import { and, asc, eq, gt, gte, inArray, isNull, lt, lte, ne } from 'drizzle-orm';
import { db } from '$lib/server/db';
import { bookings, contracts, contractRooms, rooms } from '$lib/server/db/schema';

const rentableContractRoomTypes = ['private_office', 'coworking_desk'] as const;

export type BookingRoomConflict = {
	id: string;
	roomName: string;
	startsAt: string;
	endsAt: string;
};

export type ContractRoomConflict = {
	contractId: string;
	roomId: string;
	roomName: string;
	startDate: string;
	endDate: string;
};

export function bookingIntervalsOverlap(
	startsAt: string,
	endsAt: string,
	existingStartsAt: string,
	existingEndsAt: string
) {
	return startsAt < existingEndsAt && endsAt > existingStartsAt;
}

export function contractPeriodsOverlap(
	startDate: string,
	endDate: string,
	existingStartDate: string,
	existingEndDate: string
) {
	return startDate <= existingEndDate && endDate >= existingStartDate;
}

export async function findBookingRoomConflict({
	organizationId,
	roomId,
	startsAt,
	endsAt,
	status,
	excludingBookingId
}: {
	organizationId: string;
	roomId: string;
	startsAt: string;
	endsAt: string;
	status: string;
	excludingBookingId?: string;
}): Promise<BookingRoomConflict | null> {
	if (status === 'cancelled') return null;

	const baseConditions = [
		eq(bookings.organizationId, organizationId),
		eq(bookings.roomId, roomId),
		isNull(bookings.archivedAt),
		ne(bookings.status, 'cancelled'),
		lt(bookings.startsAt, endsAt),
		gt(bookings.endsAt, startsAt)
	];
	const where = excludingBookingId
		? and(...baseConditions, ne(bookings.id, excludingBookingId))
		: and(...baseConditions);

	const [conflict] = await db
		.select({
			id: bookings.id,
			roomName: rooms.name,
			startsAt: bookings.startsAt,
			endsAt: bookings.endsAt
		})
		.from(bookings)
		.innerJoin(rooms, eq(bookings.roomId, rooms.id))
		.where(where)
		.orderBy(asc(bookings.startsAt))
		.limit(1);

	return conflict ?? null;
}

export async function findBookingContractRoomConflict({
	organizationId,
	roomId,
	startsAt,
	endsAt,
	status
}: {
	organizationId: string;
	roomId: string;
	startsAt: string;
	endsAt: string;
	status: string;
}): Promise<ContractRoomConflict | null> {
	if (status === 'cancelled') return null;

	const startDate = startsAt.slice(0, 10);
	const endDate = endsAt.slice(0, 10);

	const [conflict] = await db
		.select({
			contractId: contracts.id,
			roomId: contractRooms.roomId,
			roomName: rooms.name,
			startDate: contracts.startDate,
			endDate: contracts.endDate
		})
		.from(contractRooms)
		.innerJoin(contracts, eq(contractRooms.contractId, contracts.id))
		.innerJoin(rooms, eq(contractRooms.roomId, rooms.id))
		.where(
			and(
				eq(contracts.organizationId, organizationId),
				eq(contracts.status, 'active'),
				isNull(contracts.archivedAt),
				eq(contractRooms.roomId, roomId),
				eq(rooms.organizationId, organizationId),
				inArray(rooms.type, rentableContractRoomTypes),
				isNull(rooms.archivedAt),
				lte(contracts.startDate, endDate),
				gte(contracts.endDate, startDate)
			)
		)
		.orderBy(asc(contracts.startDate), asc(rooms.name))
		.limit(1);

	return conflict ?? null;
}

export async function findActiveContractRoomConflict({
	organizationId,
	roomIds,
	startDate,
	endDate,
	excludingContractId
}: {
	organizationId: string;
	roomIds: string[];
	startDate: string;
	endDate: string;
	excludingContractId?: string;
}): Promise<ContractRoomConflict | null> {
	const uniqueRoomIds = [...new Set(roomIds)];
	if (uniqueRoomIds.length === 0) return null;

	const baseConditions = [
		eq(contracts.organizationId, organizationId),
		eq(contracts.status, 'active'),
		isNull(contracts.archivedAt),
		inArray(contractRooms.roomId, uniqueRoomIds),
		eq(rooms.organizationId, organizationId),
		inArray(rooms.type, rentableContractRoomTypes),
		isNull(rooms.archivedAt),
		lte(contracts.startDate, endDate),
		gte(contracts.endDate, startDate)
	];
	const where = excludingContractId
		? and(...baseConditions, ne(contracts.id, excludingContractId))
		: and(...baseConditions);

	const [conflict] = await db
		.select({
			contractId: contracts.id,
			roomId: contractRooms.roomId,
			roomName: rooms.name,
			startDate: contracts.startDate,
			endDate: contracts.endDate
		})
		.from(contractRooms)
		.innerJoin(contracts, eq(contractRooms.contractId, contracts.id))
		.innerJoin(rooms, eq(contractRooms.roomId, rooms.id))
		.where(where)
		.orderBy(asc(contracts.startDate), asc(rooms.name))
		.limit(1);

	return conflict ?? null;
}

export function bookingConflictMessage(conflict: BookingRoomConflict) {
	return `${conflict.roomName} is already booked from ${conflict.startsAt} to ${conflict.endsAt}.`;
}

export function contractConflictMessage(conflict: ContractRoomConflict) {
	return `${conflict.roomName} is already assigned to an active contract from ${conflict.startDate} to ${conflict.endDate}.`;
}