From 5ec7187c37810b3de07877c05aaf8d2ed05201e7 Mon Sep 17 00:00:00 2001
From: howenc <xhowenx@gmail.com>
Date: Mon, 6 Nov 2023 18:47:05 +0800
Subject: [PATCH] Fix bug #122 & #133

---
 .../parser/FindMeetingCommandParser.java      |  5 +++
 .../address/logic/parser/ParserUtil.java      | 40 ++++++++++++++++++-
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/main/java/seedu/address/logic/parser/FindMeetingCommandParser.java b/src/main/java/seedu/address/logic/parser/FindMeetingCommandParser.java
index b5fc29e4b07..90fb0f27c72 100644
--- a/src/main/java/seedu/address/logic/parser/FindMeetingCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/FindMeetingCommandParser.java
@@ -50,6 +50,11 @@ public FindMeetingCommand parse(String args) throws ParseException {
             LocalDateTime start = LocalDateTime.MIN;
             LocalDateTime end = LocalDateTime.MAX;
 
+            if (argMultimap.getValue(PREFIX_START).isPresent() && argMultimap.getValue(PREFIX_END).isEmpty()
+                    || argMultimap.getValue(PREFIX_START).isEmpty() && argMultimap.getValue(PREFIX_END).isPresent()) {
+                throw new ParseException("Please input both start and end times");
+            }
+
             if (argMultimap.getValue(PREFIX_START).isPresent() && argMultimap.getValue(PREFIX_END).isPresent()) {
                 start = ParserUtil.parseMeetingTime(argMultimap.getValue(PREFIX_START).get());
                 end = ParserUtil.parseMeetingTime(argMultimap.getValue(PREFIX_END).get());
diff --git a/src/main/java/seedu/address/logic/parser/ParserUtil.java b/src/main/java/seedu/address/logic/parser/ParserUtil.java
index 723f114a510..d092fb86653 100644
--- a/src/main/java/seedu/address/logic/parser/ParserUtil.java
+++ b/src/main/java/seedu/address/logic/parser/ParserUtil.java
@@ -7,6 +7,8 @@
 import static seedu.address.logic.Messages.MESSAGE_TOO_MANY_INDEXES;
 
 import java.time.LocalDateTime;
+import java.time.Month;
+import java.time.Year;
 import java.time.format.DateTimeFormatter;
 import java.time.format.DateTimeParseException;
 import java.util.ArrayList;
@@ -191,7 +193,12 @@ public static LocalDateTime parseContactTime(String time) throws ParseException
             if (!LastContactedTime.isValidLastContactedTime(preppedTime)) {
                 throw new ParseException(LastContactedTime.MESSAGE_CONSTRAINTS);
             }
-            return preppedTime;
+            if (checkCorrectDay(preppedTime, time)) {
+                return preppedTime;
+            } else {
+                throw new ParseException(preppedTime.getMonth().toString()
+                        + " does not have " + time.substring(0, 2) + " days.");
+            }
         } catch (DateTimeParseException e) {
             throw new ParseException(LastContactedTime.MESSAGE_CONSTRAINTS);
         }
@@ -207,12 +214,41 @@ public static LocalDateTime parseMeetingTime(String time) throws ParseException
         requireNonNull(time);
         String trimmedStart = time.trim();
         try {
-            return LocalDateTime.parse(trimmedStart, FORMAT);
+            LocalDateTime result = LocalDateTime.parse(trimmedStart, FORMAT);
+            if (checkCorrectDay(result, time)) {
+                return result;
+            } else {
+                throw new ParseException(result.getMonth().toString()
+                        + "does not have " + time.substring(0, 2) + " days.");
+            }
         } catch (DateTimeParseException e) {
             throw new ParseException(MeetingTime.MESSAGE_CONSTRAINTS);
         }
     }
 
+    private static boolean checkCorrectDay(LocalDateTime localDateTime, String string) {
+        if (Year.isLeap(localDateTime.getYear())
+                && (localDateTime.getMonth() == Month.FEBRUARY && string.startsWith("29"))) {
+            return true;
+        }
+        Month thisMonth = localDateTime.getMonth();
+        if (!has31Days(thisMonth) && string.startsWith("31")) {
+            return false;
+        }
+        return thisMonth != Month.FEBRUARY
+                || (!string.startsWith("29") && !string.startsWith("30"));
+    }
+
+    private static boolean has31Days(Month month) {
+        requireNonNull(month);
+        switch (month) {
+        case FEBRUARY: case APRIL: case JUNE: case SEPTEMBER: case NOVEMBER:
+            return false;
+        default:
+            return true;
+        }
+    }
+
     /**
      * Parses a {@code String tag} into a {@code Tag}.
      * Leading and trailing whitespaces will be trimmed.