player.rs

/// A music track.
pub struct Track {
    pub title: String,
    pub duration: u32,
    cursor: u32,
}

impl Track {
    pub fn new(title: &'static str, duration: u32) -> Self {
        Self {
            title: title.into(),
            duration,
            cursor: 0,
        }
    }
}

/// A music player holds a playlist and it can do basic operations over it.
pub struct Player {
    playlist: Vec<Track>,
    current_track: usize,
    _volume: u8,
}

impl Default for Player {
    fn default() -> Self {
        Self {
            playlist: vec![
                Track::new("Track 1", 180),
                Track::new("Track 2", 165),
                Track::new("Track 3", 197),
                Track::new("Track 4", 205),
            ],
            current_track: 0,
            _volume: 25,
        }
    }
}

impl Player {
    pub fn next_track(&mut self) {
        self.current_track = (self.current_track + 1) % self.playlist.len();
    }

    pub fn prev_track(&mut self) {
        self.current_track = (self.playlist.len() + self.current_track - 1) % self.playlist.len();
    }

    pub fn play(&mut self) {
        self.track_mut().cursor = 10; // Playback imitation.
    }

    pub fn pause(&mut self) {
        self.track_mut().cursor = 43; // Paused at some moment.
    }

    pub fn rewind(&mut self) {
        self.track_mut().cursor = 0;
    }

    pub fn track(&self) -> &Track {
        &self.playlist[self.current_track]
    }

    fn track_mut(&mut self) -> &mut Track {
        &mut self.playlist[self.current_track]
    }
}