUT");
        transitionTo(STATE_SILENT);
      }
      break;
  }

  delay(50);
}

// ============== STATUS PUBLISHING ==============

void publishStatus() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("Status: skip (no WiFi)");
    return;
  }

  HTTPClient http;
  http.begin(STATUS_POST_URL);
  http.addHeader("Content-Type", "text/plain");

  StaticJsonDocument<256> doc;
  doc["state"] = (currentState == STATE_SILENT) ? "SILENT" : "ALERTING";
  doc["message"] = alertMessage;
  doc["timestamp"] = millis();

  String payload;
  serializeJson(doc, payload);

  int code = http.POST(payload);
  Serial.print("Status: ");
  Serial.print(payload);
  Serial.println(String(" (") + code + ")");

  http.end();
  lastPublishedState = currentState;
}

void transitionTo(State newState) {
  if (newState == currentState) return;

  Serial.print("STATE: ");
  Serial.print(currentState == STATE_SILENT ? "SILENT" : "ALERT");
  Serial.print(" -> ");
  Serial.println(newState == STATE_SILENT ? "SILENT" : "ALERT");

  currentState = newState;

  switch (currentState) {
    case STATE_SILENT:
      alertMessage = "";
      gfx->fillScreen(COLOR_BLACK);
      digitalWrite(BACKLIGHT_PIN, LOW);
      break;

    case STATE_ALERT:
      digitalWrite(BACKLIGHT_PIN, HIGH);
      blinkStartTime = millis();
      blinkPhase = false;
      drawAlertScreen(ALERT_BG_1, ALERT_TEXT_1);
      break;
  }

  publishStatus();
}

// ============== TOPIC POLLING ==============

void checkCommandTopic() {
  Serial.println("Poll COMMAND...");
  String response = fetchNtfyJson(COMMAND_POLL_URL);
  if (response.length() == 0) return;

  StaticJsonDocument<512> doc;
  DeserializationError error = deserializeJson(doc, response);
  if (error) {
    Serial.print("  JSON error: ");
    Serial.println(error.c_str());
    return;
  }

  String id = doc["id"] | "";
  String message = doc["message"] | "";

  // FIX: Arduino String.trim() modifies in place, returns void
  // Trim first, then check length
  message.trim();
  if (message.length() == 0) {
    Serial.println("  Empty message, skip");
    return;
  }

  if (id == lastCommandId && id.length() > 0) {
    Serial.println("  Same ID, skip");
    return;
  }
  lastCommandId = id;

  Serial.print("  NEW: [");
  Serial.print(message);
  Serial.println("]");

  if (message.equalsIgnoreCase("SILENCE")) {
    Serial.println("  -> SILENCE command");
    transitionTo(STATE_SILENT);
    flashConfirm("SILENCE", COLOR_MINT, COLOR_BLACK);
  } else {
    Serial.println("  -> ALERT trigger");
    alertMessage = message;
    transitionTo(STATE_ALERT);
  }
}

void checkSilenceTopic() {
  String response = fetchNtfyJson(SILENCE_POLL_URL);
  if (response.length() == 0) return;

  StaticJsonDocument<512> doc;
  DeserializationError error = deserializeJson(doc, response);
  if (error) return;

  String id = doc["id"] | "";
  String message = doc["message"] | "";

  // FIX: Arduino String.trim() modifies in place
  message.trim();
  if (message.length() == 0) return;

  if (id == lastSilenceId && id.length() > 0) return;
  lastSilenceId = id;

  Serial.print("Silence topic: [");
  Serial.print(message);
  Serial.println("]");

  if (currentState == STATE_ALERT) {
    Serial.println("  -> Force silence");
    transitionTo(STATE_SILENT);
    flashConfirm("SILENCED", COLOR_MINT, COLOR_BLACK);
  }
}

String fetchNtfyJson(const char* url) {
  HTTPClient http;
  http.begin(url);
  http.setTimeout(8000);

  int code = http.GET();

  if (code == 204) {
    http.end();
    return "";
  }

  if (code == 429 || code == 500 || code == 502 || code == 503) {
    Serial.print("  HTTP error ");
    Serial.print(code);
    Serial.println(" — backing off 60s");
    nextPollTime = millis() + ERROR_BACKOFF;
    http.end();
    return "";
  }

  if (code != 200) {
    Serial.print("  HTTP error: ");
    Serial.println(code);
    http.end();
    return "";
  }

  String payload = http.getString();
  http.end();

  int newline = payload.indexOf('\n');
  if (newline > 0) payload = payload.substring(0, newline);

  return payload;
}

// ============== VISUALS ==============

void flashConfirm(const char* text, uint16_t bgColor, uint16_t textColor) {
  digitalWrite(BACKLIGHT_PIN, HIGH);
  gfx->fillScreen(bgColor);
  drawCenteredText(text, 3, textColor, bgColor, 70);
  delay(500);
  gfx->fillScreen(COLOR_BLACK);
  digitalWrite(BACKLIGHT_PIN, LOW);
}

void drawAlertScreen(uint16_t bgColor, uint16_t textColor) {
  gfx->fillScreen(bgColor);
  drawCenteredText("ALERT", 3, textColor, bgColor, 20);
  if (alertMessage.length() > 0) {
    drawAutoSizedMessage(alertMessage, textColor, bgColor, 70);
  }
}

void drawAutoSizedMessage(String message, uint16_t textColor, uint16_t bgColor, int yPos) {
  int textSize = calculateOptimalTextSize(message, SCREEN_WIDTH - 40, SCREEN_HEIGHT - yPos - 20);
  gfx->setTextSize(textSize);
  gfx->setTextColor(textColor, bgColor);
  gfx->setTextBound(20, yPos, SCREEN_WIDTH - 20, SCREEN_HEIGHT - 10);
  gfx->setCursor(20, yPos);
  gfx->println(message);
}

int calculateOptimalTextSize(String message, int maxWidth, int maxHeight) {
  for (int size = 5; size >= 1; size--) {
    gfx->setTextSize(size);
    int charWidth = 6 * size;
    int lineHeight = 8 * size;
    int charsPerLine = maxWidth / charWidth;
    int numLines = (message.length() + charsPerLine - 1) / charsPerLine;
    int totalHeight = numLines * lineHeight;
    if (totalHeight <= maxHeight && charsPerLine >= 4) return size;
  }
  return 1;
}

void drawCenteredText(const char* text, int textSize, uint16_t textColor, uint16_t bgColor, int yPos) {
  gfx->setTextSize(textSize);
  gfx->setTextColor(textColor, bgColor);
  int textWidth = strlen(text) * 6 * textSize;
  int xPos = (SCREEN_WIDTH - textWidth) / 2;
  if (xPos < 20) xPos = 20;
  gfx->setCursor(xPos, yPos);
  gfx->println(text);
}

void showFatalError(const char* text) {
  digitalWrite(BACKLIGHT_PIN, HIGH);
  gfx->fillScreen(COLOR_BLACK);
  drawCenteredText(text, 3, COLOR_FUCHSIA, COLOR_BLACK, 70);
  delay(3000);
  digitalWrite(BACKLIGHT_PIN, LOW);
}

// ============== BUTTON ==============

void handleButton() {
  bool pressed = (digitalRead(BUTTON_PIN) == LOW);

  if (pressed && !lastButtonState) {
    Serial.println("BUTTON PRESSED");
    digitalWrite(BACKLIGHT_PIN, HIGH);
    gfx->fillScreen(COLOR_COCAINE);
    drawCenteredText("TEST MODE", 2, COLOR_BLACK, COLOR_COCAINE, 70);
  }
  else if (!pressed && lastButtonState) {
    Serial.println("BUTTON RELEASED");
    if (currentState == STATE_ALERT) {
      Serial.println("  -> Reset to SILENT");
      transitionTo(STATE_SILENT);
      flashConfirm("SILENCED", COLOR_MINT, COLOR_BLACK);
    } else {
      gfx->fillScreen(COLOR_BLACK);
      digitalWrite(BACKLIGHT_PIN, LOW);
    }
  }
  lastButtonState = pressed;
}

// ============== BLINK ==============

void updateBlink(unsigned long now) {
  unsigned long elapsed = now - blinkStartTime;
  bool newPhase = ((elapsed / BLINK_PERIOD) % 2) == 1;
  if (newPhase != blinkPhase) {
    blinkPhase = newPhase;
    uint16_t bgColor = blinkPhase ? ALERT_BG_2 : ALERT_BG_1;
    uint16_t textColor = blinkPhase ? ALERT_TEXT_2 : ALERT_TEXT_1;
    drawAlertScreen(bgColor, textColor);
  }
}

// ============== TEST ==============

void testDisplay() {
  const char* names[] = {"TEAL", "FUCHSIA", "COCAINE", "MINT", "BLACK"};
  uint16_t colors[] = {COLOR_TEAL, COLOR_FUCHSIA, COLOR_COCAINE, COLOR_MINT, COLOR_BLACK};
  for (int i = 0; i < 5; i++) {
    gfx->fillScreen(colors[i]);
    delay(100);
  }
  gfx->fillScreen(COLOR_BLACK);
  drawCenteredText("KLUBHAUS", 3, COLOR_TEAL, COLOR_BLACK, 50);
  drawCenteredText("DOORBELL", 3, COLOR_FUCHSIA, COLOR_BLACK, 90);
  delay(400);
  gfx->fillScreen(COLOR_BLACK);
}