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import z from "zod"
const prefixes = {
session: "ses",
message: "msg",
permission: "per",
user: "usr",
part: "prt",
pty: "pty",
} as const
const LENGTH = 26
let lastTimestamp = 0
let counter = 0
type Prefix = keyof typeof prefixes
export namespace Identifier {
export function schema(prefix: Prefix) {
return z.string().startsWith(prefixes[prefix])
}
export function ascending(prefix: Prefix, given?: string) {
return generateID(prefix, false, given)
}
export function descending(prefix: Prefix, given?: string) {
return generateID(prefix, true, given)
}
}
function generateID(prefix: Prefix, descending: boolean, given?: string): string {
if (!given) {
return create(prefix, descending)
}
if (!given.startsWith(prefixes[prefix])) {
throw new Error(`ID ${given} does not start with ${prefixes[prefix]}`)
}
return given
}
function create(prefix: Prefix, descending: boolean, timestamp?: number): string {
const currentTimestamp = timestamp ?? Date.now()
if (currentTimestamp !== lastTimestamp) {
lastTimestamp = currentTimestamp
counter = 0
}
counter += 1
let now = BigInt(currentTimestamp) * BigInt(0x1000) + BigInt(counter)
if (descending) {
now = ~now
}
const timeBytes = new Uint8Array(6)
for (let i = 0; i < 6; i += 1) {
timeBytes[i] = Number((now >> BigInt(40 - 8 * i)) & BigInt(0xff))
}
return prefixes[prefix] + "_" + bytesToHex(timeBytes) + randomBase62(LENGTH - 12)
}
function bytesToHex(bytes: Uint8Array): string {
let hex = ""
for (let i = 0; i < bytes.length; i += 1) {
hex += bytes[i].toString(16).padStart(2, "0")
}
return hex
}
function randomBase62(length: number): string {
const chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
const bytes = getRandomBytes(length)
let result = ""
for (let i = 0; i < length; i += 1) {
result += chars[bytes[i] % 62]
}
return result
}
function getRandomBytes(length: number): Uint8Array {
const bytes = new Uint8Array(length)
const cryptoObj = typeof globalThis !== "undefined" ? globalThis.crypto : undefined
if (cryptoObj && typeof cryptoObj.getRandomValues === "function") {
cryptoObj.getRandomValues(bytes)
return bytes
}
for (let i = 0; i < length; i += 1) {
bytes[i] = Math.floor(Math.random() * 256)
}
return bytes
}
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