Files
snort/packages/system/src/links.ts
2023-09-19 09:59:01 +01:00

121 lines
3.3 KiB
TypeScript

import * as utils from "@noble/curves/abstract/utils";
import { bech32 } from "@scure/base";
import { HexKey } from "./nostr";
export const enum NostrPrefix {
PublicKey = "npub",
PrivateKey = "nsec",
Note = "note",
// TLV prefixes
Profile = "nprofile",
Event = "nevent",
Relay = "nrelay",
Address = "naddr",
}
export enum TLVEntryType {
Special = 0,
Relay = 1,
Author = 2,
Kind = 3,
}
export interface TLVEntry {
type: TLVEntryType;
length: number;
value: string | HexKey | number;
}
export function encodeTLV(prefix: NostrPrefix, id: string, relays?: string[], kind?: number, author?: string) {
const enc = new TextEncoder();
const buf = prefix === NostrPrefix.Address ? enc.encode(id) : utils.hexToBytes(id);
const tl0 = [0, buf.length, ...buf];
const tl1 =
relays
?.map(a => {
const data = enc.encode(a);
return [1, data.length, ...data];
})
.flat() ?? [];
const tl2 = author ? [2, 32, ...utils.hexToBytes(author)] : [];
const tl3 = kind ? [3, 4, ...new Uint8Array(new Uint32Array([kind]).buffer).reverse()] : [];
return bech32.encode(prefix, bech32.toWords(new Uint8Array([...tl0, ...tl1, ...tl2, ...tl3])), 1_000);
}
export function encodeTLVEntries(prefix: NostrPrefix, ...entries: Array<TLVEntry>) {
const enc = new TextEncoder();
const buffers: Array<number> = [];
for (const v of entries) {
switch (v.type) {
case TLVEntryType.Special: {
const buf =
prefix === NostrPrefix.Address ? enc.encode(v.value as string) : utils.hexToBytes(v.value as string);
buffers.push(0, buf.length, ...buf);
break;
}
case TLVEntryType.Relay: {
const data = enc.encode(v.value as string);
buffers.push(1, data.length, ...data);
break;
}
case TLVEntryType.Author: {
if ((v.value as string).length !== 64) throw new Error("Author must be 32 bytes");
buffers.push(2, 32, ...utils.hexToBytes(v.value as string));
break;
}
case TLVEntryType.Kind: {
if (typeof v.value !== "number") throw new Error("Kind must be a number");
buffers.push(3, 4, ...new Uint8Array(new Uint32Array([v.value as number]).buffer).reverse());
break;
}
}
}
return bech32.encode(prefix, bech32.toWords(new Uint8Array(buffers)), 1_000);
}
export function decodeTLV(str: string) {
const decoded = bech32.decode(str, 1_000);
const data = bech32.fromWords(decoded.words);
const entries: TLVEntry[] = [];
let x = 0;
while (x < data.length) {
const t = data[x];
const l = data[x + 1];
const v = data.slice(x + 2, x + 2 + l);
entries.push({
type: t,
length: l,
value: decodeTLVEntry(t, decoded.prefix, new Uint8Array(v)),
});
x += 2 + l;
}
return entries;
}
function decodeTLVEntry(type: TLVEntryType, prefix: string, data: Uint8Array) {
switch (type) {
case TLVEntryType.Special: {
if (prefix === NostrPrefix.Address) {
return new TextDecoder("ASCII").decode(data);
} else {
return utils.bytesToHex(data);
}
}
case TLVEntryType.Author: {
return utils.bytesToHex(data);
}
case TLVEntryType.Kind: {
return new Uint32Array(new Uint8Array(data.reverse()).buffer)[0];
}
case TLVEntryType.Relay: {
return new TextDecoder("ASCII").decode(data);
}
}
}