#include "linear.h"
#include <stdlib.h>

int point_v[1024] = {0};
int point_l[1024] = {0};
int point_cnt = 0;
float k = 0;
float b = 0;
float theory_point[300] = {0};
float linearity = 0;
int test_cnt = 1;
uint8_t save_data[101];
uint8_t vol_loc_data[2000];

int point_v_max,max_point,point_v_min,min_point;
float bias_local = 0;

extern double fabs(double __x);

/// <LinearFit>
/// 利用两点法进行线性拟合 y = kx + b,
/// <x,y—存放长度与电压的数组>
void linear_fit()
{
    // Ax+By+C=0
    float A = 0;
    float B = 0;
	float C = 0;
	
	point_v_max = -9999;
	point_v_min = 9999;
	
	for (int i = 0; i < point_cnt; i++)
    {
		if(point_v[i] > point_v_max) 
		{
			point_v_max = point_v[i];
			max_point = i;
		}
		if(point_v[i] < point_v_min) 
		{
			point_v_min = point_v[i];
			min_point = i;
		}
	}

    A = point_v[max_point] - point_v[min_point];
    B = point_l[min_point] - point_l[max_point];
	C = point_l[max_point] * point_v[min_point] - point_l[min_point] * point_v[max_point];

    k = -(A / B);
	b = -(C / B);
}

/// <summary>
/// 更新数组y，替换为电压理论值
void linear_val()
{
    for (int i = 0; i < point_cnt; i++)
    {
        theory_point[i] = k * point_l[i] + b;
    }
}	

int write_start_addr = 0;

void get_linearity()
{
	float max_bias = 0;

	linear_fit();
	linear_val();
	for (int i = 0; i < point_cnt; i++)
    {
        if(fabs(max_bias) < fabs(point_v[i] - theory_point[i]))
		{
			max_bias = point_v[i] - theory_point[i];
			bias_local = point_l[i];
		}	

		//
		vol_loc_data[0 + 2*i] = ((uint16_t)point_v[i] >> 8) & 0xFF; 
		vol_loc_data[1 + 2*i] = (uint16_t)point_v[i] & 0xFF;
		vol_loc_data[1000 + 2*i] = ((uint16_t)point_l[i] >> 8) & 0xFF; 
		vol_loc_data[1001 + 2*i] = (uint16_t)point_l[i] & 0xFF;
		//
    }
	linearity = fabs(max_bias / (point_v_max - point_v_min));

	//
	test_cnt++;
	if(test_cnt > 10)
		test_cnt = 1;

	save_data[0 + (test_cnt-1)*10] = ((uint16_t)(linearity * 10000) >> 8) & 0xFF; 
	save_data[1 + (test_cnt-1)*10] = (uint16_t)(linearity * 10000) & 0xFF;
	save_data[2 + (test_cnt-1)*10] = ((uint16_t)(bias_local) >> 8) & 0xFF; 
	save_data[3 + (test_cnt-1)*10] = (uint16_t)(bias_local) & 0xFF;
	save_data[4 + (test_cnt-1)*10] = ((uint16_t)(point_cnt) >> 8) & 0xFF; 
	save_data[5 + (test_cnt-1)*10] = (uint16_t)(point_cnt) & 0xFF;
	save_data[6 + (test_cnt-1)*10] = ((uint16_t)(point_v_min) >> 8) & 0xFF; 
	save_data[7 + (test_cnt-1)*10] = (uint16_t)(point_v_min) & 0xFF;
	save_data[8 + (test_cnt-1)*10] = ((uint16_t)(point_v_max) >> 8) & 0xFF; 
	save_data[9 + (test_cnt-1)*10] = (uint16_t)(point_v_max) & 0xFF;
	save_data[100] = test_cnt;

	at24cxx_write(write_start_addr,save_data,101);
	at24cxx_write(1000 * (2 * test_cnt - 1),vol_loc_data,2000);
	//
}