import React, { useEffect, useState } from 'react';
import { useChatStore } from '../store/chatStore';
import { useAuthStore } from '@/stores/auth';
import { apiClient } from '@/services/api/client';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { cn } from '@/lib/utils';
import { Loader2, Plus, Trash2, LogOut } from 'lucide-react';
import { CreateRoomDialog } from './CreateRoomDialog';
import { useToast } from '@/hooks/useToast';
import { Button } from '@/components/ui/button';
import {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuTrigger,
} from '@/components/ui/dropdown-menu';
import { MoreVertical } from 'lucide-react';
import { ConfirmationDialog } from '@/components/ui/confirmation-dialog';

// FE-PAGE-005: Complete Chat page implementation - Room Management

interface ConversationItemProps {
  conversation: { id: string; name: string; type: string };
  onSelect: (id: string) => void;
  isSelected: boolean;
}

const ConversationItem: React.FC<ConversationItemProps> = ({
  conversation,
  onSelect,
  isSelected,
}) => {
  const { user } = useAuthStore();
  const queryClient = useQueryClient();
  const toast = useToast();
  const { setCurrentConversation } = useChatStore();
  const [showLeaveDialog, setShowLeaveDialog] = useState(false);
  const [showDeleteDialog, setShowDeleteDialog] = useState(false);

  const leaveRoomMutation = useMutation({
    mutationFn: async (roomId: string) => {
      await apiClient.delete(`/conversations/${roomId}/participants/${user?.id}`);
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['chatConversations', user?.id] });
      toast.success('Left room successfully');
      setCurrentConversation(null);
      setShowLeaveDialog(false);
    },
    onError: (error: any) => {
      toast.error(error.response?.data?.error || 'Failed to leave room');
    },
  });

  const deleteRoomMutation = useMutation({
    mutationFn: async (roomId: string) => {
      await apiClient.delete(`/conversations/${roomId}`);
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['chatConversations', user?.id] });
      toast.success('Room deleted successfully');
      setCurrentConversation(null);
      setShowDeleteDialog(false);
    },
    onError: (error: any) => {
      toast.error(error.response?.data?.error || 'Failed to delete room');
    },
  });

  const handleLeave = (e: React.MouseEvent) => {
    e.stopPropagation();
    setShowLeaveDialog(true);
  };

  const handleDelete = (e: React.MouseEvent) => {
    e.stopPropagation();
    setShowDeleteDialog(true);
  };

  const confirmLeave = () => {
    leaveRoomMutation.mutate(conversation.id);
  };

  const confirmDelete = () => {
    deleteRoomMutation.mutate(conversation.id);
  };

  return (
    <>
      <div
        onClick={() => onSelect(conversation.id)}
        className={cn(
          'flex items-center justify-between p-3 rounded-lg cursor-pointer transition-colors group',
          isSelected ? 'bg-blue-100 text-blue-800' : 'hover:bg-gray-100',
        )}
      >
        <span className="font-medium flex-1 truncate">
          {conversation.name || `Conversation ${conversation.id.substring(0, 8)}`}
        </span>
        <DropdownMenu>
          <DropdownMenuTrigger asChild onClick={(e) => e.stopPropagation()}>
            <Button
              variant="ghost"
              size="sm"
              className="h-6 w-6 p-0 opacity-0 group-hover:opacity-100"
            >
              <MoreVertical className="h-4 w-4" />
            </Button>
          </DropdownMenuTrigger>
          <DropdownMenuContent align="end">
            <DropdownMenuItem onClick={handleLeave}>
              <LogOut className="mr-2 h-4 w-4" />
              Leave Room
            </DropdownMenuItem>
            {conversation.type !== 'direct' && (
              <DropdownMenuItem onClick={handleDelete} className="text-destructive">
                <Trash2 className="mr-2 h-4 w-4" />
                Delete Room
              </DropdownMenuItem>
            )}
          </DropdownMenuContent>
        </DropdownMenu>
      </div>
      <ConfirmationDialog
        open={showLeaveDialog}
        onClose={() => setShowLeaveDialog(false)}
        onConfirm={confirmLeave}
        title="Leave Room"
        description="Are you sure you want to leave this room? You will no longer receive messages from this conversation."
        confirmLabel="Leave"
        cancelLabel="Cancel"
        variant="default"
        isLoading={leaveRoomMutation.isPending}
      />
      <ConfirmationDialog
        open={showDeleteDialog}
        onClose={() => setShowDeleteDialog(false)}
        onConfirm={confirmDelete}
        title="Delete Room"
        description="Are you sure you want to delete this room? This action cannot be undone. All messages and participants will be removed."
        confirmLabel="Delete"
        cancelLabel="Cancel"
        variant="destructive"
        isLoading={deleteRoomMutation.isPending}
      />
    </>
  );
};

export const ChatSidebar: React.FC = () => {
  const { user } = useAuthStore();
  const userId = user?.id;
  const {
    conversations,
    currentConversationId,
    setCurrentConversation,
    addConversation,
  } = useChatStore();
  const [isCreateDialogOpen, setIsCreateDialogOpen] = useState(false);

  // Fetch conversations from backend
  const { data, isLoading, error } = useQuery({
    queryKey: ['chatConversations', userId],
    queryFn: async () => {
      if (!userId) return [];
      const response = await apiClient.get('/conversations');
      return response.data.conversations;
    },
    enabled: !!userId,
  });

  useEffect(() => {
    if (data) {
      data.forEach((conv: any) =>
        addConversation({
          id: conv.id,
          name: conv.name,
          type: conv.type,
          participants: conv.participants,
          unread_count: 0, // Default for now
        }),
      );
    }
  }, [data, addConversation]);

  if (isLoading) {
    return (
      <div className="w-64 border-r bg-gray-50 flex items-center justify-center">
        <Loader2 className="animate-spin text-blue-500" size={24} />
      </div>
    );
  }

  if (error) {
    return (
      <div className="w-64 border-r bg-gray-50 flex items-center justify-center text-red-500 p-4">
        Erreur:{' '}
        {(error as any).message || 'Impossible de charger les conversations'}
      </div>
    );
  }

  return (
    <div className="w-64 border-r bg-gray-50 flex flex-col">
      <div className="p-4 border-b">
        <h2 className="text-xl font-bold">Conversations</h2>
      </div>
      <div className="flex-1 overflow-y-auto p-2">
        {conversations.length === 0 ? (
          <div className="text-gray-500 text-sm p-2">
            Aucune conversation. Créez-en une !
          </div>
        ) : (
          conversations.map((conv) => (
            <ConversationItem
              key={conv.id}
              conversation={conv}
              onSelect={setCurrentConversation}
              isSelected={conv.id === currentConversationId}
            />
          ))
        )}
      </div>
      <div className="p-4 border-t">
        <Button
          onClick={() => setIsCreateDialogOpen(true)}
          className="w-full"
          variant="default"
        >
          <Plus className="mr-2 h-4 w-4" />
          Nouvelle Conversation
        </Button>
      </div>
      <CreateRoomDialog
        open={isCreateDialogOpen}
        onClose={() => setIsCreateDialogOpen(false)}
      />
    </div>
  );
};
