fix(code-quality): resolve SonarCloud code smells and warnings

src/TheOfficeAPI/Common/Data/OfficeEpisodesData.cs

@@ -1,19 +1,21 @@
-using TheOfficeAPI.Common.Models;
+using System.Collections.ObjectModel;
+using TheOfficeAPI.Common.Models;
 
 namespace TheOfficeAPI.Common.Data
 {
     public static class OfficeEpisodesData
     {
-        public static readonly List<Episode> Episodes = new List<Episode>()
-            .Concat(Season1Episodes.Episodes)
-            .Concat(Season2Episodes.Episodes)
-            .Concat(Season3Episodes.Episodes)
-            .Concat(Season4Episodes.Episodes)
-            .Concat(Season5Episodes.Episodes)
-            .Concat(Season6Episodes.Episodes)
-            .Concat(Season7Episodes.Episodes)
-            .Concat(Season8Episodes.Episodes)
-            .Concat(Season9Episodes.Episodes)
-            .ToList();
+        public static readonly ReadOnlyCollection<Episode> Episodes = new(
+            new List<Episode>()
+                .Concat(Season1Episodes.Episodes)
+                .Concat(Season2Episodes.Episodes)
+                .Concat(Season3Episodes.Episodes)
+                .Concat(Season4Episodes.Episodes)
+                .Concat(Season5Episodes.Episodes)
+                .Concat(Season6Episodes.Episodes)
+                .Concat(Season7Episodes.Episodes)
+                .Concat(Season8Episodes.Episodes)
+                .Concat(Season9Episodes.Episodes)
+                .ToList());
     }
 }

src/TheOfficeAPI/Common/Data/Season3EpisodesData.cs

@@ -1,10 +1,13 @@
+using System.Collections.ObjectModel;
 using TheOfficeAPI.Common.Models;
 
+namespace TheOfficeAPI.Common.Data;
+
 public static class Season3Episodes
 {
     private const int SeasonNumber = 3;
-    
-    public static readonly List<Episode> Episodes = new List<Episode>
+
+    public static readonly ReadOnlyCollection<Episode> Episodes = new(new List<Episode>
     {
         new Episode { Season = SeasonNumber, EpisodeNumber = 1, Title = "Gay Witch Hunt", ReleasedDate = "2006-09-21" },
         new Episode { Season = SeasonNumber, EpisodeNumber = 2, Title = "The Convention", ReleasedDate = "2006-09-28" },
@@ -29,5 +32,5 @@ public static class Season3Episodes
         new Episode { Season = SeasonNumber, EpisodeNumber = 21, Title = "Women's Appreciation", ReleasedDate = "2007-05-03" },
         new Episode { Season = SeasonNumber, EpisodeNumber = 22, Title = "Beach Games", ReleasedDate = "2007-05-10" },
         new Episode { Season = SeasonNumber, EpisodeNumber = 23, Title = "The Job", ReleasedDate = "2007-05-17" }
-    };
+    });
 }

src/TheOfficeAPI/Level0/Controllers/HealthController.cs

@@ -7,7 +7,8 @@
 public class HealthController : ControllerBase
 {
     [HttpGet]
+    [ProducesResponseType(StatusCodes.Status200OK)]
     public IActionResult Get()
     {
         return Ok(new { status = "Healthy", timestamp = DateTime.UtcNow });
     }

src/TheOfficeAPI/Level0/Controllers/OfficeApiController.cs

@@ -8,6 +8,7 @@
 [Route("api")]
 public class Level0Controller : ControllerBase
 {
+    private const string InvalidRequestMessage = "Invalid request";
     private readonly TheOfficeService _theOfficeService;
 
     public Level0Controller(TheOfficeService theOfficeService)
@@ -116,7 +117,8 @@
     /// </code>
     /// </example>
     [HttpPost("theOffice")]
+    [ProducesResponseType(StatusCodes.Status200OK)]
     public IActionResult HandleRequest([FromBody] ApiRequest request)
     {
         // Level 0: Always return 200 OK, put actual status in response body
         try
@@ -165,7 +167,7 @@
             {
                 Success = false,
                 Error = "Season parameter is required",
-                Message = "Invalid request"
+                Message = InvalidRequestMessage
             });
 
         return null;
@@ -178,7 +180,7 @@
             {
                 Success = false,
                 Error = "Both season and episode parameters are required",
-                Message = "Invalid request"
+                Message = InvalidRequestMessage
             });
 
         return null;
@@ -193,7 +195,7 @@
             {
                 Success = false,
                 Error = $"Season parameter is outside of the scope. Please select the season number between 1 and {seasonsCount} (inclusive).",
-                Message = "Invalid request"
+                Message = InvalidRequestMessage
             });
         }
         return null;
@@ -208,7 +210,7 @@
             {
                 Success = false,
                 Error = $"Episode parameter is outside of the scope. Please select the episode number between 1 and {episodesCountFromSpecificSeason} (inclusive).",
-                Message = "Invalid request"
+                Message = InvalidRequestMessage
             });
         }
         return null;

src/TheOfficeAPI/Level0/Services/TheOfficeService.cs

@@ -10,7 +10,7 @@ public class TheOfficeService
 
         public TheOfficeService()
         {
-            _episodes = OfficeEpisodesData.Episodes;
+            _episodes = OfficeEpisodesData.Episodes.ToList();
             _seasons = InitializeSeasons();
         }
 

src/TheOfficeAPI/Program.cs

@@ -6,6 +6,12 @@
 
 public class Program
 {
+    // Protected constructor to satisfy S1118 (utility class should not have public constructor)
+    // while keeping the class non-static for WebApplicationFactory<Program> compatibility
+    protected Program()
+    {
+    }
+
     public static void Main(string[] args)
     {
         CreateWebApplication(args).Run();
@@ -28,10 +34,12 @@
         // RAILWAY: Use Railway's PORT environment variable and bind to 0.0.0.0
         var port = Environment.GetEnvironmentVariable("PORT");
         string url;
-        
+
         if (port != null)
         {
+            #pragma warning disable S5332 // HTTP is required for Railway deployment behind reverse proxy
             url = $"http://0.0.0.0:{port}";
+            #pragma warning restore S5332
             Console.WriteLine($"=== RAILWAY/PRODUCTION MODE ===");
             Console.WriteLine($"PORT from environment: {port}");
             Console.WriteLine($"Binding to: {url}");
@@ -39,7 +47,7 @@
         }
         else
         {
             url = serverOptions?.DefaultUrl ?? "http://localhost:5000";
             Console.WriteLine($"=== LOCAL DEVELOPMENT MODE ===");
             Console.WriteLine($"Using config URL: {url}");
             Console.WriteLine($"================================");