From 66f76e7f06d474c3af3d332b161cff7df8ae1b0b Mon Sep 17 00:00:00 2001
From: Hanakla <8597982+hanakla@users.noreply.github.com>
Date: Sat, 2 Apr 2022 15:10:12 +0900
Subject: [PATCH] wip: poc: useOpSuspence

---
 packages/react/src/useOpSuspense.tsx | 122 +++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 packages/react/src/useOpSuspense.tsx

diff --git a/packages/react/src/useOpSuspense.tsx b/packages/react/src/useOpSuspense.tsx
new file mode 100644
index 00000000..98a4ae73
--- /dev/null
+++ b/packages/react/src/useOpSuspense.tsx
@@ -0,0 +1,122 @@
+import { Operation, OperationArgs, StoreClass } from '@fleur/fleur'
+import { OperationAborter } from '@fleur/fleur/dist/Operations'
+import { useEffect, useReducer } from 'react'
+import { ComponentFleurContext } from './ComponentReactContext'
+import { useFleurContext } from './useFleurContext'
+
+type StoreStateGetter = <T extends StoreClass<any>>(
+  StoreClass: T,
+) => InstanceType<T>['state']
+
+type KeyPromiseMap = { [key: string]: Promise<void> | void }
+
+const contextCache = new WeakMap<
+  ComponentFleurContext,
+  Map<Operation, KeyPromiseMap>
+>()
+
+export const createOpSupenseHook = <
+  O extends Operation & Partial<OperationAborter>,
+  D,
+  E
+>(
+  op: O,
+  {
+    getKey,
+    getData,
+    getError,
+  }: {
+    getKey: (args: OperationArgs<O>) => string
+    getData: (get: StoreStateGetter, key: string) => D | undefined
+    getError?: (get: StoreStateGetter, key: string) => E | undefined
+  },
+) => {
+  const hook = (...args: OperationArgs<O>) => {
+    const key = getKey(args)
+
+    const x = useFleurContext()
+    const data = getData((s) => x.getStore(s).state, key)
+    if (data !== undefined) return data
+
+    const caches = contextCache.get(x)
+    const promiseCache =
+      caches.get(op) ?? (Object.create(null) as KeyPromiseMap)
+    caches.set(op, promiseCache)
+
+    if (promiseCache[key]) throw promiseCache[key]
+
+    return x.executeOperation((xx) => {
+      promiseCache[key] = xx.executeOperation(op, ...args).then()
+    })
+  }
+
+  hook.noSuspence = (...args: OperationArgs<O>) => {
+    const key = getKey(args)
+
+    const [, rerender] = useReducer((s) => s + 1, 0)
+    const x = useFleurContext()
+
+    useEffect(() => {
+      return () => {
+        if ('abort' in op) op.abort.byKey(key)
+      }
+    }, [])
+
+    const data = getData((s) => x.getStore(s).state, key)
+    const error = getError((s) => x.getStore(s).state, key)
+    if (data !== undefined || error !== undefined)
+      return { data, error, loading: false }
+
+    const caches = contextCache.get(x)
+    const promiseCache =
+      caches.get(op) ?? (Object.create(null) as KeyPromiseMap)
+    caches.set(op, promiseCache)
+
+    if (promiseCache[key]) {
+      return { data: null, error: null, loading: true }
+    } else {
+      x.executeOperation((xx) => {
+        promiseCache[key] = xx.executeOperation(op, ...args).then(() => {
+          rerender()
+        })
+      })
+
+      return { data: null, error: null, loading: false }
+    }
+  }
+
+  return hook
+}
+
+// const [AppStore, AppOps] = minOps('App', {
+//   initialState: () => ({
+//     users: {},
+//   }),
+//   ops: {
+//     async fetchUser(x, userId: string) {
+//       x.acceptAbort(userId)
+
+//       const [user, error] = await rescue(async () =>
+//         (
+//           await fetch('...', { body: `?id=${userId}`, signal: x.abort.signal })
+//         ).json(),
+//       )
+
+//       x.commit((draft) => {
+//         if (error) draft.users[userId] = { error }
+//         else draft.users[userId] = { user }
+//       })
+//     },
+//   },
+// })
+
+// const useUser = createOpSupenseHook(AppOps.fetchUser, {
+//   getKey: ([userId]) => userId,
+//   getData: (get, key) => get(AppStore).users[key]?.user,
+//   getError: (get, key) => get(AppStore).users[key]?.error,
+// })
+
+// const Comp = () => {
+//   const user = useUser('1')
+//   const { data, loading, error } = useUser.noSuspence('1')
+// }