#include <sta/devices/stm32/delay.hpp>

#ifdef STA_PLATFORM_STM32

#include <sta/devices/stm32/hal.hpp>
#include <sta/devices/stm32/clocks.hpp>

#include <sta/debug/assert.hpp>
#include <sta/lang.hpp>


namespace sta
{
    void delayMs(uint32_t ms)
    {
        HAL_Delay(ms);
    }
} // namespace sta


#ifdef STA_STM32_DELAY_US_TIM

#ifndef HAL_TIM_MODULE_ENABLED
#  error "STM32 HAL TIM module not enabled!"
#endif // HAL_TIM_MODULE_ENABLED

#include <tim.h>

namespace sta
{
    uint32_t gDelayUsMul = 1;

    bool isValidDelayUsTIM()
	{
		// Get PCLK multiplier for TIM clock
		uint32_t pclkMul = 1;
		switch (STA_STM32_DELAY_US_TIM.Init.ClockDivision)
		{
		case TIM_CLOCKDIVISION_DIV1:
			pclkMul = 1;
			break;
		case TIM_CLOCKDIVISION_DIV2:
			pclkMul = 2;
			break;
		case TIM_CLOCKDIVISION_DIV4:
			pclkMul = 4;
			break;
		default:
			STA_ASSERT(false);
			STA_UNREACHABLE();
		}

		// Calculate TIM clock frequency
		uint32_t clkFreq = pclkMul * STA_STM32_GET_HANDLE_PCLK_FREQ_FN(STA_STM32_DELAY_US_TIM)() * STA_STM32_GET_HANDLE_PCLK_TIM_PRESCALER(STA_STM32_DELAY_US_TIM);

		// Calculate update frequency based on prescaler value
		uint32_t prescaler = (STA_STM32_DELAY_US_TIM.Init.Prescaler) ? STA_STM32_DELAY_US_TIM.Init.Prescaler : 1;
		uint32_t updateFreq = clkFreq / prescaler;

		gDelayUsMul = updateFreq / 1000000;

		// TIM must have at least microsecond precision (>= 1 MHz frequency)
		return (updateFreq >= 1000000);
	}

    void delayUs(uint32_t us)
    {
    	// Check if the specified timer is usable for microsecond delays.
    	STA_ASSERT(isValidDelayUsTIM());

		// Save the current value of the counter.
		uint32_t current = __HAL_TIM_GET_COUNTER(&STA_STM32_DELAY_US_TIM);

		// Set the timer counter to zero to avoid overflows during delay-
		__HAL_TIM_SET_COUNTER(&STA_STM32_DELAY_US_TIM, 0);

		// Wait for the desired microseconds.
		while (__HAL_TIM_GET_COUNTER(&STA_STM32_DELAY_US_TIM) < us * gDelayUsMul);

		// Set the timer counter to the previous value and add the waited duration to it.
		// This avoids collisions with code relying on timeUs measurements.
		__HAL_TIM_SET_COUNTER(&STA_STM32_DELAY_US_TIM, current + us * gDelayUsMul);
    }

} // namespace sta

#endif // STA_STM32_DELAY_US_TIM

#endif // STA_PLATFORM_STM32