1import { useCallback, useEffect, useState } from "preact/hooks";2import type { RowOf, WriteHandle } from "@nzip/lofi";3import { useLiveQuery, useWrite } from "@nzip/lofi/preact";4import { s } from "@nzip/lofi/schema";5import { app } from "../app.ts";67/**8 * Author-owned example. Tables are the nouns of your app; verbs are what9 * happens to them. This module declares two verbs over the `tasks` table —10 * `addTask` carries effects that run when the write's sync fate settles, and11 * `setTaskCompleted` is a plain verb — then wraps them in a domain hook.12 * Replace `tasks` and the verbs below with your own model; framework runtime13 * code remains in `@nzip/lofi`.14 */15const tasksTable = app.schema.tasks;1617/** The row type comes straight from the declared schema. */18export type Task = RowOf<typeof tasksTable>;1920/** A one-line consequence or compensation surfaced to the UI. */21export type TaskNotice = { kind: "synced" | "rejected"; text: string };2223// A tiny author-owned notice channel: effect handlers run outside any24// component, so they publish through module state and hooks subscribe.25let notice: TaskNotice | null = null;26const noticeListeners = new Set<() => void>();2728function publishNotice(next: TaskNotice | null): void {29 notice = next;30 for (const listener of [...noticeListeners]) listener();31}3233/**34 * The verb call sites use. Its effect units are declared once, here: the35 * consequence runs when the store confirms the task, the compensation runs if36 * a stale-policy write is denied — even if the app restarted in between.37 */38export const addTask = s.mutation("addTask", s.insert(tasksTable), {39 effects: [s.log("task-added")],40 onSynced: (task) => {41 publishNotice({ kind: "synced", text: `"${task.text ?? "Task"}" synced to your account` });42 },43 onRejected: (task) => {44 // The engine already rolled the denied row back out of local reads; this45 // compensates what the user was told.46 publishNotice({47 kind: "rejected",48 text: `"${task.text ?? "Task"}" was declined by the store and has been removed`,49 });50 },51});5253/** Toggling completion is a plain verb: no consequences, same lifecycle. */54export const setTaskCompleted = s.mutation("setTaskCompleted", s.update(tasksTable));5556/** Subscribes to the latest effect notice; `null` until one is published. */57export function useTaskNotice(): TaskNotice | null {58 const [current, setCurrent] = useState<TaskNotice | null>(notice);59 useEffect(() => {60 const listener = () => setCurrent(notice);61 noticeListeners.add(listener);62 listener();63 return () => void noticeListeners.delete(listener);64 }, []);65 return current;66}6768export function useTasks() {69 const query = useLiveQuery(() => tasksTable.orderBy("createdAt", "desc"), []);70 const [lastWrite, setLastWrite] = useState<WriteHandle<Task> | null>(null);71 const [writeError, setWriteError] = useState<string | null>(null);72 const write = useWrite(lastWrite);7374 const create = useCallback((text: string) => {75 // The verb returns a WriteHandle: awaiting it means saved on this device;76 // `.synced` and the declared effects follow the store's confirmation.77 const handle = addTask({ text, completed: false, createdAt: new Date() });78 setLastWrite(handle);79 setWriteError(null);80 handle.saved.then(undefined, (error) => {81 setWriteError(error instanceof Error ? error.message : String(error));82 });83 return handle;84 }, []);85 const setCompleted = useCallback(86 (id: string, completed: boolean) => setTaskCompleted(id, { completed }),87 [],88 );8990 const durability = write.stage === "synced"91 ? "global" as const92 : write.stage === "saved" || write.stage === "syncing"93 ? "local" as const94 : write.stage === "rejected"95 ? "failed" as const96 : "none" as const;9798 return {99 status: query.status === "error" || writeError !== null ? "error" as const : query.status,100 error: query.error ?? writeError,101 durability,102 lastWriteStage: write.stage,103 lastWriteReason: write.reason,104 tasks: query.rows,105 failureKind: query.status === "error" ? "read" as const : "write" as const,106 create,107 setCompleted,108 };109}