#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHTesp.h>

// ==================== 引脚定义 ====================
#define OLED_SDA   41
#define OLED_SCL   42
#define DHT_PIN    40
#define MQ2_AO_PIN 19
#define LDR_AO_PIN 20          // D20
#define BUZZER_PIN 37
#define FAN_RELAY  46
#define LIGHT_RELAY 5

// ==================== 常量配置 ====================
#define TEMP_ON_THRESH  30.0f
#define TEMP_OFF_THRESH 26.0f
#define LUX_ON_THRESH   100.0f
#define SMOKE_ALARM_TH  100.0f    // ppm

// LDR Gamma 校准参数
#define GAMMA     0.7
#define RL10      50.0
#define FIXED_R   2000.0
#define VCC       3.3

#define SCREEN_WIDTH  128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

DHTesp dhtSensor;

bool autoMode = true;
bool manualFan = false;
bool manualLight = false;
bool smokeAlarmActive = false;

float temperature = 0.0f;
float humidity = 0.0f;
float realLux = 0.0f;
int   realPPM = 0;
int smokeRaw = 0;

unsigned long lastSensorRead = 0;
unsigned long lastWiFiPrint = 0;
unsigned long lastDisplayUpdate = 0;

// ==================== 烟雾校准（查表插值）====================
const float ppm_real[] = {0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 10, 20, 55, 209};
const int ppm_wrong[] = {2249, 2595, 2974, 3216, 3426, 4043, 4835, 6312, 6945, 7749, 8561};
const int ppm_points = 11;

float correctPPM(int wrong) {
  if (wrong <= ppm_wrong[0]) return ppm_real[0];
  if (wrong >= ppm_wrong[ppm_points-1]) return ppm_real[ppm_points-1];
  for (int i = 0; i < ppm_points-1; i++) {
    if (wrong >= ppm_wrong[i] && wrong <= ppm_wrong[i+1]) {
      float t = (float)(wrong - ppm_wrong[i]) / (ppm_wrong[i+1] - ppm_wrong[i]);
      return ppm_real[i] + t * (ppm_real[i+1] - ppm_real[i]);
    }
  }
  return ppm_real[ppm_points-1];
}

// ==================== LDR 读取（Gamma，无缩放）====================
float readLux() {
  int adc = analogRead(LDR_AO_PIN);
  float voltage = adc * (VCC / 4095.0);
  float resistance = FIXED_R * voltage / (VCC - voltage);
  float lux = pow(RL10 * 1000 * pow(10, GAMMA) / resistance, (1.0 / GAMMA))/10;
  return lux;
}

int readSmokePPM() {
  smokeRaw = analogRead(MQ2_AO_PIN);
  int wrongPPM = map(smokeRaw, 0, 4095, 0, 10000)-30;
  return (int)correctPPM(wrongPPM);
}

// ==================== 自动控制 ====================
void updateFanByTemp() {
  if (temperature > TEMP_ON_THRESH) {
    digitalWrite(FAN_RELAY, HIGH);
  } else if (temperature < TEMP_OFF_THRESH) {
    digitalWrite(FAN_RELAY, LOW);
  }
}

void updateLightByLux() {
  if (realLux < LUX_ON_THRESH) {
    digitalWrite(LIGHT_RELAY, HIGH);
  } else if (realLux > LUX_ON_THRESH) {
    digitalWrite(LIGHT_RELAY, LOW);
  }
}

void applyNormalControl() {
  if (autoMode) {
    updateFanByTemp();
    updateLightByLux();
  } else {
    digitalWrite(FAN_RELAY, manualFan ? HIGH : LOW);
    digitalWrite(LIGHT_RELAY, manualLight ? HIGH : LOW);
  }
}

// ==================== 烟雾报警 ====================
void handleSmokeAlarm() {
  realPPM = readSmokePPM();
  bool nowAlarm = (realPPM > SMOKE_ALARM_TH);
  if (nowAlarm && !smokeAlarmActive) {
    smokeAlarmActive = true;
    digitalWrite(FAN_RELAY, HIGH);
    tone(BUZZER_PIN, 2000);
  } 
  else if (!nowAlarm && smokeAlarmActive) {
    smokeAlarmActive = false;
    noTone(BUZZER_PIN);
    applyNormalControl();
  }
}

// ==================== OLED 显示（每行单独，行间距 16 像素）====================
void updateDisplay() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  
  int y = 0;
  int lineHeight = 16;   // textSize(2) 时实际高度16，行距可略增
  char buf[16];
  
  // 第一行：温度 + 报警标志（右侧）
  snprintf(buf, sizeof(buf), "T:%.0fC%s", temperature, smokeAlarmActive ? "alarm" : "normal");
  display.setCursor(0, y);
  display.print(buf);
  y += lineHeight;
  
  // 第二行：湿度
  snprintf(buf, sizeof(buf), "H:%.0f%%", humidity);
  display.setCursor(0, y);
  display.print(buf);
  y += lineHeight;
  
  // 第三行：光照
  snprintf(buf, sizeof(buf), "L:%.0fLx", realLux);
  display.setCursor(0, y);
  display.print(buf);
  y += lineHeight;
  
  // 第四行：烟雾
  snprintf(buf, sizeof(buf), "S:%dppm", realPPM);
  display.setCursor(0, y);
  display.print(buf);
  
  display.display();
}

// ==================== 辅助功能 ====================
void wifiUploadSim() {
  Serial.printf("[WiFi] T=%.1f H=%.1f Lx=%.0f PPM=%d Fan=%d Light=%d Alarm=%d\n",
                temperature, humidity, realLux, realPPM,
                digitalRead(FAN_RELAY), digitalRead(LIGHT_RELAY), smokeAlarmActive);
}

// ==================== 串口命令处理（简化版）====================
void handleSerialCommands() {
  if (!Serial.available()) return;
  String cmd = Serial.readStringUntil('\n');
  cmd.trim(); cmd.toLowerCase();

  if (cmd == "auto") {
    autoMode = true;
    Serial.println("[CMD] AUTO");
    if (!smokeAlarmActive) applyNormalControl();
  } 
  else if (cmd == "manual") {
    autoMode = false;
    manualFan = digitalRead(FAN_RELAY);
    manualLight = digitalRead(LIGHT_RELAY);
    Serial.println("[CMD] MANUAL");
  } 
  else if (cmd == "fon" && !autoMode) {
    manualFan = true;
    if (!smokeAlarmActive) digitalWrite(FAN_RELAY, HIGH);
    Serial.println("[CMD] Fan ON");
  } 
  else if (cmd == "foff" && !autoMode) {
    manualFan = false;
    if (!smokeAlarmActive) digitalWrite(FAN_RELAY, LOW);
    Serial.println("[CMD] Fan OFF");
  } 
  else if (cmd == "lon" && !autoMode) {
    manualLight = true;
    if (!smokeAlarmActive) digitalWrite(LIGHT_RELAY, HIGH);
    Serial.println("[CMD] Light ON");
  } 
  else if (cmd == "loff" && !autoMode) {
    manualLight = false;
    if (!smokeAlarmActive) digitalWrite(LIGHT_RELAY, LOW);
    Serial.println("[CMD] Light OFF");
  } 
  else if (cmd == "status") {
    // 输出完整状态，包含温湿度光照等
    Serial.printf("Mode:%s Temp:%.1fC Hum:%.1f%% Lux:%.0f PPM:%d Fan:%s Light:%s Alarm:%d\n",
                  autoMode?"AUTO":"MANUAL",
                  temperature, humidity, realLux, realPPM,
                  digitalRead(FAN_RELAY)?"ON":"OFF",
                  digitalRead(LIGHT_RELAY)?"ON":"OFF",
                  smokeAlarmActive);
  } 
  else {
    if (!autoMode) Serial.println("Use: fon, foff, lon, loff, auto, manual, status");
    else Serial.println("Use: manual, status  (auto mode)");
  }
}

// ==================== 初始化 ====================
void setup() {
  Serial.begin(115200);
  pinMode(FAN_RELAY, OUTPUT);
  pinMode(LIGHT_RELAY, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(FAN_RELAY, LOW);
  digitalWrite(LIGHT_RELAY, LOW);
  noTone(BUZZER_PIN);

  Wire.begin(OLED_SDA, OLED_SCL);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED init fail");
  }
  display.clearDisplay();
  display.display();

  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);
  Serial.println("System Ready");
  Serial.println("Commands: auto, manual, fon, foff, lon, loff, status");
}

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

  if (now - lastSensorRead >= 2000) {
    lastSensorRead = now;
    TempAndHumidity data = dhtSensor.getTempAndHumidity();
    if (!isnan(data.temperature) && !isnan(data.humidity)) {
      temperature = data.temperature;
      humidity = data.humidity;
    } else {
      Serial.println("DHT22 error");
    }
    realLux = readLux();
  }

  handleSmokeAlarm();

  if (!smokeAlarmActive) {
    if (autoMode) {
      updateFanByTemp();
      updateLightByLux();
    } else {
      digitalWrite(FAN_RELAY, manualFan ? HIGH : LOW);
      digitalWrite(LIGHT_RELAY, manualLight ? HIGH : LOW);
    }
  } else {
    // 报警时风扇强制开，灯光按模式控制
    if (autoMode) updateLightByLux();
    else digitalWrite(LIGHT_RELAY, manualLight ? HIGH : LOW);
  }

  if (now - lastDisplayUpdate >= 200) {
    lastDisplayUpdate = now;
    updateDisplay();
  }

  if (now - lastWiFiPrint >= 5000) {
    lastWiFiPrint = now;
    wifiUploadSim();
  }

  handleSerialCommands();
  delay(50);
}