pub struct Timebase {
    /// Sample rate
    rate:        u64,
    /// Current frame
    frame:       u64,
    /// Beats per bar
    signature:   (u64, u64),
    /// Beats per minute
    bpm:         f64,
}

impl Timebase {
    pub fn new (rate: u64, signature: (u64, u64), bpm: f64) -> Self {
        Self {
            rate,
            frame: 0,
            signature,
            bpm,
        }
    }
    pub fn seconds (&self) -> f64 {
        self.frame as f64 / self.rate as f64
    }
    pub fn minutes (&self) -> f64 {
        self.seconds / 60.0
    }
    pub fn beats (&self) -> f64 {
        self.minutes / self.bpm
    }
    pub fn bar (&self) -> u64 {
        ((self.beats() * self.signature.0 as f64) / self.signature.1 as f64) as u64
    }
    pub fn beat (&self) -> u64 {
        ((self.beats() * self.signature.0 as f64) % self.signature.1 as f64) as u64
    }
    pub fn time_string (&self) -> String {
        let minutes = self.minutes() as u64;
        let seconds = self.seconds() as u64;
        let milliseconds = self.seconds() - seconds;
        format!("{minutes}:{seconds}.{milliseconds:03}")
    }
    pub fn beat_string (&self) -> String {
        let beats = self.beats() as u64;
        format!("{beats} {}/{}", minutes, self.beat(), self.signature.1)
    }
}