From fe00a0146291a7012c7fd6843c1a5084d5c3f160 Mon Sep 17 00:00:00 2001
From: rex <rex>
Date: Fri, 25 Oct 2024 21:05:34 +0800
Subject: [PATCH 1/2] add array extension for deadline sorting

---
 .../ToDoList/Helper/ToDoArrayExtensions.swift | 23 +++++++++++++++++++
 .../ToDoList/Model/ToDoLocalService.swift     | 10 +++-----
 .../ToDoList/Model/ToDoRemoteService.swift    |  6 +----
 .../ToDoListTests/ToDoReducerTests.swift      |  8 +++----
 4 files changed, 30 insertions(+), 17 deletions(-)
 create mode 100644 mobile-client/ToDoList/Helper/ToDoArrayExtensions.swift

diff --git a/mobile-client/ToDoList/Helper/ToDoArrayExtensions.swift b/mobile-client/ToDoList/Helper/ToDoArrayExtensions.swift
new file mode 100644
index 0000000..fb2711a
--- /dev/null
+++ b/mobile-client/ToDoList/Helper/ToDoArrayExtensions.swift
@@ -0,0 +1,23 @@
+import Foundation
+
+// Extensions for ToDoItemData
+extension [ToDoItemData] {
+    mutating func sortedByDeadline() {
+        sort { first, second in
+            let firstDeadline = ToDoDateFormatter.isoDateFormatter.date(from: first.deadline ?? "") ?? Date.distantFuture
+            let secondDeadline = ToDoDateFormatter.isoDateFormatter.date(from: second.deadline ?? "") ?? Date.distantFuture
+            return firstDeadline < secondDeadline
+        }
+    }
+}
+
+// Extensions for ToDoItem
+extension [ToDoItem] {
+    mutating func sortedByDeadline() {
+        sort { first, second in
+            let firstDeadline = ToDoDateFormatter.isoDateFormatter.date(from: first.deadline ?? "") ?? Date.distantFuture
+            let secondDeadline = ToDoDateFormatter.isoDateFormatter.date(from: second.deadline ?? "") ?? Date.distantFuture
+            return firstDeadline < secondDeadline
+        }
+    }
+}
diff --git a/mobile-client/ToDoList/Model/ToDoLocalService.swift b/mobile-client/ToDoList/Model/ToDoLocalService.swift
index 3d54f74..1343218 100644
--- a/mobile-client/ToDoList/Model/ToDoLocalService.swift
+++ b/mobile-client/ToDoList/Model/ToDoLocalService.swift
@@ -17,13 +17,9 @@ class ToDoLocalService: ToDoLocalServiceProtocol {
 
     func fetchTodos() throws -> [ToDoItemData] {
         let fetchDescriptor = FetchDescriptor<ToDoItemData>()
-        let todos = try context.fetch(fetchDescriptor)
-        let sortedTodos = todos.sorted { first, second in
-            let firstDeadline = ToDoDateFormatter.isoDateFormatter.date(from: first.deadline ?? "") ?? Date.distantFuture
-            let secondDeadline = ToDoDateFormatter.isoDateFormatter.date(from: second.deadline ?? "") ?? Date.distantFuture
-            return firstDeadline < secondDeadline
-        }
-        return sortedTodos
+        var todos = try context.fetch(fetchDescriptor)
+        todos.sortedByDeadline()
+        return todos
     }
 
     func save(todo: ToDoItemData) throws {
diff --git a/mobile-client/ToDoList/Model/ToDoRemoteService.swift b/mobile-client/ToDoList/Model/ToDoRemoteService.swift
index f7d42eb..7112606 100644
--- a/mobile-client/ToDoList/Model/ToDoRemoteService.swift
+++ b/mobile-client/ToDoList/Model/ToDoRemoteService.swift
@@ -75,11 +75,7 @@ final class ToDoRemoteService: ToDoRemoteServiceProtocol {
             var remoteTodos = decodedResponse.data
 
             // Sort remote todos by deadline (nil values will be placed at the end)
-            remoteTodos.sort { first, second in
-                let firstDeadline = ToDoDateFormatter.isoDateFormatter.date(from: first.deadline ?? "") ?? Date.distantFuture
-                let secondDeadline = ToDoDateFormatter.isoDateFormatter.date(from: second.deadline ?? "") ?? Date.distantFuture
-                return firstDeadline < secondDeadline
-            }
+            remoteTodos.sortedByDeadline()
 
             // Sync local data with remote data:
             // 1. For each remote ToDo, update the matching local item if IDs match, replacing its properties.
diff --git a/mobile-client/ToDoListTests/ToDoReducerTests.swift b/mobile-client/ToDoListTests/ToDoReducerTests.swift
index 52d929c..26e582b 100644
--- a/mobile-client/ToDoListTests/ToDoReducerTests.swift
+++ b/mobile-client/ToDoListTests/ToDoReducerTests.swift
@@ -137,7 +137,7 @@ struct ToDoReducerTests {
 
     /// Tests the performance of inserting a new ToDo item into the list.
     @Test
-    func testInsertingNewToDoItemPerformance() async {
+    func testNewToDoItemInsertionPerformance() async {
         let totalAdditionDay = 6000
 
         // Generate a list of ToDo items to be added.
@@ -154,10 +154,8 @@ struct ToDoReducerTests {
         }
 
         // Sort ToDo items by their deadline.
-        todos.sort {
-            ($0.deadline.flatMap(ToDoDateFormatter.isoDateFormatter.date(from:)) ?? Date.distantFuture) <
-                ($1.deadline.flatMap(ToDoDateFormatter.isoDateFormatter.date(from:)) ?? Date.distantFuture)
-        }
+        todos.sortedByDeadline()
+
         // Select a random deadline for the new ToDo item to be inserted between two existing items.
         let inBetweenDeadline = randomDeadlineInBetween(between: todos[4217].deadline!, and: todos[4218].deadline!)
 

From b55c8365f03a0c87ddbf11f232f84e8637478090 Mon Sep 17 00:00:00 2001
From: rex <rex>
Date: Sat, 26 Oct 2024 00:09:29 +0800
Subject: [PATCH 2/2] fix date formatter issues

---
 .../ToDoList/Helper/ToDoDateFormatter.swift   | 49 ++++++++++++++-----
 .../ToDoList/View/ToDoListView.swift          |  4 +-
 .../ToDoDateFormatterTests.swift              | 37 ++++++++++++++
 3 files changed, 77 insertions(+), 13 deletions(-)
 create mode 100644 mobile-client/ToDoListTests/ToDoDateFormatterTests.swift

diff --git a/mobile-client/ToDoList/Helper/ToDoDateFormatter.swift b/mobile-client/ToDoList/Helper/ToDoDateFormatter.swift
index 29f3ce1..e319d9e 100644
--- a/mobile-client/ToDoList/Helper/ToDoDateFormatter.swift
+++ b/mobile-client/ToDoList/Helper/ToDoDateFormatter.swift
@@ -7,25 +7,50 @@ enum ToDoDateFormatter {
         return formatter
     }()
 
+    /// Formats an ISO 8601 deadline string into a user-friendly date string
+    /// while preserving the timezone information.
+    ///
+    /// Returns a format like "Jan 1, 2023, 10:35:00 PM (+08:00)" or
+    /// "Apr 8, 2024, 11:46:14 AM (+0)".
+    ///
+    /// - Parameter deadline: An ISO 8601 formatted deadline string, which may include
+    ///   a timezone offset (e.g., "2024-04-08T11:46:14.349Z" or "2024-12-14T12:34:56.789+05:30").
+    /// - Returns: A formatted string representing the deadline, or an empty string if
+    ///   the input is nil or invalid.
     static func formattedDeadline(deadline: String?) -> String {
-        guard let deadline, let date = isoDateFormatter.date(from: deadline) else {
+        guard let deadline else {
             return ""
         }
 
-        // - dateStyle: .medium formats a date transforming "2024-07-31" to "Jul 31, 2024"
-        // - timeStyle: .medium formats the time to something like "12:34 PM"
-        let displayFormatter = DateFormatter()
-        displayFormatter.dateStyle = .medium
-        displayFormatter.timeStyle = .medium
-
-        let formattedDate = displayFormatter.string(from: date)
+        let hasTimezone = deadline.hasSuffix("Z") || deadline.contains("+") || deadline.contains("-")
+        let timezoneString: String
+        let deadlineWithoutTimezone: String
 
-        let timeZoneString = if deadline.hasSuffix("Z") {
-            ""
+        if hasTimezone {
+            if deadline.hasSuffix("Z") {
+                timezoneString = "(+0)"
+                deadlineWithoutTimezone = String(deadline.dropLast(1)) // Remove the "Z"
+            } else {
+                let timezoneIndex = deadline.index(deadline.endIndex, offsetBy: -6)
+                timezoneString = "(\(deadline[timezoneIndex...]))"
+                deadlineWithoutTimezone = String(deadline[..<timezoneIndex])
+            }
         } else {
-            " (\(String(deadline.suffix(5))))"
+            timezoneString = ""
+            deadlineWithoutTimezone = deadline
+        }
+
+        let displayFormatter = DateFormatter()
+        displayFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS"
+        displayFormatter.timeZone = TimeZone(secondsFromGMT: 0)
+
+        guard let date = displayFormatter.date(from: deadlineWithoutTimezone) else {
+            return ""
         }
 
-        return "\(formattedDate)\(timeZoneString)"
+        displayFormatter.dateFormat = "MMM d, yyyy, h:mm:ss a"
+        let formattedDate = displayFormatter.string(from: date)
+
+        return "\(formattedDate) \(timezoneString)"
     }
 }
diff --git a/mobile-client/ToDoList/View/ToDoListView.swift b/mobile-client/ToDoList/View/ToDoListView.swift
index d0f076c..1b519e3 100644
--- a/mobile-client/ToDoList/View/ToDoListView.swift
+++ b/mobile-client/ToDoList/View/ToDoListView.swift
@@ -149,7 +149,9 @@ struct TodoRow: View {
                     .font(.headline)
                 Spacer()
                 Text(todo.status)
-                    .padding(6)
+                    .font(.footnote)
+                    .fontWeight(.semibold)
+                    .padding(7)
                     .background(statusColor(for: todo.status))
                     .foregroundColor(.white)
                     .cornerRadius(5)
diff --git a/mobile-client/ToDoListTests/ToDoDateFormatterTests.swift b/mobile-client/ToDoListTests/ToDoDateFormatterTests.swift
new file mode 100644
index 0000000..cdcca1b
--- /dev/null
+++ b/mobile-client/ToDoListTests/ToDoDateFormatterTests.swift
@@ -0,0 +1,37 @@
+import Foundation
+import Testing
+@testable import ToDoList
+
+struct ToDoDateFormatterTests {
+    /// Tests formatting of deadlines provided in UTC time zone.
+    @Test
+    func testDeadlineWithUTCTimeZone() {
+        let utcDeadline1 = "2024-04-08T11:46:14.349Z"
+        let formattedUtcDeadline1 = ToDoDateFormatter.formattedDeadline(deadline: utcDeadline1)
+        #expect(formattedUtcDeadline1 == "Apr 8, 2024, 11:46:14 AM (+0)")
+
+        let utcDeadline2 = "2022-11-08T23:46:00.119Z"
+        let formattedUtcDeadline2 = ToDoDateFormatter.formattedDeadline(deadline: utcDeadline2)
+        #expect(formattedUtcDeadline2 == "Nov 8, 2022, 11:46:00 PM (+0)")
+    }
+
+    /// Tests formatting of deadlines provided in specific time zones.
+    @Test
+    func testDeadlineWithSpecificTimeZone() {
+        let taipeiDeadline = "2023-01-01T22:35:00.000+08:00"
+        let formattedTaipeiDeadline = ToDoDateFormatter.formattedDeadline(deadline: taipeiDeadline)
+        #expect(formattedTaipeiDeadline == "Jan 1, 2023, 10:35:00 PM (+08:00)")
+
+        let indiaDeadline1 = "2024-12-14T12:34:56.789+05:30"
+        let formattedIndiaDeadline1 = ToDoDateFormatter.formattedDeadline(deadline: indiaDeadline1)
+        #expect(formattedIndiaDeadline1 == "Dec 14, 2024, 12:34:56 PM (+05:30)")
+
+        let indiaDeadline2 = "2024-12-14T11:59:59.999+05:30"
+        let formattedIndiaDeadline2 = ToDoDateFormatter.formattedDeadline(deadline: indiaDeadline2)
+        #expect(formattedIndiaDeadline2 == "Dec 14, 2024, 11:59:59 AM (+05:30)")
+
+        let vancouverDeadline = "2024-05-02T18:19:11.199-08:00"
+        let formattedVancouverDeadline = ToDoDateFormatter.formattedDeadline(deadline: vancouverDeadline)
+        #expect(formattedVancouverDeadline == "May 2, 2024, 6:19:11 PM (-08:00)")
+    }
+}