/**
 * pH 传感器 ADC 采样 — PA1 (ADC1_IN1)
 * 10次采样取平均, 线性换算为 pH 值, 钳位 6.5~9.5
 */
float pH_Read(void) {
    u32 adc_sum = 0;

    for (int i = 0; i < 10; i++) {
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);
        while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC));
        adc_sum += ADC_GetConversionValue(ADC1);
    }
    float adc_avg = adc_sum / 10.0;

    // 线性换算: pH = ADC值 × 14 / 4096
    float ph = adc_avg * 14.0 / 4096.0;

    // 钳位到土壤合理范围
    if (ph < 6.5) ph = 6.5;
    if (ph > 9.5) ph = 9.5;

    return ph;
}

/**
 * EC 电导率 ADC 采样 — PA0 (ADC1_IN0)
 * 10次采样取平均, 电压换算 + 温度补偿 → μS/cm
 */
u16 EC_Read(float temp) {
    u32 adc_sum = 0;

    for (int i = 0; i < 10; i++) {
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);
        while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC));
        adc_sum += ADC_GetConversionValue(ADC1);
    }
    float adc_avg = adc_sum / 10.0;

    // 电压换算: V = ADC × 3.3V / 4096
    float voltage = adc_avg * 3.3 / 4096.0;

    // EC 计算 (含温度补偿): EC = V × coeff / (1 + 0.02×(temp-25))
    float compensation = 1.0 + 0.02 * (temp - 25.0);
    u16 ec = (u16)(voltage * 600.0 / compensation);

    return ec;
}

/**
 * 主循环: 100ms 周期采集 → OLED 显示 → 串口输出
 * 串口格式: [timestamp] pH=xxx EC=xxx raw0=xxx raw1=xxx\r\n
 */
int main(void) {
    System_Init();                              // 时钟 72MHz
    ADC1_Init();                                // PA0+PA1 双通道, 12bit
    UART1_Init(115200);                      // PA9 TX, 8N1
    OLED_Init();                                // SSD1306, I2C 软模拟

    float ph;
    u16 ec, raw_ec, raw_ph;
    u32 tick = 0;
    char buf[64];

    while (1) {
        ph = pH_Read();                         // ADC1_IN1 → pH 值
        ec = EC_Read(20.0);                    // ADC1_IN0 → EC 值 (默认25°C补偿)

        // OLED 本地显示 (三行)
        OLED_Clear();
        OLED_Printf(0, 0, "pH : %.1f", ph);
        OLED_Printf(0, 2, "EC : %d uS", ec);
        OLED_Printf(0, 5, "Time: %ds", tick / 10);

        // 串口输出 → 浏览器 Web Serial API 读取
        // 格式: [时间戳] pH=整数值 EC=整数值 raw0=ADC raw1=ADC
        u16 ph_int = (u16)(ph * 100);    // pH 7.0 → 700
        sprintf(buf, "[%lu] pH=%d EC=%d\r\n",
                tick, ph_int, ec);
        UART1_SendString(buf);

        delay_ms(100);                      // 10Hz 采集频率
        tick++;
    }
}

# ===== 玉米生长阶段 AI 分析 (PIL + NumPy) =====
def analyze_corn_stage(image_bytes):
    from PIL import Image
    import numpy as np

    img = Image.open(io.BytesIO(image_bytes))\
              .convert('RGB').resize((400, 400))
    arr = np.array(img, dtype=np.float32)
    r, g, b = arr[:,:,0], arr[:,:,1], arr[:,:,2]

    # ExG 植被指数 (Woebbecke 1995)
    exg = np.clip(2.0*g - r - b, -255, 255)
    exg_mean = float(np.mean(exg))

    # GLI 绿叶指数 (Gitelson 2002)
    denominator = 2.0*g + r + b + 1e-6
    gli = (2.0*g - r - b) / denominator
    gli_mean = float(np.mean(gli))

    # 植被覆盖度
    veg_cover = float(np.mean(exg > 20)) * 100

    # HSV 色彩分割 — 绿色/黄色比例
    hsv = np.array(Image.fromarray(
        np.clip(arr, 0, 255).astype(np.uint8)
    ).convert('HSV'), dtype=np.float32)
    h, s, v = hsv[:,:,0], hsv[:,:,1]/255.0, hsv[:,:,2]/255.0

    green_h_pct  = float(np.mean((h>40)&(h<150)&(s>0.15))) * 100
    yellow_h_pct = float(np.mean((h>10)&(h<50)&(s>0.08)&(s<0.6))) * 100
    soil_pct     = float(np.mean((s<0.2)&(v<0.5))) * 100

    # 纹理分析 (20×20 局部标准差)
    patch = 20
    tex_map = np.zeros_like(gli)
    for y in range(0, 400, patch):
        for x in range(0, 400, patch):
            yy = slice(y, min(y+patch, 400))
            xx = slice(x, min(x+patch, 400))
            tex_map[yy, xx] = np.std(exg[yy, xx])
    tex_mean = float(np.mean(tex_map))

    # 四条件级联阶段判定
    yg_ratio = yellow_h_pct / (green_h_pct + 1e-6)

    if yellow_h_pct > 10 and yg_ratio > 0.28 and green_h_pct < 55:
        stage, conf = 4, 70 + min(20, int(yg_ratio * 50))  # 腊熟期
    elif veg_cover > 40 and yellow_h_pct > 8:
        stage, conf = 3, 60 + min(30, int(yellow_h_pct * 3))  # 开花期
    elif veg_cover < 28 and soil_pct > 22:
        stage, conf = 1, 60 + min(25, int(soil_pct / 2))  # 三叶期
    elif veg_cover > 35 and exg_mean > 15:
        stage, conf = 2, 60 + min(30, int((veg_cover-35)/2))  # 抽雄期
    else:
        stage, conf = 1, 50

    return {
        "stage": stage,
        "name": STAGES[stage]["name"],    # 三叶期/抽雄期/开花期/腊熟期
        "confidence": min(95, conf),
        "veg_cover": round(veg_cover, 1),
        "exg_mean": round(exg_mean, 1),
        "gli_mean": round(gli_mean, 4),
        "green_h_pct": round(green_h_pct, 1),
        "yellow_h_pct": round(yellow_h_pct, 1),
        "soil_pct": round(soil_pct, 1),
        "texture": round(tex_mean, 1),
        "method": "ExG+GLI+HSV"
    }