Create simulator.py

engine_03/flow/simulator.py

@@ -0,0 +1,41 @@
+from typing import List, Set
+
+from .graph_models import FlowGraph, Node, Edge
+
+
+def _find_start_nodes(flow: FlowGraph) -> List[Node]:
+    targets = {e.target for e in flow.edges}
+    return [n for n in flow.nodes if n.id not in targets] or (flow.nodes[:1] if flow.nodes else [])
+
+
+def simulate_flowgraph(flow: FlowGraph) -> str:
+    if not flow.nodes:
+        return "No nodes defined. Add some nodes first."
+
+    start_nodes = _find_start_nodes(flow)
+    visited: Set[str] = set()
+    logs: List[str] = []
+
+    def dfs(node: Node, depth: int = 0):
+        if node.id in visited:
+            logs.append(f"{'  '*depth}- Node `{node.id}` (already visited, skipping to avoid loops)")
+            return
+        visited.add(node.id)
+
+        type_tag = f" [{node.type}]" if node.type else ""
+        logs.append(f"{'  '*depth}- Node `{node.id}`{type_tag}: {node.label}")
+
+        # Outgoing edges
+        for edge in flow.edges:
+            if edge.source == node.id:
+                next_node = flow.find_node(edge.target)
+                if next_node:
+                    dfs(next_node, depth + 1)
+
+    for start in start_nodes:
+        dfs(start, 0)
+
+    if not logs:
+        return "No execution path found. Check your edges."
+
+    return "### Simulated Flow Execution\n" + "\n".join(logs)