File-Upload: Attachments-Tabelle, Base64-Speicherung, Frontend mit Drag&Drop/Paste/Preview, Error-Handling Fix

Models/ChatModels.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 
 namespace Gott.Models;
@@ -9,7 +10,118 @@ public class ChatMessage
     public string Role { get; set; } = "";
 
     [JsonPropertyName("content")]
-    public string Content { get; set; } = "";
+    public JsonElement Content { get; set; }
+
+    /// <summary>
+    /// Extrahiert den reinen Text aus Content (egal ob string oder content-block array).
+    /// </summary>
+    public string GetTextContent()
+    {
+        if (Content.ValueKind == JsonValueKind.String)
+            return Content.GetString() ?? "";
+
+        if (Content.ValueKind == JsonValueKind.Array)
+        {
+            var parts = new List<string>();
+            foreach (var block in Content.EnumerateArray())
+            {
+                if (block.TryGetProperty("type", out var t) && t.GetString() == "text"
+                    && block.TryGetProperty("text", out var txt))
+                    parts.Add(txt.GetString() ?? "");
+            }
+            return string.Join("\n", parts);
+        }
+
+        return Content.ToString();
+    }
+
+    /// <summary>
+    /// Prüft ob Datei-Attachments (image/document) enthalten sind.
+    /// </summary>
+    public bool HasAttachments()
+    {
+        if (Content.ValueKind != JsonValueKind.Array) return false;
+        foreach (var block in Content.EnumerateArray())
+        {
+            if (block.TryGetProperty("type", out var t))
+            {
+                var type = t.GetString();
+                if (type == "image" || type == "document") return true;
+            }
+        }
+        return false;
+    }
+
+    /// <summary>
+    /// Gibt Attachment-Infos zurück (type + media_type).
+    /// </summary>
+    public List<AttachmentInfo> GetAttachments()
+    {
+        var result = new List<AttachmentInfo>();
+        if (Content.ValueKind != JsonValueKind.Array) return result;
+        foreach (var block in Content.EnumerateArray())
+        {
+            if (block.TryGetProperty("type", out var t))
+            {
+                var type = t.GetString();
+                if (type == "image" || type == "document")
+                {
+                    var mediaType = "";
+                    if (block.TryGetProperty("source", out var src) && src.TryGetProperty("media_type", out var mt))
+                        mediaType = mt.GetString() ?? "";
+                    result.Add(new AttachmentInfo { Type = type, MediaType = mediaType });
+                }
+            }
+        }
+        return result;
+    }
+
+    /// <summary>
+    /// Gibt vollständige Attachment-Blöcke zurück (inkl. Base64-Daten).
+    /// </summary>
+    public List<AttachmentBlock> GetAttachmentBlocks()
+    {
+        var result = new List<AttachmentBlock>();
+        if (Content.ValueKind != JsonValueKind.Array) return result;
+        foreach (var block in Content.EnumerateArray())
+        {
+            if (block.TryGetProperty("type", out var t))
+            {
+                var type = t.GetString();
+                if (type == "image" || type == "document")
+                {
+                    var mediaType = "";
+                    var data = "";
+                    var fileName = "";
+                    if (block.TryGetProperty("source", out var src))
+                    {
+                        if (src.TryGetProperty("media_type", out var mt))
+                            mediaType = mt.GetString() ?? "";
+                        if (src.TryGetProperty("data", out var d))
+                            data = d.GetString() ?? "";
+                    }
+                    if (block.TryGetProperty("_file_name", out var fn))
+                        fileName = fn.GetString() ?? "";
+                    result.Add(new AttachmentBlock { Type = type, MediaType = mediaType, Data = data, FileName = fileName });
+                }
+            }
+        }
+        return result;
+    }
+}
+
+public class AttachmentBlock
+{
+    public string Type { get; set; } = "";
+    public string MediaType { get; set; } = "";
+    public string Data { get; set; } = "";
+    public string FileName { get; set; } = "";
+}
+
+public class AttachmentInfo
+{
+    public string Type { get; set; } = "";
+    public string MediaType { get; set; } = "";
 }
 
 public class ChatRequest