#include "balance.h"
#include "stdint.h"
#include "arm_math.h"

/**
 * @brief 根据状态反馈计算当前腿长,查表获得LQR的反馈增益,并列式计算LQR的输出
 * @note 得到的腿部力矩输出还要经过综合运动控制系统补偿后映射为两个关节电机输出
 *
 */
static void CalcLQR(LinkNPodParam *p, ChassisParam *chassis)
{
    static float k[12][3] = {152.073959,-322.787113,4.602472,
    -18.091924,-50.039341,3.160226,
    124.677598,-113.871572,-13.279757,
    86.314525,-98.184173,-8.140564,
    162.907111,-185.705008,74.114015,
    14.280240,-18.420891,8.593112,
    -148.548074,99.259778,48.506697,
    -37.972970,41.871624,3.715364,
    192.255883,-224.641960,95.484838,
    93.227296,-117.550338,60.336158,
    -343.472953,311.036102,57.349362,
    -41.609057,38.668058,-0.809331,};
    float T[2] = {0};       // 0 T_wheel  1 T_hip
    float l = p->leg_len;
    float lsqr = l * l;

    uint8_t i, j;

    // 离地时轮子输出置0
    i = 0; j = i * 6;
    T[i] = p->fly_flag ? 0 :
           ((k[j + 0][0] * lsqr + k[j + 0][1] * l + k[j + 0][2]) * -p->theta +
            (k[j + 1][0] * lsqr + k[j + 1][1] * l + k[j + 1][2]) * -p->theta_w + 
            (k[j + 2][0] * lsqr + k[j + 2][1] * l + k[j + 2][2]) * (chassis->target_dist - chassis->dist) +
            (k[j + 3][0] * lsqr + k[j + 3][1] * l + k[j + 3][2]) * (chassis->target_v - chassis->vel) +
            (k[j + 4][0] * lsqr + k[j + 4][1] * l + k[j + 4][2]) * -chassis->pitch +
            (k[j + 5][0] * lsqr + k[j + 5][1] * l + k[j + 5][2]) * -chassis->pitch_w);
    
    // 离地时关节输出仅保留 theta 和 theta_dot，保证滞空时腿部竖直
    i = 1; j = i * 6;
    T[i] = (k[j + 0][0] * lsqr + k[j + 0][1] * l + k[j + 0][2]) * -p->theta +
           (k[j + 1][0] * lsqr + k[j + 1][1] * l + k[j + 1][2]) * -p->theta_w + (p->fly_flag ? 0 :
           ((k[j + 2][0] * lsqr + k[j + 2][1] * l + k[j + 2][2]) * (chassis->target_dist - chassis->dist) +
            (k[j + 3][0] * lsqr + k[j + 3][1] * l + k[j + 3][2]) * (chassis->target_v - chassis->vel) +
            (k[j + 4][0] * lsqr + k[j + 4][1] * l + k[j + 4][2]) * -chassis->pitch +
            (k[j + 5][0] * lsqr + k[j + 5][1] * l + k[j + 5][2]) * -chassis->pitch_w));
    
    p->T_wheel = T[0];
    p->T_hip = T[1];
}