opencode/packages/core/src/state.ts

64 lines
2.5 KiB
TypeScript

export * as State from "./state"
import { Effect, Scope, Semaphore } from "effect"
import type { Draft, Objectish } from "immer"
export type Transform<Editor> = (editor: Editor) => void
export type MakeEditor<State extends Objectish, Editor> = (draft: Draft<State>) => Editor
export interface Options<State extends Objectish, Editor> {
readonly initial: () => State
readonly editor: MakeEditor<State, Editor>
/** Completes every committed edit; reason identifies exceptional update origins. */
readonly finalize?: (editor: Editor, reason?: string) => Effect.Effect<void>
}
export interface Interface<State extends Objectish, Editor> {
readonly get: () => State
readonly transform: () => Effect.Effect<(transform: Transform<Editor>) => Effect.Effect<void>, never, Scope.Scope>
readonly update: (update: (editor: Editor) => Effect.Effect<void>, reason?: string) => Effect.Effect<void>
}
export function create<State extends Objectish, Editor>(options: Options<State, Editor>): Interface<State, Editor> {
let state = options.initial()
let transforms: { update: Transform<Editor> }[] = []
const semaphore = Semaphore.makeUnsafe(1)
const commit = Effect.fn("State.commit")(function* (next: State, reason?: string) {
const api = options.editor(next as Draft<State>)
if (options.finalize) yield* options.finalize(api, reason)
state = next
})
const rebuild = Effect.fn("State.rebuild")(function* () {
const next = options.initial()
const api = options.editor(next as Draft<State>)
for (const transform of transforms)
yield* Effect.sync(() => transform.update(api)).pipe(Effect.withSpan("State.rebuild.update", {}))
yield* commit(next)
}, semaphore.withPermit)
return {
get: () => state,
transform: Effect.fn("State.transform")(function* () {
const transform = { update: (_editor: Editor) => {} }
transforms = [...transforms, transform]
const scope = yield* Scope.Scope
yield* Scope.addFinalizer(
scope,
Effect.sync(() => {
transforms = transforms.filter((item) => item !== transform)
}).pipe(Effect.andThen(rebuild())),
)
return Effect.fnUntraced(function* (update: Transform<Editor>) {
transform.update = update
yield* rebuild()
})
}),
update: Effect.fn("State.update")(function* (update, reason) {
const api = options.editor(state as Draft<State>)
yield* update(api)
if (options.finalize) yield* options.finalize(api, reason)
}, semaphore.withPermit),
}
}