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

//// 🔥 改用Arduino标准引脚标识（适配STM32L031K6的Arduino框架）
#define DHT_PIN   A7      // DHT22 DATA → A7（直接用A7，无需PA7）
#define DHT_TYPE   DHT22
#define PIR_PIN    D13     // PIR → D13（直接用D13，无需PC13）

//// SSD1306 I2C 引脚（直接用D0/D1，无需PD0/PD1）
#define SSD1306_ADDR 0x3C
#define SSD1306_SDA  D1     // OLED SDA → D1
#define SSD1306_SCL  D0     // OLED SCL → D0

// 全局变量（精简内存）
DHT dht(DHT_PIN, DHT_TYPE);
char display_buf[32];
char pir_str[10];

// ==================== 极简 SSD1306 驱动 ====================
void I2C_Write(uint8_t reg, uint8_t data) {
  Wire.beginTransmission(SSD1306_ADDR);
  Wire.write(reg);
  Wire.write(data);
  Wire.endTransmission();
}

void SSD1306_Init() {
  Wire.setClock(100000); // 适配STM32L031K6的I2C速率
  Wire.begin(SSD1306_SDA, SSD1306_SCL);
  
  // 核心初始化命令
  I2C_Write(0x00, 0xAE); // 关显示
  I2C_Write(0x00, 0x20); // 页寻址模式
  I2C_Write(0x00, 0x10);
  I2C_Write(0x00, 0xB0); // 起始页
  I2C_Write(0x00, 0xC8); // 行扫描方向
  I2C_Write(0x00, 0x81); // 对比度
  I2C_Write(0x00, 0xFF);
  I2C_Write(0x00, 0xA1); // 段重映射
  I2C_Write(0x00, 0xA6); // 正常显示
  I2C_Write(0x00, 0xAF); // 开显示
}

void SSD1306_Clear() {
  for(uint8_t page=0; page<8; page++) {
    I2C_Write(0x00, 0xB0+page);
    I2C_Write(0x00, 0x00);
    I2C_Write(0x00, 0x10);
    for(uint8_t col=0; col<128; col++) I2C_Write(0x40, 0x00);
  }
}

// 极简字库（仅保留实验必需字符）
const uint8_t font8x8[] = {
  0x3E,0x51,0x49,0x45,0x3E,0x00,0x00,0x00, // 0
  0x00,0x42,0x7F,0x40,0x00,0x00,0x00,0x00, // 1
  0x42,0x61,0x51,0x49,0x46,0x00,0x00,0x00, // 2
  0x22,0x41,0x49,0x49,0x36,0x00,0x00,0x00, // 3
  0x18,0x14,0x12,0x7F,0x10,0x00,0x00,0x00, // 4
  0x27,0x45,0x45,0x45,0x39,0x00,0x00,0x00, // 5
  0x3C,0x4A,0x49,0x49,0x30,0x00,0x00,0x00, // 6
  0x01,0x71,0x09,0x05,0x03,0x00,0x00,0x00, // 7
  0x36,0x49,0x49,0x49,0x36,0x00,0x00,0x00, // 8
  0x06,0x49,0x49,0x29,0x1E,0x00,0x00,0x00, // 9
  0x00,0x00,0x54,0x38,0x00,0x00,0x00,0x00, // %
  0x00,0x00,0x60,0x90,0x00,0x00,0x00,0x00, // °
  0x3E,0x41,0x41,0x41,0x3E,0x00,0x00,0x00, // C
  0x7C,0x12,0x11,0x12,0x7C,0x00,0x00,0x00, // H
  0x7C,0x0A,0x09,0x0A,0x7C,0x00,0x00,0x00, // T
  0x70,0x18,0x14,0x12,0x7C,0x00,0x00,0x00, // P
  0x7C,0x08,0x14,0x22,0x41,0x00,0x00,0x00, // I
  0x3E,0x41,0x41,0x22,0x1C,0x00,0x00,0x00, // R
  0x1C,0x22,0x41,0x00,0x00,0x00,0x00,0x00, // Y
  0x7E,0x01,0x01,0x01,0x7E,0x00,0x00,0x00, // E
  0x7F,0x41,0x41,0x41,0x7F,0x00,0x00,0x00, // S
  0x7E,0x01,0x01,0x01,0x01,0x00,0x00,0x00, // N
  0x3E,0x41,0x41,0x41,0x3E,0x00,0x00,0x00, // O
  0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, // :/空格
};

void SSD1306_Print(uint8_t x, uint8_t y, char* str) {
  uint8_t page = y/8, col = x;
  I2C_Write(0x00, 0xB0+page);
  I2C_Write(0x00, col&0x0F);
  I2C_Write(0x00, 0x10|(col>>4));
  
  while(*str) {
    uint8_t idx = 24; // 默认空格/:
    if(*str>='0'&&*str<='9') idx=*str-'0';
    else if(*str=='%') idx=10;
    else if(*str=='°') idx=11;
    else if(*str=='C') idx=12;
    else if(*str=='H') idx=13;
    else if(*str=='T') idx=14;
    else if(*str=='P') idx=15;
    else if(*str=='I') idx=16;
    else if(*str=='R') idx=17;
    else if(*str=='Y') idx=18;
    else if(*str=='E') idx=19;
    else if(*str=='S') idx=20;
    else if(*str=='N') idx=21;
    else if(*str=='O') idx=22;
    
    for(uint8_t i=0; i<8; i++) I2C_Write(0x40, font8x8[idx*8+i]);
    col +=8; str++;
  }
}

// ==================== 主程序（无HAL库依赖） ====================
void setup() {
  // 初始化引脚（Arduino标准函数，适配L031K6）
  pinMode(PIR_PIN, INPUT);
  pinMode(DHT_PIN, INPUT);
  
  // 初始化传感器和屏幕
  dht.begin();
  SSD1306_Init();
  SSD1306_Clear();
  
  // 初始显示
  SSD1306_Print(0,0,"STM32L031 Ready");
  delay(1000);
}

void loop() {
  // 定时读取传感器（避免阻塞）
  static uint32_t last_read = 0;
  if(millis() - last_read >= 1000) {
    last_read = millis();
    
    // 读取数据（转整数，减少运算）
    int temp = (int)dht.readTemperature();
    int humi = (int)dht.readHumidity();
    int pir  = digitalRead(PIR_PIN);

    // 处理PIR状态
    sprintf(pir_str, "PIR:%s", pir?"YES":"NO");

    // 屏幕显示
    SSD1306_Clear();
    sprintf(display_buf, "T:%d°C", temp);
    SSD1306_Print(0,0, display_buf);
    sprintf(display_buf, "H:%d%%", humi);
    SSD1306_Print(0,16, display_buf);
    SSD1306_Print(0,32, pir_str);
  }
}