/*******************************************************************************
 * 文件名称 : motion_control.c
 * 文件说明 : 割草机纯追踪运动控制器（C 语言实现）
 * 创建日期 : 2025-11-22
 *******************************************************************************/

#include "motion_control.h"

#include <math.h>
#include <string.h>

#include "arm_math.h"

#include "motion_config.h"

#ifndef M_PI
#define M_PI (3.14159265358979323846f)
#endif

#define DEG2RAD                (0.017453292519943295769236907684886f)
#define RAD2DEG                (57.295779513082320876798154814105f)
#define MC_CLAMP(v, lo, hi)    ((v) < (lo) ? (lo) : (((v) > (hi)) ? (hi) : (v)))
/* 当航向误差逼近 ±π 时的判决窗口（约 0.5°） */
#define MC_HEADING_PI_EPS      (0.00872664626f)

/* 将角度约束到 [-pi, pi]，避免航向跳变 */
static float mc_wrap_angle(float angle)
{
    while (angle > (float)M_PI)
    {
        angle -= 2.0f * (float)M_PI;
    }
    while (angle < -(float)M_PI)
    {
        angle += 2.0f * (float)M_PI;
    }
    return angle;
}

/* 在误差接近 ±π 时保持上一周期的转向方向，避免来回反转 */
static float mc_heading_error_with_hysteresis(MC_State *state, float desired_heading)
{
    float err = mc_wrap_angle(desired_heading - state->heading_rad);
    float abs_err = fabsf(err);
    float pi_delta = (float)M_PI - abs_err;

    if (pi_delta <= MC_HEADING_PI_EPS)
    {
        float preferred_sign = state->last_turn_sign;
        if (preferred_sign == 0.0f)
        {
            preferred_sign = (err >= 0.0f) ? 1.0f : -1.0f;
        }
        float old_err = err;
        err = preferred_sign * abs_err;
        state->last_turn_sign = preferred_sign;
        
    }
    else if (abs_err > 1.0e-6f)
    {
        state->last_turn_sign = (err > 0.0f) ? 1.0f : -1.0f;
    }

    return err;
}

/* 读取路径点，索引越界时截到末尾 */
static void mc_get_point(const MC_State *state, HIDO_UINT32 idx, float outPt[2])
{
    /* 防御性检查：如果路径数据未初始化，返回原点 */
    if (state->path_xy == HIDO_NULL || state->path_count == 0U)
    {
        outPt[0] = 0.0f;
        outPt[1] = 0.0f;
        return;
    }
    
    if (idx >= state->path_count)
    {
        idx = state->path_count - 1U;
    }
    outPt[0] = state->path_xy[idx * 2U];
    outPt[1] = state->path_xy[idx * 2U + 1U];
}

/* 计算两个二维点的平方距离 */
static float mc_distance_sq(const float a[2], const float b[2])
{
    float dx = a[0] - b[0];
    float dy = a[1] - b[1];
    return dx * dx + dy * dy;
}

/* 计算两点距离（含 sqrt 防护） */
static float mc_distance(const float a[2], const float b[2])
{
    float dist_sq = mc_distance_sq(a, b);
    float dist = 0.0f;
    if (dist_sq > 0.0f)
    {
        arm_sqrt_f32(dist_sq, &dist);
    }
    return dist;
}

/* 数学坐标（东为 0°，逆时针为正）→ 罗盘坐标（北为 0°，顺时针为正） */
static float mc_math_rad_to_compass_deg(float heading_rad)
{
    float compass_deg = 90.0f - (heading_rad * RAD2DEG);
    while (compass_deg >= 360.0f)
    {
        compass_deg -= 360.0f;
    }
    while (compass_deg < 0.0f)
    {
        compass_deg += 360.0f;
    }
    return compass_deg;
}

/* 罗盘坐标（北为 0°，顺时针为正）→ 数学坐标（东为 0°，逆时针为正） */
static float mc_compass_deg_to_math_rad(float heading_deg)
{
    float math_deg = 90.0f - heading_deg;
    return mc_wrap_angle(math_deg * DEG2RAD);
}

/* 判断车辆是否已经"到达"某个路径点
 * 标准：距离该点小于阈值（0.5米）即为到达 */
static HIDO_BOOL mc_is_point_reached(const MC_State *state, HIDO_UINT32 point_idx)
{
    if (point_idx >= state->path_count)
    {
        return HIDO_FALSE;
    }
    
    float pos[2] = {state->pos[0], state->pos[1]};
    float point[2];
    mc_get_point(state, point_idx, point);
    
    float dist = mc_distance(pos, point);
    
    /* 定义"到达"阈值为0.5米 */
    const float REACH_THRESHOLD_M = 0.1f;
    
    return (dist < REACH_THRESHOLD_M) ? HIDO_TRUE : HIDO_FALSE;
}

/* 搜索当前位置最近的路径点（只允许向前推进，必须到达才推进）
 * 类似航点导航：必须先到达航点0，才能导航到航点1 */
static HIDO_UINT32 mc_find_nearest(const MC_State *state)
{
    HIDO_UINT32 current_idx = state->nearest_index;
    
    /* 检查是否到达当前点 */
    if (mc_is_point_reached(state, current_idx) == HIDO_TRUE)
    {
        /* 到达了，推进到下一个点（如果不是最后一个） */
        if (current_idx < state->path_count - 1U)
        {
            return current_idx + 1U;
        }
    }
    
    /* 否则保持当前索引不变 */
    return current_idx;
}

/* 沿路径累积距离，直到达到前视目标
 * 注意：lookahead点始终至少是start_idx的下一个点，确保顺序导航 */
static HIDO_UINT32 mc_find_lookahead(const MC_State *state, HIDO_UINT32 start_idx, float lookahead_m)
{
    /* 如果已经是最后一个点，直接返回 */
    if (start_idx >= state->path_count - 1U)
    {
        return state->path_count - 1U;
    }
    
    /* lookahead点至少是start_idx的下一个点（顺序导航：必须先经过下一个点） */
    HIDO_UINT32 next_idx = start_idx + 1U;
    
    /* 简化逻辑：直接返回下一个点，确保按顺序访问每个航点 */
    return start_idx;
}

/* 计算带符号横向误差（左正右负） */
static float mc_cross_track_error(const MC_State *state, HIDO_UINT32 nearest_idx)
{
    if (state->path_count < 2U)
    {
        return 0.0f;
    }

    HIDO_UINT32 idx0, idx1;
    if (nearest_idx == 0U)
    {
        idx0 = 0U;
        idx1 = (state->path_count > 1U) ? 1U : 0U;
    }
    else
    {
        idx0 = nearest_idx - 1U;
        idx1 = nearest_idx;
    }

    float p0[2];
    float p1[2];
    float pos[2] = {state->pos[0], state->pos[1]};
    mc_get_point(state, idx0, p0);
    mc_get_point(state, idx1, p1);

    float vx = p1[0] - p0[0];
    float vy = p1[1] - p0[1];
    float wx = pos[0] - p0[0];
    float wy = pos[1] - p0[1];
    float seg_len_sq = vx * vx + vy * vy;

    float t = 0.0f;
    if (seg_len_sq > 0.0f)
    {
        t = (wx * vx + wy * vy) / seg_len_sq;
    }
    if (t < 0.0f)
    {
        t = 0.0f;
    }
    else if (t > 1.0f)
    {
        t = 1.0f;
    }

    float proj_x = p0[0] + vx * t;
    float proj_y = p0[1] + vy * t;
    float dx = pos[0] - proj_x;
    float dy = pos[1] - proj_y;
    float dist_sq = dx * dx + dy * dy;
    float dist = 0.0f;
    if (dist_sq > 0.0f)
    {
        arm_sqrt_f32(dist_sq, &dist);
    }
    float cross = vx * (pos[1] - p0[1]) - vy * (pos[0] - p0[0]);
    return (cross >= 0.0f) ? dist : -dist;
}

/* 阶段：旋转/接近起点，使车准备好跟踪路径 */
static void mc_compute_goto_start(MC_State *state, float dt_s, MC_Output *out)
{
    float start_point[2];
    mc_get_point(state, 0U, start_point);
    
    /* 检测目标点变化并记录 - 已移除LOG */
    static HIDO_UINT32 s_goto_log_idx = 0U;
    
    state->current_target_xy[0] = start_point[0];
    state->current_target_xy[1] = start_point[1];
    out->target_valid = HIDO_TRUE;
    out->target_xy[0] = start_point[0];
    out->target_xy[1] = start_point[1];
    float vec_x = start_point[0] - state->pos[0];
    float vec_y = start_point[1] - state->pos[1];
    float dist = mc_distance(start_point, state->pos);

    float desired_heading;
    arm_status status = arm_atan2_f32(vec_y, vec_x, &desired_heading);
    out->target_heading_deg = mc_math_rad_to_compass_deg(desired_heading);
    float heading_err = mc_heading_error_with_hysteresis(state, desired_heading);
    float yaw_rate_cmd = state->config.heading_kp * heading_err;
    yaw_rate_cmd = MC_CLAMP(yaw_rate_cmd, -state->config.max_turn_rate, state->config.max_turn_rate);
    
    float forward = 0.0f;
    if (dist > state->config.start_pos_tolerance_m)
    {
        if (fabsf(heading_err) < state->config.start_heading_tolerance_rad)
        {
            float desired = state->config.base_speed_mps + 0.5f * dist;
            forward = MC_CLAMP(desired,
                               state->config.min_follow_speed_mps,
                               state->config.max_forward_mps);
        }
    }
    else if (fabsf(heading_err) < state->config.start_heading_tolerance_rad)
    {
        /* 到达起点且航向对准，切换到路径跟踪模式 */
        state->stage = MC_STAGE_FOLLOW_PATH;
        state->nearest_index = 0U;  /* 重置为路径第一个点 */
    }

    out->forward_mps = forward;
    out->turn_rate = yaw_rate_cmd;
    out->heading_error = heading_err;
    out->cross_track_error = dist;
    out->active = (forward != 0.0f) || (fabsf(yaw_rate_cmd) > 0.01f);
    (void)dt_s;
}

/* 阶段：纯追踪 + 航向/横向误差补偿 */
static void mc_compute_follow_path(MC_State *state, float dt_s, MC_Output *out)
{
    /* 安全检查：路径必须至少有1个点 */
    if (state->path_count == 0U)
    {
        out->forward_mps = 0.0f;
        out->turn_rate = 0.0f;
        out->active = HIDO_FALSE;
        return;
    }
    
    HIDO_UINT32 nearest_idx = mc_find_nearest(state);
    
    /* 安全检查：nearest_idx 必须在有效范围内 */
    if (nearest_idx >= state->path_count)
    {
        nearest_idx = state->path_count - 1U;
    }
    state->nearest_index = nearest_idx;

    float lookahead = state->config.lookahead_min_m;
    float speed_ratio = MC_CLAMP(state->speed_mps / state->config.max_forward_mps, 0.0f, 1.0f);
    lookahead += (state->config.lookahead_max_m - state->config.lookahead_min_m) * speed_ratio;
    HIDO_UINT32 lookahead_idx = mc_find_lookahead(state, nearest_idx, lookahead);
    
    /* 安全检查：lookahead_idx 必须在有效范围内 */
    if (lookahead_idx >= state->path_count)
    {
        lookahead_idx = state->path_count - 1U;
    }
    state->lookahead_index = lookahead_idx;
    
    /* 调试：每20帧输出一次路径跟踪状态 */
    static HIDO_UINT32 s_path_log_idx = 0U;
    static HIDO_UINT32 s_last_nearest = 0xFFFFFFFF;
    static HIDO_UINT32 s_last_lookahead = 0xFFFFFFFF;
    
    /* 如果索引发生变化，立即输出LOG */
    /* 路径点调试LOG - 已移除 */
//    static HIDO_UINT32 s_last_nearest = 0xFFFFFFFF;
//    static HIDO_UINT32 s_last_lookahead = 0xFFFFFFFF;
    HIDO_BOOL index_changed = (nearest_idx != s_last_nearest) || (lookahead_idx != s_last_lookahead);
    
    if (index_changed)
    {
        s_last_nearest = nearest_idx;
        s_last_lookahead = lookahead_idx;
    }

    float target[2];
    mc_get_point(state, lookahead_idx, target);
    
    /* 检测目标点变化并记录 - 已移除LOG */
    
    state->current_target_xy[0] = target[0];
    state->current_target_xy[1] = target[1];
    out->target_valid = HIDO_TRUE;
    out->target_xy[0] = target[0];
    out->target_xy[1] = target[1];

    float vec_x = target[0] - state->pos[0];
    float vec_y = target[1] - state->pos[1];
    float desired_heading;
    arm_atan2_f32(vec_y, vec_x, &desired_heading);
    out->target_heading_deg = mc_math_rad_to_compass_deg(desired_heading);
    float heading_err = mc_heading_error_with_hysteresis(state, desired_heading);
    float heading_err_rate = (heading_err - state->last_heading_err) / (dt_s > 0.0f ? dt_s : 0.013f);
    state->last_heading_err = heading_err;

    float cross_track = mc_cross_track_error(state, nearest_idx);
    float p_term = state->config.heading_kp * heading_err;
    float d_term = state->config.heading_kd * heading_err_rate;
    float x_term = state->config.xtrack_kp * cross_track;
    
    float yaw_rate_cmd = p_term + d_term + x_term;
    yaw_rate_cmd = MC_CLAMP(yaw_rate_cmd, -state->config.max_turn_rate, state->config.max_turn_rate);
    
    /* 调试LOG：每10帧打印一次PID控制详情，帮助分析死区/不转向问题 - 已移除 */
    
    float forward = state->config.base_speed_mps
                  - state->config.heading_speed_scale * fabsf(heading_err)
                  - state->config.xtrack_speed_scale * fabsf(cross_track);
    forward = MC_CLAMP(forward,
                       state->config.min_follow_speed_mps,
                       state->config.max_forward_mps);

    float goal[2];
    mc_get_point(state, state->path_count - 1U, goal);
    float goal_dist = mc_distance(goal, state->pos);
    if (goal_dist < state->config.goal_tolerance_m)
    {
        state->stage = MC_STAGE_FINISHED;
        forward = 0.0f;
        yaw_rate_cmd = 0.0f;
    }

    out->forward_mps = forward;
    out->turn_rate = yaw_rate_cmd;
    out->heading_error = heading_err;
    out->cross_track_error = cross_track;
    out->active = (state->stage != MC_STAGE_FINISHED);
}

/* 填充默认配置 */
HIDO_VOID MC_DefaultConfig(MC_Config *_cfg)
{
    if (_cfg == HIDO_NULL)
    {
        return;
    }
    _cfg->max_forward_mps = MC_CFG_MAX_FORWARD_MPS;
    _cfg->max_reverse_mps = MC_CFG_MAX_REVERSE_MPS;
    _cfg->max_turn_rate = MC_CFG_MAX_TURN_RATE_RAD;
    _cfg->base_speed_mps = MC_CFG_BASE_SPEED_MPS;
    _cfg->min_follow_speed_mps = MC_CFG_MIN_FOLLOW_SPEED_MPS;
    _cfg->lookahead_min_m = MC_CFG_LOOKAHEAD_MIN_M;
    _cfg->lookahead_max_m = MC_CFG_LOOKAHEAD_MAX_M;
    _cfg->start_pos_tolerance_m = MC_CFG_START_POS_TOL_M;
    _cfg->start_heading_tolerance_rad = MC_CFG_START_HEADING_TOL_RAD;
    _cfg->goal_tolerance_m = MC_CFG_GOAL_TOL_M;
    _cfg->heading_kp = MC_CFG_HEADING_KP;
    _cfg->heading_kd = MC_CFG_HEADING_KD;
    _cfg->xtrack_kp = MC_CFG_XTRACK_KP;
    _cfg->heading_speed_scale = MC_CFG_HEADING_SPEED_SCALE;
    _cfg->xtrack_speed_scale = MC_CFG_XTRACK_SPEED_SCALE;
}

/* MC_Init */
HIDO_VOID MC_Init(MC_State *_state, const MC_Config *_cfg, const float *_path_xy, HIDO_UINT32 _point_count)
{
    if (_state == HIDO_NULL || _cfg == HIDO_NULL || _path_xy == HIDO_NULL || _point_count < 2U)
    {
        return;
    }

    memset(_state, 0, sizeof(MC_State));
    _state->config = *_cfg;
    _state->path_xy = _path_xy;
    _state->path_count = _point_count;
    _state->stage = MC_STAGE_GOTO_START;
    _state->nearest_index = 0U;
    _state->lookahead_index = 0U;
}

/* 注入最新 ENU 位姿及航向/速度 */
HIDO_VOID MC_UpdateGps(MC_State *_state, const float _enu[3], const ST_GPRMI *_gprmi)
{
    if (_state == HIDO_NULL || _enu == HIDO_NULL || _gprmi == HIDO_NULL)
    {
        return;
    }

    _state->pos[0] = _enu[0];
    _state->pos[1] = _enu[1];
    _state->pos[2] = _enu[2];
    float old_heading_deg = _state->heading_deg;
    float gps_heading_rad = mc_compass_deg_to_math_rad(_gprmi->m_fHeadingAngle);
    _state->heading_rad = gps_heading_rad;
    _state->heading_deg = mc_math_rad_to_compass_deg(_state->heading_rad);
    
    float old_heading_rad = mc_compass_deg_to_math_rad(old_heading_deg);
    _state->pitch_deg = _gprmi->m_fPitchAngle;
    _state->roll_deg = _gprmi->m_fRollAngle;
    _state->vel[0] = _gprmi->m_fEastVelocity;
    _state->vel[1] = _gprmi->m_fNorthVelocity;
    float speed_sq = _state->vel[0] * _state->vel[0] + _state->vel[1] * _state->vel[1];
    float speed = 0.0f;
    if (speed_sq > 0.0f)
    {
        arm_sqrt_f32(speed_sq, &speed);
    }
    _state->speed_mps = speed;
    _state->pose_valid = HIDO_TRUE;
}

/* 更新 IMU 陀螺 Z 轴（yaw 角速度） */
HIDO_VOID MC_UpdateImu(MC_State *_state, const ST_GPIMU *_gpimu)
{
    if (_state == HIDO_NULL || _gpimu == HIDO_NULL)
    {
        return;
    }

    /* GyroZ符号定义：顺时针正，逆时针负（从上往下看Z轴，右手螺旋定则）
     * 数学坐标系：东为0°，逆时针为正（CCW>0）
     * 所以：GyroZ正值（顺时针）→ yaw_rate_rad负值，GyroZ负值（逆时针）→ yaw_rate_rad正值
     * 需要取反：yaw_rate_rad = -GyroZ * DEG2RAD */
    _state->yaw_rate_rad = -(_gpimu->m_fGyroZ * DEG2RAD);
    _state->imu_valid = HIDO_TRUE;
    
}

/* 入口：根据阶段计算控制量 */ 
HIDO_VOID MC_Compute(MC_State *_state, float _dt_s, MC_Output *_out)
{
    if (_state == HIDO_NULL || _out == HIDO_NULL)
    {
        return;
    }

    memset(_out, 0, sizeof(MC_Output));
    _out->target_valid = HIDO_FALSE;
    _out->target_xy[0] = 0.0f;
    _out->target_xy[1] = 0.0f;

    /* 记录target_valid变为FALSE的原因 */
    static HIDO_BOOL s_last_path_valid = HIDO_TRUE;
    static HIDO_BOOL s_last_pose_valid = HIDO_TRUE;
    
    if (_state->path_xy == HIDO_NULL || _state->path_count < 2U)
    {
        if (s_last_path_valid)
        {
            s_last_path_valid = HIDO_FALSE;
        }
        return;
    }
    s_last_path_valid = HIDO_TRUE;

    if (_state->pose_valid == HIDO_FALSE)
    {
        if (s_last_pose_valid)
        {
            s_last_pose_valid = HIDO_FALSE;
        }
        return;
    }
    s_last_pose_valid = HIDO_TRUE;

    if (_state->imu_valid == HIDO_TRUE && _dt_s > 0.0f)
    {
        float old_heading_rad = _state->heading_rad;
        float old_heading_deg = _state->heading_deg;
        float delta_rad = _state->yaw_rate_rad * _dt_s;
        _state->heading_rad = mc_wrap_angle(_state->heading_rad + delta_rad);
        float new_heading_rad = _state->heading_rad;
        _state->heading_deg = mc_math_rad_to_compass_deg(_state->heading_rad);
        
        (void)new_heading_rad;
    }

    if (_state->stage == MC_STAGE_IDLE)
    {
        _state->stage = MC_STAGE_GOTO_START;
    }

    _out->target_heading_deg = _state->heading_deg;

    switch (_state->stage)
    {
    case MC_STAGE_GOTO_START:
        mc_compute_goto_start(_state, _dt_s, _out);
        break;
    case MC_STAGE_FOLLOW_PATH:
        mc_compute_follow_path(_state, _dt_s, _out);
        break;
    case MC_STAGE_FINISHED:
        _out->active = HIDO_FALSE;
        _out->target_heading_deg = _state->heading_deg;
        break;
    default:
        break;
    }

    /* 不再取反：yaw_rate_cmd（数学坐标系，正=CCW）直接作为turn_rate输出
     * motion_control_task.c中，正值=左转(逆时针)，负值=右转(顺时针)，与数学坐标系一致 */
    // _out->turn_rate = -_out->turn_rate;  // 已注释：此取反导致方向错误
    _out->stage = _state->stage;
    _out->pos_enu[0] = _state->pos[0];
    _out->pos_enu[1] = _state->pos[1];
    _out->pos_enu[2] = _state->pos[2];
    _out->heading_deg = _state->heading_deg;
    _out->pitch_deg = _state->pitch_deg;
    _out->roll_deg = _state->roll_deg;
    static HIDO_BOOL s_last_target_valid = HIDO_FALSE;
    static E_MCStage s_last_stage_for_target = MC_STAGE_IDLE;
    
    if (_state->stage == MC_STAGE_FOLLOW_PATH || _state->stage == MC_STAGE_GOTO_START)
    {
        _out->target_valid = HIDO_TRUE;
        _out->target_xy[0] = _state->current_target_xy[0];
        _out->target_xy[1] = _state->current_target_xy[1];
        
        if (!s_last_target_valid)
        {
        }
    }
    else
    {
        _out->target_valid = HIDO_FALSE;
        _out->target_xy[0] = 0.0f;
        _out->target_xy[1] = 0.0f;
        
        if (s_last_target_valid || _state->stage != s_last_stage_for_target)
        {
        }
    }
    
    s_last_target_valid = _out->target_valid;
    s_last_stage_for_target = _state->stage;
}