use chrono::{DateTime, Duration, Local};

#[derive(Debug, Clone)]
pub struct TimerData {
    pub total: Duration,
    pub start_moments: Vec<DateTime<Local>>, // moments at which the timer resumes; the first is the start monent
    pub pause_moments: Vec<DateTime<Local>>, // moments at which the timer is paused; the last is the stop moment
}

/// A countdown timer
#[derive(Clone, Debug)]
pub struct Timer {
    pub remaining: Duration,
    pub total: Duration,
    pub start_moments: Vec<DateTime<Local>>, // moments at which the timer resumes; the first is the start monent
    pub pause_moments: Vec<DateTime<Local>>, // moments at which the timer is paused; the last is the stop moment
    pub paused: bool,
    //pub data: TimerData,
}

impl Timer {
    /// Returns stopwatch reset to zero
    pub fn new(duration: Duration) -> Self {
        Self {
            remaining: duration,
            total: duration,
            start_moments: Vec::new(),
            pause_moments: Vec::new(),
            paused: true, // finished by default; start by explicitly calling `.resume()`
        }
    }
    pub fn read(&self) -> Duration {
        if self.paused {
            self.remaining
        } else {
            self.remaining - (Local::now() - self.last_start())
        }
    }
    pub fn pause_or_resume(&mut self) {
        if self.paused {
            self.resume();
        } else {
            self.pause();
        }
    }
    pub fn start_moment(&self) -> DateTime<Local> {
        self.start_moments[0]
    }
    pub fn stop_moment(&self) -> DateTime<Local> {
        self.pause_moments[self.pause_moments.len() - 1]
    }

    fn last_start(&self) -> DateTime<Local> {
        self.start_moments[self.start_moments.len() - 1]
    }
    pub fn pause(&mut self) {
        let moment = Local::now();
        self.pause_moments.push(moment);
        self.remaining = self.remaining - (moment - self.last_start());
        self.paused = true;
    }
    pub fn resume(&mut self) {
        self.start_moments.push(Local::now());
        self.paused = false;
    }
}