#include "ss49e.h"

void ss49e_init(SS49E_State *self, enum MagnetPolarityType magnetPolarityType, ss49e_tick_callback_t tickCallback) {
  self->workingPhase = SS49E_WORKING_PHASE_NORMAL;
  self->tickCallback = tickCallback;

  self->magnetPolType = magnetPolarityType;
  const float level0 = 2445.0f / 4095.0f;
  const float deviation = 380.0f / 4095.0f;
  if (magnetPolarityType == MAGNET_POLTYPE_BIPOLAR) {
    // self->threshold01 = level0 + deviation * 0.75;
    // self->threshold10 = level0 - deviation * 0.75;
    self->threshold01 = (2447.0 + 520.0 * 2.0 / 3.0) / 4095.0;
    self->threshold10 = (2447.0 - 800.0 * 2.0 / 3.0) / 4095.0;
  } else {
    float activeLevel = level0 + (magnetPolarityType == MAGNET_POLTYPE_UNIPOLAR_POSITIVE ? deviation : -deviation);
    self->threshold01 = level0 * 1 / 3 + activeLevel * 2 / 3;
    self->threshold10 = activeLevel * 1 / 3 + level0 * 2 / 3;
  }
  self->currentLevel = 0;
}

void ss49e_process_sample(SS49E_State *self, uint16_t sample) {
  float normalized = (float)sample / 4095.0f;
  if (self->currentLevel == 0) {
    if (normalized >= self->threshold01) {
      self->currentLevel = 1;
      if (self->magnetPolType == MAGNET_POLTYPE_BIPOLAR || self->magnetPolType == MAGNET_POLTYPE_UNIPOLAR_POSITIVE)
        self->tickCallback();
    }
  } else {
    if (normalized <= self->threshold10) {
      self->currentLevel = 0;
      if (self->magnetPolType == MAGNET_POLTYPE_BIPOLAR || self->magnetPolType == MAGNET_POLTYPE_UNIPOLAR_NEGATIVE)
        self->tickCallback();
    }
  }
}