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

export default class AtomicReadFile extends BacnetAckService {
	public static encode(
		buffer: EncodeBuffer,
		isStream: boolean,
		objectId: BACNetObjectID,
		position: number,
		count: number,
	): void {
		baAsn1.encodeApplicationObjectId(
			buffer,
			objectId.type,
			objectId.instance,
		)
		if (isStream) {
			baAsn1.encodeOpeningTag(buffer, 0)
			baAsn1.encodeApplicationSigned(buffer, position)
			baAsn1.encodeApplicationUnsigned(buffer, count)
			baAsn1.encodeClosingTag(buffer, 0)
		} else {
			baAsn1.encodeOpeningTag(buffer, 1)
			baAsn1.encodeApplicationSigned(buffer, position)
			baAsn1.encodeApplicationUnsigned(buffer, count)
			baAsn1.encodeClosingTag(buffer, 1)
		}
	}

	public static decode(buffer: Buffer, offset: number) {
		let len = 0
		let result
		let decodedValue
		let isStream = true
		let objectId: BACNetObjectID = { type: 0, instance: 0 } // Properly initialized with type
		let position = -1
		let count = 0
		result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
		len += result.len
		if (result.tagNumber !== ApplicationTag.OBJECTIDENTIFIER)
			return undefined
		decodedValue = baAsn1.decodeObjectId(buffer, offset + len)
		len += decodedValue.len
		objectId = {
			type: decodedValue.objectType,
			instance: decodedValue.instance,
		}
		if (baAsn1.decodeIsOpeningTagNumber(buffer, offset + len, 0)) {
			isStream = true
			len++
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
			if (result.tagNumber !== ApplicationTag.SIGNED_INTEGER)
				return undefined
			decodedValue = baAsn1.decodeSigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			position = decodedValue.value
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
			if (result.tagNumber !== ApplicationTag.UNSIGNED_INTEGER)
				return undefined
			decodedValue = baAsn1.decodeUnsigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			count = decodedValue.value
			if (!baAsn1.decodeIsClosingTagNumber(buffer, offset + len, 0))
				return undefined
			len++
		} else if (baAsn1.decodeIsOpeningTagNumber(buffer, offset + len, 1)) {
			isStream = false
			len++
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
			if (result.tagNumber !== ApplicationTag.SIGNED_INTEGER)
				return undefined
			decodedValue = baAsn1.decodeSigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			position = decodedValue.value
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
			if (result.tagNumber !== ApplicationTag.UNSIGNED_INTEGER)
				return undefined
			decodedValue = baAsn1.decodeUnsigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			count = decodedValue.value
			if (!baAsn1.decodeIsClosingTagNumber(buffer, offset + len, 1))
				return undefined
			len++
		} else {
			return undefined
		}
		return {
			len,
			isStream,
			objectId,
			position,
			count,
		}
	}

	public static encodeAcknowledge(
		buffer: EncodeBuffer,
		isStream: boolean,
		endOfFile: boolean,
		position: number,
		blockCount: number,
		blocks: number[][],
		counts: number[],
	): void {
		baAsn1.encodeApplicationBoolean(buffer, endOfFile)
		if (isStream) {
			baAsn1.encodeOpeningTag(buffer, 0)
			baAsn1.encodeApplicationSigned(buffer, position)
			baAsn1.encodeApplicationOctetString(buffer, blocks[0], 0, counts[0])
			baAsn1.encodeClosingTag(buffer, 0)
		} else {
			baAsn1.encodeOpeningTag(buffer, 1)
			baAsn1.encodeApplicationSigned(buffer, position)
			baAsn1.encodeApplicationUnsigned(buffer, blockCount)
			for (let i = 0; i < blockCount; i++) {
				baAsn1.encodeApplicationOctetString(
					buffer,
					blocks[i],
					0,
					counts[i],
				)
			}
			baAsn1.encodeClosingTag(buffer, 1)
		}
	}

	public static decodeAcknowledge(buffer: Buffer, offset: number) {
		let len = 0
		let result: any
		let decodedValue: any
		let isStream = false
		let position = 0
		let targetBuffer: Buffer

		result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
		len += result.len
		if (result.tagNumber !== ApplicationTag.BOOLEAN) return undefined
		const endOfFile = result.value > 0

		if (baAsn1.decodeIsOpeningTagNumber(buffer, offset + len, 0)) {
			isStream = true
			len++
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
			if (result.tagNumber !== ApplicationTag.SIGNED_INTEGER)
				return undefined
			decodedValue = baAsn1.decodeSigned(
				buffer,
				offset + len,
				result.value,
			)
			len += decodedValue.len
			position = decodedValue.value
			result = baAsn1.decodeTagNumberAndValue(buffer, offset + len)
			len += result.len
			if (result.tagNumber !== ApplicationTag.OCTET_STRING)
				return undefined
			targetBuffer = buffer.slice(
				offset + len,
				offset + len + result.value,
			)
			len += result.value
			if (!baAsn1.decodeIsClosingTagNumber(buffer, offset + len, 0))
				return undefined
			len++
		} else if (baAsn1.decodeIsOpeningTagNumber(buffer, offset + len, 1)) {
			isStream = false
			throw new Error('NotImplemented')
		} else {
			return undefined
		}

		return {
			len,
			endOfFile,
			isStream,
			position,
			buffer: targetBuffer,
		}
	}
}