from typing import TypedDict, List
from langgraph.graph import StateGraph, END


class RagState(TypedDict):
    query: str
    query_embedding: List[float]
    retrieved_docs: List[dict]
    context: str
    answer: str
    sources: List[dict]


def embed_query(state: RagState) -> dict:
    """将查询转为向量"""
    from app.services import embedding_service
    embedding = embedding_service.embed_single(state["query"])
    return {"query_embedding": embedding}


def retrieve_docs(state: RagState) -> dict:
    """向量检索"""
    from app.services import milvus_service
    from app.core.config import settings
    docs = milvus_service.search(
        state["query_embedding"],
        top_k=settings.vector_top_k,
    )
    return {"retrieved_docs": docs[:settings.final_top_k]}


def build_context(state: RagState) -> dict:
    """构建上下文"""
    context_parts = []
    sources = []

    for doc in state["retrieved_docs"]:
        context_parts.append(f"【{doc['doc_name']} - {doc.get('clause_id', '')}】\n{doc['content']}")
        sources.append({
            "name": doc["doc_name"],
            "clause": doc.get("clause_id"),
        })

    context = "\n\n".join(context_parts)
    return {"context": context, "sources": sources}


def generate_answer(state: RagState) -> dict:
    """生成答案"""
    from app.services import llm_service
    prompt = f"""请根据以下法规内容回答用户问题，并在回答中标注引用的法规条款。

法规内容：
{state['context']}

用户问题：{state['query']}

请给出准确、简洁的回答，并引用相关法规条款。"""

    answer = ""
    for chunk in llm_service.generate_stream(prompt):
        answer += chunk

    return {"answer": answer}


# 构建工作流图
rag_graph = StateGraph(RagState)

rag_graph.add_node("embed", embed_query)
rag_graph.add_node("retrieve", retrieve_docs)
rag_graph.add_node("build_context", build_context)
rag_graph.add_node("generate", generate_answer)

rag_graph.set_entry_point("embed")
rag_graph.add_edge("embed", "retrieve")
rag_graph.add_edge("retrieve", "build_context")
rag_graph.add_edge("build_context", "generate")
rag_graph.add_edge("generate", END)

rag_workflow = rag_graph.compile()


async def run_rag_workflow(query: str) -> RagState:
    """运行RAG工作流"""
    initial_state: RagState = {"query": query}
    result = rag_workflow.invoke(initial_state)
    return result


def stream_rag_workflow(query: str):
    """流式运行RAG工作流"""
    from app.services import llm_service

    # 先完成检索阶段
    state: RagState = {"query": query}
    state.update(embed_query(state))
    state.update(retrieve_docs(state))
    state.update(build_context(state))

    # 流式生成阶段
    prompt = f"""请根据以下法规内容回答用户问题，并在回答中标注引用的法规条款。

法规内容：
{state['context']}

用户问题：{state['query']}

请给出准确、简洁的回答，并引用相关法规条款。"""

    for chunk in llm_service.generate_stream(prompt):
        yield {"type": "chunk", "text": chunk}

    yield {"type": "done", "sources": state["sources"]}