'use strict';

const zlib = require('zlib');
const crypto = require('crypto');
const BN = require('bn.js');

const Crypto = require('../../crypto/Crypto');

const { DOMParser, XMLSerializer } = require('xmldom');
const xpath = require('xpath');

const DEFAULT_IV = Buffer.from(Array(16).fill(0, 0, 15));

const lastChild = (node) => {
	let y = node.lastChild;

	while (y.nodeType !== 1) y = y.previousSibling;

	return y;
};

module.exports = (xml, keys) => ({
	keys,
	doc: new DOMParser().parseFromString(xml, 'text/xml'),

	isSegmented() {
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const node = select('//xmlns:header/xmlns:mutable/xmlns:SegmentNumber', this.doc);

		return !!node.length;
	},

	isLastSegment() {
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const node = select("//xmlns:header/xmlns:mutable/*[@lastSegment='true']", this.doc);

		return !!node.length;
	},

	orderData() {
		const orderDataNode = this.doc.getElementsByTagNameNS('urn:org:ebics:H004', 'OrderData');

		if (!orderDataNode.length) return {};

		const orderData = orderDataNode[0].textContent;
		const decipher = crypto.createDecipheriv('aes-128-cbc', this.transactionKey(), DEFAULT_IV).setAutoPadding(false);
		const data = Buffer.from(decipher.update(orderData, 'base64', 'binary') + decipher.final('binary'), 'binary');

		return zlib.inflateSync(data).toString();
	},

	transactionKey() {
		const keyNodeText = this.doc.getElementsByTagNameNS('urn:org:ebics:H004', 'TransactionKey')[0].textContent;

		return Crypto.privateDecrypt(this.keys.e(), Buffer.from(keyNodeText, 'base64'));
	},

	transactionId() {
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const node = select('//xmlns:header/xmlns:static/xmlns:TransactionID', this.doc);

		return node.length ? node[0].textContent : '';
	},

	orderId() {
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const node = select('//xmlns:header/xmlns:mutable/xmlns:OrderID', this.doc);

		return node.length ? node[0].textContent : '';
	},

	returnCode(where = 'header') {
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const node = where === 'header'
			? select('//xmlns:header/xmlns:mutable/xmlns:ReturnCode', this.doc)
			: select('//xmlns:body/xmlns:ReturnCode', this.doc);

		return node.length ? node[0].textContent : '';
	},

	reportText() {
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const node = select('//xmlns:header/xmlns:mutable/xmlns:ReportText', this.doc);

		return node.length ? node[0].textContent : '';
	},

	bankKeys() {
		const orderData = this.orderData();
		if (!Object.keys(orderData).length) return {};

		const doc = new DOMParser().parseFromString(orderData, 'text/xml');
		const select = xpath.useNamespaces({ xmlns: 'urn:org:ebics:H004' });
		const keyNodes = select('//xmlns:PubKeyValue', doc);
		const bankKeys = {};

		if (!keyNodes.length) return {};

		for (let i = 0; i < keyNodes.length; i++) {
			const type = lastChild(keyNodes[i].parentNode).textContent;
			const modulus = xpath.select("//*[local-name(.)='Modulus']", keyNodes[i])[0].textContent;
			const exponent = xpath.select("//*[local-name(.)='Exponent']", keyNodes[i])[0].textContent;

			const mod = new BN(Buffer.from(modulus, 'base64'), 2).toBuffer();
			const exp = new BN(Buffer.from(exponent, 'base64')).toNumber();

			bankKeys[`bank${type}`] = { mod, exp };
		}

		return bankKeys;
	},

	toXML() {
		return new XMLSerializer().serializeToString(this.doc);
	},
});