whichtime_sys/parsers/en/
weekday.rs

1//! Weekday parser: Monday, next Friday, last Tuesday, etc.
2
3use crate::components::Component;
4use crate::context::ParsingContext;
5use crate::dictionaries::RelativeModifier;
6use crate::dictionaries::en::{get_relative_modifier, get_weekday};
7use crate::error::Result;
8use crate::parsers::Parser;
9use crate::results::ParsedResult;
10use crate::scanner::TokenType;
11use chrono::{Datelike, Duration};
12use regex::Regex;
13use std::sync::LazyLock;
14
15static PATTERN: LazyLock<Regex> = LazyLock::new(|| {
16    Regex::new(
17        r"(?i)(?:^|\W)(?:(this|next|last|past|previous)\s+)?(sun(?:day)?|mon(?:day)?|tue(?:s(?:day)?)?|wed(?:nesday)?|thu(?:rs(?:day)?)?|fri(?:day)?|sat(?:urday)?)(?:\W|$)"
18    ).unwrap()
19});
20
21/// Parser for English weekday expressions such as "next Friday".
22pub struct WeekdayParser;
23
24impl Parser for WeekdayParser {
25    fn name(&self) -> &'static str {
26        "WeekdayParser"
27    }
28
29    fn should_apply(&self, context: &ParsingContext) -> bool {
30        context.has_token_type(TokenType::Weekday)
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        let ref_weekday = ref_date.weekday().num_days_from_sunday();
37
38        for mat in PATTERN.find_iter(context.text) {
39            let matched_text = mat.as_str();
40            let index = mat.start();
41
42            let Some(caps) = PATTERN.captures(matched_text) else {
43                continue;
44            };
45
46            let modifier_str = caps.get(1).map(|m| m.as_str().to_lowercase());
47            let weekday_str = caps
48                .get(2)
49                .map(|m| m.as_str().to_lowercase())
50                .unwrap_or_default();
51
52            let Some(weekday) = get_weekday(&weekday_str) else {
53                continue;
54            };
55
56            let modifier = modifier_str.as_deref().and_then(get_relative_modifier);
57
58            // Calculate days offset
59            let days_offset = match modifier {
60                Some(RelativeModifier::Next) => {
61                    let diff = (weekday as i64) - (ref_weekday as i64);
62                    if diff <= 0 { diff + 7 } else { diff }
63                }
64                Some(RelativeModifier::Last) => {
65                    let diff = (weekday as i64) - (ref_weekday as i64);
66                    if diff >= 0 { diff - 7 } else { diff }
67                }
68                Some(RelativeModifier::This) | None => {
69                    let diff = (weekday as i64) - (ref_weekday as i64);
70                    if diff == 0 {
71                        0
72                    } else if diff > 0 {
73                        if diff <= 3 { diff } else { diff - 7 }
74                    } else if diff >= -3 {
75                        diff
76                    } else {
77                        diff + 7
78                    }
79                }
80            };
81
82            let target_date = ref_date + Duration::days(days_offset);
83
84            let mut components = context.create_components();
85            components.assign(Component::Year, target_date.year());
86            components.assign(Component::Month, target_date.month() as i32);
87            components.assign(Component::Day, target_date.day() as i32);
88            components.assign(Component::Weekday, weekday as i32);
89
90            // Find actual text bounds
91            let actual_start = matched_text
92                .find(|c: char| c.is_alphanumeric())
93                .unwrap_or(0);
94            let actual_end = matched_text
95                .rfind(|c: char| c.is_alphanumeric())
96                .map(|i| i + matched_text[i..].chars().next().map_or(1, char::len_utf8))
97                .unwrap_or(matched_text.len());
98
99            results.push(context.create_result(
100                index + actual_start,
101                index + actual_end,
102                components,
103                None,
104            ));
105        }
106
107        Ok(results)
108    }
109}
whichtime_sys/parsers/en/weekday.rs

whichtime_sys/parsers/en/
weekday.rs
