GuestLog - User message improvements

- Added UserMessageService to have common methods for showing messages and errors to the user.
- Added Result record so services can return status on operation error (so it can be shown in the UI messages).
- Updated services to use the new Result record.
- Updated pages to use the new IUserMessageService.

src/Somnia.GuestLog/Services/UserMessageService.cs

@@ -0,0 +1,88 @@
+using Microsoft.Extensions.Localization;
+using MudBlazor;
+using Somnia.GuestLog.Models;
+using Somnia.GuestLog.Models.DTOs;
+using Somnia.GuestLog.Resources;
+using MessageKind = Somnia.GuestLog.Services.IUserMessageService.MessageKind;
+
+namespace Somnia.GuestLog.Services;
+
+public class UserMessageService(
+    IServiceProvider serviceProvider,
+    ISnackbar snackbar
+) : IUserMessageService
+{
+    private IStringLocalizer<LanguageLocale> _localizer
+    {
+        get
+        {
+            return serviceProvider.GetRequiredService<IStringLocalizer<LanguageLocale>>();
+        }
+    }
+
+
+    public void ShowMessage(string text, MessageKind kind, params object[] parameters)
+    {
+        string formatedMsg = GetFormatedMessage(text, parameters);
+        ShowSnackbar(formatedMsg, kind);
+    }
+
+
+    public void ShowResult(Result resultDto)
+    {
+        ShowResultWithMessage(resultDto, message: null);
+    }
+
+    public void ShowResultWithMessage(Result resultDto, string? message)
+    {
+        string resultMsg = GetMsgForResultCode(resultDto.ResultCode);
+        resultMsg = GetFormatedMessage(resultMsg, resultDto.Context);
+
+        string finalMsg = message is not null ? $"{message.Trim().TrimEnd(':')}: {resultMsg}" : resultMsg;
+
+        //Show success when OK, error for UnknownErrors and warning otherwise.
+        MessageKind kind = resultDto switch
+        {
+            { IsSuccess: true } => MessageKind.Success,
+            { ResultCode: ResultCode.UnknownError } => MessageKind.Error,
+            _ => MessageKind.Warning
+        };
+
+        ShowSnackbar(finalMsg, kind);
+    }
+
+
+    #region Internal Methods
+
+    private void ShowSnackbar(string msg, MessageKind kind)
+    {
+        snackbar.Add(message: msg, severity: GetSnackbarSeveryForMessageKind(kind));
+    }
+
+    private string GetMsgForResultCode(string resultCode)
+    {
+        return _localizer[$"resultCode.{resultCode}"];
+    }
+
+    private static string GetFormatedMessage(string template, params object[]? parameters)
+    {
+        if (parameters is null || parameters.Length == 0)
+        {
+            return template;
+        }
+
+        return string.Format(template, parameters);
+    }
+
+    private static MudBlazor.Severity GetSnackbarSeveryForMessageKind(MessageKind kind) => kind switch
+    {
+        MessageKind.Info => MudBlazor.Severity.Info,
+        MessageKind.Warning => MudBlazor.Severity.Warning,
+        MessageKind.Error => MudBlazor.Severity.Error,
+        MessageKind.Success => MudBlazor.Severity.Success,
+        MessageKind.Normal => MudBlazor.Severity.Normal,
+        _ => throw new ArgumentOutOfRangeException(nameof(kind), $"Not expected MessageKind value: {kind}")
+    };
+
+    #endregion
+}