Files
aviation/crates/lib/src/metars/utils.rs

114 lines
3.3 KiB
Rust

use crate::error::{CoreError, CoreErrorKind, CoreResult};
use chrono::{Datelike, NaiveDate, Utc};
pub fn parse_metar_time(observation_time: &str) -> CoreResult<String> {
if observation_time.len() != 7 {
return Err(CoreError::new(
CoreErrorKind::InvalidInput,
format!("Unable to parse observation time in {}", observation_time),
));
}
let observation_day = match observation_time[0..2].parse::<u32>() {
Ok(day) => day,
Err(err) => return Err(err.into()),
};
let observation_hour = match observation_time[2..4].parse::<u32>() {
Ok(hour) => hour,
Err(err) => return Err(err.into()),
};
let observation_minute = match observation_time[4..6].parse::<u32>() {
Ok(minute) => minute,
Err(err) => return Err(err.into()),
};
let current_time = Utc::now().naive_utc();
let current_year = current_time.year();
let current_month = current_time.month();
let candidate_date = NaiveDate::from_ymd_opt(current_year, current_month, observation_day)
.ok_or_else(|| {
CoreError::new(
CoreErrorKind::InvalidInput,
format!(
"Invalid date with day {} for current month",
observation_day
),
)
})?;
let candidate_date = match candidate_date.and_hms_opt(observation_hour, observation_minute, 0) {
Some(date) => date,
None => {
return Err(CoreError::new(
CoreErrorKind::InvalidInput,
format!(
"Invalid time for time '{}': hour {}, minute {}",
observation_time, observation_hour, observation_minute
),
));
}
};
let obs_datetime = if candidate_date > current_time {
// Subtract one month. (Handle year rollover carefully.)
let (month, year) = if current_month == 1 {
(12, current_year - 1)
} else {
(current_month - 1, current_year)
};
let adjusted_date = NaiveDate::from_ymd_opt(year, month, observation_day).ok_or_else(|| {
CoreError::new(
CoreErrorKind::InvalidInput,
format!(
"Invalid date with day {} for month {}",
observation_day, month
),
)
})?;
adjusted_date
.and_hms_opt(observation_hour, observation_minute, 0)
.unwrap()
} else {
candidate_date
};
Ok(obs_datetime.format("%Y-%m-%dT%H:%M:00Z").to_string())
}
#[cfg(test)]
mod tests {
use super::*;
use chrono::NaiveDateTime;
#[test]
fn test_parse_metar_time() {
for day in 1..=31 {
for hour in 0..24 {
for minute in 0..60 {
// METAR form "DDHHMMZ"
let obs_time = format!("{:02}{:02}{:02}Z", day, hour, minute);
let result = parse_metar_time(&obs_time);
match result {
Ok(datetime_str) => {
// "YYYY-MM-DDTHH:MM:00Z"
assert_eq!(
datetime_str.len(),
20,
"Unexpected length for input {} yielded {}",
obs_time,
datetime_str
);
// Remove the trailing 'Z' and parse
let trimmed = &datetime_str[..19];
NaiveDateTime::parse_from_str(trimmed, "%Y-%m-%dT%H:%M:%S").unwrap_or_else(|e| {
panic!(
"Parsing '{}' from input {} failed: {}",
trimmed, obs_time, e
)
});
}
Err(_err) => {}
}
}
}
}
}
}