/**
 * Real-time Collaboration Store
 * Manages collaboration state, sessions, and real-time updates
 */

import { create } from 'zustand';
import { io, Socket } from 'socket.io-client';
import {
  CollaboratorInfo,
  CollaborationSession,
  ChatMessage,
  CursorPosition,
  SelectionRange,
  CodeChange,
  ConnectionState,
  SessionSettings,
  DEFAULT_SESSION_SETTINGS,
  getCollaboratorColor,
  PermissionLevel,
} from '@/lib/collaboration/types';

interface CollaborationState {
  // Connection
  socket: Socket | null;
  connectionState: ConnectionState;
  reconnectAttempts: number;

  // Session
  currentSession: CollaborationSession | null;
  collaborators: CollaboratorInfo[];
  myInfo: CollaboratorInfo | null;
  myPermission: PermissionLevel;

  // Chat
  chatMessages: ChatMessage[];
  unreadChatCount: number;

  // Settings
  settings: SessionSettings;

  // UI State
  isChatOpen: boolean;
  isCollaboratorsPanelOpen: boolean;

  // Actions
  connect: (serverUrl?: string) => void;
  disconnect: () => void;
  createSession: (name: string, fileId: string, fileName: string, isPublic: boolean) => Promise<string>;
  joinSession: (sessionId: string, name: string, avatarUrl?: string) => Promise<boolean>;
  leaveSession: () => void;

  // Real-time updates
  updateCursor: (position: CursorPosition) => void;
  updateSelection: (selection: SelectionRange | null) => void;
  sendCodeChange: (change: CodeChange) => void;
  setTyping: (isTyping: boolean) => void;

  // Chat
  sendChatMessage: (content: string) => void;
  markChatAsRead: () => void;

  // Settings
  updateSettings: (settings: Partial<SessionSettings>) => void;
  setFollowUser: (userId: string | null) => void;

  // UI
  toggleChat: () => void;
  toggleCollaboratorsPanel: () => void;

  // Permissions
  updateCollaboratorPermission: (collaboratorId: string, permission: PermissionLevel) => void;
  kickCollaborator: (collaboratorId: string) => void;
}

// Generate unique ID
const generateId = () => `${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;

export const useCollaborationStore = create<CollaborationState>((set, get) => ({
  // Initial state
  socket: null,
  connectionState: 'disconnected',
  reconnectAttempts: 0,

  currentSession: null,
  collaborators: [],
  myInfo: null,
  myPermission: 'viewer',

  chatMessages: [],
  unreadChatCount: 0,

  settings: DEFAULT_SESSION_SETTINGS,

  isChatOpen: false,
  isCollaboratorsPanelOpen: true,

  // Connection
  connect: (serverUrl = 'ws://localhost:3001') => {
    const { socket, connectionState } = get();

    if (socket || connectionState === 'connecting') return;

    set({ connectionState: 'connecting' });

    const newSocket = io(serverUrl, {
      transports: ['websocket'],
      reconnection: true,
      reconnectionAttempts: 5,
      reconnectionDelay: 1000,
    });

    newSocket.on('connect', () => {
      set({
        connectionState: 'connected',
        reconnectAttempts: 0,
      });
    });

    newSocket.on('disconnect', () => {
      set({ connectionState: 'disconnected' });
    });

    newSocket.on('reconnect_attempt', (attempt) => {
      set({
        connectionState: 'reconnecting',
        reconnectAttempts: attempt,
      });
    });

    newSocket.on('connect_error', () => {
      set({ connectionState: 'error' });
    });

    // Session events
    newSocket.on('session_joined', (data: { session: CollaborationSession; collaborators: CollaboratorInfo[] }) => {
      set({
        currentSession: data.session,
        collaborators: data.collaborators,
      });
    });

    newSocket.on('collaborator_joined', (collaborator: CollaboratorInfo) => {
      set((state) => ({
        collaborators: [...state.collaborators, collaborator],
      }));
    });

    newSocket.on('collaborator_left', (collaboratorId: string) => {
      set((state) => ({
        collaborators: state.collaborators.filter((c) => c.id !== collaboratorId),
      }));
    });

    newSocket.on('cursor_updated', (data: { id: string; cursor: CursorPosition }) => {
      set((state) => ({
        collaborators: state.collaborators.map((c) =>
          c.id === data.id ? { ...c, cursor: data.cursor, lastActive: Date.now() } : c
        ),
      }));
    });

    newSocket.on('selection_updated', (data: { id: string; selection: SelectionRange | null }) => {
      set((state) => ({
        collaborators: state.collaborators.map((c) =>
          c.id === data.id ? { ...c, selection: data.selection ?? undefined, lastActive: Date.now() } : c
        ),
      }));
    });

    newSocket.on('typing_changed', (data: { id: string; isTyping: boolean }) => {
      set((state) => ({
        collaborators: state.collaborators.map((c) =>
          c.id === data.id ? { ...c, isTyping: data.isTyping } : c
        ),
      }));
    });

    newSocket.on('chat_message', (message: ChatMessage) => {
      set((state) => ({
        chatMessages: [...state.chatMessages, message],
        unreadChatCount: state.isChatOpen ? 0 : state.unreadChatCount + 1,
      }));
    });

    newSocket.on('code_changed', (change: CodeChange & { senderId: string }) => {
      // This would be handled by the editor integration
      // The editor should listen to this event and apply the change
    });

    set({ socket: newSocket });
  },

  disconnect: () => {
    const { socket } = get();
    if (socket) {
      socket.disconnect();
    }
    set({
      socket: null,
      connectionState: 'disconnected',
      currentSession: null,
      collaborators: [],
      myInfo: null,
      chatMessages: [],
    });
  },

  createSession: async (name: string, fileId: string, fileName: string, isPublic: boolean): Promise<string> => {
    const { socket, myInfo } = get();

    if (!socket || !myInfo) {
      throw new Error('Not connected');
    }

    return new Promise((resolve, reject) => {
      const sessionId = generateId();

      socket.emit('create_session', {
        sessionId,
        name,
        fileId,
        fileName,
        isPublic,
        ownerId: myInfo.id,
        ownerName: myInfo.name,
      });

      socket.once('session_created', (data: { sessionId: string }) => {
        const session: CollaborationSession = {
          id: data.sessionId,
          name,
          ownerId: myInfo.id,
          ownerName: myInfo.name,
          createdAt: Date.now(),
          collaborators: [myInfo],
          fileId,
          fileName,
          isPublic,
          maxCollaborators: 10,
        };

        set({
          currentSession: session,
          collaborators: [myInfo],
          myPermission: 'owner',
        });

        resolve(data.sessionId);
      });

      socket.once('session_error', (error: string) => {
        reject(new Error(error));
      });

      // Timeout
      setTimeout(() => reject(new Error('Session creation timed out')), 10000);
    });
  },

  joinSession: async (sessionId: string, name: string, avatarUrl?: string): Promise<boolean> => {
    const { socket } = get();

    if (!socket) {
      throw new Error('Not connected');
    }

    const myId = generateId();
    const colorIndex = Math.floor(Math.random() * 10);

    const myInfo: CollaboratorInfo = {
      id: myId,
      name,
      color: getCollaboratorColor(colorIndex),
      avatarUrl,
      lastActive: Date.now(),
      isTyping: false,
    };

    set({ myInfo });

    return new Promise((resolve, reject) => {
      socket.emit('join_session', {
        sessionId,
        collaborator: myInfo,
      });

      socket.once('session_joined', () => {
        set({ myPermission: 'editor' });
        resolve(true);
      });

      socket.once('session_error', (error: string) => {
        reject(new Error(error));
      });

      setTimeout(() => reject(new Error('Join timed out')), 10000);
    });
  },

  leaveSession: () => {
    const { socket, currentSession, myInfo } = get();

    if (socket && currentSession && myInfo) {
      socket.emit('leave_session', {
        sessionId: currentSession.id,
        collaboratorId: myInfo.id,
      });
    }

    set({
      currentSession: null,
      collaborators: [],
      myPermission: 'viewer',
      chatMessages: [],
    });
  },

  updateCursor: (position: CursorPosition) => {
    const { socket, currentSession, myInfo, settings } = get();

    if (!socket || !currentSession || !myInfo || !settings.showCursors) return;

    socket.emit('cursor_update', {
      sessionId: currentSession.id,
      collaboratorId: myInfo.id,
      cursor: position,
    });
  },

  updateSelection: (selection: SelectionRange | null) => {
    const { socket, currentSession, myInfo, settings } = get();

    if (!socket || !currentSession || !myInfo || !settings.showSelections) return;

    socket.emit('selection_update', {
      sessionId: currentSession.id,
      collaboratorId: myInfo.id,
      selection,
    });
  },

  sendCodeChange: (change: CodeChange) => {
    const { socket, currentSession, myInfo, myPermission } = get();

    if (!socket || !currentSession || !myInfo) return;
    if (!['editor', 'admin', 'owner'].includes(myPermission)) return;

    socket.emit('code_change', {
      sessionId: currentSession.id,
      collaboratorId: myInfo.id,
      change,
    });
  },

  setTyping: (isTyping: boolean) => {
    const { socket, currentSession, myInfo } = get();

    if (!socket || !currentSession || !myInfo) return;

    socket.emit('typing_change', {
      sessionId: currentSession.id,
      collaboratorId: myInfo.id,
      isTyping,
    });

    set((state) => ({
      myInfo: state.myInfo ? { ...state.myInfo, isTyping } : null,
    }));
  },

  sendChatMessage: (content: string) => {
    const { socket, currentSession, myInfo, settings } = get();

    if (!socket || !currentSession || !myInfo || !settings.allowChat) return;
    if (!content.trim()) return;

    const message: ChatMessage = {
      id: generateId(),
      senderId: myInfo.id,
      senderName: myInfo.name,
      senderColor: myInfo.color,
      content: content.trim(),
      timestamp: Date.now(),
    };

    socket.emit('chat_message', {
      sessionId: currentSession.id,
      message,
    });

    // Add to local state immediately
    set((state) => ({
      chatMessages: [...state.chatMessages, message],
    }));
  },

  markChatAsRead: () => {
    set({ unreadChatCount: 0 });
  },

  updateSettings: (newSettings: Partial<SessionSettings>) => {
    set((state) => ({
      settings: { ...state.settings, ...newSettings },
    }));
  },

  setFollowUser: (userId: string | null) => {
    set((state) => ({
      settings: {
        ...state.settings,
        followMode: userId !== null,
        followUserId: userId ?? undefined,
      },
    }));
  },

  toggleChat: () => {
    set((state) => ({
      isChatOpen: !state.isChatOpen,
      unreadChatCount: !state.isChatOpen ? 0 : state.unreadChatCount,
    }));
  },

  toggleCollaboratorsPanel: () => {
    set((state) => ({
      isCollaboratorsPanelOpen: !state.isCollaboratorsPanelOpen,
    }));
  },

  updateCollaboratorPermission: (collaboratorId: string, permission: PermissionLevel) => {
    const { socket, currentSession, myPermission } = get();

    if (!socket || !currentSession) return;
    if (myPermission !== 'owner' && myPermission !== 'admin') return;

    socket.emit('update_permission', {
      sessionId: currentSession.id,
      collaboratorId,
      permission,
    });
  },

  kickCollaborator: (collaboratorId: string) => {
    const { socket, currentSession, myPermission } = get();

    if (!socket || !currentSession) return;
    if (myPermission !== 'owner' && myPermission !== 'admin') return;

    socket.emit('kick_collaborator', {
      sessionId: currentSession.id,
      collaboratorId,
    });
  },
}));

// Demo/mock mode for when no server is available
export function enableMockMode() {
  const store = useCollaborationStore.getState();

  // Create mock session
  const mockMyInfo: CollaboratorInfo = {
    id: 'mock-user-1',
    name: 'You',
    color: getCollaboratorColor(0),
    lastActive: Date.now(),
    isTyping: false,
  };

  const mockCollaborators: CollaboratorInfo[] = [
    mockMyInfo,
    {
      id: 'mock-user-2',
      name: 'Alice',
      color: getCollaboratorColor(1),
      cursor: { lineNumber: 5, column: 10 },
      lastActive: Date.now(),
      isTyping: false,
    },
    {
      id: 'mock-user-3',
      name: 'Bob',
      color: getCollaboratorColor(2),
      cursor: { lineNumber: 12, column: 25 },
      lastActive: Date.now() - 30000,
      isTyping: true,
    },
  ];

  const mockSession: CollaborationSession = {
    id: 'mock-session',
    name: 'Demo Collaboration',
    ownerId: mockMyInfo.id,
    ownerName: mockMyInfo.name,
    createdAt: Date.now(),
    collaborators: mockCollaborators,
    fileId: 'file-1',
    fileName: 'script.lua',
    isPublic: true,
    maxCollaborators: 10,
  };

  useCollaborationStore.setState({
    connectionState: 'connected',
    currentSession: mockSession,
    collaborators: mockCollaborators,
    myInfo: mockMyInfo,
    myPermission: 'owner',
    chatMessages: [
      {
        id: '1',
        senderId: 'mock-user-2',
        senderName: 'Alice',
        senderColor: getCollaboratorColor(1),
        content: 'Hey, I just pushed some changes to the combat system!',
        timestamp: Date.now() - 120000,
      },
      {
        id: '2',
        senderId: 'mock-user-3',
        senderName: 'Bob',
        senderColor: getCollaboratorColor(2),
        content: 'Nice! Let me take a look at the damage calculation.',
        timestamp: Date.now() - 60000,
      },
    ],
  });
}