'use strict';

const { parseXML, childAttr, required } = require('../parser');
const { create, fragment } = require('xmlbuilder2');

const oadrPayloadNs = 'http://www.w3.org/2000/09/xmldsig#';
const oadrNs = 'http://openadr.org/oadr-2.0b/2012/07';
const energyInteropNs = 'http://docs.oasis-open.org/ns/energyinterop/201110';
const energyInteropPayloadsNs =
  'http://docs.oasis-open.org/ns/energyinterop/201110/payloads';

function parseEiResponse(response) {
  const result = {
    code: required(childAttr(response, 'responseCode'), 'responseCode'),
    description: childAttr(response, 'responseDescription'),
  };

  const requestId = childAttr(response, 'requestID');
  if (requestId != null) {
    result.requestId = requestId;
  }

  return result;
}

async function parse(input) {
  const json = await parseXML(input);
  const o =
    json['oadrPayload']['$$']['oadrSignedObject'][0]['$$']['oadrResponse'][0][
      '$$'
    ];

  const { code, description, requestId } = parseEiResponse(
    o['eiResponse'][0]['$$'],
  );

  const result = {
    _type: 'oadrResponse',
    responseCode: code,
    responseDescription: description,
    responseRequestId: requestId,
  };

  if (code < 200 || code >= 300) {
    return result;
  }

  const venId = childAttr(o, 'venID');
  if (venId != null) result.venId = venId;

  return result;
}

function serializeEiResponse(code, description, requestId) {
  const descriptionFrag =
    description != null
      ? fragment()
        .ele(energyInteropNs, 'ei:responseDescription')
        .txt(description)
      : fragment();
  return fragment()
    .ele(energyInteropNs, 'ei:responseCode')
    .txt(code)
    .up()
    .import(descriptionFrag)
    .ele(energyInteropPayloadsNs, 'pyld:requestID')
    .txt(requestId || '')
    .up();
}

function validate(obj) {
  if (!obj.responseCode) {
    throw new Error('Missing responseCode');
  }
}

function serialize(obj) {
  validate(obj);

  const venId =
    obj.venId != null
      ? fragment()
        .ele(energyInteropNs, 'ei:venID')
        .txt(obj.venId)
      : fragment();

  const doc = create({
    namespaceAlias: {
      ns: oadrPayloadNs,
      oadr2b: oadrNs,
      ei: energyInteropNs,
      pyld: energyInteropPayloadsNs,
    },
  })
    .ele('@oadr2b', 'oadr2b:oadrPayload')
    .ele('oadr2b:oadrSignedObject')
    .ele('oadr2b:oadrResponse')
    .att('@ei', 'ei:schemaVersion', '2.0b')
    .ele('@ei', 'ei:eiResponse')
    .import(
      serializeEiResponse(
        obj.responseCode,
        obj.responseDescription,
        obj.responseRequestId,
      ),
    )
    .up()
    .import(venId)
    .doc();
  return doc.end({ headless: true, prettyPrint: false });
}

module.exports = {
  parse,
  serialize,
};