hypermail/
search.rs

1use std::collections::{HashMap, HashSet};
2use std::path::Path;
3
4use crate::config::Config;
5use crate::error::Result;
6use crate::message::EmailInfo;
7use crate::structs::EmailStore;
8
9type BigramIndex = HashMap<String, Vec<usize>>;
10
11pub fn build_bigram_index(store: &EmailStore) -> BigramIndex {
12    let mut index: BigramIndex = HashMap::new();
13
14    for (i, email) in store.emails.iter().enumerate() {
15        let text = extract_searchable_text(email);
16        let bigrams = extract_bigrams(&text);
17        for bigram in bigrams {
18            index.entry(bigram).or_default().push(i);
19        }
20    }
21
22    index
23}
24
25pub fn search_bigrams(query: &str, index: &BigramIndex, _store: &EmailStore) -> Vec<usize> {
26    let query_bigrams = extract_bigrams(query);
27    if query_bigrams.is_empty() {
28        return Vec::new();
29    }
30
31    let mut result_scores: HashMap<usize, usize> = HashMap::new();
32
33    for bigram in &query_bigrams {
34        if let Some(entries) = index.get(bigram) {
35            for &idx in entries {
36                *result_scores.entry(idx).or_default() += 1;
37            }
38        }
39    }
40
41    let threshold = query_bigrams.len().saturating_sub(1);
42    let mut results: Vec<(usize, usize)> =
43        result_scores.into_iter().filter(|(_, score)| *score >= threshold).collect();
44
45    results.sort_by_key(|b| std::cmp::Reverse(b.1));
46
47    results.into_iter().map(|(idx, _)| idx).collect()
48}
49
50fn extract_searchable_text(email: &EmailInfo) -> String {
51    let mut text = String::new();
52
53    if let Some(ref subject) = email.subject {
54        text.push_str(subject);
55        text.push(' ');
56    }
57    if let Some(ref name) = email.name {
58        text.push_str(name);
59        text.push(' ');
60    }
61    if let Some(ref addr) = email.email_addr {
62        text.push_str(addr);
63        text.push(' ');
64    }
65
66    for body in &email.bodylist.bodies {
67        if !body.attached && !body.header {
68            text.push_str(&body.line);
69            text.push(' ');
70        }
71    }
72
73    text
74}
75
76fn extract_bigrams(text: &str) -> Vec<String> {
77    let lower = text.to_lowercase();
78    let chars: Vec<char> =
79        lower.chars().filter(|c| c.is_alphanumeric() || c.is_whitespace()).collect();
80
81    let mut bigrams = HashSet::new();
82    for window in chars.windows(2) {
83        let bigram: String = window.iter().collect();
84        bigrams.insert(bigram);
85    }
86
87    bigrams.into_iter().collect()
88}
89
90pub fn write_search_index(store: &EmailStore, config: &Config) -> Result<String> {
91    let dir = config.dir.as_deref().unwrap_or(".");
92    let search_path = Path::new(dir).join("search_index.txt");
93
94    let mut content = String::new();
95    for email in &store.emails {
96        let text = extract_searchable_text(email);
97        let line = format!("{}|{}", email.msgnum, sanitize_for_search(&text));
98        content.push_str(&line);
99        content.push('\n');
100    }
101
102    std::fs::write(&search_path, &content)?;
103    Ok(content)
104}
105
106fn sanitize_for_search(s: &str) -> String {
107    s.chars()
108        .filter(|c| c.is_alphanumeric() || c.is_whitespace() || *c == '.' || *c == '@' || *c == '-')
109        .collect()
110}
111
112#[cfg(test)]
113mod tests {
114    use super::*;
115    use crate::message::{Body, BodyChain, EmailInfo};
116
117    fn make_email(msgnum: i32, subject: &str, name: &str, body_text: &str) -> EmailInfo {
118        EmailInfo {
119            msgnum,
120            subject: Some(subject.to_string()),
121            name: Some(name.to_string()),
122            bodylist: BodyChain {
123                bodies: vec![Body {
124                    line: body_text.to_string(),
125                    html: false,
126                    header: false,
127                    parsed_header: false,
128                    attached: false,
129                    demimed: false,
130                    msgnum,
131                }],
132            },
133            ..Default::default()
134        }
135    }
136
137    #[test]
138    fn test_bigram_extraction() {
139        let bigrams = extract_bigrams("hello");
140        assert!(bigrams.contains(&"he".to_string()));
141        assert!(bigrams.contains(&"el".to_string()));
142        assert!(bigrams.contains(&"ll".to_string()));
143        assert!(bigrams.contains(&"lo".to_string()));
144    }
145
146    #[test]
147    fn test_bigram_index() {
148        let mut store = EmailStore::new();
149        store.add_email(make_email(1, "Hello World", "Alice", "This is a test"));
150        store.add_email(make_email(2, "Goodbye World", "Bob", "Another test message"));
151
152        let index = build_bigram_index(&store);
153        assert!(index.contains_key("wo"));
154        assert!(index.contains_key("te"));
155    }
156
157    #[test]
158    fn test_search() {
159        let mut store = EmailStore::new();
160        store.add_email(make_email(1, "Hello World", "Alice", "This is a test message"));
161        store.add_email(make_email(2, "Goodbye World", "Bob", "Another different message"));
162
163        let index = build_bigram_index(&store);
164        let results = search_bigrams("hello", &index, &store);
165        assert_eq!(results.len(), 1);
166        assert_eq!(store.emails[results[0]].msgnum, 1);
167    }
168
169    #[test]
170    fn test_extract_searchable_text() {
171        let email = make_email(1, "Test Subject", "Alice", "Body content");
172        let text = extract_searchable_text(&email);
173        assert!(text.contains("Test Subject"));
174        assert!(text.contains("Alice"));
175        assert!(text.contains("Body content"));
176    }
177}
hypermail/search.rs

hypermail/
search.rs
