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

// OLED显示屏设置
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// DHT22设置
#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// 引脚定义
const int pumpPin = 5;          // 水泵控制

// 系统参数
const int DRY_THRESHOLD = 50;   // 干燥阈值百分比
const int WET_THRESHOLD = 70;   // 湿润阈值百分比
const int MIN_TEMP_FOR_WATERING = 9;  // 最低浇水温度
const int MAX_TEMP_FOR_WATERING = 23; // 最高浇水温度

// 灌溉系统参数
const float AREA = 100.0;       // 种植面积(平方米)
const float DEPTH = 0.4;        // 土壤深度(米)
const float PUMP_FLOW_RATE = 2.0; // 水泵流量(升/分钟)
const float WATER_ABSORPTION_RATE = 0.2; // 土壤吸水率(%/升水/平方米)

// 系统状态
bool watering = false;
unsigned long lastWateringTime = 0;
const unsigned long WATERING_COOLDOWN = 60000; // 1分钟浇水冷却时间
unsigned long wateringStartTime = 0;
float soilMoisture = 50.0;      // 初始土壤湿度(%)

void setup() {
  Serial.begin(115200);
  
  // 初始化OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306分配失败"));
    for(;;);
  }
  display.display();
  delay(2000);
  display.clearDisplay();
  
  // 初始化DHT传感器
  dht.begin();
  
  // 设置引脚模式
  pinMode(pumpPin, OUTPUT);
  digitalWrite(pumpPin, LOW);
  
  // 显示初始信息
  displayWelcomeMessage();
}

void loop() {
  // 读取空气温湿度数据
  float airHumidity = dht.readHumidity();
  float airTemperature = dht.readTemperature();
  
  // 检查传感器读数是否有效
  if (isnan(airHumidity) || isnan(airTemperature)) {
    Serial.println("无法从DHT传感器读取数据!");
    displaySensorError();
    delay(2000);
    return;
  }
  
  // 更新土壤湿度(模拟吸水/蒸发过程)
  updateSoilMoisture();
  
  // 控制逻辑
  bool shouldWater = shouldStartWatering(soilMoisture, airTemperature) && 
                    !watering && 
                    (millis() - lastWateringTime > WATERING_COOLDOWN);
  
  bool shouldStop = shouldStopWatering(soilMoisture, airTemperature) && watering;
  
  if (shouldWater) {
    startWatering();
  } else if (shouldStop) {
    stopWatering();
  }
  
  // 在OLED上显示数据
  displaySensorData(airTemperature, airHumidity, soilMoisture);
  
  // 串口输出调试信息
  logSensorData(airTemperature, airHumidity, soilMoisture);
  
  delay(2000); // 2秒更新一次
}

// 更新土壤湿度(模拟吸水/蒸发过程)
void updateSoilMoisture() {
  unsigned long currentTime = millis();
  
  if (watering) {
    // 计算浇水时间(分钟)
    float wateringDuration = (currentTime - wateringStartTime) / 60000.0;
    // 计算总浇水量(升)
    float waterAmount = PUMP_FLOW_RATE * wateringDuration;
    // 计算湿度增加量
    float moistureIncrease = (waterAmount * WATER_ABSORPTION_RATE) / (AREA * DEPTH);
    soilMoisture += moistureIncrease;
    
    // 限制最大湿度
    if (soilMoisture > 100.0) {
      soilMoisture = 100.0;
    }
  } else {
    // 模拟自然蒸发过程(每小时降低0.5%)
    float evaporationRate = 0.5 / 3600.0 * (currentTime - lastWateringTime) / 1000.0;
    soilMoisture -= evaporationRate;
    
    // 限制最小湿度
    if (soilMoisture < 0.0) {
      soilMoisture = 0.0;
    }
  }
}

// 辅助函数
void displayWelcomeMessage() {
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.println("智能灌溉系统");
  display.println("空气土壤温湿度控制");
  display.display();
  delay(2000);
}

// 条件判断
bool shouldStartWatering(float soilMoisture, float temp) {
  return soilMoisture < DRY_THRESHOLD && 
         temp >= MIN_TEMP_FOR_WATERING && 
         temp <= MAX_TEMP_FOR_WATERING;
}

bool shouldStopWatering(float soilMoisture, float temp) {
  return soilMoisture >= WET_THRESHOLD || 
         temp < MIN_TEMP_FOR_WATERING || 
         temp > MAX_TEMP_FOR_WATERING;
}

void startWatering() {
  digitalWrite(pumpPin, HIGH);
  watering = true;
  wateringStartTime = millis();
  lastWateringTime = millis();
  Serial.println("开始浇水");
}

void stopWatering() {
  digitalWrite(pumpPin, LOW);
  watering = false;
  lastWateringTime = millis();
  Serial.println("停止浇水");
}

void displaySensorData(float airTemp, float airHum, float soilHum) {
  display.clearDisplay();
  display.setCursor(0,0);
  
  // 显示空气数据
  display.print("WENDU: ");
  display.print(airTemp, 1);
  display.println("C");
  
  display.print("KONGSHI: ");
  display.print(airHum, 0);
  display.println("%");
  
  // 显示土壤数据
  display.print("TURANSHI: ");
  display.print(soilHum, 1);
  display.println("%");
  
  // 显示系统状态
  if (watering) {
    display.println("ZT: ZHENGZAIJIAOSHUI");
    // 显示已浇水时间
    display.print("TIME: ");
    display.print((millis() - wateringStartTime)/1000);
    display.println("s");
  } else if (soilHum < DRY_THRESHOLD) {
    display.println("ZT: YUYAOJIAOSHUI");
  } else if (soilHum > WET_THRESHOLD) {
    display.println("ZT: SHUIFENCHONGZU");
  } else {
    display.println("ZT: ZHENGZHANG");
  }
  
  display.display();
}

void displaySensorError() {
  display.clearDisplay();
  display.setCursor(0,0);
  display.println("传感器错误!");
  display.println("请检查连接");
  display.display();
}

void logSensorData(float airTemp, float airHum, float soilHum) {
  Serial.print("空气温度: ");
  Serial.print(airTemp);
  Serial.print("C, 空气湿度: ");
  Serial.print(airHum);
  Serial.print("%, 土壤湿度: ");
  Serial.print(soilHum);
  Serial.println("%");
  
  if(watering) {
    Serial.print("当前状态: 正在浇水 (已浇水");
    Serial.print((millis() - wateringStartTime)/1000);
    Serial.println("秒)");
  } else if(soilHum < DRY_THRESHOLD) {
    Serial.println("当前状态: 需要浇水");
  }
}