revenge-bundle-next/lib/discord/src/flux/dispatcher.ts

import { fPatches, fPatchesAll } from '../patches/flux'
import type { DiscordModules } from '../types'

export type FluxEventDispatchPatch<T extends object = object> = (
    payload: DiscordModules.Flux.DispatcherPayload & T,
) => (DiscordModules.Flux.DispatcherPayload & T) | undefined | void

/**
 * Registers a patch for all Flux events.
 *
 * @see {@link onFluxEventDispatched} for more details.
 *
 * @param patch The patch function to apply when any Flux event is dispatched.
 * @returns A function that can be used to remove the patch.
 */
export function onAnyFluxEventDispatched(patch: FluxEventDispatchPatch) {
    fPatchesAll.add(patch)

    return () => {
        fPatchesAll.delete(patch)
    }
}

/**
 * Registers a patch for a specific Flux event type.
 * @param type The type of the Flux event to patch.
 * @param patch The patch function to apply when the event is dispatched.
 * @returns A function that can be used to remove the patch.
 *
 * @example Blocking the dispatch
 * ```ts
 * // Returning falsy values will prevent the event from being dispatched.
 * onFluxEventDispatched('TYPING_START', () => {})
 * ```
 *
 * @example Modifying the payload
 * ```ts
 * onFluxEventDispatched('TYPING_START', payload => {
 *   // Send the typing event to this channel instead.
 *   payload.channelId = '123456789012345678'
 *   // Make sure to return the modified payload!
 *   return payload
 * })
 * ```
 *
 * @example Reading and passing through the payload
 * ```ts
 * onFluxEventDispatched('TYPING_START', payload => {
 *   console.log('Typing started:', payload)
 *   // Do nothing, just return the payload.
 *   return payload
 * })
 * ```
 */
export function onFluxEventDispatched<T extends object = object>(
    type: DiscordModules.Flux.DispatcherPayload['type'],
    patch: FluxEventDispatchPatch<T>,
) {
    let set = fPatches.get(type)
    if (!set) fPatches.set(type, (set = new Set<FluxEventDispatchPatch>()))

    set.add(patch)

    return () => {
        set.delete(patch)
    }
}