use chrono::{Datelike, NaiveDate};
use serde::{Deserialize, Serialize};
use crate::error::Result;
use crate::time::daycounters::DayCounters;
#[derive(Deserialize, Serialize, Debug)]
pub enum Actual365FixedMarket {
Standard,
NoLeap,
}
#[derive(Deserialize, Serialize, Default, Debug)]
pub struct Actual365Fixed {
market: Option<Actual365FixedMarket>,
}
impl Actual365Fixed {
fn regular_day_count(&self, d1: NaiveDate, d2: NaiveDate) -> i64 {
let duration = d2 - d1;
duration.num_days()
}
fn nl_day_count(&self, d1: NaiveDate, d2: NaiveDate) -> i64 {
const MONTH_OFFSET: [i64; 12] = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 344];
let mut s1 =
d1.day() as i64 + MONTH_OFFSET[d1.month() as usize - 1usize] + (d1.year() as i64 * 365);
let mut s2 =
d2.day() as i64 + MONTH_OFFSET[d2.month() as usize - 1usize] + (d2.year() as i64 * 365);
if d1.month() == 2 && d1.day() == 29 {
s1 -= 1;
}
if d2.month() == 2 && d2.day() == 29 {
s2 -= 1;
}
s2 - s1
}
}
#[typetag::serde]
impl DayCounters for Actual365Fixed {
fn day_count(&self, d1: NaiveDate, d2: NaiveDate) -> Result<i64> {
Ok(match self.market {
Some(Actual365FixedMarket::Standard) | None => self.regular_day_count(d1, d2),
Some(Actual365FixedMarket::NoLeap) => self.nl_day_count(d1, d2),
})
}
fn year_fraction(&self, d1: NaiveDate, d2: NaiveDate) -> Result<f64> {
Ok(self.day_count(d1, d2)? as f64 / 365.0)
}
}
#[cfg(test)]
mod tests {
use super::Actual365Fixed;
use crate::error::Result;
use crate::time::daycounters::DayCounters;
use chrono::NaiveDate;
#[test]
fn test_day_counter_actual_365_fixed() -> Result<()> {
let d1 = NaiveDate::from_ymd_opt(2023, 10, 26).unwrap();
let d2 = NaiveDate::from_ymd_opt(2023, 10, 27).unwrap();
assert_eq!(Actual365Fixed::default().day_count(d1, d2)?, 1);
assert_eq!(
Actual365Fixed::default().year_fraction(d1, d2)?,
1f64 / 365.0
);
Ok(())
}
}