from langchain_core.messages import HumanMessage, AIMessageChunk, AIMessage

from agent import agent, checkpointer, title_agent
from model import ChatRequest
from services.db_service import exists_session, save_session, query_session_messages
from utils import dicts_to_messages


def generate_title(messages: list[dict[str, str]]) -> str:
    response = title_agent.invoke({
        "messages": dicts_to_messages(messages)
    })
    return response["messages"][-1].content.strip()


async def search_recipes(request: ChatRequest):
    """调用agent搜索食谱"""
    print(f"[用户] {request.username}: {request.message}, thread_id: {request.thread_id}")
    try:
        message = HumanMessage(content=request.message)

        # 流式调用Agent
        for chunk, metadata in agent.stream(
                {"messages": [message]},
                {"configurable": {"thread_id": request.thread_id}},
                stream_mode="messages"
        ):
            if isinstance(chunk, AIMessageChunk) and chunk.content:
                yield chunk.content

        # 总结对话标题并保存
        if not exists_session(request.thread_id, request.username):
            title = generate_title(get_messages(request.thread_id))
            save_session(request.thread_id, request.username, title)

    except Exception as e:
        print(f"\n[错误]: {str(e)}")
        yield "信息检索失败，试试看手动输入食物列表？"


# 清空会话
def clear_messages(thread_id: str):
    """清空会话"""
    print(f"清空历史消息，thread_id: {thread_id}")
    checkpointer.delete_thread(thread_id)


# 查询会话历史
def get_messages(thread_id: str) -> list[dict[str, str]]:
    """获取会话历史"""
    print(f"获取历史消息，thread_id: {thread_id}")

    # 根据 thread_id 查询 checkpoint
    checkpoint = checkpointer.get({"configurable": {"thread_id": thread_id}})

    # 如果不存在，返回空列表
    if not checkpoint:
        return []

    # 安全获取 messages
    channel_values = checkpoint.get("channel_values")
    if not channel_values:
        return []

    messages = channel_values.get("messages", [])
    if not messages:
        return []

    # 转换消息格式
    result = []
    for msg in messages:
        if not msg.content:
            continue

        if isinstance(msg, HumanMessage):
            result.append({"role": "user", "content": msg.content})
        elif isinstance(msg, AIMessage):
            result.append({"role": "ai", "content": msg.content})

    return result


# 查询历史会话消息
def get_user_session_messages(username: str):
    """查询历史会话消息"""
    print(f"查询历史会话消息，username: {username}")
    return query_session_messages(username)