#include <Arduino.h>
#include <Wire.h>
#include <U8g2lib.h>
#include <WiFi.h>
#include <HTTPClient.h>

// ==================== WiFi ====================
const char* ssid = "X.factory2.4G";
const char* password = "make0314";
const char* serverUrl = "http://192.168.100.18:3000/api/status";

// ==================== OLED ====================
U8G2_SH1107_SEEED_128X128_F_HW_I2C u8g2(U8G2_R0);

// ==================== Touch ====================
const int touchPin = D2;

unsigned long lastTouchMs = 0;
const unsigned long debounceMs = 1500;
const unsigned long cooldownMs = 3000;

bool isPressing = false;
String lastIP = "";
bool wifiWasConnected = false;

// ==================== Forward ====================
void connectWiFi();
void drawIdleScreen();
void sendTouchEvent();

// ==================== Idle screen ====================
void drawIdleScreen() {
  u8g2.clearBuffer();

  // Main greeting
  u8g2.setFont(u8g2_font_logisoso22_tf);
  u8g2.drawStr(12, 45, "WELCOME");

  u8g2.setFont(u8g2_font_logisoso18_tf);
  u8g2.drawStr(14, 78, ">> TOUCH ME");

  // Bottom status bar
  u8g2.setFont(u8g2_font_5x7_tf);
  String status;
  if (WiFi.status() == WL_CONNECTED) {
    status = "WiFi " + WiFi.localIP().toString();
  } else {
    status = "WiFi ...";
  }
  u8g2.drawStr(0, 125, status.c_str());

  u8g2.sendBuffer();
}

// ==================== WiFi ====================
void connectWiFi() {
  if (WiFi.status() == WL_CONNECTED) return;

  Serial.print("Connecting WiFi: ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  int tries = 0;
  while (WiFi.status() != WL_CONNECTED && tries < 40) {
    delay(500);
    Serial.print(".");
    tries++;
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\nWiFi OK");
    Serial.print("IP: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("\nWiFi FAIL");
  }
}

// ==================== Touch send ====================
void sendTouchEvent() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi down, skip send");
    return;
  }

  HTTPClient http;
  http.begin(serverUrl);
  http.addHeader("Content-Type", "application/x-www-form-urlencoded");

  int code = http.POST("status=coming");

  if (code > 0) {
    Serial.print("POST ok, code: ");
    Serial.println(code);
  } else {
    Serial.print("POST fail: ");
    Serial.println(http.errorToString(code).c_str());
  }
  http.end();
}

// ==================== Setup ====================
void setup() {
  Serial.begin(115200);

  pinMode(touchPin, INPUT_PULLUP);
  Wire.begin();
  u8g2.begin();

  connectWiFi();
  drawIdleScreen();
}

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

  // Static idle screen unless WiFi state changes
  bool wifiNow = (WiFi.status() == WL_CONNECTED);
  String ipNow = wifiNow ? WiFi.localIP().toString() : "";
  if (wifiNow != wifiWasConnected || (wifiNow && ipNow != lastIP)) {
    wifiWasConnected = wifiNow;
    lastIP = ipNow;
    drawIdleScreen();
  }

  int raw = digitalRead(touchPin);
  bool touched = (raw == HIGH);

  if (touched && !isPressing && (now - lastTouchMs > debounceMs)) {
    isPressing = true;
    lastTouchMs = now;

    Serial.println("Touch detected");

    u8g2.clearBuffer();
    u8g2.setFont(u8g2_font_logisoso32_tf);
    u8g2.drawStr(14, 50, "Hello");

    u8g2.setFont(u8g2_font_logisoso18_tf);
    u8g2.drawStr(14, 82, "My Friend");
    u8g2.sendBuffer();

    sendTouchEvent();

    delay(2000);

    drawIdleScreen();
  }

  if (!touched && isPressing) {
    isPressing = false;
  }

  if (touched && isPressing && (now - lastTouchMs < cooldownMs)) {
    delay(10);
    return;
  }

  if (WiFi.status() != WL_CONNECTED) {
    connectWiFi();
  }

  delay(50);
}