/**
 ******************************************************************************
 * @file    CadenceStrideModelConfig.hpp
 * @brief   Tunables for the read-side cadence/stride model and live estimator.
 *
 * Extends the existing SDK::Calibration::Config namespace. Reuses the outdoor
 * calibrator's bin layout, stride bounds, phase-2 gate, and tick-gap clamp from
 * OutdoorStrideCalibConfig.hpp — those are NOT duplicated here.
 ******************************************************************************
 */

#ifndef __CADENCE_STRIDE_MODEL_CONFIG_HPP
#define __CADENCE_STRIDE_MODEL_CONFIG_HPP

#include <cstdint>

namespace SDK::Calibration
{

namespace Config
{

// --- Phase-1 demographic stride ----------------------------------------------

// The Phase-1 (uncalibrated) demographic stride is CADENCE-DEPENDENT: stride
// length grows with cadence, so a single static value badly underestimates
// running speed (a constant ~walking stride reports ~half speed at run
// cadences). Treadmill stride length grows roughly linearly with cadence (no
// overground plateau, per the speed-research doc), so SL(c) is modelled as a
// straight line through two population anchors at a reference height, then
// scaled by the user's height: SL(c,h) = (h / kDemoRefHeightM) * line(c).
// Anchors are firmware-tunable. The model is unisex by design — a
// gender-specific stride model is not planned (no robust sex effect at matched
// running speeds).
constexpr float kDemoRefHeightM   = 1.75f;    ///< Reference height for the anchors
constexpr float kDemoCadenceLoSpm = 110.0f;   ///< Walk anchor cadence
constexpr float kDemoStrideLoM    = 1.51f;    ///<   stride there (~5.0 km/h @ 110 SPM)
constexpr float kDemoCadenceHiSpm = 170.0f;   ///< Run anchor cadence
constexpr float kDemoStrideHiM    = 2.35f;    ///<   stride there (~12.0 km/h @ 170 SPM)

/// Fallback height (m) when the profile height is missing/implausible.
constexpr float kDefaultHeightM = 1.70f;

/// Plausible height clamp window, metres.
constexpr float kHeightMinM = 1.40f;
constexpr float kHeightMaxM = 2.10f;

// --- Post-run delta learning -------------------------------------------------

/// Post-run delta learning rate η (0 < η <= 1).
constexpr float kLearningRateEta = 0.4f;

/// D_actual sanity band as a fraction of D_estimated.
constexpr float kDActualRatioMin = 0.5f;
constexpr float kDActualRatioMax = 2.0f;

/// Minimum estimated (pre-correction) session distance, metres, before a
/// post-run correction may *learn* the delta LUT. The Calibrate & Save screen
/// is always offered (the user can correct the recorded distance / avg speed on
/// any run), but delta learning additionally requires the outdoor-calibrated
/// tier AND this much integrated distance — short runs lack the cadence-bin
/// coverage to attribute a correction reliably.
constexpr float kDeltaLearnMinDistanceM = 2000.0f;

// --- Live estimator ----------------------------------------------------------

/// Live hold-forward window on cadence loss, seconds.
constexpr float kCadenceHoldSeconds = 5.0f;

// --- Delta LUT persistence ---------------------------------------------------

/// Delta-LUT filename in the Treadmill app's own root (NOT under SharedData).
constexpr const char *kDeltaLutPath = "treadmill_delta.json";

/// Delta-LUT schema version.
constexpr int32_t kDeltaLutVersion = 1;

} // namespace Config

} // namespace SDK::Calibration

#endif /* __CADENCE_STRIDE_MODEL_CONFIG_HPP */