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import z from "zod"
export namespace Identifier {
const prefixes = {
session: "ses",
message: "msg",
permission: "per",
user: "usr",
part: "prt",
pty: "pty",
} as const
export type Prefix = keyof typeof prefixes
type CryptoLike = {
getRandomValues<T extends ArrayBufferView>(array: T): T
}
const TOTAL_LENGTH = 26
const RANDOM_LENGTH = TOTAL_LENGTH - 12
const BASE62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
let lastTimestamp = 0
let counter = 0
const fillRandomBytes = (buffer: Uint8Array) => {
const cryptoLike = (globalThis as { crypto?: CryptoLike }).crypto
if (cryptoLike?.getRandomValues) {
cryptoLike.getRandomValues(buffer)
return buffer
}
for (let i = 0; i < buffer.length; i++) {
buffer[i] = Math.floor(Math.random() * 256)
}
return buffer
}
const randomBase62 = (length: number) => {
const bytes = fillRandomBytes(new Uint8Array(length))
let result = ""
for (let i = 0; i < length; i++) {
result += BASE62[bytes[i] % BASE62.length]
}
return result
}
const createSuffix = (descending: boolean, timestamp?: number) => {
const currentTimestamp = timestamp ?? Date.now()
if (currentTimestamp !== lastTimestamp) {
lastTimestamp = currentTimestamp
counter = 0
}
counter += 1
let value = BigInt(currentTimestamp) * 0x1000n + BigInt(counter)
if (descending) value = ~value
const timeBytes = new Uint8Array(6)
for (let i = 0; i < 6; i++) {
timeBytes[i] = Number((value >> BigInt(40 - 8 * i)) & 0xffn)
}
const hex = Array.from(timeBytes)
.map((byte) => byte.toString(16).padStart(2, "0"))
.join("")
return hex + randomBase62(RANDOM_LENGTH)
}
const generateID = (prefix: Prefix, descending: boolean, given?: string, timestamp?: number) => {
if (given) {
const expected = `${prefixes[prefix]}_`
if (!given.startsWith(expected)) throw new Error(`ID ${given} does not start with ${expected}`)
return given
}
return `${prefixes[prefix]}_${createSuffix(descending, timestamp)}`
}
export const schema = (prefix: Prefix) => z.string().startsWith(`${prefixes[prefix]}_`)
export function ascending(): string
export function ascending(prefix: Prefix, given?: string): string
export function ascending(prefix?: Prefix, given?: string) {
if (prefix) return generateID(prefix, false, given)
return create(false)
}
export function descending(): string
export function descending(prefix: Prefix, given?: string): string
export function descending(prefix?: Prefix, given?: string) {
if (prefix) return generateID(prefix, true, given)
return create(true)
}
export function create(descending: boolean, timestamp?: number) {
return createSuffix(descending, timestamp)
}
export function createPrefixed(prefix: Prefix, descending: boolean, timestamp?: number) {
return generateID(prefix, descending, undefined, timestamp)
}
}
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