Add logger dependency and implement PromptBuilder for workflow management

lib/src/comfyui_api.dart

@@ -2,8 +2,8 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:http/http.dart' as http;
-import 'package:uuid/uuid.dart';
 
+import 'package:logger/logger.dart';
 import 'models/websocket_event.dart';
 import 'models/progress_event.dart';
 import 'models/execution_event.dart';
@@ -22,14 +22,17 @@ class ComfyUiApi {
   final String clientId;
   final http.Client _httpClient;
   final WebSocketManager _webSocketManager;
+  final Logger logger;
 
   /// Creates a new ComfyUI API client
   ComfyUiApi({
     required this.host,
     required this.clientId,
+    Logger? logger,
     http.Client? httpClient,
   })  : _httpClient = httpClient ?? http.Client(),
-        _webSocketManager = WebSocketManager(host: host, clientId: clientId);
+        _webSocketManager = WebSocketManager(host: host, clientId: clientId),
+        logger = logger ?? Logger();
 
   /// Expose WebSocketManager streams and methods
   Stream<WebSocketEvent> get events => _webSocketManager.events;

lib/src/prompt_builder.dart

@@ -0,0 +1,89 @@
+class PromptBuilder {
+  final String clientId;
+  final Map<String, dynamic> _nodes = {};
+  final Map<String, Map<String, String>> _outputToNode =
+      {}; // Maps output tags to node IDs
+  int _nodeIdCounter = 1;
+
+  PromptBuilder({required this.clientId});
+
+  /// Adds a node to the workflow
+  void addNode(String classType, Map<String, dynamic> inputs,
+      {String? title, Map<String, String>? outputTags}) {
+    final nodeId = _nodeIdCounter.toString();
+
+    // Resolve dependencies for inputs
+    inputs.forEach((key, value) {
+      if (value is List && value.length == 2 && value[1] is int) {
+        final outputTag = value[0];
+        if (_outputToNode.containsKey(outputTag)) {
+          inputs[key] = [_outputToNode[outputTag]!["nodeId"], value[1]];
+        } else {
+          throw Exception(
+              "Unresolved dependency: No node provides output tag '$outputTag'");
+        }
+      }
+    });
+
+    _nodes[nodeId] = {
+      "inputs": inputs,
+      "class_type": classType,
+      "_meta": {"title": title ?? classType}
+    };
+
+    // Register outputs of this node with optional tags
+    final defaultOutputs = _getDefaultOutputs(classType);
+    for (var i = 0; i < defaultOutputs.length; i++) {
+      final outputTag = outputTags?[defaultOutputs[i]] ?? defaultOutputs[i];
+      _outputToNode[outputTag] = {
+        "nodeId": nodeId,
+        "outputIndex": i.toString()
+      };
+    }
+
+    _nodeIdCounter++;
+  }
+
+  /// Generates the final workflow map
+  Map<String, dynamic> build() {
+    return {
+      "client_id": clientId,
+      "prompt": _nodes,
+    };
+  }
+
+  /// Validates the workflow against object info (optional)
+  void validate(Map<String, dynamic> objectInfo) {
+    for (var nodeId in _nodes.keys) {
+      final node = _nodes[nodeId];
+      final classType = node["class_type"];
+      if (!objectInfo.containsKey(classType)) {
+        throw Exception("Invalid node class type: $classType");
+      }
+      final requiredInputs = objectInfo[classType]["input"]["required"];
+      for (var inputKey in requiredInputs.keys) {
+        if (!node["inputs"].containsKey(inputKey)) {
+          throw Exception(
+              "Missing required input '$inputKey' for node $nodeId");
+        }
+      }
+    }
+  }
+
+  /// Helper method to get default outputs for a class type
+  List<String> _getDefaultOutputs(String classType) {
+    if (classType == "CheckpointLoaderSimple") {
+      return ["MODEL", "CLIP", "VAE"];
+    } else if (classType == "CLIPTextEncode") {
+      return ["CONDITIONING"];
+    } else if (classType == "EmptyLatentImage" ||
+        classType == "KSampler" ||
+        classType == "LatentUpscale" ||
+        classType == "LatentUpscaleBy") {
+      return ["LATENT"];
+    } else if (classType == "VAEDecode") {
+      return ["IMAGE"];
+    }
+    return [];
+  }
+}