import OpenIMSDK, {
  LoginStatus,
  OpenIMEvent,
  type ConversationItem as OpenIMConversationItem,
  type MessageItem,
} from "@openim/rn-client-sdk";
import { useCallback, useEffect, useMemo, useState } from "react";

import type { ConversationItem } from "@/features/im/types/conversation";

function sortConversations(items: OpenIMConversationItem[]) {
  return [...items].sort((a, b) => {
    if (a.isPinned !== b.isPinned) {
      return a.isPinned ? -1 : 1;
    }

    return (b.latestMsgSendTime ?? 0) - (a.latestMsgSendTime ?? 0);
  });
}

function upsertConversations(
  current: OpenIMConversationItem[],
  changed: OpenIMConversationItem[]
) {
  if (!changed.length) {
    return current;
  }

  const map = new Map(current.map((item) => [item.conversationID, item]));
  changed.forEach((item) => {
    map.set(item.conversationID, item);
  });

  return sortConversations([...map.values()]);
}

function formatRelativeTime(timestamp: number) {
  if (!timestamp) {
    return "";
  }

  const now = Date.now();
  const diff = Math.max(0, now - timestamp);
  const minute = 60 * 1000;
  const hour = 60 * minute;
  const day = 24 * hour;

  if (diff < minute) {
    return "刚刚";
  }
  if (diff < hour) {
    return `${Math.floor(diff / minute)}分钟前`;
  }
  if (diff < day) {
    return `${Math.floor(diff / hour)}小时前`;
  }
  if (diff < day * 2) {
    return "昨天";
  }

  const date = new Date(timestamp);
  const month = `${date.getMonth() + 1}`.padStart(2, "0");
  const dayOfMonth = `${date.getDate()}`.padStart(2, "0");
  return `${month}-${dayOfMonth}`;
}

function parseLatestMessagePreview(latestMsg: string, draftText: string) {
  if (draftText) {
    return `[草稿] ${draftText}`;
  }

  if (!latestMsg) {
    return "";
  }

  try {
    const message = JSON.parse(latestMsg) as MessageItem;
    if (message.textElem?.content) {
      return message.textElem.content;
    }
    if (message.quoteElem?.text) {
      return `[引用] ${message.quoteElem.text}`;
    }
    if (message.pictureElem) {
      return "[图片]";
    }
    if (message.videoElem) {
      return "[视频]";
    }
    if (message.fileElem) {
      return "[文件]";
    }
    if (message.soundElem) {
      return "[语音]";
    }
    if (message.notificationElem) {
      return "[系统通知]";
    }
  } catch {
    return latestMsg;
  }

  return "[暂不支持的消息]";
}

function toViewModel(item: OpenIMConversationItem): ConversationItem {
  const title = item.showName || item.userID || item.groupID || "未命名会话";

  return {
    id: item.conversationID,
    kind: "direct",
    title,
    preview: parseLatestMessagePreview(item.latestMsg, item.draftText),
    timeLabel: formatRelativeTime(item.latestMsgSendTime),
    avatarUrl: item.faceURL || undefined,
    unreadCount: item.unreadCount,
  };
}

export function useConversationList() {
  const [conversations, setConversations] = useState<OpenIMConversationItem[]>([]);
  const [isLoading, setIsLoading] = useState(true);
  const [isLoggedIn, setIsLoggedIn] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const reload = useCallback(async () => {
    try {
      setError(null);
      const status = await OpenIMSDK.getLoginStatus();
      const logged = status === LoginStatus.Logged;
      setIsLoggedIn(logged);

      if (!logged) {
        setConversations([]);
        return;
      }

      const list = await OpenIMSDK.getAllConversationList();
      setConversations(sortConversations(list));
    } catch (err) {
      const message = err instanceof Error ? err.message : "拉取会话失败";
      setError(message);
    } finally {
      setIsLoading(false);
    }
  }, []);

  useEffect(() => {
    reload();
  }, [reload]);

  useEffect(() => {
    const onConversationChanged = (changed: OpenIMConversationItem[]) => {
      setConversations((prev) => upsertConversations(prev, changed));
    };

    const onNewConversation = (created: OpenIMConversationItem[]) => {
      setConversations((prev) => upsertConversations(prev, created));
    };

    const onRecvNewMessages = () => {
      reload();
    };

    OpenIMSDK.on(OpenIMEvent.OnConversationChanged, onConversationChanged);
    OpenIMSDK.on(OpenIMEvent.OnNewConversation, onNewConversation);
    OpenIMSDK.on(OpenIMEvent.OnRecvNewMessages, onRecvNewMessages);

    return () => {
      OpenIMSDK.off(OpenIMEvent.OnConversationChanged, onConversationChanged);
      OpenIMSDK.off(OpenIMEvent.OnNewConversation, onNewConversation);
      OpenIMSDK.off(OpenIMEvent.OnRecvNewMessages, onRecvNewMessages);
    };
  }, [reload]);

  const items = useMemo(() => conversations.map(toViewModel), [conversations]);

  return {
    items,
    isLoading,
    isLoggedIn,
    error,
    reload,
  };
}