#include "vl53_board.h"
#include "FreeRTOS.h"
#include "task.h"
#include "robot_params.h"
#include "vl53_calibration_config.h"

/* ================= EMA滤波底层实现 ================= */
static void vl53_ema_init(Vl53EMA_t *ema, float alpha) {
    ema->x = 0.0f;
    ema->alpha = alpha;
    ema->initialized = 0;
}

static float vl53_ema_update(Vl53EMA_t *ema, float measurement) {
    if (ema->initialized == 0) {
        ema->x = measurement;
        ema->initialized = 1;
        return ema->x;
    }
    // EMA公式: x_new = alpha * measurement + (1 - alpha) * x_old
    ema->x = ema->alpha * measurement + (1.0f - ema->alpha) * ema->x;
    return ema->x;
}

static const Vl53RuntimeCalibration_t *vl53_get_runtime_calibration(uint8_t id)
{
    switch (id) {
    case 0: return &k_vl53_left_calibration[0];
    case 1: return &k_vl53_left_calibration[1];
    case 2: return &k_vl53_right_calibration[0];
    case 3: return &k_vl53_right_calibration[1];
    default: return NULL;
    }
}

static VL53L0X_Error vl53_apply_runtime_calibration(VL53L0X_DEV dev, uint8_t id)
{
    const Vl53RuntimeCalibration_t *cal = vl53_get_runtime_calibration(id);
    VL53L0X_Error status;

    if (cal == NULL) return VL53L0X_ERROR_NONE;

    if (cal->offset_calibrated != 0U) {
        status = VL53L0X_SetOffsetCalibrationDataMicroMeter(dev, cal->offset_micro_meters);
        if (status != VL53L0X_ERROR_NONE) return status;
    }

    if (cal->xtalk_calibrated != 0U) {
        status = VL53L0X_SetXTalkCompensationRateMegaCps(dev, cal->xtalk_compensation_rate_mcps);
        if (status != VL53L0X_ERROR_NONE) return status;

        status = VL53L0X_SetXTalkCompensationEnable(dev, 1u);
        if (status != VL53L0X_ERROR_NONE) return status;
    } else {
        status = VL53L0X_SetXTalkCompensationEnable(dev, 0u);
        if (status != VL53L0X_ERROR_NONE) return status;
    }

    return VL53L0X_ERROR_NONE;
}

/* ================= ST 官方配置序列 ================= */
static VL53L0X_Error vl53_do_static_init(VL53L0X_DEV dev, uint32_t timing_budget_us)
{
    VL53L0X_Error status;
    uint32_t ref_spad_count = 0u;
    uint8_t is_aperture_spads = 0u;
    uint8_t vhv_settings = 0u;
    uint8_t phase_cal = 0u;

    status = VL53L0X_StaticInit(dev);
    if (status != VL53L0X_ERROR_NONE) return status;

    status = VL53L0X_PerformRefSpadManagement(dev, &ref_spad_count, &is_aperture_spads);
    if (status != VL53L0X_ERROR_NONE) return status;

    status = VL53L0X_PerformRefCalibration(dev, &vhv_settings, &phase_cal);
    if (status != VL53L0X_ERROR_NONE) return status;

    status = VL53L0X_SetDeviceMode(dev, VL53L0X_DEVICEMODE_CONTINUOUS_RANGING);
    if (status != VL53L0X_ERROR_NONE) return status;

    status = VL53L0X_SetMeasurementTimingBudgetMicroSeconds(dev, timing_budget_us);
    if (status != VL53L0X_ERROR_NONE) return status;

    /* 连续测量采用 back-to-back 模式，让下一次测量在上一帧完成后立即开始。
     * 这样任务轮询周期变快时，能尽可能拿到最新帧，而不是被固定间隔再次拖慢。 */
    status = VL53L0X_SetInterMeasurementPeriodMilliSeconds(dev, 0u);
    if (status != VL53L0X_ERROR_NONE) return status;

    status = VL53L0X_SetLimitCheckEnable(dev, VL53L0X_CHECKENABLE_SIGMA_FINAL_RANGE, 1u);
    if (status != VL53L0X_ERROR_NONE) return status;

    status = VL53L0X_SetLimitCheckEnable(dev, VL53L0X_CHECKENABLE_SIGNAL_RATE_FINAL_RANGE, 1u);
    if (status != VL53L0X_ERROR_NONE) return status;

    return VL53L0X_ERROR_NONE;
}

/* ================= 核心管理器 API ================= */
VL53L0X_Error Vl53Board_Init(Vl53Board_t *board, const Vl53BoardHwCfg_t *hw_cfgs, uint8_t count, uint32_t timing_budget_us)
{
    if ((board == NULL) || (hw_cfgs == NULL) || (count == 0) || (count > VL53_MAX_DEVS_PER_BOARD)) {
        return VL53L0X_ERROR_INVALID_PARAMS;
    }

    memset(board, 0, sizeof(Vl53Board_t));
    board->dev_count = count;
    board->timing_budget_us = (timing_budget_us == 0u) ? 33000u : timing_budget_us;

    for (uint8_t i = 0; i < count; i++) {
        board->dev[i].name = hw_cfgs[i].name;
        board->dev[i].id = hw_cfgs[i].id;
        board->dev[i].comms_type = 1u;
        board->dev[i].comms_speed_khz = 400u;
        board->dev[i].is_present = 0u;

        VL53L0X_PlatformAttachBus(&board->dev[i], hw_cfgs[i].hi2c, VL53L0X_DEFAULT_ADDR_8BIT, 100u, NULL);
        VL53L0X_PlatformAttachPins(&board->dev[i], hw_cfgs[i].xshut_port, hw_cfgs[i].xshut_pin, NULL, 0);

        VL53L0X_PlatformSetXShut(&board->dev[i], GPIO_PIN_RESET);

        /* 初始化EMA滤波器：alpha 从 robot_params.h 读取 */
        vl53_ema_init(&board->ema[i], PARAM_VL53_EMA_ALPHA);
    }

    vTaskDelay(pdMS_TO_TICKS(10));

    for (uint8_t i = 0; i < count; i++) {
        if (VL53L0X_PlatformSetXShut(&board->dev[i], GPIO_PIN_SET) != VL53L0X_ERROR_NONE) continue;
        vTaskDelay(pdMS_TO_TICKS(20));

        board->dev[i].I2cDevAddr = VL53L0X_DEFAULT_ADDR_8BIT;
        if (VL53L0X_PlatformChangeAddress(&board->dev[i], hw_cfgs[i].runtime_addr_8bit) != VL53L0X_ERROR_NONE) continue;
        if (VL53L0X_DataInit(&board->dev[i]) != VL53L0X_ERROR_NONE) continue;
        if (vl53_do_static_init(&board->dev[i], board->timing_budget_us) != VL53L0X_ERROR_NONE) continue;
        if (vl53_apply_runtime_calibration(&board->dev[i], hw_cfgs[i].id) != VL53L0X_ERROR_NONE) continue;

        board->init_mask |= (uint8_t)(1u << i);
        board->dev[i].is_present = 1u;
    }

    return VL53L0X_ERROR_NONE;
}

VL53L0X_Error Vl53Board_StartContinuous(Vl53Board_t *board)
{
    if (board == NULL) return VL53L0X_ERROR_INVALID_PARAMS;
    for (uint8_t i = 0; i < board->dev_count; i++) {
        if (board->init_mask & (1u << i)) VL53L0X_StartMeasurement(&board->dev[i]);
    }
    return VL53L0X_ERROR_NONE;
}

VL53L0X_Error Vl53Board_StopContinuous(Vl53Board_t *board)
{
    if (board == NULL) return VL53L0X_ERROR_INVALID_PARAMS;
    for (uint8_t i = 0; i < board->dev_count; i++) {
        if (board->init_mask & (1u << i)) VL53L0X_StopMeasurement(&board->dev[i]);
    }
    return VL53L0X_ERROR_NONE;
}

VL53L0X_Error Vl53Board_ReadAll(Vl53Board_t *board, Vl53BoardSnapshot_t *snapshot)
{
    if (board == NULL || snapshot == NULL) return VL53L0X_ERROR_INVALID_PARAMS;

    memset(snapshot, 0, sizeof(Vl53BoardSnapshot_t));
    snapshot->tick_ms = xTaskGetTickCount() * portTICK_PERIOD_MS;

    for (uint8_t i = 0; i < board->dev_count; i++) {
        if ((board->init_mask & (1u << i)) == 0u) {
            snapshot->range_status[i] = 255u;
            continue;
        }

        uint8_t ready = 0u;
        if (VL53L0X_GetMeasurementDataReady(&board->dev[i], &ready) != VL53L0X_ERROR_NONE) continue;

        if (ready) {
            VL53L0X_RangingMeasurementData_t data;
            memset(&data, 0, sizeof(data));

            if (VL53L0X_GetRangingMeasurementData(&board->dev[i], &data) == VL53L0X_ERROR_NONE) {
                /* 1. 写入原始数据 */
                snapshot->range_mm[i] = data.RangeMilliMeter;
                snapshot->range_status[i] = data.RangeStatus;

                if (data.RangeStatus == 0u) {
                    /* 2. 标记有效并按开关决定是否应用EMA滤波 */
                    snapshot->valid_mask |= (1u << i);
#if PARAM_VL53_USE_EMA_FILTER
                    snapshot->range_mm_filtered[i] = vl53_ema_update(&board->ema[i], (float)data.RangeMilliMeter);
#else
                    snapshot->range_mm_filtered[i] = (float)data.RangeMilliMeter;
                    board->ema[i].x = (float)data.RangeMilliMeter;
                    board->ema[i].initialized = 1u;
#endif
                } else {
                    /* 测距失败时，滤波值维持上一次的历史最佳估计不变 */
                    snapshot->range_mm_filtered[i] = board->ema[i].x;
                }

                VL53L0X_ClearInterruptMask(&board->dev[i], 0u);
            }
        } else {
            /* 如果没准备好，把上一帧的历史值顺延下来，防止读到 0 */
            snapshot->range_mm_filtered[i] = board->ema[i].x;
        }
    }
    return VL53L0X_ERROR_NONE;
}