feat(util & Client): add createOAuthURL

mod.ts

@@ -183,3 +183,4 @@ export * from './src/structures/threadChannel.ts'
 export * from './src/structures/resolvable.ts'
 export * from './src/utils/channelTypes.ts'
 export * from './src/structures/messageSticker.ts'
+export * from './src/utils/oauthURL.ts'

src/client/client.ts

@@ -25,6 +25,7 @@ import type { DMChannel } from '../structures/dmChannel.ts'
 import { Template } from '../structures/template.ts'
 import { VoiceManager } from './voice.ts'
 import { StickersManager } from '../managers/stickers.ts'
+import { createOAuthURL, OAuthURLOptions } from '../utils/oauthURL.ts'
 
 /** OS related properties sent with Gateway Identify */
 export interface ClientProperties {
@@ -464,6 +465,18 @@ export class Client extends HarmonyEventEmitter<ClientEvents> {
     const payload = await this.rest.api.guilds.templates[code].get()
     return new Template(this, payload)
   }
+
+  /** Creates an OAuth2 URL */
+  createOAuthURL(options: Omit<OAuthURLOptions, 'clientID'>): string {
+    return createOAuthURL(
+      Object.assign(
+        {
+          clientID: this.getEstimatedID()
+        },
+        options
+      )
+    )
+  }
 }
 
 /** Event decorator to create an Event handler from function */

src/types/oauth.ts

@@ -0,0 +1,23 @@
+export type OAuthScope =
+  | 'identify'
+  | 'email'
+  | 'connections'
+  | 'guilds'
+  | 'guilds.join'
+  | 'gdm.join'
+  | 'rpc'
+  | 'rpc.notifications.read'
+  | 'rpc.voice.read'
+  | 'rpc.voice.write'
+  | 'rpc.activities.write'
+  | 'bot'
+  | 'webhook.incoming'
+  | 'messages.read'
+  | 'applications.builds.upload'
+  | 'applications.builds.read'
+  | 'applications.commands'
+  | 'applications.store.update'
+  | 'applications.entitlements'
+  | 'activities.read'
+  | 'activities.write'
+  | 'relationships.read'

src/types/permissionFlags.ts

@@ -1,6 +1,6 @@
 // https://discord.com/developers/docs/topics/permissions#permissions-bitwise-permission-flags
 
-export const PermissionFlags: { [key: string]: bigint } = {
+export const PermissionFlags = {
   CREATE_INSTANT_INVITE: 1n << 0n,
   KICK_MEMBERS: 1n << 1n,
   BAN_MEMBERS: 1n << 2n,
@@ -46,4 +46,4 @@ export const PermissionFlags: { [key: string]: bigint } = {
   USE_PUBLIC_THREADS: 1n << 35n,
   USE_PRIVATE_THREADS: 1n << 36n,
   USE_EXTERNAL_STICKERS: 1n << 37n
-}
+} as const

src/utils/oauthURL.ts

@@ -0,0 +1,68 @@
+import { PermissionFlags } from '../../mod.ts'
+import { Constants } from '../types/constants.ts'
+import type { OAuthScope } from '../types/oauth.ts'
+import { Permissions } from './permissions.ts'
+
+export interface OAuthURLOptions {
+  clientID: string
+  scopes: OAuthScope[]
+  permissions?:
+    | string
+    | bigint
+    | Permissions
+    | Array<keyof typeof PermissionFlags | bigint>
+  redirectURI?: string
+}
+
+export function createOAuthURL(options: OAuthURLOptions): string {
+  if (options.scopes.length < 1)
+    throw new Error('Must provide at least one scope')
+
+  const params = new URLSearchParams({
+    client_id: options.clientID,
+    scopes: [new Set(options.scopes)].join(' ')
+  })
+
+  if (options.permissions !== undefined) {
+    let perms: string
+
+    if (
+      typeof options.permissions === 'string' ||
+      typeof options.permissions === 'bigint'
+    ) {
+      perms = String(options.permissions)
+    } else if (
+      typeof options.permissions === 'object' &&
+      options.permissions !== null &&
+      options.permissions instanceof Permissions
+    ) {
+      perms = String(options.permissions.bitfield)
+    } else if (Array.isArray(options.permissions)) {
+      let acum = 0n
+      for (const perm of options.permissions) {
+        if (typeof perm === 'string') {
+          const flag = PermissionFlags[perm]
+          if (typeof flag !== 'number')
+            throw new TypeError(`Invalid Permission Flag: ${flag}`)
+          acum |= flag
+        } else if (typeof perm === 'bigint') {
+          acum |= perm
+        } else throw new TypeError('Unexpected value in permissions array')
+      }
+      perms = String(acum)
+    } else throw new TypeError(`Unexpected value for permissions`)
+    params.set('permissions', perms)
+  }
+
+  if (options.permissions === undefined && options.scopes.includes('bot')) {
+    params.set('permissions', '0')
+  }
+
+  if (typeof options.redirectURI === 'string') {
+    params.set('redirect_uri', options.redirectURI)
+  }
+
+  return `${Constants.DISCORD_API_URL}/${
+    Constants.DISCORD_API_VERSION
+  }/oauth2/authorize?${params.toString()}`
+}