import type { ILivechatDepartment, ILivechatInquiryRecord, IOmnichannelAgent, Serialized } from '@rocket.chat/core-typings';

import { useLivechatInquiryStore } from '../../../../../client/hooks/useLivechatInquiryStore';
import { queryClient } from '../../../../../client/lib/queryClient';
import { roomsQueryKeys } from '../../../../../client/lib/queryKeys';
import { settings } from '../../../../../client/lib/settings';
import { dispatchToastMessage } from '../../../../../client/lib/toast';
import { mapMessageFromApi } from '../../../../../client/lib/utils/mapMessageFromApi';
import { sdk } from '../../../../utils/client/lib/SDKClient';

const departments = new Set();

const events = {
	added: async (inquiry: ILivechatInquiryRecord) => {
		if (!departments.has(inquiry.department)) {
			return;
		}

		useLivechatInquiryStore.getState().add({ ...inquiry, alert: true });
		await invalidateRoomQueries(inquiry.rid);
	},
	changed: async (inquiry: ILivechatInquiryRecord) => {
		if (inquiry.status !== 'queued' || (inquiry.department && !departments.has(inquiry.department))) {
			return removeInquiry(inquiry);
		}

		useLivechatInquiryStore.getState().merge({ ...inquiry, alert: true });
		await invalidateRoomQueries(inquiry.rid);
	},
	removed: (inquiry: ILivechatInquiryRecord) => removeInquiry(inquiry),
};

type InquiryEventType = keyof typeof events;
type InquiryEventArgs = { type: InquiryEventType } & Omit<ILivechatInquiryRecord, 'type'>;

const processInquiryEvent = async (args: unknown): Promise<void> => {
	if (!args || typeof args !== 'object' || !('type' in args)) {
		return;
	}

	const { type, ...inquiry } = args as InquiryEventArgs;
	if (type in events) {
		await events[type](inquiry as ILivechatInquiryRecord);
	}
};

const invalidateRoomQueries = async (rid: string) => {
	await Promise.all([
		queryClient.invalidateQueries({ queryKey: ['rooms', { reference: rid, type: 'l' }] }),
		queryClient.invalidateQueries({ queryKey: roomsQueryKeys.room(rid) }),
		queryClient.invalidateQueries({ queryKey: roomsQueryKeys.info(rid) }),
	]);
};

const removeInquiry = async (inquiry: ILivechatInquiryRecord) => {
	useLivechatInquiryStore.getState().discard(inquiry._id);
	return queryClient.invalidateQueries({ queryKey: ['rooms', { reference: inquiry.rid, type: 'l' }] });
};

const getInquiriesFromAPI = async () => {
	const count = settings.peek('Livechat_guest_pool_max_number_incoming_livechats_displayed') ?? 0;
	const { inquiries } = await sdk.rest.get('/v1/livechat/inquiries.queuedForUser', { count });
	return inquiries;
};

const removeListenerOfDepartment = (departmentId: ILivechatDepartment['_id']) => {
	sdk.stop('livechat-inquiry-queue-observer', `department/${departmentId}`);
	departments.delete(departmentId);
};

const appendListenerToDepartment = (departmentId: ILivechatDepartment['_id']) => {
	departments.add(departmentId);
	sdk.stream('livechat-inquiry-queue-observer', [`department/${departmentId}`], async (args) => {
		await processInquiryEvent(args);
	});
	return () => removeListenerOfDepartment(departmentId);
};
const addListenerForeachDepartment = (departments: ILivechatDepartment['_id'][] = []) => {
	const cleanupFunctions = departments.map((department) => appendListenerToDepartment(department));
	return () => cleanupFunctions.forEach((cleanup) => cleanup());
};

const updateInquiries = async (inquiries: Serialized<ILivechatInquiryRecord>[] = []) =>
	inquiries.forEach((inquiry) => {
		useLivechatInquiryStore.getState().merge({
			...inquiry,
			alert: true,
			ts: new Date(inquiry.ts),
			v: { ...inquiry.v, lastMessageTs: inquiry.v.lastMessageTs ? new Date(inquiry.v.lastMessageTs) : undefined },
			estimatedInactivityCloseTimeAt: inquiry.estimatedInactivityCloseTimeAt ? new Date(inquiry.estimatedInactivityCloseTimeAt) : undefined,
			lockedAt: inquiry.lockedAt ? new Date(inquiry.lockedAt) : undefined,
			lastMessage: inquiry.lastMessage ? mapMessageFromApi(inquiry.lastMessage) : undefined,
			_updatedAt: new Date(inquiry._updatedAt),
		});
	});

const getAgentsDepartments = async (userId: IOmnichannelAgent['_id']) => {
	const { departments } = await sdk.rest.get(`/v1/livechat/agents/${userId}/departments`, { enabledDepartmentsOnly: 'true' });
	return departments;
};

const removeGlobalListener = () => sdk.stop('livechat-inquiry-queue-observer', 'public');

const addGlobalListener = () => {
	sdk.stream('livechat-inquiry-queue-observer', ['public'], async (args) => {
		await processInquiryEvent(args);
	});
	return removeGlobalListener;
};

const removeAgentListener = (userId: IOmnichannelAgent['_id']) => {
	sdk.stop('livechat-inquiry-queue-observer', `agent/${userId}`);
};

const addAgentListener = (userId: IOmnichannelAgent['_id']) => {
	sdk.stream('livechat-inquiry-queue-observer', [`agent/${userId}`], async (args) => {
		await processInquiryEvent(args);
	});
	return () => removeAgentListener(userId);
};

const subscribe = async (userId: IOmnichannelAgent['_id']) => {
	try {
		const { config } = await sdk.rest.get('/v1/livechat/config/routing');
		if (config?.autoAssignAgent) {
			return;
		}

		const agentDepartments = (await getAgentsDepartments(userId)).map((department) => department.departmentId);

		// Register to agent-specific queue, all depts + public queue to match the inquiry list returned by backend
		const cleanAgentListener = addAgentListener(userId);
		const cleanDepartmentListeners = addListenerForeachDepartment(agentDepartments);
		const globalCleanup = addGlobalListener();

		const computation = Tracker.autorun(async () => {
			const inquiriesFromAPI = await getInquiriesFromAPI();

			await updateInquiries(inquiriesFromAPI);
		});

		return () => {
			useLivechatInquiryStore.getState().discardAll();
			removeGlobalListener();
			cleanAgentListener?.();
			cleanDepartmentListeners?.();
			globalCleanup?.();
			departments.clear();
			computation.stop();
		};
	} catch (error) {
		dispatchToastMessage({ type: 'error', message: error });
		throw error;
	}
};

export const initializeLivechatInquiryStream = (() => {
	let cleanUp: (() => void) | undefined;

	return async (...args: Parameters<typeof subscribe>) => {
		cleanUp?.();
		cleanUp = await subscribe(...args);
	};
})();