import * as baAsn1 from '../asn1'
import { EncodeBuffer, BACNetObjectID } from '../types'
import { BacnetService } from './AbstractServices'

export default class SubscribeCov extends BacnetService {
	public static encode(
		buffer: EncodeBuffer,
		subscriberProcessId: number,
		monitoredObjectId: BACNetObjectID,
		cancellationRequest: boolean,
		issueConfirmedNotifications = false,
		lifetime = 0,
	) {
		baAsn1.encodeContextUnsigned(buffer, 0, subscriberProcessId)
		baAsn1.encodeContextObjectId(
			buffer,
			1,
			monitoredObjectId.type,
			monitoredObjectId.instance,
		)
		if (!cancellationRequest) {
			baAsn1.encodeContextBoolean(buffer, 2, issueConfirmedNotifications)
			baAsn1.encodeContextUnsigned(buffer, 3, lifetime)
		}
	}

	public static decode(buffer: Buffer, offset: number, apduLen: number) {
		let len = 0
		const value: any = {}
		let result: any
		let decodedValue: any
		if (!baAsn1.decodeIsContextTag(buffer, offset + len, 0))
			return undefined
		result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
		len += result.len
		decodedValue = baAsn1.decodeUnsigned(buffer, offset + len, result.value)
		len += decodedValue.len
		value.subscriberProcessId = decodedValue.value
		if (!baAsn1.decodeIsContextTag(buffer, offset + len, 1))
			return undefined
		result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
		len += result.len
		decodedValue = baAsn1.decodeObjectId(buffer, offset + len)
		len += decodedValue.len
		value.monitoredObjectId = {
			type: decodedValue.objectType,
			instance: decodedValue.instance,
		}
		value.cancellationRequest = true
		if (len < apduLen) {
			value.issueConfirmedNotifications = false
			if (baAsn1.decodeIsContextTag(buffer, offset + len, 2)) {
				value.cancellationRequest = false
				result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
				len += result.len
				value.issueConfirmedNotifications = buffer[offset + len] > 0
				len++
			}
			value.lifetime = 0
			if (baAsn1.decodeIsContextTag(buffer, offset + len, 3)) {
				result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
				len += result.len
				decodedValue = baAsn1.decodeUnsigned(
					buffer,
					offset + len,
					result.value,
				)
				len += decodedValue.len
				value.lifetime = decodedValue.value
			}
		}
		value.len = len
		return value
	}
}