import { api } from '@rocket.chat/core-services';
import type {
	ILivechatDepartment,
	IOmnichannelRoom,
	IOmnichannelServiceLevelAgreements,
	InquiryWithAgentInfo,
} from '@rocket.chat/core-typings';
import type { Updater } from '@rocket.chat/models';
import {
	Rooms as RoomRaw,
	LivechatRooms,
	LivechatDepartment as LivechatDepartmentRaw,
	LivechatCustomField,
	LivechatInquiry,
	Users,
} from '@rocket.chat/models';
import moment from 'moment';
import type { Document } from 'mongodb';

import { OmnichannelQueueInactivityMonitor } from './QueueInactivityMonitor';
import { updateInquiryQueueSla } from './SlaHelper';
import { memoizeDebounce } from './debounceByParams';
import { logger } from './logger';
import { getOmniChatSortQuery } from '../../../../app/livechat/lib/inquiries';
import { callbacks } from '../../../../server/lib/callbacks';
import { getInquirySortMechanismSetting } from '../../../../server/lib/omnichannel/settings';
import { settings } from '../../../../server/settings';

type QueueInfo = {
	message: {
		text: any;
		user: {
			_id: string;
			username: string;
		};
	};
	statistics: Document;
	numberMostRecentChats: number;
};

export const isAgentWithinChatLimits = async ({
	agentId,
	departmentId,
	totalChats,
	departmentChats,
}: {
	agentId: string;
	departmentId?: string;
	totalChats: number;
	departmentChats: number;
}): Promise<boolean> => {
	let agentLimit = 0;
	let globalLimit = 0;

	const user = await Users.getAgentInfo(agentId, settings.get('Livechat_show_agent_info'));
	const rawAgentLimit = user?.livechat?.maxNumberSimultaneousChat;

	if (rawAgentLimit !== undefined && rawAgentLimit !== null) {
		const numericAgentLimit = Number(rawAgentLimit);
		if (numericAgentLimit > 0) {
			agentLimit = numericAgentLimit;
		}
	}

	if (agentLimit === 0) {
		const settingLimit = settings.get<number>('Livechat_maximum_chats_per_agent');
		if (settingLimit > 0) {
			globalLimit = settingLimit;
		}
	}

	if (departmentId) {
		const department = await LivechatDepartmentRaw.findOneById<Pick<ILivechatDepartment, 'maxNumberSimultaneousChat'>>(departmentId, {
			projection: { maxNumberSimultaneousChat: 1 },
		});
		let departmentLimit = 0;

		if (department?.maxNumberSimultaneousChat !== undefined && department.maxNumberSimultaneousChat !== null) {
			const numericDeptLimit = Number(department.maxNumberSimultaneousChat);
			if (numericDeptLimit > 0) {
				departmentLimit = numericDeptLimit;
			}
		}

		if (departmentLimit > 0) {
			if (agentLimit > 0) {
				logger.debug({
					msg: 'Applying chat limits',
					departmentId,
					agentId,
					limits: ['department', 'agent'],
					totalChats,
					departmentChats,
					agentLimit,
					departmentLimit,
				});
				return departmentChats < departmentLimit && totalChats < agentLimit;
			}

			if (globalLimit > 0) {
				logger.debug({
					msg: 'Applying chat limits',
					departmentId,
					agentId,
					limits: ['department', 'global'],
					totalChats,
					departmentChats,
					globalLimit,
					departmentLimit,
				});
				return departmentChats < departmentLimit && totalChats < globalLimit;
			}

			logger.debug({
				msg: 'Applying chat limits',
				departmentId,
				agentId,
				limits: ['department'],
				totalChats,
				departmentChats,
				departmentLimit,
			});
			return departmentChats < departmentLimit;
		}
	}

	if (agentLimit > 0) {
		logger.debug({
			msg: 'Applying chat limits',
			departmentId,
			agentId,
			limits: ['agent'],
			totalChats,
			agentLimit,
		});
		return totalChats < agentLimit;
	}

	if (globalLimit > 0) {
		logger.debug({
			msg: 'Applying chat limits',
			departmentId,
			agentId,
			limits: ['global'],
			totalChats,
			globalLimit,
		});
		return totalChats < globalLimit;
	}

	logger.debug({ msg: 'No applicable limit found for user', agentId });
	return true;
};

const getWaitingQueueMessage = async (departmentId?: string) => {
	const department = departmentId ? await LivechatDepartmentRaw.findOneById(departmentId) : null;
	if (department?.waitingQueueMessage) {
		return department.waitingQueueMessage;
	}

	return settings.get<string>('Livechat_waiting_queue_message');
};

const getQueueInfo = async (department?: string) => {
	const numberMostRecentChats = settings.get<number>('Livechat_number_most_recent_chats_estimate_wait_time');
	const statistics = await RoomRaw.getMostRecentAverageChatDurationTime(numberMostRecentChats, department);
	const text = await getWaitingQueueMessage(department);
	const message = {
		text,
		user: { _id: 'rocket.cat', username: 'rocket.cat' },
	};
	return { message, statistics, numberMostRecentChats };
};

const getSpotEstimatedWaitTime = (spot: number, maxNumberSimultaneousChat: number, avgChatDuration: number) => {
	if (!maxNumberSimultaneousChat || !avgChatDuration) {
		return;
	}
	// X = spot
	// N = maxNumberSimultaneousChat
	// Estimated Wait Time = ([(N-1)/X]+1) *Average Chat Time of Most Recent X(Default = 100) Chats
	return ((spot - 1) / maxNumberSimultaneousChat + 1) * avgChatDuration;
};

const normalizeQueueInfo = async ({
	position,
	queueInfo,
	department,
}: {
	position: number;
	department?: string;
	queueInfo?: QueueInfo;
}) => {
	if (!queueInfo) {
		queueInfo = await getQueueInfo(department);
	}

	const { message, numberMostRecentChats, statistics: { avgChatDuration } = {} } = queueInfo;
	const spot = position + 1;
	const estimatedWaitTimeSeconds = getSpotEstimatedWaitTime(spot, numberMostRecentChats, avgChatDuration);
	return { spot, message, estimatedWaitTimeSeconds };
};

export const dispatchInquiryPosition = async (inquiry: Omit<InquiryWithAgentInfo, 'v'>, queueInfo?: QueueInfo) => {
	const { position, department } = inquiry;
	// Avoid broadcasting if no position was determined
	if (position === undefined) {
		return;
	}
	const data = await normalizeQueueInfo({ position, queueInfo, department });
	return setTimeout(() => {
		void api.broadcast('omnichannel.room', inquiry.rid, {
			type: 'queueData',
			data,
		});
	}, 1000);
};

const dispatchWaitingQueueStatus = async (department?: string) => {
	if (!settings.get('Livechat_waiting_queue') && !settings.get('Omnichannel_calculate_dispatch_service_queue_statistics')) {
		return;
	}

	const queue = await LivechatInquiry.getCurrentSortedQueueAsync({
		department,
		queueSortBy: getOmniChatSortQuery(getInquirySortMechanismSetting()),
	});

	if (!queue.length) {
		return;
	}

	const queueInfo = await getQueueInfo(department);
	queue.forEach((inquiry) => {
		void dispatchInquiryPosition(inquiry, queueInfo);
	});
};

// When dealing with lots of queued items we need to make sure to notify their position
// but we don't need to notify _each_ change that takes place, just their final position
export const debouncedDispatchWaitingQueueStatus = memoizeDebounce(dispatchWaitingQueueStatus, 1200);

export const setPredictedVisitorAbandonmentTime = async (
	room: Pick<IOmnichannelRoom, '_id' | 'responseBy' | 'departmentId'>,
	roomUpdater?: Updater<IOmnichannelRoom>,
) => {
	if (
		!room.responseBy?.firstResponseTs ||
		!settings.get('Livechat_abandoned_rooms_action') ||
		settings.get('Livechat_abandoned_rooms_action') === 'none'
	) {
		return;
	}

	let secondsToAdd = settings.get<number>('Livechat_visitor_inactivity_timeout');

	const department = room.departmentId ? await LivechatDepartmentRaw.findOneById(room.departmentId) : null;
	if (department?.visitorInactivityTimeoutInSeconds) {
		secondsToAdd = department.visitorInactivityTimeoutInSeconds;
	}

	if (secondsToAdd <= 0) {
		return;
	}

	const willBeAbandonedAt = moment(room.responseBy.firstResponseTs).add(Number(secondsToAdd), 'seconds').toDate();
	if (roomUpdater) {
		await LivechatRooms.getPredictedVisitorAbandonmentByRoomIdUpdateQuery(willBeAbandonedAt, roomUpdater);
	} else {
		await LivechatRooms.setPredictedVisitorAbandonmentByRoomId(room._id, willBeAbandonedAt);
	}
};

export const updatePredictedVisitorAbandonment = async () => {
	if (!settings.get('Livechat_abandoned_rooms_action') || settings.get('Livechat_abandoned_rooms_action') === 'none') {
		await LivechatRooms.unsetAllPredictedVisitorAbandonment();
	} else {
		// Eng day: use a promise queue to update the predicted visitor abandonment time instead of all at once
		const extraQuery = await callbacks.run('livechat.applyRoomRestrictions', {});
		const promisesArray: Promise<void>[] = [];
		await LivechatRooms.findOpen(extraQuery).forEach((room) => {
			promisesArray.push(setPredictedVisitorAbandonmentTime(room));
		});

		await Promise.all(promisesArray);
	}
};

export const updateQueueInactivityTimeout = async () => {
	const queueTimeout = settings.get<number>('Livechat_max_queue_wait_time');
	if (queueTimeout <= 0) {
		await OmnichannelQueueInactivityMonitor.stop();
		return;
	}

	await LivechatInquiry.getQueuedInquiries({ projection: { _updatedAt: 1 } }).forEach((inq) => {
		const aggregatedDate = moment(inq._updatedAt).add(queueTimeout, 'minutes');
		try {
			void OmnichannelQueueInactivityMonitor.scheduleInquiry(inq._id, new Date(aggregatedDate.format()));
		} catch (e) {
			// this will usually happen if other instance attempts to re-create a job
			logger.error({ err: e });
		}
	});
};

export const updateSLAInquiries = async (
	executedBy: string,
	sla?: Pick<IOmnichannelServiceLevelAgreements, '_id' | 'dueTimeInMinutes'>,
) => {
	if (!sla) {
		return;
	}

	const { _id: slaId } = sla;
	const promises: Promise<void>[] = [];
	const extraQuery = await callbacks.run('livechat.applyRoomRestrictions', {}, { userId: executedBy });
	await LivechatRooms.findOpenBySlaId(slaId, {}, extraQuery).forEach((room) => {
		promises.push(updateInquiryQueueSla(room._id, sla));
	});
	await Promise.allSettled(promises);
};

export const getLivechatCustomFields = async () => {
	const customFields = await LivechatCustomField.find({
		visibility: 'visible',
		scope: 'visitor',
		public: true,
	}).toArray();
	return customFields.map(({ _id, label, regexp, required = false, type, defaultValue = null, options }) => ({
		_id,
		label,
		regexp,
		required,
		type,
		defaultValue,
		...(options && options !== '' && { options: options.split(',') }),
	}));
};

export const getLivechatQueueInfo = async (room?: IOmnichannelRoom) => {
	if (!room) {
		return null;
	}

	if (!settings.get('Livechat_waiting_queue')) {
		return null;
	}

	if (!settings.get('Omnichannel_calculate_dispatch_service_queue_statistics')) {
		return null;
	}

	const { _id: rid, departmentId: department } = room;
	const inquiry = await LivechatInquiry.findOneByRoomId(rid, { projection: { _id: 1, status: 1 } });
	if (!inquiry) {
		return null;
	}

	const { _id, status } = inquiry;
	if (status !== 'queued') {
		return null;
	}

	const [inq] = await LivechatInquiry.getCurrentSortedQueueAsync({
		inquiryId: _id,
		department,
		queueSortBy: getOmniChatSortQuery(getInquirySortMechanismSetting()),
	});

	if (!inq) {
		return null;
	}

	return normalizeQueueInfo(inq);
};