#include "FanControl.h"

#include "TMP144.h"
#include "main.h"

#include "stm32f4xx_hal_def.h"
#include "stm32f4xx_hal_tim.h"

#include <stdint.h>

TIM_HandleTypeDef* timer;
uint32_t channel;
FanState fan_state;

HAL_StatusTypeDef fan_ctrl_init(TIM_HandleTypeDef* handle, uint32_t channel_) {
  timer = handle;
  channel = channel_;
  fan_state = FANS_OFF;

  return HAL_TIM_PWM_Start(timer, channel);
}

void fan_ctrl_update() {
  if (fan_state == FANS_OFF && max_temperature > THRESH_FANS_ON_HALF) {
    fan_state = FANS_ON;
  } else if (fan_state == FANS_ON && max_temperature < THRESH_FANS_OFF) {
    fan_state = FANS_OFF;
  }

  uint32_t power;
  if (fan_state == FANS_OFF) {
    power = 0;
  } else {
    if (max_temperature < THRESH_FANS_ON_HALF) {
      power = 50;
    } else if (max_temperature > THRESH_FANS_ON_FULL) {
      power = 100;
    } else {
      power = (100 * (max_temperature - THRESH_FANS_ON_HALF)) /
              (THRESH_FANS_ON_FULL - THRESH_FANS_ON_HALF);
    }
  }
  fan_ctrl_set_power(power);
}

void fan_ctrl_set_power(uint32_t percent) {
  if (percent > 100) {
    percent = 100;
  }

  // The PWM signal switches a low side switch, so we need to invert the duty
  // cycle.
  percent = 100 - percent;

  uint32_t counter = timer->Init.Period * percent / 100;
  __HAL_TIM_SET_COMPARE(timer, channel, counter);
}