catcher 0.11.0

A minimal, local-first markdown notes TUI over plain files
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261

//! Search in all files: the third tab of ^O. The ranked list finds a note by
//! what it is called; this finds one by what it says, one row per matching
//! line, grouped under the note the line came from.
//!
//! Everything here is pure over strings, so the matcher, the snippet trim and
//! the grouping all test without a file on disk. Reading the bodies is the
//! caller's job, and it does that once per visit to the tab rather than once
//! per keystroke.

use std::fs;
use std::path::Path;

/// Lines past this are not offered: the list stops being something to read.
pub const MAX_HITS: usize = 200;
/// A file bigger than this is not a note, whatever its extension says.
const MAX_BODY_BYTES: u64 = 256 * 1024;

/// The words of a query, lowered once so every line is not lowering them
/// again. Empty for a blank query, which matches nothing: every line of
/// every note is not an answer to anything.
pub fn words(query: &str) -> Vec<String> {
    query.split_whitespace().map(|w| w.to_lowercase()).collect()
}

/// Where in `line` a `words` query hits: the char offset of the earliest
/// word, or `None`. Every word has to be somewhere on the line, in any
/// order — `milk buy` finds "buy milk" — and case never matters.
pub fn find(words: &[String], line: &str) -> Option<usize> {
    if words.is_empty() {
        return None;
    }
    let lower = line.to_lowercase();
    let mut first = usize::MAX;
    for w in words {
        let at = lower.find(w.as_str())?;
        first = first.min(lower[..at].chars().count());
    }
    Some(first)
}

/// The body to search, or nothing for a file that is too big or not text.
pub fn body_of(path: &Path) -> Option<String> {
    let too_big = fs::metadata(path).is_ok_and(|m| m.len() > MAX_BODY_BYTES);
    if too_big {
        return None;
    }
    fs::read_to_string(path).ok()
}

/// One matching line of one note.
#[derive(Clone, Debug, PartialEq)]
pub struct Hit {
    /// Index into the quick-open index the bodies were read for.
    pub entry: usize,
    pub line: usize,
    pub text: String,
}

/// Every hit across `bodies` (one per index entry, `None` where it could not
/// be read), in index order, cut at `cap`. The second number is how many
/// more there were — what "…and N more" says.
pub fn search(bodies: &[Option<String>], query: &str, cap: usize) -> (Vec<Hit>, usize) {
    let words = words(query);
    let mut hits = Vec::new();
    let mut over = 0;
    if words.is_empty() {
        return (hits, over);
    }
    for (entry, body) in bodies.iter().enumerate() {
        let Some(body) = body else { continue };
        for (line, text) in body.lines().enumerate() {
            if find(&words, text).is_none() {
                continue;
            }
            if hits.len() >= cap {
                over += 1;
                continue;
            }
            hits.push(Hit {
                entry,
                line,
                text: text.trim().to_string(),
            });
        }
    }
    (hits, over)
}

/// What one drawn row of the contents tab stands for.
#[derive(Clone, Debug, PartialEq)]
pub enum Row {
    /// The note the hits under it came from.
    Note(usize),
    Hit(Hit),
    /// "…and N more": the cap was reached.
    More(usize),
}

/// Hits grouped under their note: a header row each time the note changes,
/// which is once per note because `search` walks the index in order.
pub fn rows(hits: &[Hit], more: usize) -> Vec<Row> {
    let mut out = Vec::new();
    let mut last = None;
    for h in hits {
        if last != Some(h.entry) {
            out.push(Row::Note(h.entry));
            last = Some(h.entry);
        }
        out.push(Row::Hit(h.clone()));
    }
    if more > 0 {
        out.push(Row::More(more));
    }
    out
}

/// `text` cut to `width` columns around the first match, as (piece, is a
/// match) pairs: the pieces marked true are what the row draws in the accent.
/// A line that starts well before its match is trimmed from the left, with an
/// ellipsis, so the match is on screen rather than off the end of the row.
pub fn snippet(text: &str, words: &[String], width: usize) -> Vec<(String, bool)> {
    let chars: Vec<char> = text.chars().collect();
    let first = find(words, text).unwrap_or(0);
    // keep a few characters of context before the match
    let lead = 12.min(width / 3);
    let start = if chars.len() <= width {
        0
    } else {
        first.saturating_sub(lead)
    };
    let mut window: String = chars[start..].iter().collect();
    if start > 0 {
        // the ellipsis takes the place of the first kept char, not a column
        // of its own, so the trim never pushes the match off the right edge
        window = format!("…{}", window.chars().skip(1).collect::<String>());
    }
    let window = crate::md::truncate(&window, width);
    mark(&window, words)
}

/// Split `text` into pieces, marking every occurrence of every word.
fn mark(text: &str, words: &[String]) -> Vec<(String, bool)> {
    let lower: Vec<char> = text.to_lowercase().chars().collect();
    let chars: Vec<char> = text.chars().collect();
    // lowering can change a string's length in chars for a few scripts; the
    // marking is by char position and gives up rather than misalign
    if lower.len() != chars.len() {
        return vec![(text.to_string(), false)];
    }
    let mut hit = vec![false; chars.len()];
    for w in words {
        let wc: Vec<char> = w.chars().collect();
        if wc.is_empty() || wc.len() > chars.len() {
            continue;
        }
        for i in 0..=chars.len() - wc.len() {
            if lower[i..i + wc.len()] == wc[..] {
                hit[i..i + wc.len()].iter_mut().for_each(|h| *h = true);
            }
        }
    }
    let mut out: Vec<(String, bool)> = Vec::new();
    for (c, h) in chars.iter().zip(hit) {
        match out.last_mut() {
            Some((s, was)) if *was == h => s.push(*c),
            _ => out.push((c.to_string(), h)),
        }
    }
    out
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn every_word_must_be_on_the_line_in_any_order_and_any_case() {
        let w = words("Milk buy");
        assert_eq!(find(&w, "Buy MILK today"), Some(0));
        assert_eq!(find(&w, "buy bread"), None);
        assert_eq!(find(&w, "some milk"), None);
        // the offset is the earliest word, in chars not bytes
        assert_eq!(find(&words("milk"), "ééé milk"), Some(4));
        assert_eq!(find(&words("   "), "anything"), None);
    }

    #[test]
    fn hits_are_capped_and_the_overflow_counted() {
        let bodies = vec![
            Some("a\nb\na\n".to_string()),
            None,
            Some("A here\nnothing\n".to_string()),
        ];
        let (hits, more) = search(&bodies, "a", 10);
        assert_eq!(hits.len(), 3);
        assert_eq!(more, 0);
        assert_eq!(
            hits[2],
            Hit {
                entry: 2,
                line: 0,
                text: "A here".into()
            }
        );
        let (hits, more) = search(&bodies, "a", 2);
        assert_eq!(hits.len(), 2);
        assert_eq!(more, 1);
        assert!(search(&bodies, "", 10).0.is_empty());
    }

    #[test]
    fn rows_group_hits_under_their_note_with_a_more_row_when_cut() {
        let hit = |entry, line| Hit {
            entry,
            line,
            text: String::new(),
        };
        let hits = vec![hit(0, 1), hit(0, 5), hit(3, 0)];
        let grouped = rows(&hits, 2);
        assert_eq!(grouped.len(), 6);
        assert_eq!(grouped[0], Row::Note(0));
        assert_eq!(grouped[1], Row::Hit(hit(0, 1)));
        assert_eq!(grouped[2], Row::Hit(hit(0, 5)));
        assert_eq!(grouped[3], Row::Note(3));
        assert_eq!(grouped[5], Row::More(2));
        assert!(rows(&[], 0).is_empty());
    }

    #[test]
    fn a_snippet_marks_the_match_and_keeps_a_short_line_whole() {
        let s = snippet("Buy milk and Milk again", &words("milk"), 80);
        assert_eq!(
            s,
            vec![
                ("Buy ".to_string(), false),
                ("milk".to_string(), true),
                (" and ".to_string(), false),
                ("Milk".to_string(), true),
                (" again".to_string(), false),
            ]
        );
    }

    #[test]
    fn a_long_line_is_trimmed_around_the_first_match() {
        let text = format!("{}needle and then more words after it", "x".repeat(60));
        let s = snippet(&text, &words("needle"), 30);
        let joined: String = s.iter().map(|(p, _)| p.as_str()).collect();
        assert!(joined.starts_with('…'), "{joined}");
        assert!(joined.ends_with('…'), "{joined}");
        assert!(s.iter().any(|(p, m)| *m && p == "needle"), "{joined}");
        assert!(crate::md::str_width(&joined) <= 30);
        // a match near the start keeps the start
        let s = snippet(&text[60..], &words("needle"), 30);
        assert!(!s
            .iter()
            .map(|(p, _)| p.as_str())
            .collect::<String>()
            .starts_with('…'));
    }
}