feat: improve build script, error handling, logging

src/abbr.rs

@@ -1,31 +1,92 @@
 use chrono::FixedOffset;
 
-// Generated by build.rs, phf_codegen
-include!(concat!(env!("OUT_DIR"), "/codegen.rs"));
+// Generated by build.rs - timezone abbreviation to UTC offset mapping
+include!(concat!(env!("OUT_DIR"), "/timezone_map.rs"));
 
-/*
-    Parse an abbreviation of a timezone into a UTC offset.
-    Note: This is not standardized at all and is simply built on a reference of Time Zone abbreviations
-    from Wikipedia (as of 2023-7-20).
- */
+/// Parse a timezone abbreviation into a UTC offset.
+///
+/// This uses a pre-generated map of timezone abbreviations to their UTC offsets
+/// in seconds. The mapping is based on the Wikipedia reference of timezone
+/// abbreviations (as of 2023-07-20).
+///
+/// Note: Timezone abbreviations are not standardized and can be ambiguous.
+/// This implementation uses preferred interpretations for conflicting abbreviations.
+///
+/// # Arguments
+/// * `abbreviation` - The timezone abbreviation (e.g., "CST", "EST", "PST")
+///
+/// # Returns
+/// * `Ok(FixedOffset)` - The UTC offset for the timezone
+/// * `Err(String)` - Error message if abbreviation is not found or invalid
+///
+/// # Examples
+/// ```
+/// use chrono::FixedOffset;
+///
+/// let cst = parse_abbreviation("CST").unwrap();
+/// assert_eq!(cst, FixedOffset::west_opt(6 * 3600).unwrap());
+/// ```
 pub fn parse_abbreviation(abbreviation: &str) -> Result<FixedOffset, String> {
-    let offset_integer_string = TIMEZONES.get(abbreviation);
-    if offset_integer_string.is_none() {
-        return Err("Failed to find abbreviation".to_string());
-    }
+    let offset_seconds = TIMEZONE_OFFSETS
+        .get(abbreviation)
+        .ok_or_else(|| format!("Unknown timezone abbreviation: {}", abbreviation))?;
 
-    let offset = FixedOffset::east_opt(offset_integer_string.unwrap().parse().expect("Failed to parse stored offset"));
-    return offset.ok_or("Failed to parse offset".to_string());
+    // Convert seconds to FixedOffset
+    // Positive offsets are east of UTC, negative are west
+    let offset = if *offset_seconds >= 0 {
+        FixedOffset::east_opt(*offset_seconds)
+    } else {
+        FixedOffset::west_opt(-*offset_seconds)
+    };
+
+    offset.ok_or_else(|| {
+        format!(
+            "Invalid offset for timezone {}: {} seconds",
+            abbreviation, offset_seconds
+        )
+    })
 }
 
-
 #[cfg(test)]
 mod tests {
-    use chrono::FixedOffset;
     use crate::abbr::parse_abbreviation;
+    use chrono::FixedOffset;
 
     #[test]
-    fn parse_offset() {
-        assert_eq!(parse_abbreviation("CST").unwrap(), FixedOffset::west_opt(6 * 3600).unwrap());
+    fn test_parse_cst() {
+        // CST (Central Standard Time) is UTC-6
+        let cst = parse_abbreviation("CST").unwrap();
+        assert_eq!(cst, FixedOffset::west_opt(6 * 3600).unwrap());
     }
-}
+
+    #[test]
+    fn test_parse_est() {
+        // EST (Eastern Standard Time) is UTC-5
+        let est = parse_abbreviation("EST").unwrap();
+        assert_eq!(est, FixedOffset::west_opt(5 * 3600).unwrap());
+    }
+
+    #[test]
+    fn test_parse_utc() {
+        // UTC should be zero offset
+        let utc = parse_abbreviation("UTC").unwrap();
+        assert_eq!(utc, FixedOffset::east_opt(0).unwrap());
+    }
+
+    #[test]
+    fn test_parse_unknown() {
+        // Unknown abbreviation should return error
+        let result = parse_abbreviation("INVALID");
+        assert!(result.is_err());
+        assert!(result
+            .unwrap_err()
+            .contains("Unknown timezone abbreviation"));
+    }
+
+    #[test]
+    fn test_parse_positive_offset() {
+        // JST (Japan Standard Time) is UTC+9
+        let jst = parse_abbreviation("JST").unwrap();
+        assert_eq!(jst, FixedOffset::east_opt(9 * 3600).unwrap());
+    }
+}