refactor: rewrite in rust

src/localize/datetime.rs

@@ -0,0 +1,365 @@
+use chrono::{DateTime, NaiveDate, NaiveDateTime, NaiveTime, Utc};
+use once_cell::sync::Lazy;
+use regex::Regex;
+use std::path::Path;
+
+/// Regex for extracting date and optional time from file names.
+/// Format: YYYYMMDD or YYYYMMDD-HHMMSS (time can be 4-6 digits)
+static FILE_NAME_REGEX: Lazy<Regex> =
+    Lazy::new(|| Regex::new(r"^(?P<date>\d{8})(?:-(?P<time>\d{4,6}))?.+\.md$").unwrap());
+
+/// Regex for validating datetime marker format (14 digits).
+static DATETIME_MARKER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"^\d{14}$").unwrap());
+
+/// Regex for validating date marker format (8 digits).
+static DATE_MARKER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"^\d{8}$").unwrap());
+
+/// Regex for validating time marker format (6 digits).
+static TIME_MARKER_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"^\d{6}$").unwrap());
+
+/// Extract a datetime from a file name in the format YYYYMMDD-HHMMSS.
+///
+/// The time component is optional and can be 4-6 digits (HHMM, HHMMS, or HHMMSS).
+///
+/// # Examples
+/// - "20230101-123456 Some Text.md" -> DateTime for 2023-01-01 12:34:56
+/// - "20230101 Some Text.md" -> DateTime for 2023-01-01 00:00:00
+/// - "invalid-file-name.md" -> None
+pub fn extract_datetime_from_file_name(file_name: &str) -> Option<DateTime<Utc>> {
+    let base_name = Path::new(file_name)
+        .file_name()
+        .and_then(|s| s.to_str())
+        .unwrap_or(file_name);
+
+    let captures = FILE_NAME_REGEX.captures(base_name)?;
+    let date_str = captures.name("date")?.as_str();
+    let time_str = captures.name("time").map(|m| m.as_str()).unwrap_or("");
+
+    // Pad time string to 6 digits
+    let time_str = format!("{:0<6}", time_str);
+
+    let datetime_str = format!(
+        "{} {}:{}:{}",
+        date_str,
+        &time_str[0..2],
+        &time_str[2..4],
+        &time_str[4..6]
+    );
+
+    NaiveDateTime::parse_from_str(&datetime_str, "%Y%m%d %H:%M:%S")
+        .ok()
+        .map(|dt| dt.and_utc())
+}
+
+/// Extract a datetime from a marker string in the exact format: YYYYMMDDHHMMSS.
+///
+/// Returns the parsed datetime if the format matches and values are valid.
+pub fn extract_datetime_from_marker(marker: &str) -> Option<DateTime<Utc>> {
+    if !DATETIME_MARKER_REGEX.is_match(marker) {
+        return None;
+    }
+
+    NaiveDateTime::parse_from_str(marker, "%Y%m%d%H%M%S")
+        .ok()
+        .map(|dt| dt.and_utc())
+}
+
+/// Extract a date from a marker string in the exact format: YYYYMMDD.
+///
+/// Returns the parsed date if the format matches and values are valid.
+pub fn extract_date_from_marker(marker: &str) -> Option<NaiveDate> {
+    if !DATE_MARKER_REGEX.is_match(marker) {
+        return None;
+    }
+
+    NaiveDate::parse_from_str(marker, "%Y%m%d").ok()
+}
+
+/// Extract a time from a marker string in the exact format: HHMMSS.
+///
+/// Returns the parsed time if the format matches and values are valid.
+pub fn extract_time_from_marker(marker: &str) -> Option<NaiveTime> {
+    if !TIME_MARKER_REGEX.is_match(marker) {
+        return None;
+    }
+
+    NaiveTime::parse_from_str(marker, "%H%M%S").ok()
+}
+
+/// Extract a datetime from a list of markers, using an inherited datetime as fallback.
+///
+/// The function processes markers in reverse order, allowing later markers to override
+/// earlier ones. It combines date-only and time-only markers when both are present.
+///
+/// Rules:
+/// - If a full datetime marker (14 digits) is found, it sets both date and time
+/// - If only a date marker is found, the time defaults to midnight
+/// - If only a time marker is found, the date is inherited
+/// - If no valid markers are found, the inherited datetime is returned
+pub fn extract_datetime_from_marker_list(
+    markers: &[String],
+    inherited_datetime: DateTime<Utc>,
+) -> DateTime<Utc> {
+    let mut shard_time: Option<NaiveTime> = None;
+    let mut shard_date: Option<NaiveDate> = None;
+
+    // Process markers in reverse order (last wins)
+    for marker in markers.iter().rev() {
+        if let Some(time) = extract_time_from_marker(marker) {
+            shard_time = Some(time);
+        }
+        if let Some(date) = extract_date_from_marker(marker) {
+            shard_date = Some(date);
+        }
+        if let Some(datetime) = extract_datetime_from_marker(marker) {
+            shard_date = Some(datetime.naive_utc().date());
+            shard_time = Some(datetime.naive_utc().time());
+        }
+    }
+
+    // Combine date and time, applying defaults as needed
+    let final_date = shard_date.unwrap_or_else(|| inherited_datetime.naive_utc().date());
+    let final_time = match (shard_date, shard_time) {
+        // If we have a date but no time, use midnight
+        (Some(_), None) => NaiveTime::from_hms_opt(0, 0, 0).unwrap(),
+        // Otherwise use the shard time or inherit
+        _ => shard_time.unwrap_or_else(|| inherited_datetime.naive_utc().time()),
+    };
+
+    NaiveDateTime::new(final_date, final_time).and_utc()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use chrono::TimeZone;
+
+    #[test]
+    fn test_extract_date_from_file_name_valid() {
+        let file_name = "20230101-123456 Some Text.md";
+        assert_eq!(
+            extract_datetime_from_file_name(file_name),
+            Some(Utc.with_ymd_and_hms(2023, 1, 1, 12, 34, 56).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_date_from_file_name_invalid() {
+        let file_name = "invalid-file-name.md";
+        assert_eq!(extract_datetime_from_file_name(file_name), None);
+    }
+
+    #[test]
+    fn test_extract_date_from_file_name_without_time() {
+        let file_name = "20230101 Some Text.md";
+        assert_eq!(
+            extract_datetime_from_file_name(file_name),
+            Some(Utc.with_ymd_and_hms(2023, 1, 1, 0, 0, 0).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_date_from_file_name_short_time() {
+        let file_name = "20230101-1234 Some Text.md";
+        assert_eq!(
+            extract_datetime_from_file_name(file_name),
+            Some(Utc.with_ymd_and_hms(2023, 1, 1, 12, 34, 0).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_date_from_file_name_empty_string() {
+        let file_name = "";
+        assert_eq!(extract_datetime_from_file_name(file_name), None);
+    }
+
+    #[test]
+    fn test_extract_date_from_file_name_with_full_path() {
+        let file_name = "/path/to/20230101-123456 Some Text.md";
+        assert_eq!(
+            extract_datetime_from_file_name(file_name),
+            Some(Utc.with_ymd_and_hms(2023, 1, 1, 12, 34, 56).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_datetime_from_marker_valid() {
+        let marker = "20250101150000";
+        assert_eq!(
+            extract_datetime_from_marker(marker),
+            Some(Utc.with_ymd_and_hms(2025, 1, 1, 15, 0, 0).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_datetime_from_marker_invalid_format() {
+        assert_eq!(extract_datetime_from_marker("2025010115000"), None); // too short
+        assert_eq!(extract_datetime_from_marker("202501011500000"), None); // too long
+        assert_eq!(extract_datetime_from_marker("2025-01-01T150000"), None); // separators
+        assert_eq!(extract_datetime_from_marker("2025010115000a"), None); // non-digit
+        assert_eq!(extract_datetime_from_marker(""), None);
+    }
+
+    #[test]
+    fn test_extract_datetime_from_marker_invalid_values() {
+        assert_eq!(extract_datetime_from_marker("20250230120000"), None); // Feb 30
+        assert_eq!(extract_datetime_from_marker("20250101126000"), None); // minute 60
+        assert_eq!(extract_datetime_from_marker("20250101240000"), None); // hour 24
+    }
+
+    #[test]
+    fn test_extract_date_from_marker_valid() {
+        let marker = "20250101";
+        assert_eq!(
+            extract_date_from_marker(marker),
+            Some(NaiveDate::from_ymd_opt(2025, 1, 1).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_date_from_marker_invalid_format() {
+        assert_eq!(extract_date_from_marker("2025010"), None); // too short
+        assert_eq!(extract_date_from_marker("202501011"), None); // too long
+        assert_eq!(extract_date_from_marker("2025-01-01"), None); // separators
+        assert_eq!(extract_date_from_marker("2025010a"), None); // non-digit
+        assert_eq!(extract_date_from_marker(""), None);
+    }
+
+    #[test]
+    fn test_extract_date_from_marker_invalid_values() {
+        assert_eq!(extract_date_from_marker("20250230"), None); // Feb 30
+        assert_eq!(extract_date_from_marker("20251301"), None); // month 13
+        assert_eq!(extract_date_from_marker("20250132"), None); // day 32
+    }
+
+    #[test]
+    fn test_extract_time_from_marker_valid() {
+        let marker = "150000";
+        assert_eq!(
+            extract_time_from_marker(marker),
+            Some(NaiveTime::from_hms_opt(15, 0, 0).unwrap())
+        );
+    }
+
+    #[test]
+    fn test_extract_time_from_marker_invalid_format() {
+        assert_eq!(extract_time_from_marker("15000"), None); // too short
+        assert_eq!(extract_time_from_marker("1500000"), None); // too long
+        assert_eq!(extract_time_from_marker("15:00:00"), None); // separators
+        assert_eq!(extract_time_from_marker("15000a"), None); // non-digit
+        assert_eq!(extract_time_from_marker(""), None);
+    }
+
+    #[test]
+    fn test_extract_time_from_marker_invalid_values() {
+        assert_eq!(extract_time_from_marker("240000"), None); // hour 24
+        assert_eq!(extract_time_from_marker("156000"), None); // minute 60
+                                                              // Note: chrono allows leap seconds (60), so 150060 is valid
+    }
+
+    #[test]
+    fn test_no_markers_inherits_datetime() {
+        let inherited = Utc.with_ymd_and_hms(2025, 1, 2, 3, 4, 5).unwrap();
+        assert_eq!(extract_datetime_from_marker_list(&[], inherited), inherited);
+    }
+
+    #[test]
+    fn test_unrelated_markers_inherits_datetime() {
+        let inherited = Utc.with_ymd_and_hms(2025, 1, 2, 3, 4, 5).unwrap();
+        let markers: Vec<String> = vec![
+            "not-a-marker".to_string(),
+            "2025-01-01".to_string(),
+            "1500".to_string(),
+            "1234567".to_string(),
+        ];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            inherited
+        );
+    }
+
+    #[test]
+    fn test_date_only_marker_sets_midnight() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec!["20250101".to_string()];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 1, 1, 0, 0, 0).unwrap()
+        );
+    }
+
+    #[test]
+    fn test_time_only_marker_inherits_date() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec!["150000".to_string()];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 6, 7, 15, 0, 0).unwrap()
+        );
+    }
+
+    #[test]
+    fn test_datetime_marker_overrides_both_date_and_time() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec!["20250101150000".to_string()];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 1, 1, 15, 0, 0).unwrap()
+        );
+    }
+
+    #[test]
+    fn test_combined_date_and_time_markers() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec!["20250101".to_string(), "150000".to_string()];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 1, 1, 15, 0, 0).unwrap()
+        );
+    }
+
+    #[test]
+    fn test_first_marker_wins_when_multiple_dates_or_times() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec![
+            "20250101".to_string(),
+            "150000".to_string(),
+            "20250102".to_string(),
+            "160000".to_string(),
+        ];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 1, 1, 15, 0, 0).unwrap()
+        );
+    }
+
+    #[test]
+    fn test_last_separated_date_and_time_win() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec![
+            "20250101".to_string(),
+            "150000".to_string(),
+            "20250102160000".to_string(),
+        ];
+        // The first date (20250101) and first time (150000) should win over the later combined datetime
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 1, 1, 15, 0, 0).unwrap()
+        );
+    }
+
+    #[test]
+    fn test_invalid_date_or_time_markers_are_ignored() {
+        let inherited = Utc.with_ymd_and_hms(2025, 6, 7, 8, 9, 10).unwrap();
+        let markers = vec![
+            "20251301".to_string(), // invalid month
+            "240000".to_string(),   // invalid hour
+            "20250101".to_string(), // valid
+            "150000".to_string(),   // valid
+        ];
+        assert_eq!(
+            extract_datetime_from_marker_list(&markers, inherited),
+            Utc.with_ymd_and_hms(2025, 1, 1, 15, 0, 0).unwrap()
+        );
+    }
+}