import {default as xdr} from "./generated/digitalbits-xdr_generated";
import {Keypair} from "./keypair";
import {StrKey} from "./strkey";
import clone from 'lodash/clone';
import padEnd from 'lodash/padEnd';
import trimEnd from 'lodash/trimEnd';
/**
* Asset class represents an asset, either the native asset (`XLM`)
* or an asset code / issuer account ID pair.
*
* An asset code describes an asset code and issuer pair. In the case of the native
* asset XLM, the issuer will be null.
*
* @constructor
* @param {string} code - The asset code.
* @param {string} issuer - The account ID of the issuer.
*/
export class Asset {
constructor(code, issuer) {
if (!/^[a-zA-Z0-9]{1,12}$/.test(code)) {
throw new Error("Asset code is invalid (maximum alphanumeric, 12 characters at max)");
}
if (String(code).toLowerCase() !== "xlm" && !issuer) {
throw new Error("Issuer cannot be null");
}
if (issuer && !StrKey.isValidEd25519PublicKey(issuer)) {
throw new Error("Issuer is invalid");
}
this.code = code;
this.issuer = issuer;
}
/**
* Returns an asset object for the native asset.
* @Return {Asset}
*/
static native() {
return new Asset("XLM");
}
/**
* Returns an asset object from its XDR object representation.
* @param {xdr.Asset} assetXdr - The asset xdr object.
* @returns {Asset}
*/
static fromOperation(assetXdr) {
let anum, code, issuer;
switch(assetXdr.switch()) {
case xdr.AssetType.assetTypeNative():
return this.native();
case xdr.AssetType.assetTypeCreditAlphanum4():
anum = assetXdr.alphaNum4();
issuer = StrKey.encodeEd25519PublicKey(anum.issuer().ed25519());
code = trimEnd(anum.assetCode(), '\0');
return new this(code, issuer);
case xdr.AssetType.assetTypeCreditAlphanum12():
anum = assetXdr.alphaNum12();
issuer = StrKey.encodeEd25519PublicKey(anum.issuer().ed25519());
code = trimEnd(anum.assetCode(), '\0');
return new this(code, issuer);
default:
throw new Error(`Invalid asset type: ${assetXdr.switch().name}`);
}
}
/**
* Returns the xdr object for this asset.
* @returns {xdr.Asset}
*/
toXDRObject() {
if (this.isNative()) {
return xdr.Asset.assetTypeNative();
} else {
let xdrType, xdrTypeString;
if (this.code.length <= 4) {
xdrType = xdr.AssetAlphaNum4;
xdrTypeString = 'assetTypeCreditAlphanum4';
} else {
xdrType = xdr.AssetAlphaNum12;
xdrTypeString = 'assetTypeCreditAlphanum12';
}
// pad code with null bytes if necessary
let padLength = this.code.length <= 4 ? 4 : 12;
let paddedCode = padEnd(this.code, padLength, '\0');
var assetType = new xdrType({
assetCode: paddedCode,
issuer: Keypair.fromPublicKey(this.issuer).xdrAccountId()
});
return new xdr.Asset(xdrTypeString, assetType);
}
}
/**
* Return the asset code
* @returns {string}
*/
getCode() {
return clone(this.code);
}
/**
* Return the asset issuer
* @returns {string}
*/
getIssuer() {
return clone(this.issuer);
}
/**
* Return the asset type. Can be one of following types:
*
* * `native`
* * `credit_alphanum4`
* * `credit_alphanum12`
*
* @see [Assets concept](https://developer.digitalbits.io/learn/concepts/assets.html)
* @returns {string}
*/
getAssetType() {
if (this.isNative()) {
return 'native';
} else {
if (this.code.length >= 1 && this.code.length <= 4) {
return "credit_alphanum4";
} else if (this.code.length >= 5 && this.code.length <= 12) {
return "credit_alphanum12";
}
}
}
/**
* Returns true if this asset object is the native asset.
* @returns {boolean}
*/
isNative() {
return !this.issuer;
}
/**
* Returns true if this asset equals the given asset.
* @param {Asset} asset Asset to compare
* @returns {boolean}
*/
equals(asset) {
return this.code == asset.getCode() && this.issuer == asset.getIssuer();
}
}