import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { File } from 'expo-file-system';
import { useCallback, useEffect, useRef, useState } from 'react';

import type { WsConnectionState } from '@/core/ws/types';

import { conversationApi } from './api';
import { conversationKeys } from './query-keys';
import {
  RealtimeSession,
  type ErrorCallback,
  type StreamingTextCallback,
} from './realtime-session';
import type {
  ConversationListItem,
  MessageItem,
  StreamingAgentMessage,
} from './types';

// ─── Query hooks ───

// TODO: 连接不上后端时 isLoading 可能一直为 true，需加超时或展示错误态
export function useConversations() {
  return useQuery({
    queryKey: conversationKeys.lists(),
    queryFn: () => conversationApi.list(),
  });
}

export function useConversationDetail(conversationId: string) {
  return useQuery({
    queryKey: conversationKeys.detail(conversationId),
    queryFn: () => conversationApi.detail(conversationId),
    enabled: !!conversationId,
  });
}

export function useMessages(conversationId: string) {
  return useQuery({
    queryKey: conversationKeys.messages(conversationId),
    queryFn: () => conversationApi.messages(conversationId),
    enabled: !!conversationId,
  });
}

// ─── Mutation hooks ───

export function useCreateConversation() {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: () => conversationApi.create(),
    onSuccess: (newConversation) => {
      queryClient.setQueryData<ConversationListItem[]>(
        conversationKeys.lists(),
        (old) => {
          const item: ConversationListItem = {
            id: newConversation.id,
            title: '岁月知己',
            avatarUrl: null,
            latestMessagePreview: '',
            latestMessageTime: Date.now(),
            unreadCount: 0,
            isDefaultAssistant: true,
          };
          return [item, ...(old ?? [])];
        },
      );
    },
  });
}

export function useDeleteConversation() {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: (conversationId: string) =>
      conversationApi.delete(conversationId),
    onSuccess: (_, conversationId) => {
      queryClient.setQueryData<ConversationListItem[]>(
        conversationKeys.lists(),
        (old) => old?.filter((item) => item.id !== conversationId),
      );
      queryClient.removeQueries({
        queryKey: conversationKeys.detail(conversationId),
      });
      queryClient.removeQueries({
        queryKey: conversationKeys.messages(conversationId),
      });
    },
  });
}

export function useEndConversation() {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: (conversationId: string) => conversationApi.end(conversationId),
    onSuccess: (_, conversationId) => {
      queryClient.invalidateQueries({
        queryKey: conversationKeys.detail(conversationId),
      });
      queryClient.invalidateQueries({
        queryKey: conversationKeys.lists(),
      });
    },
  });
}

// ─── Realtime session hook ───

interface UseRealtimeSessionOptions {
  conversationId: string;
  enabled?: boolean;
  onTtsAudio?: (audioBase64: string) => void;
}

const MIN_RECORDING_DURATION_SEC = 1;

function generateUUID(): string {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
    const r = (Math.random() * 16) | 0;
    const v = c === 'x' ? r : (r & 0x3) | 0x8;
    return v.toString(16);
  });
}

interface RealtimeSessionState {
  connectionState: WsConnectionState;
  streamingMessage: StreamingAgentMessage | null;
  error: string | null;
  sendText: (text: string) => void;
  sendVoiceMessage: (uri: string, durationMs: number) => Promise<boolean>;
  sendEndConversation: () => void;
}

export function useRealtimeSession({
  conversationId,
  enabled = true,
  onTtsAudio,
}: UseRealtimeSessionOptions): RealtimeSessionState {
  const queryClient = useQueryClient();
  const sessionRef = useRef<RealtimeSession | null>(null);

  const [connectionState, setConnectionState] =
    useState<WsConnectionState>('disconnected');
  const [streamingMessage, setStreamingMessage] =
    useState<StreamingAgentMessage | null>(null);
  const [error, setError] = useState<string | null>(null);

  const handleStreamingText: StreamingTextCallback = useCallback(
    (text, isComplete) => {
      if (isComplete) {
        setStreamingMessage(null);
        return;
      }
      setStreamingMessage({ text, isComplete });
    },
    [],
  );

  const handleError: ErrorCallback = useCallback((message) => {
    setError(message);
  }, []);

  useEffect(() => {
    if (!enabled || !conversationId) return;

    const session = new RealtimeSession({
      conversationId,
      queryClient,
      onStreamingText: handleStreamingText,
      onTtsAudio,
      onError: handleError,
      onStateChange: setConnectionState,
    });

    sessionRef.current = session;
    session.connect();

    return () => {
      session.dispose();
      sessionRef.current = null;
      setConnectionState('disconnected');
      setStreamingMessage(null);
    };
  }, [conversationId, enabled, queryClient, handleStreamingText, handleError, onTtsAudio]);

  const sendText = useCallback(
    (text: string) => {
      if (!sessionRef.current) return;

      const sent = sessionRef.current.sendText(text);
      if (!sent) {
        setError('消息发送失败，连接未就绪');
        return;
      }

      const localId = `pending_${Date.now()}`;

      queryClient.setQueryData<MessageItem[]>(
        conversationKeys.messages(conversationId),
        (old) => {
          const msg: MessageItem = {
            id: localId,
            conversationId,
            content: text,
            senderType: 'user',
            timestamp: Date.now(),
            messageType: 'text',
          };
          return [...(old ?? []), msg];
        },
      );
    },
    [conversationId, queryClient],
  );

  const sendVoiceMessage = useCallback(
    async (uri: string, durationMs: number): Promise<boolean> => {
      const session = sessionRef.current;
      if (!session) return false;

      const durationSec = Math.round(durationMs / 1000);
      if (durationSec < MIN_RECORDING_DURATION_SEC) return false;

      try {
        const file = new File(uri);
        const base64 = await file.base64();
        if (!base64) return false;

        const voiceSessionId = generateUUID();
        const sent = session.sendAudioSegment(base64, 0, {
          voiceSessionId,
          clientSegmentId: `${voiceSessionId}-0`,
          isLast: true,
          duration: durationSec,
        });
        if (!sent) {
          setError('语音发送失败，连接未就绪');
          return false;
        }

        const localId = `pending_voice_${Date.now()}`;
        queryClient.setQueryData<MessageItem[]>(
          conversationKeys.messages(conversationId),
          (old) => {
            const msg: MessageItem = {
              id: localId,
              conversationId,
              content: '',
              senderType: 'user',
              timestamp: Date.now(),
              messageType: 'voice',
              durationSeconds: durationSec,
              audioUri: uri,
            };
            return [...(old ?? []), msg];
          },
        );
        return true;
      } catch {
        setError('语音文件读取失败');
        return false;
      }
    },
    [conversationId, queryClient],
  );

  const sendEndConversation = useCallback(() => {
    sessionRef.current?.sendEndConversation();
  }, []);

  return {
    connectionState,
    streamingMessage,
    error,
    sendText,
    sendVoiceMessage,
    sendEndConversation,
  };
}