Fixed parsing of opening hours with a discount. Fixes #4

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/backend/data.rs

@@ -309,7 +309,19 @@ impl TryFrom<&str> for DayHour {
             return Err(AppError::HourParseError)
         }
 
-        let times = value.split("-")
+        // Optional discount in parentheses after the interval: "08:00 - 12:00 (10)"
+        let (interval, discount) = match value.trim().strip_suffix(")") {
+            Some(rest) => {
+                let (interval, discount) = rest.rsplit_once("(").ok_or(AppError::HourParseError)?;
+                if discount.is_empty() || !discount.chars().all(|c| c.is_ascii_digit()) {
+                    return Err(AppError::HourParseError)
+                }
+                (interval, Some(discount.parse::<i32>().map_err(|_| AppError::HourParseError)?))
+            }
+            None => (value, None)
+        };
+
+        let times = interval.split("-")
             .map(|t| t.trim()).collect::<Vec<_>>();
 
         if times.len() != 2 {
@@ -326,7 +338,7 @@ impl TryFrom<&str> for DayHour {
         Ok(DayHour {
             from: from.unwrap(),
             to: to.unwrap(),
-            discount: None
+            discount
         })
     }
 }
@@ -892,6 +904,24 @@ mod tests {
         }
     }
 
+    #[test]
+    fn day_hour_parses_discount() {
+        let expected = DayHour::new(time(8, 0), time(12, 30), Some(10));
+
+        assert_eq!(DayHour::try_from("08:00 - 12:30 (10)"), Ok(expected.clone()));
+        assert_eq!(DayHour::try_from("08:00-12:30(10)"), Ok(expected));
+        assert_eq!(DayHour::try_from("08:00 - 12:30 (0)"), Ok(DayHour::new(time(8, 0), time(12, 30), Some(0))));
+    }
+
+    #[test]
+    fn day_hour_rejects_malformed_discount() {
+        for input in ["08:00 - 12:00 ()", "08:00 - 12:00 (x)", "08:00 - 12:00 (-5)", "08:00 - 12:00 (1.5)", "08:00 - 12:00 (10",
+            "08:00 - 12:00 10)", "(10) 08:00 - 12:00", "08:00 (10) - 12:00", "08:00 - 12:00 (10) (20)", "(10)",
+            "08:00 - 12:00 (99999999999)"] {
+            assert_eq!(DayHour::try_from(input), Err(AppError::HourParseError), "input: {:?}", input);
+        }
+    }
+
     #[test]
     fn day_hours_empty_string_is_closed_day() {
         let hours = DayHours::try_new("").unwrap();
@@ -930,7 +960,8 @@ mod tests {
     fn day_hours_display_round_trip() {
         let hours = DayHours(vec![
             DayHour::new(time(8, 0), time(12, 0), None),
-            DayHour::new(time(13, 0), time(17, 0), None)
+            DayHour::new(time(13, 0), time(17, 0), Some(10)),
+            DayHour::new(time(18, 0), time(20, 0), Some(0))
         ]);
 
         let parsed = DayHours::try_new(&hours.to_string()).unwrap();
@@ -950,9 +981,11 @@ mod tests {
 
     #[test]
     fn week_hours_accepts_valid_hours() {
-        for input in ["", "08:00 - 12:00", "08:00-12:00", "08:00 - 12:00, 13:00 - 17:00"] {
+        for input in ["", "08:00 - 12:00", "08:00-12:00", "08:00 - 12:00, 13:00 - 17:00",
+            "08:00 - 12:00 (10)", "08:00 - 12:00 (10), 13:00 - 17:00", "08:00 - 12:00, 13:00 - 17:00(20)"] {
             let hours = WeekHours { day: Weekday::Mon, hours: input.to_string() };
             assert!(hours.validate().is_ok(), "input: {:?}", input);
+            assert!(DayHours::try_new(input).is_ok(), "input: {:?}", input);
         }
     }
 
@@ -978,7 +1011,7 @@ mod tests {
     #[test]
     fn week_hours_validation_agrees_with_parser() {
         for input in ["", "08:00 - 12:00", "08:00-12:00", "08:00 - 12:00,13:00 - 17:00", "08:00 - 12:00 , 13:00 - 17:00",
-            "08:00 - 12:00, nonsense", "08:00 - 12:00,", "25:00 - 26:00", "08:00 - 12:00 garbage"] {
+            "08:00 - 12:00 (10)", "08:00 - 12:00 (10) , 13:00 - 17:00 (5)", "08:00 - 12:00 (99999999999)", "08:00 - 12:00, nonsense", "08:00 - 12:00,", "25:00 - 26:00", "08:00 - 12:00 garbage"] {
             let hours = WeekHours { day: Weekday::Mon, hours: input.to_string() };
             if hours.validate().is_ok() {
                 assert!(DayHours::try_new(input).is_ok(), "input: {:?}", input);
@@ -1003,7 +1036,7 @@ mod tests {
 
     #[test]
     fn week_hours_rejects_to_before_from() {
-        for input in ["12:00 - 08:00", "08:00 - 08:00", "08:00 - 12:00, 17:00 - 13:00"] {
+        for input in ["12:00 - 08:00", "08:00 - 08:00", "08:00 - 12:00, 17:00 - 13:00", "12:00 - 08:00 (10)"] {
             let hours = WeekHours { day: Weekday::Mon, hours: input.to_string() };
             assert!(has_field_error(&hours, "__all__"), "input: {:?}", input);
         }