#ifndef LOWESS_SMOOTHER_H
#define LOWESS_SMOOTHER_H

#include <vector>
#include <algorithm>
#include <cmath>
#include <stdexcept>

// lowess
namespace Lowess {

// 配置参数结构体
struct Config {
    double smoothingFactor = 0.25;
    int robustnessIterations = 3;
};

// 验证参数有效性
void validateConfig(const Config& config);

// 三次权重函数
double weightFunction(double x);

// 计算中位数绝对偏差
double medianAbsoluteDeviation(const std::vector<double>& residuals);

// 计算带宽
std::vector<double> computeBandwidths(const std::vector<double>& x, double smoothingFactor);

// 核心平滑函数
std::vector<double> smooth(
    const std::vector<double>& x,
    const std::vector<double>& y,
    const Config& config = Config()
);

} // namespace Lowess

#endif // LOWESS_SMOOTHER_H