feat(fase4): add advanced nodes - switch, delay, random, loop, goto

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

services/flow-engine/app/nodes/advanced.py

@@ -0,0 +1,110 @@
+import asyncio
+import random as random_module
+from typing import Any, Optional
+
+from app.context import FlowContext
+from app.nodes.base import NodeExecutor
+
+
+class SwitchExecutor(NodeExecutor):
+    """Multi-branch switch based on variable value"""
+
+    async def execute(
+        self, config: dict, context: FlowContext, session: Any
+    ) -> Optional[str]:
+        variable = config.get("variable", "")
+        cases = config.get("cases", [])
+
+        actual = context.get(variable) or context.message.get("content", "")
+        actual_str = str(actual).lower().strip()
+
+        for case in cases:
+            case_value = str(case.get("value", "")).lower().strip()
+            if actual_str == case_value:
+                return case.get("branch", "default")
+
+        return config.get("default_branch", "default")
+
+
+class DelayExecutor(NodeExecutor):
+    """Wait for a specified duration before continuing"""
+
+    async def execute(
+        self, config: dict, context: FlowContext, session: Any
+    ) -> Optional[str]:
+        delay_seconds = config.get("seconds", 0)
+        delay_type = config.get("type", "fixed")
+
+        if delay_type == "random":
+            min_delay = config.get("min_seconds", 1)
+            max_delay = config.get("max_seconds", 5)
+            delay_seconds = random_module.uniform(min_delay, max_delay)
+
+        if delay_seconds > 0:
+            await asyncio.sleep(min(delay_seconds, 30))
+
+        return "default"
+
+
+class RandomExecutor(NodeExecutor):
+    """Random branch selection for A/B testing"""
+
+    async def execute(
+        self, config: dict, context: FlowContext, session: Any
+    ) -> Optional[str]:
+        branches = config.get("branches", [])
+
+        if not branches:
+            return "default"
+
+        total_weight = sum(b.get("weight", 1) for b in branches)
+        rand_value = random_module.uniform(0, total_weight)
+
+        cumulative = 0
+        for branch in branches:
+            cumulative += branch.get("weight", 1)
+            if rand_value <= cumulative:
+                test_name = config.get("test_name", "ab_test")
+                context.set(f"_ab_{test_name}", branch.get("branch", "default"))
+                return branch.get("branch", "default")
+
+        return branches[-1].get("branch", "default") if branches else "default"
+
+
+class LoopExecutor(NodeExecutor):
+    """Loop a certain number of times"""
+
+    async def execute(
+        self, config: dict, context: FlowContext, session: Any
+    ) -> Optional[str]:
+        loop_var = config.get("counter_variable", "_loop_counter")
+        max_iterations = config.get("max_iterations", 10)
+
+        current = int(context.get(loop_var) or 0)
+
+        if current < max_iterations:
+            context.set(loop_var, current + 1)
+            return "continue"
+        else:
+            context.set(loop_var, 0)
+            return "done"
+
+
+class GoToExecutor(NodeExecutor):
+    """Jump to another node or flow"""
+
+    async def execute(
+        self, config: dict, context: FlowContext, session: Any
+    ) -> Optional[str]:
+        target_node_id = config.get("target_node_id")
+        target_flow_id = config.get("target_flow_id")
+
+        if target_flow_id:
+            context.set("_goto_flow_id", target_flow_id)
+            return "sub_flow"
+
+        if target_node_id:
+            context.set("_goto_node_id", target_node_id)
+            return "goto"
+
+        return "default"