whichtime_sys/parsers/en/
time_unit_ago.rs

1//! Time unit ago parser: "5 days ago", "2 hours ago", etc.
2
3use crate::components::Component;
4use crate::context::ParsingContext;
5use crate::dictionaries::en::{get_time_unit, parse_number_pattern};
6use crate::error::Result;
7use crate::parsers::Parser;
8use crate::results::ParsedResult;
9use crate::scanner::TokenType;
10use crate::types::{Duration, TimeUnit, add_duration};
11use chrono::Datelike;
12use regex::Regex;
13use std::sync::LazyLock;
14
15static PATTERN: LazyLock<Regex> = LazyLock::new(|| {
16    Regex::new(
17        r"(?i)(\d+|one|two|three|four|five|six|seven|eight|nine|ten|eleven|twelve|a|an|the|few|several|couple)\s*(seconds?|minutes?|hours?|days?|weeks?|months?|years?|mins?|hrs?|secs?)\s*(?:ago|before|earlier)\b"
18    ).unwrap()
19});
20
21/// Parser for English relative expressions such as "3 days ago".
22pub struct TimeUnitAgoParser;
23
24impl Parser for TimeUnitAgoParser {
25    fn name(&self) -> &'static str {
26        "TimeUnitAgoParser"
27    }
28
29    fn should_apply(&self, context: &ParsingContext) -> bool {
30        context.has_token_type(TokenType::Ago) && context.has_token_type(TokenType::TimeUnit)
31    }
32
33    fn parse(&self, context: &ParsingContext) -> Result<Vec<ParsedResult>> {
34        let mut results = Vec::new();
35        let ref_date = context.reference.instant;
36
37        for mat in PATTERN.find_iter(context.text) {
38            let matched_text = mat.as_str();
39            let index = mat.start();
40
41            let Some(caps) = PATTERN.captures(matched_text) else {
42                continue;
43            };
44
45            let num_str = caps.get(1).map(|m| m.as_str()).unwrap_or("1");
46            let unit_str = caps
47                .get(2)
48                .map(|m| m.as_str().to_lowercase())
49                .unwrap_or_default();
50
51            let num = parse_number_pattern(num_str);
52            let Some(unit) = get_time_unit(&unit_str) else {
53                continue;
54            };
55
56            // Create negative duration
57            let mut duration = Duration::new();
58            match unit {
59                TimeUnit::Second => duration.second = Some(-num),
60                TimeUnit::Minute => duration.minute = Some(-num),
61                TimeUnit::Hour => duration.hour = Some(-num),
62                TimeUnit::Day => duration.day = Some(-num),
63                TimeUnit::Week => duration.week = Some(-num),
64                TimeUnit::Month => duration.month = Some(-num),
65                TimeUnit::Year => duration.year = Some(-num),
66                TimeUnit::Quarter => duration.quarter = Some(-num),
67                TimeUnit::Millisecond => duration.millisecond = Some(-num),
68            }
69
70            let target_date = add_duration(ref_date, &duration);
71
72            let mut components = context.create_components();
73            components.assign(Component::Year, target_date.year());
74            components.assign(Component::Month, target_date.month() as i32);
75            components.assign(Component::Day, target_date.day() as i32);
76
77            if duration.has_time_component() {
78                use chrono::Timelike;
79                components.assign(Component::Hour, target_date.hour() as i32);
80                components.assign(Component::Minute, target_date.minute() as i32);
81                components.assign(Component::Second, target_date.second() as i32);
82            }
83
84            results.push(context.create_result(
85                index,
86                index + matched_text.len(),
87                components,
88                None,
89            ));
90        }
91
92        Ok(results)
93    }
94}
whichtime_sys/parsers/en/time_unit_ago.rs

whichtime_sys/parsers/en/
time_unit_ago.rs
