use serde::{Serialize, Serializer};
use std::{
    fmt::{Display, Formatter, Result as FmtResult},
    ops::Sub,
    time::{SystemTime, UNIX_EPOCH},
};

#[derive(PartialEq, PartialOrd, Copy, Clone, Debug)]
pub struct EpochTimestamp(SystemTime);

impl EpochTimestamp {
    pub fn now() -> Self {
        EpochTimestamp(SystemTime::now())
    }
}

impl Sub for EpochTimestamp {
    type Output = u64;
    fn sub(self, other: EpochTimestamp) -> u64 {
        self.0.duration_since(other.0).unwrap_or_default().as_secs()
    }
}

impl Display for EpochTimestamp {
    fn fmt(&self, f: &mut Formatter) -> FmtResult {
        write!(
            f,
            "{}",
            self.0
                .duration_since(UNIX_EPOCH)
                .unwrap_or_default()
                .as_secs()
        )
    }
}

impl Serialize for EpochTimestamp {
    fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        s.serialize_u64(
            self.0
                .duration_since(SystemTime::from(UNIX_EPOCH))
                .unwrap_or_default()
                .as_secs(),
        )
    }
}