import type { HumanMessage } from "@langchain/core/messages";
import type { ThreadsClient } from "@langchain/langgraph-sdk/client";
import { useStream, type UseStream } from "@langchain/langgraph-sdk/react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { useCallback } from "react";

import type { PromptInputMessage } from "@/components/ai-elements/prompt-input";

import { getAPIClient } from "../api";

import type {
  AgentThread,
  AgentThreadContext,
  AgentThreadState,
} from "./types";

export function useThreadStream({
  threadId,
  isNewThread,
}: {
  isNewThread: boolean;
  threadId: string | null | undefined;
}) {
  const queryClient = useQueryClient();
  const thread = useStream<AgentThreadState>({
    client: getAPIClient(),
    assistantId: "lead_agent",
    threadId: isNewThread ? undefined : threadId,
    reconnectOnMount: true,
    fetchStateHistory: true,
    onFinish(state) {
      // void queryClient.invalidateQueries({ queryKey: ["threads", "search"] });
      queryClient.setQueriesData(
        {
          queryKey: ["threads", "search"],
          exact: false,
        },
        (oldData: Array<AgentThread>) => {
          return oldData.map((t) => {
            if (t.thread_id === threadId) {
              return {
                ...t,
                values: {
                  ...t.values,
                  title: state.values.title,
                },
              };
            }
            return t;
          });
        },
      );
    },
  });
  return thread;
}

export function useSubmitThread({
  threadId,
  thread,
  threadContext,
  isNewThread,
  afterSubmit,
}: {
  isNewThread: boolean;
  threadId: string | null | undefined;
  thread: UseStream<AgentThreadState>;
  threadContext: Omit<AgentThreadContext, "thread_id">;
  afterSubmit?: () => void;
}) {
  const queryClient = useQueryClient();
  const callback = useCallback(
    async (message: PromptInputMessage) => {
      const text = message.text.trim();
      await thread.submit(
        {
          messages: [
            {
              type: "human",
              content: [
                {
                  type: "text",
                  text,
                },
              ],
            },
          ] as HumanMessage[],
        },
        {
          threadId: isNewThread ? threadId! : undefined,
          streamSubgraphs: true,
          streamResumable: true,
          config: {
            recursion_limit: 100,
          },
          context: {
            ...threadContext,
            thread_id: threadId,
          },
        },
      );
      void queryClient.invalidateQueries({ queryKey: ["threads", "search"] });
      afterSubmit?.();
    },
    [thread, isNewThread, threadId, threadContext, queryClient, afterSubmit],
  );
  return callback;
}

export function useThreads(
  params: Parameters<ThreadsClient["search"]>[0] = {
    limit: 50,
    sortBy: "updated_at",
    sortOrder: "desc",
  },
) {
  const apiClient = getAPIClient();
  return useQuery<AgentThread[]>({
    queryKey: ["threads", "search", params],
    queryFn: async () => {
      const response = await apiClient.threads.search<AgentThreadState>(params);
      return response as AgentThread[];
    },
  });
}

export function useDeleteThread() {
  const queryClient = useQueryClient();
  const apiClient = getAPIClient();
  return useMutation({
    mutationFn: async ({ threadId }: { threadId: string }) => {
      await apiClient.threads.delete(threadId);
    },
    onSuccess(_, { threadId }) {
      queryClient.setQueriesData(
        {
          queryKey: ["threads", "search"],
          exact: false,
        },
        (oldData: Array<AgentThread>) => {
          return oldData.filter((t) => t.thread_id !== threadId);
        },
      );
    },
  });
}