feat: solution for 'Повторный экзамен: Граф с рефлексией и доработкой'

src/nodes.py

@@ -0,0 +1,80 @@
+from typing import TypedDict, Dict, Any
+from langchain_openai import ChatOpenAI
+from langchain.prompts import PromptTemplate
+
+# Define the state structure
+class ReflectState(TypedDict):
+    question: str
+    draft: str
+    critique: str
+    verdict: str  # "ok" or "needs_revision"
+    round: int
+    max_rounds: int
+
+# Initialize the LLM (requires OPENAI_API_KEY environment variable)
+llm = ChatOpenAI(model_name="gpt-3.5-turbo", temperature=0.2)
+
+# Prompt templates
+DRAFT_PROMPT = PromptTemplate(
+    input_variables=["question"],
+    template=(
+        "You are an expert tutor. Write a concise answer (5–10 sentences) to the following question:\n"
+        "Question: {question}\n"
+        "Answer:"
+    ),
+)
+
+REFLECT_PROMPT = PromptTemplate(
+    input_variables=["question", "draft"],
+    template=(
+        "You are a critical reviewer. Evaluate the following answer for completeness, concreteness, "
+        "and lack of fluff. Provide a verdict ('ok' or 'needs_revision') and 2–3 critique points.\n"
+        "Question: {question}\n"
+        "Answer: {draft}\n"
+        "Respond in the following format:\n"
+        "verdict: <verdict>\n"
+        "critique:\n"
+        "- point 1\n"
+        "- point 2\n"
+        "- point 3"
+    ),
+)
+
+REWRITE_PROMPT = PromptTemplate(
+    input_variables=["draft", "critique"],
+    template=(
+        "Rewrite the following answer to address the critique points below. "
+        "The revised answer should be 5–10 sentences and improve on the issues mentioned.\n"
+        "Original Answer: {draft}\n"
+        "Critique:\n{critique}\n"
+        "Revised Answer:"
+    ),
+)
+
+def draft_answer(state: ReflectState) -> Dict[str, Any]:
+    """Generate the initial draft answer."""
+    question = state["question"]
+    response = llm.invoke(DRAFT_PROMPT.format(question=question))
+    draft = response.content.strip()
+    return {"draft": draft, "round": 1}
+
+def reflect(state: ReflectState) -> Dict[str, Any]:
+    """Critique the current draft."""
+    question = state["question"]
+    draft = state["draft"]
+    response = llm.invoke(REFLECT_PROMPT.format(question=question, draft=draft))
+    text = response.content.strip()
+    # Parse verdict and critique
+    verdict_line, critique_section = text.split("critique:", 1)
+    verdict = verdict_line.replace("verdict:", "").strip().lower()
+    critique = critique_section.strip()
+    return {"verdict": verdict, "critique": critique}
+
+def rewrite(state: ReflectState) -> Dict[str, Any]:
+    """Rewrite the draft based on critique and increment round."""
+    draft = state["draft"]
+    critique = state["critique"]
+    response = llm.invoke(REWRITE_PROMPT.format(draft=draft, critique=critique))
+    new_draft = response.content.strip()
+    new_round = state["round"] + 1
+    return {"draft": new_draft, "round": new_round}