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//! no_std implementation of DelayMs and DelayUs for cortex-m

#![deny(missing_docs)]
#![no_std]

use bitrate::*;
use cortex_m::asm::delay;
use embedded_hal::blocking::delay::DelayMs;
use embedded_hal::blocking::delay::DelayUs;

/// asm::delay based Timer
pub struct AsmDelay {
    freq_base_ms: u32,
    freq_base_us: u32,
}

impl AsmDelay {
    /// Consturct new delay timer of CPU frequency (Hertz)
    pub fn new<F>(freq: F) -> Self
    where
        F: Into<Hertz<u32>>,
    {
        let freq_hz = freq.into().0;
        AsmDelay {
            freq_base_ms: (freq_hz / 1_000) / 2,
            freq_base_us: (freq_hz / 1_000_000) / 2,
        }
    }
}

impl<U> DelayMs<U> for AsmDelay
where
    U: Into<u32>,
{
    fn delay_ms(&mut self, ms: U) {
        delay(self.freq_base_ms * ms.into())
    }
}
impl<U> DelayUs<U> for AsmDelay
where
    U: Into<u32>,
{
    fn delay_us(&mut self, us: U) {
        delay(self.freq_base_us * us.into())
    }
}

/// Convert cycles back to time
pub struct CyclesToTime {
    freq_base_ms: f32,
    freq_base_us: f32,
}

impl CyclesToTime {
    /// Consturct new cycles to time converter of CPU frequency (Hertz)
    pub fn new<F>(freq: F) -> Self
    where
        F: Into<Hertz<u32>>,
    {
        let freq_hz = freq.into().0;
        CyclesToTime {
            freq_base_ms: (freq_hz / 1_000) as f32,
            freq_base_us: (freq_hz / 1_000_000) as f32,
        }
    }

    /// Converts cycles to ms
    pub fn to_ms<U>(&self, cycles: U) -> f32
    where
        U: Into<u32>,
    {
        (cycles.into() as f32) / self.freq_base_ms
    }

    /// Converts cycles to us
    pub fn to_us<U>(&self, cycles: U) -> f32
    where
        U: Into<u32>,
    {
        (cycles.into() as f32) / self.freq_base_us
    }
}