refactor: implement unified startup validator architecture with IStartupValidator interface

octo-fiesta/Services/Validation/BaseStartupValidator.cs

@@ -0,0 +1,95 @@
+namespace octo_fiesta.Services.Validation;
+
+/// <summary>
+/// Base class for startup validators providing common functionality
+/// </summary>
+public abstract class BaseStartupValidator : IStartupValidator
+{
+    protected readonly HttpClient _httpClient;
+
+    protected BaseStartupValidator(HttpClient httpClient)
+    {
+        _httpClient = httpClient;
+    }
+
+    /// <summary>
+    /// Gets the name of the service being validated
+    /// </summary>
+    public abstract string ServiceName { get; }
+
+    /// <summary>
+    /// Validates the service configuration and connectivity
+    /// </summary>
+    public abstract Task<ValidationResult> ValidateAsync(CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Writes a status line to the console with colored output
+    /// </summary>
+    protected static void WriteStatus(string label, string value, ConsoleColor valueColor)
+    {
+        Console.Write($"  {label}: ");
+        var originalColor = Console.ForegroundColor;
+        Console.ForegroundColor = valueColor;
+        Console.WriteLine(value);
+        Console.ForegroundColor = originalColor;
+    }
+
+    /// <summary>
+    /// Writes a detail line to the console in dark gray
+    /// </summary>
+    protected static void WriteDetail(string message)
+    {
+        var originalColor = Console.ForegroundColor;
+        Console.ForegroundColor = ConsoleColor.DarkGray;
+        Console.WriteLine($"    -> {message}");
+        Console.ForegroundColor = originalColor;
+    }
+
+    /// <summary>
+    /// Masks a secret string for display, showing only the first few characters
+    /// </summary>
+    protected static string MaskSecret(string secret)
+    {
+        if (string.IsNullOrEmpty(secret))
+        {
+            return "(empty)";
+        }
+
+        const int visibleChars = 4;
+        if (secret.Length <= visibleChars)
+        {
+            return new string('*', secret.Length);
+        }
+
+        return secret[..visibleChars] + new string('*', Math.Min(secret.Length - visibleChars, 8));
+    }
+
+    /// <summary>
+    /// Handles common HTTP exceptions and returns appropriate validation result
+    /// </summary>
+    protected static ValidationResult HandleException(Exception ex, string fieldName)
+    {
+        return ex switch
+        {
+            TaskCanceledException => ValidationResult.Failure("TIMEOUT", 
+                "Could not reach service within timeout period", ConsoleColor.Yellow),
+            
+            HttpRequestException httpEx => ValidationResult.Failure("UNREACHABLE", 
+                httpEx.Message, ConsoleColor.Yellow),
+            
+            _ => ValidationResult.Failure("ERROR", ex.Message, ConsoleColor.Red)
+        };
+    }
+
+    /// <summary>
+    /// Writes validation result to console
+    /// </summary>
+    protected void WriteValidationResult(string fieldName, ValidationResult result)
+    {
+        WriteStatus(fieldName, result.Status, result.StatusColor);
+        if (!string.IsNullOrEmpty(result.Details))
+        {
+            WriteDetail(result.Details);
+        }
+    }
+}