import { useStableCallback } from '@rocket.chat/fuselage-hooks';
import { usePermission, useSetting, useTranslation, useUser } from '@rocket.chat/ui-contexts';
import type { DragEvent, ReactNode } from 'react';
import { useMemo, useSyncExternalStore } from 'react';

import { useDropTarget } from './useDropTarget';
import { roomCoordinator } from '../../../../lib/rooms/roomCoordinator';
import { useIsRoomOverMacLimit } from '../../../omnichannel/hooks/useIsRoomOverMacLimit';
import { useChat } from '../../contexts/ChatContext';
import { useRoom, useRoomSubscription } from '../../contexts/RoomContext';

export const useFileUploadDropTarget = (): readonly [
	fileUploadTriggerProps: {
		onDragEnter: (event: DragEvent<Element>) => void;
	},
	fileUploadOverlayProps: {
		visible: boolean;
		onDismiss: () => void;
		enabled: boolean;
		reason?: ReactNode;
	},
] => {
	const room = useRoom();
	const { triggerProps, overlayProps } = useDropTarget();

	const isRoomOverMacLimit = useIsRoomOverMacLimit(room);

	const t = useTranslation();

	const fileUploadEnabled = useSetting('FileUpload_Enabled', true);
	const user = useUser();
	const postReadOnly = usePermission('post-readonly', room._id);
	const fileUploadAllowedForUser = useMemo(
		() => !roomCoordinator.readOnly(room, { username: user?.username }),
		// eslint-disable-next-line react-hooks/exhaustive-deps
		[room, user?.username, postReadOnly],
	);

	const chat = useChat();
	const subscription = useRoomSubscription();

	const isEditing = useSyncExternalStore(
		chat?.composer?.editing.subscribe ?? (() => () => undefined),
		chat?.composer?.editing.get ?? (() => false),
	);

	const onFileDrop = useStableCallback(async (files: File[]) => {
		const { getMimeType } = await import('../../../../../app/utils/lib/mimeTypes');
		const getUniqueFiles = () => {
			const uniqueFiles: File[] = [];
			const st: Set<string> = new Set();
			files.forEach((file) => {
				const key = `${file.name}-${file.size}-${file.lastModified}`;
				if (!st.has(key)) {
					uniqueFiles.push(file);
					st.add(key);
				}
			});
			return uniqueFiles;
		};
		const uniqueFiles = getUniqueFiles();

		const uploads = Array.from(uniqueFiles).map((file) => {
			Object.defineProperty(file, 'type', { value: getMimeType(file.type, file.name) });
			return file;
		});

		chat?.flows.uploadFiles({ files: uploads });
	});

	const allOverlayProps = useMemo(() => {
		if (!fileUploadEnabled || isRoomOverMacLimit) {
			return {
				enabled: false,
				reason: t('FileUpload_Disabled'),
				...overlayProps,
			} as const;
		}

		if (!fileUploadAllowedForUser || !subscription || isEditing) {
			return {
				enabled: false,
				reason: t('error-not-allowed'),
				...overlayProps,
			} as const;
		}

		return {
			enabled: true,
			onFileDrop,
			...overlayProps,
		} as const;
	}, [isEditing, fileUploadAllowedForUser, fileUploadEnabled, isRoomOverMacLimit, onFileDrop, overlayProps, subscription, t]);

	return [triggerProps, allOverlayProps] as const;
};