/**
 * STM32 单芯片安防系统
 * 第一环节：门磁(PA1) + 红外(PA2) 触发舵机(PB1)旋转60°，5秒后复位，同时串口发送"CAMERA WORK"
 * 第二环节：串口接收 "alarm" → LCD报警 + 红蓝LED闪烁；接收 "owner" → LCD显示欢迎
 * 两部分独立并行，互不干扰
 */

#include <Arduino.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Servo.h>

// ==================== 引脚定义 ====================
#define DOOR_SENSOR_PIN   PA1
#define PIR_SENSOR_PIN    PA2
#define SERVO_PIN         PB1
#define LCD_SDA_PIN       PB7
#define LCD_SCL_PIN       PB6
#define RED_LED_PIN       PA0
#define BLUE_LED_PIN      PA3
#define ALARM_BTN_PIN     PB5
#define OWNER_BTN_PIN     PB4

// ==================== 全局对象 ====================
Servo lightServo;
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ==================== 第一环节状态机 ====================
enum DoorState {
  DOOR_IDLE,
  DOOR_OPEN,
  DOOR_TRIGGERED
};
DoorState doorState = DOOR_IDLE;

unsigned long servoStartTime = 0;
bool servoMoved = false;

// ==================== 报警状态 ====================
bool alarmActive = false;
unsigned long alarmBlinkTime = 0;
bool redOn = true;

// ==================== 串口接收缓冲 ====================
String serialBuffer = "";

// ==================== 初始化 ====================
void setup() {
  pinMode(DOOR_SENSOR_PIN, INPUT_PULLDOWN);
  pinMode(PIR_SENSOR_PIN, INPUT_PULLUP);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(BLUE_LED_PIN, OUTPUT);
  pinMode(ALARM_BTN_PIN, INPUT_PULLUP);
  pinMode(OWNER_BTN_PIN, INPUT_PULLUP);
  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(BLUE_LED_PIN, LOW);

  Serial.begin(9600);

  Wire.begin(LCD_SDA_PIN, LCD_SCL_PIN);
  lcd.init();
  lcd.backlight();
  lcd.print("System Ready");

  lightServo.attach(SERVO_PIN);
  lightServo.write(0);

  Serial.println("safeguard_system ready");
}

// ==================== 处理串口指令 ====================
void processCommand(String cmd) {
  cmd.trim();
  cmd.toLowerCase();

  Serial.print("Received: ");
  Serial.println(cmd);

  if (cmd == "alarm") {
    if (!alarmActive) {
      alarmActive = true;
      Serial.println("ESP32_TX——>STRANGER——>STM32_PA10_RX");
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Alert! Intruder");
      lcd.setCursor(0, 1);
      lcd.print("Stranger detected");
      alarmBlinkTime = millis();
      redOn = true;
      digitalWrite(RED_LED_PIN, HIGH);
      digitalWrite(BLUE_LED_PIN, LOW);
    }
  } else if (cmd == "owner") {
    alarmActive = false;
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(BLUE_LED_PIN, LOW);
    Serial.println("ESP32_TX——>OWNER——>STM32_PA10_RX");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Owner Welcome");
  }
}

// ==================== 主循环 ====================
void loop() {
  // ---------- 第一环节：门磁 + 红外 → 舵机 ----------
  switch (doorState) {
    case DOOR_IDLE:
      if (digitalRead(DOOR_SENSOR_PIN) == HIGH) {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("DOOR OPEN");
        doorState = DOOR_OPEN;
      }
      break;

    case DOOR_OPEN:
      if (digitalRead(DOOR_SENSOR_PIN) == HIGH) {
        if (digitalRead(PIR_SENSOR_PIN) == HIGH) {
          lcd.clear();
          lcd.setCursor(0, 0);
          lcd.print("Moving heat");
          lcd.setCursor(0, 1);
          lcd.print("source detected");
          Serial.println("门被打开");
          Serial.println("检测到热源活动");
          lightServo.write(60);
          servoStartTime = millis();
          servoMoved = true;
          Serial.println("STM32_PA9_TX——>CAMERA WORK——>ESP32_RX");
          Serial.println("电路闭合-补光灯开启");
          doorState = DOOR_TRIGGERED;
        }
      } else {
        doorState = DOOR_IDLE;
      }
      break;

    case DOOR_TRIGGERED:
      if (servoMoved && (millis() - servoStartTime >= 5000)) {
        lightServo.write(0);
        servoMoved = false;
        doorState = DOOR_IDLE;
      }
      break;
  }

  // ---------- 第二环节：读取串口指令或按钮 ----------
  // 检测 ALARM 按钮
  if (digitalRead(ALARM_BTN_PIN) == LOW) {
    if (!alarmActive) {
      alarmActive = true;
      Serial.println("ESP32_TX——>STRANGER——>STM32_RX");
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Alert! Intruder");
      lcd.setCursor(0, 1);
      lcd.print("Stranger detected");
      alarmBlinkTime = millis();
      redOn = true;
      digitalWrite(RED_LED_PIN, HIGH);
      digitalWrite(BLUE_LED_PIN, LOW);
      delay(200);
    }
  }

  // 检测 OWNER 按钮
  if (digitalRead(OWNER_BTN_PIN) == LOW) {
    alarmActive = false;
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(BLUE_LED_PIN, LOW);
    Serial.println("ESP32_TX——>OWNER——>STM32_RX");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Owner Welcome");
    delay(200);
  }

  // 串口接收字符串（支持 "alarm" 和 "owner"）
  while (Serial.available()) {
    char c = Serial.read();
    if (c == '\n' || c == '\r') {
      if (serialBuffer.length() > 0) {
        processCommand(serialBuffer);
        serialBuffer = "";
      }
    } else {
      serialBuffer += c;
    }
  }

  while (Serial1.available()) {
    char c = Serial1.read();
    if (c == '\n' || c == '\r') {
      if (serialBuffer.length() > 0) {
        processCommand(serialBuffer);
        serialBuffer = "";
      }
    } else {
      serialBuffer += c;
    }
  }

  // ---------- 红蓝LED交替闪烁（报警时） ----------
  if (alarmActive) {
    if (millis() - alarmBlinkTime >= 500) {
      redOn = !redOn;
      digitalWrite(RED_LED_PIN, redOn ? HIGH : LOW);
      digitalWrite(BLUE_LED_PIN, redOn ? LOW : HIGH);
      alarmBlinkTime = millis();
    }
  }

  delay(10);
}