recall_echo/
frontmatter.rs

1/// YAML frontmatter for conversation archives.
2///
3/// Parses and renders a minimal subset: log number, date, session_id,
4/// message_count, duration, source, topics.
5/// No external YAML dependency — hand-rolled for the fixed schema.
6
7#[derive(Debug, Clone, PartialEq)]
8pub struct Frontmatter {
9    pub log: u32,
10    pub date: String,
11    pub session_id: String,
12    pub message_count: u32,
13    pub duration: String,
14    pub source: String,
15    pub topics: Vec<String>,
16}
17
18impl Frontmatter {
19    pub fn render(&self) -> String {
20        let topics = if self.topics.is_empty() {
21            "[]".to_string()
22        } else {
23            let items: Vec<String> = self.topics.iter().map(|t| format!("\"{t}\"")).collect();
24            format!("[{}]", items.join(", "))
25        };
26
27        format!(
28            "---\nlog: {}\ndate: \"{}\"\nsession_id: \"{}\"\nmessage_count: {}\nduration: \"{}\"\nsource: \"{}\"\ntopics: {}\n---",
29            self.log, self.date, self.session_id, self.message_count, self.duration, self.source, topics
30        )
31    }
32}
33
34/// Parse frontmatter from file content. Returns None if no valid frontmatter found.
35pub fn parse(content: &str) -> Option<Frontmatter> {
36    let trimmed = content.trim();
37    if !trimmed.starts_with("---") {
38        return None;
39    }
40
41    let after_first = &trimmed[3..];
42    let end = after_first.find("---")?;
43    let block = &after_first[..end];
44
45    let mut log = None;
46    let mut date = None;
47    let mut session_id = None;
48    let mut message_count = None;
49    let mut duration = None;
50    let mut source = None;
51    let mut topics = Vec::new();
52
53    for line in block.lines() {
54        let line = line.trim();
55        if line.is_empty() {
56            continue;
57        }
58        let (key, val) = line.split_once(':')?;
59        let key = key.trim();
60        let val = val.trim().trim_matches('"');
61
62        match key {
63            "log" => log = val.parse().ok(),
64            "date" => date = Some(val.to_string()),
65            "session_id" => session_id = Some(val.to_string()),
66            "message_count" => message_count = val.parse().ok(),
67            "duration" => duration = Some(val.to_string()),
68            "source" => source = Some(val.to_string()),
69            "topics" => {
70                let inner = val.trim_matches(|c| c == '[' || c == ']');
71                if !inner.is_empty() {
72                    topics = inner
73                        .split(',')
74                        .map(|t| t.trim().trim_matches('"').to_string())
75                        .filter(|t| !t.is_empty())
76                        .collect();
77                }
78            }
79            _ => {}
80        }
81    }
82
83    Some(Frontmatter {
84        log: log?,
85        date: date?,
86        session_id: session_id.unwrap_or_default(),
87        message_count: message_count.unwrap_or(0),
88        duration: duration.unwrap_or_default(),
89        source: source.unwrap_or_default(),
90        topics,
91    })
92}
93
94#[cfg(test)]
95mod tests {
96    use super::*;
97
98    #[test]
99    fn render_parse_roundtrip() {
100        let fm = Frontmatter {
101            log: 42,
102            date: "2026-03-05T14:30:00Z".to_string(),
103            session_id: "abc123".to_string(),
104            message_count: 34,
105            duration: "45m".to_string(),
106            source: "jsonl".to_string(),
107            topics: vec!["auth".to_string(), "JWT".to_string()],
108        };
109        let rendered = fm.render();
110        let parsed = parse(&rendered).unwrap();
111        assert_eq!(fm, parsed);
112    }
113
114    #[test]
115    fn render_empty_topics() {
116        let fm = Frontmatter {
117            log: 1,
118            date: "2026-03-05T00:00:00Z".to_string(),
119            session_id: "xyz".to_string(),
120            message_count: 0,
121            duration: "< 1m".to_string(),
122            source: "jsonl".to_string(),
123            topics: vec![],
124        };
125        let rendered = fm.render();
126        assert!(rendered.contains("topics: []"));
127        let parsed = parse(&rendered).unwrap();
128        assert_eq!(parsed.topics, Vec::<String>::new());
129    }
130
131    #[test]
132    fn parse_missing_frontmatter() {
133        assert!(parse("no frontmatter here").is_none());
134    }
135
136    #[test]
137    fn parse_malformed_frontmatter() {
138        assert!(parse("---\nlog: abc\n---").is_none());
139    }
140}
recall_echo/frontmatter.rs

recall_echo/
frontmatter.rs
