//
// Created by IRIS on 25-2-12.
//

#include "data_analyse.h"
#define WINDOW_SIZE 5  // 高斯滑动窗口大小（建议为奇数）
#define SIGMA 1.5      // 平滑程度，值越大平滑越强


// 计算高斯权重
void compute_gaussian_weights(double weights[], int size, double sigma) {
    double sum = 0.0;
    int half_size = size / 2;

    for (int i = -half_size; i <= half_size; i++) {
        weights[i + half_size] = exp(- (i * i) / (2 * sigma * sigma));  // 高斯分布公式
        sum += weights[i + half_size];
    }
    // 归一化，使权重之和为 1
    for (int i = 0; i < size; i++) {
        weights[i] /= sum;
    }
}

// SGI 平滑算法 (适用于 uint16_t 数据)
void sgi_smoothing(uint16_t data[], uint16_t result[], int size) {
    double weights[WINDOW_SIZE];
    compute_gaussian_weights(weights, WINDOW_SIZE, SIGMA);

    int half_size = WINDOW_SIZE / 2;

    for (int i = 0; i < size; i++) {
        double sum = 0.0;
        double weight_sum = 0.0;

        for (int j = -half_size; j <= half_size; j++) {
            int idx = i + j;
            if (idx >= 0 && idx < size) {  // 确保索引有效
                sum += data[idx] * weights[j + half_size];
                weight_sum += weights[j + half_size];
            }
        }
        // 四舍五入并转换为 uint16_t
        result[i] = (uint16_t)round(sum / weight_sum);
    }
}


void sgi(uint16_t *data, uint16_t *result) {
    int size = sizeof(data) / sizeof(data[0]);
    sgi_smoothing(data, result, size);
}