add error handling and defaults

Program.cs

@@ -1,37 +1,123 @@
 using System.Diagnostics;
 using System.Text;
+using System.Text.Json;
 using CodeContext;
 
 Console.OutputEncoding = Encoding.UTF8;
-var path = args.FirstOrDefault() ?? MyAppsContext.GetUserInput("Enter the path to index: ");
-var defaultOutput = Path.Combine(Path.GetDirectoryName(path), "context.txt");
-var output = args.ElementAtOrDefault(1) ?? MyAppsContext.GetUserInput($"Enter output file (default: {defaultOutput}): ");
-output = string.IsNullOrWhiteSpace(output) ? defaultOutput : output;
-
-var sw = Stopwatch.StartNew();
-var structure = MyAppsContext.GetProjectStructure(path);
-var contents = MyAppsContext.GetFileContents(path);
-
-var content = new StringBuilder()
-    .AppendLine("Project Structure:")
-    .AppendLine(structure)
-    .AppendLine("\nFile Contents:")
-    .AppendLine(contents)
-    .ToString();
-
-var fileCount = Directory.GetFiles(path, "*", SearchOption.AllDirectories).Length;
-var lineCount = content.Count(c => c == '\n');
-var timeTaken = sw.Elapsed;
-
-var stats = $"""
-             📊 Stats:
-             📁 Files processed: {fileCount}
-             📝 Total lines: {lineCount}
-             ⏱️ Time taken: {timeTaken.TotalSeconds:F2}s
-             💾 Output size: {content.Length} characters
-             """;
-
-var outputPath = Directory.Exists(output) ? Path.Combine(output, "context.txt") : output;
-File.WriteAllText(outputPath, content);
-Console.WriteLine($"✅ Output written to {outputPath}");
-Console.WriteLine(stats);
+
+try
+{
+    var config = LoadConfig();
+    var path = GetValidPath(args.FirstOrDefault() ?? config.DefaultInputPath);
+    var defaultOutput = Path.Combine(Path.GetDirectoryName(path) ?? ".", config.DefaultOutputFileName);
+    var output = GetValidOutputPath(args.ElementAtOrDefault(1) ?? defaultOutput);
+
+    var sw = Stopwatch.StartNew();
+    var (structure, contents) = GetProjectInfo(path);
+    var content = BuildContent(structure, contents);
+    var stats = CalculateStats(path, content, sw.Elapsed);
+
+    WriteOutput(output, content, config.OutputFormat);
+    Console.WriteLine($"✅ Output written to {output}");
+    Console.WriteLine(stats);
+}
+catch (Exception ex)
+{
+    Console.WriteLine($"❌ Error: {ex.Message}");
+    Environment.Exit(1);
+}
+
+static Config LoadConfig()
+{
+    const string configPath = "config.json";
+    try
+    {
+        return File.Exists(configPath)
+            ? JsonSerializer.Deserialize<Config>(File.ReadAllText(configPath)) ?? new Config()
+            : new Config();
+    }
+    catch (JsonException ex)
+    {
+        throw new InvalidOperationException("Error parsing config file", ex);
+    }
+}
+
+static string GetValidPath(string defaultPath)
+{
+    var path = MyAppsContext.GetUserInput($"Enter the path to index (default: {defaultPath}): ");
+    var finalPath = string.IsNullOrWhiteSpace(path) ? defaultPath : path;
+    return Directory.Exists(finalPath)
+        ? finalPath
+        : throw new DirectoryNotFoundException($"Invalid directory path: {finalPath}");
+}
+
+static string GetValidOutputPath(string defaultOutput)
+{
+    var output = MyAppsContext.GetUserInput($"Enter output file (default: {defaultOutput}): ");
+    return string.IsNullOrWhiteSpace(output) ? defaultOutput : output;
+}
+
+static (string structure, string contents) GetProjectInfo(string path)
+{
+    try
+    {
+        return (MyAppsContext.GetProjectStructure(path), MyAppsContext.GetFileContents(path));
+    }
+    catch (Exception ex)
+    {
+        throw new InvalidOperationException($"Error processing project at {path}", ex);
+    }
+}
+
+static string BuildContent(string structure, string contents) =>
+    new StringBuilder()
+        .AppendLine("Project Structure:")
+        .AppendLine(structure)
+        .AppendLine("\nFile Contents:")
+        .AppendLine(contents)
+        .ToString();
+
+static string CalculateStats(string path, string content, TimeSpan timeTaken)
+{
+    try
+    {
+        var fileCount = Directory.GetFiles(path, "*", SearchOption.AllDirectories).Length;
+        var lineCount = content.Count(c => c == '\n');
+        return $"""
+            📊 Stats:
+            📁 Files processed: {fileCount}
+            📝 Total lines: {lineCount}
+            ⏱️ Time taken: {timeTaken.TotalSeconds:F2}s
+            💾 Output size: {content.Length} characters
+            """;
+    }
+    catch (Exception ex)
+    {
+        throw new InvalidOperationException("Error calculating stats", ex);
+    }
+}
+
+static void WriteOutput(string output, string content, string format)
+{
+    try
+    {
+        var outputPath = Directory.Exists(output) ? Path.Combine(output, "context.txt") : output;
+        var formattedContent = format.ToLower() switch
+        {
+            "json" => JsonSerializer.Serialize(new { content, timestamp = DateTime.Now }),
+            _ => content
+        };
+        File.WriteAllText(outputPath, formattedContent);
+    }
+    catch (Exception ex)
+    {
+        throw new IOException($"Error writing output to {output}", ex);
+    }
+}
+
+record Config
+{
+    public string DefaultInputPath { get; init; } = ".";
+    public string DefaultOutputFileName { get; init; } = "context.txt";
+    public string OutputFormat { get; init; } = "text";
+}