#include "Pwm.h"
#include "Config.h"

void PwmGenerator::begin() { pinMode(GPIO_PWM, OUTPUT); stop(); }

bool PwmGenerator::start(uint32_t hz, uint8_t dutyPct, ActualPwm &a) {
  stop();
  uint8_t bits = LEDC_MAX_BITS;
  while (bits > 1 && static_cast<uint64_t>(hz) * (1ULL << bits) > 80000000ULL) --bits;
  if (!ledcAttachChannel(GPIO_PWM, hz, bits, LEDC_CHANNEL)) return false;
  const uint32_t top = (1UL << bits) - 1UL;
  const uint32_t duty = (static_cast<uint64_t>(top) * dutyPct + 50U) / 100U;
  if (!ledcWriteChannel(LEDC_CHANNEL, duty)) { ledcDetach(GPIO_PWM); return false; }
  const uint32_t actualHz = ledcReadFreq(GPIO_PWM);
  if (!actualHz) { ledcDetach(GPIO_PWM); return false; }
  a = {hz, actualHz, 100.0f * duty / top, bits};
  running_ = true;
  return true;
}

bool PwmGenerator::preview(uint32_t hz, uint8_t dutyPct, ActualPwm &a) {
  stop();
  uint8_t bits = LEDC_MAX_BITS;
  while (bits > 1 && static_cast<uint64_t>(hz) * (1ULL << bits) > 80000000ULL) --bits;
  if (!ledcAttachChannel(GPIO_PWM, hz, bits, LEDC_CHANNEL)) return false;
  ledcWriteChannel(LEDC_CHANNEL, 0); // query hardware without emitting test pulses
  const uint32_t actualHz = ledcReadFreq(GPIO_PWM);
  const uint32_t top = (1UL << bits) - 1UL;
  const uint32_t duty = (static_cast<uint64_t>(top) * dutyPct + 50U) / 100U;
  a = {hz, actualHz, 100.0f * duty / top, bits};
  ledcDetach(GPIO_PWM); pinMode(GPIO_PWM, OUTPUT); digitalWrite(GPIO_PWM, PWM_SAFE_LEVEL);
  return actualHz != 0;
}

void PwmGenerator::stop() {
  if (running_) ledcDetach(GPIO_PWM);
  pinMode(GPIO_PWM, OUTPUT); digitalWrite(GPIO_PWM, PWM_SAFE_LEVEL);
  running_ = false;
}