out-of-your-element/discord/utils.js

127 lines
4.7 KiB
JavaScript

// @ts-check
const DiscordTypes = require("discord-api-types/v10")
const assert = require("assert").strict
const EPOCH = 1420070400000
/**
* @param {string[]} userRoles
* @param {DiscordTypes.APIGuild["roles"]} guildRoles
* @param {string} [userID]
* @param {DiscordTypes.APIGuildChannel["permission_overwrites"]} [channelOverwrites]
*/
function getPermissions(userRoles, guildRoles, userID, channelOverwrites) {
let allowed = BigInt(0)
let everyoneID
// Guild allows
for (const role of guildRoles) {
if (role.name === "@everyone") {
allowed |= BigInt(role.permissions)
everyoneID = role.id
}
if (userRoles.includes(role.id)) {
allowed |= BigInt(role.permissions)
}
}
if (channelOverwrites) {
/** @type {((overwrite: Required<DiscordTypes.APIOverwrite>) => any)[]} */
const actions = [
// Channel @everyone deny
overwrite => overwrite.id === everyoneID && (allowed &= ~BigInt(overwrite.deny)),
// Channel @everyone allow
overwrite => overwrite.id === everyoneID && (allowed |= BigInt(overwrite.allow)),
// Role deny
overwrite => userRoles.includes(overwrite.id) && (allowed &= ~BigInt(overwrite.deny)),
// Role allow
overwrite => userRoles.includes(overwrite.id) && (allowed |= BigInt(overwrite.allow)),
// User deny
overwrite => overwrite.id === userID && (allowed &= ~BigInt(overwrite.deny)),
// User allow
overwrite => overwrite.id === userID && (allowed |= BigInt(overwrite.allow))
]
for (let i = 0; i < actions.length; i++) {
for (const overwrite of channelOverwrites) {
actions[i](overwrite)
}
}
}
return allowed
}
/**
* Note: You can only provide one permission bit to permissionToCheckFor. To check multiple permissions, call `hasAllPermissions` or `hasSomePermissions`.
* It is designed like this to avoid developer error with bit manipulations.
*
* @param {bigint} resolvedPermissions
* @param {bigint} permissionToCheckFor
* @returns {boolean} whether the user has the requested permission
* @example
* const permissions = getPermissions(userRoles, guildRoles, userID, channelOverwrites)
* hasPermission(permissions, DiscordTypes.PermissionFlagsBits.ViewChannel)
*/
function hasPermission(resolvedPermissions, permissionToCheckFor) {
// Make sure permissionToCheckFor has exactly one permission in it
assert.equal(permissionToCheckFor.toString(2).match(/1/g)?.length, 1)
// Do the actual calculation
return (resolvedPermissions & permissionToCheckFor) === permissionToCheckFor
}
/**
* @param {bigint} resolvedPermissions
* @param {(keyof DiscordTypes.PermissionFlagsBits)[]} permissionsToCheckFor
* @returns {boolean} whether the user has any of the requested permissions
* @example
* const permissions = getPermissions(userRoles, guildRoles, userID, channelOverwrites)
* hasSomePermissions(permissions, ["ViewChannel", "ReadMessageHistory"])
*/
function hasSomePermissions(resolvedPermissions, permissionsToCheckFor) {
return permissionsToCheckFor.some(x => hasPermission(resolvedPermissions, DiscordTypes.PermissionFlagsBits[x]))
}
/**
* @param {bigint} resolvedPermissions
* @param {(keyof DiscordTypes.PermissionFlagsBits)[]} permissionsToCheckFor
* @returns {boolean} whether the user has all of the requested permissions
* @example
* const permissions = getPermissions(userRoles, guildRoles, userID, channelOverwrites)
* hasAllPermissions(permissions, ["ViewChannel", "ReadMessageHistory"])
*/
function hasAllPermissions(resolvedPermissions, permissionsToCheckFor) {
return permissionsToCheckFor.every(x => hasPermission(resolvedPermissions, DiscordTypes.PermissionFlagsBits[x]))
}
/**
* Command interaction responses have a webhook_id for some reason, but still have real author info of a real bot user in the server.
* @param {DiscordTypes.APIMessage} message
*/
function isWebhookMessage(message) {
return message.webhook_id && message.type !== DiscordTypes.MessageType.ChatInputCommand
}
/**
* @param {Pick<DiscordTypes.APIMessage, "flags">} message
*/
function isEphemeralMessage(message) {
return message.flags && (message.flags & DiscordTypes.MessageFlags.Ephemeral)
}
/** @param {string} snowflake */
function snowflakeToTimestampExact(snowflake) {
return Number(BigInt(snowflake) >> 22n) + EPOCH
}
/** @param {number} timestamp */
function timestampToSnowflakeInexact(timestamp) {
return String((timestamp - EPOCH) * 2**22)
}
module.exports.getPermissions = getPermissions
module.exports.hasPermission = hasPermission
module.exports.hasSomePermissions = hasSomePermissions
module.exports.hasAllPermissions = hasAllPermissions
module.exports.isWebhookMessage = isWebhookMessage
module.exports.isEphemeralMessage = isEphemeralMessage
module.exports.snowflakeToTimestampExact = snowflakeToTimestampExact
module.exports.timestampToSnowflakeInexact = timestampToSnowflakeInexact