use core::fmt;

use serde::{de::Visitor, Deserializer, Serializer};
use time::OffsetDateTime;

pub(crate) fn serialize<S: Serializer>(
    time: &OffsetDateTime,
    ser: S,
) -> Result<S::Ok, S::Error> {
    ser.serialize_i64(time.unix_timestamp())
}

struct I64Visitor;

impl<'de> Visitor<'de> for I64Visitor {
    type Value = i64;

    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        write!(formatter, "an integer")
    }

    fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E> {
        Ok(v)
    }

    fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E> {
        Ok(v as i64)
    }
}

pub(crate) fn deserialize<'de, D: Deserializer<'de>>(
    de: D,
) -> Result<OffsetDateTime, D::Error> {
    Ok(
        OffsetDateTime::from_unix_timestamp(de.deserialize_i64(I64Visitor)?)
            .unwrap_or_else(|_| OffsetDateTime::now_utc()),
    )
}