finished ocr daemon update

tools/OcrDaemon/Daemon.cs

@@ -0,0 +1,87 @@
+namespace OcrDaemon;
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Tesseract;
+
+static class Daemon
+{
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+    };
+
+    public static int Run()
+    {
+        ScreenCapture.InitDpiAwareness();
+
+        // Pre-create the Tesseract OCR engine (reused across all requests)
+        var tessdataPath = Path.Combine(AppContext.BaseDirectory, "tessdata");
+        var tessLang = File.Exists(Path.Combine(tessdataPath, "poe2.traineddata")) ? "poe2" : "eng";
+        TesseractEngine tessEngine;
+        try
+        {
+            tessEngine = new TesseractEngine(tessdataPath, tessLang, EngineMode.LstmOnly);
+            tessEngine.DefaultPageSegMode = PageSegMode.SingleBlock;
+            tessEngine.SetVariable("preserve_interword_spaces", "1");
+            Console.Error.WriteLine($"Tesseract engine loaded with language: {tessLang}");
+        }
+        catch (Exception ex)
+        {
+            WriteResponse(new ErrorResponse($"Failed to create Tesseract engine: {ex.Message}. Ensure tessdata/eng.traineddata exists."));
+            return 1;
+        }
+
+        // Signal ready
+        WriteResponse(new ReadyResponse());
+
+        var ocrHandler = new OcrHandler(tessEngine);
+        var gridHandler = new GridHandler();
+        var detectGridHandler = new DetectGridHandler();
+
+        // Main loop: read one JSON line, handle, write one JSON line
+        string? line;
+        while ((line = Console.In.ReadLine()) != null)
+        {
+            line = line.Trim();
+            if (line.Length == 0) continue;
+
+            try
+            {
+                var request = JsonSerializer.Deserialize<Request>(line, JsonOptions);
+                if (request == null)
+                {
+                    WriteResponse(new ErrorResponse("Failed to parse request"));
+                    continue;
+                }
+
+                object response = request.Cmd?.ToLowerInvariant() switch
+                {
+                    "ocr"         => ocrHandler.HandleOcr(request),
+                    "screenshot"  => ocrHandler.HandleScreenshot(request),
+                    "capture"     => ocrHandler.HandleCapture(request),
+                    "snapshot"    => ocrHandler.HandleSnapshot(request),
+                    "diff-ocr"    => ocrHandler.HandleDiffOcr(request),
+                    "grid"        => gridHandler.HandleGrid(request),
+                    "detect-grid" => detectGridHandler.HandleDetectGrid(request),
+                    _             => new ErrorResponse($"Unknown command: {request.Cmd}"),
+                };
+                WriteResponse(response);
+            }
+            catch (Exception ex)
+            {
+                WriteResponse(new ErrorResponse(ex.Message));
+            }
+        }
+
+        return 0;
+    }
+
+    private static void WriteResponse(object response)
+    {
+        var json = JsonSerializer.Serialize(response, JsonOptions);
+        Console.Out.WriteLine(json);
+        Console.Out.Flush();
+    }
+}