import * as baAsn1 from '../asn1'
import { ASN1_MAX_INSTANCE } from '../enum'
import { BACNetObjectID, EncodeBuffer } from '../types'
import { BacnetService } from './AbstractServices'

export default class WhoHas extends BacnetService {
	public static encode(
		buffer: EncodeBuffer,
		lowLimit: number,
		highLimit: number,
		objectId: BACNetObjectID,
		objectName?: string,
	) {
		if (
			lowLimit >= 0 &&
			lowLimit <= ASN1_MAX_INSTANCE &&
			highLimit >= 0 &&
			highLimit <= ASN1_MAX_INSTANCE
		) {
			baAsn1.encodeContextUnsigned(buffer, 0, lowLimit)
			baAsn1.encodeContextUnsigned(buffer, 1, highLimit)
		}
		if (objectName && objectName !== '') {
			baAsn1.encodeContextCharacterString(buffer, 3, objectName)
		} else {
			baAsn1.encodeContextObjectId(
				buffer,
				2,
				objectId.type,
				objectId.instance,
			)
		}
	}

	public static decode(buffer: Buffer, offset: number, apduLen: number) {
		let len = 0
		const value: any = {}
		let decodedValue: any
		let result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
		len += result.len
		if (result.tagNumber === 0) {
			decodedValue = baAsn1.decodeUnsigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			if (decodedValue.value <= ASN1_MAX_INSTANCE) {
				value.lowLimit = decodedValue.value
			}
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
		}
		if (result.tagNumber === 1) {
			decodedValue = baAsn1.decodeUnsigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			if (decodedValue.value <= ASN1_MAX_INSTANCE) {
				value.highLimit = decodedValue.value
			}
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
		}
		if (result.tagNumber === 2) {
			decodedValue = baAsn1.decodeObjectId(buffer, offset + len)
			len += decodedValue.len
			value.objectId = {
				type: decodedValue.objectType,
				instance: decodedValue.instance,
			}
		}
		if (result.tagNumber === 3) {
			decodedValue = baAsn1.decodeCharacterString(
				buffer,
				offset + len,
				apduLen - (offset + len),
				result.value,
			)
			len += decodedValue.len
			value.objectName = decodedValue.value
		}
		value.len = len
		return value
	}
}