Reorganize state models for clarity (#378)

src/state/models/content/post.ts

@@ -0,0 +1,103 @@
+import {makeAutoObservable} from 'mobx'
+import {AppBskyFeedPost as Post} from '@atproto/api'
+import {AtUri} from '../../../third-party/uri'
+import {RootStoreModel} from '../root-store'
+import {cleanError} from 'lib/strings/errors'
+
+type RemoveIndex<T> = {
+  [P in keyof T as string extends P
+    ? never
+    : number extends P
+    ? never
+    : P]: T[P]
+}
+export class PostModel implements RemoveIndex<Post.Record> {
+  // state
+  isLoading = false
+  hasLoaded = false
+  error = ''
+  uri: string = ''
+
+  // data
+  text: string = ''
+  entities?: Post.Entity[]
+  reply?: Post.ReplyRef
+  createdAt: string = ''
+
+  constructor(public rootStore: RootStoreModel, uri: string) {
+    makeAutoObservable(
+      this,
+      {
+        rootStore: false,
+        uri: false,
+      },
+      {autoBind: true},
+    )
+    this.uri = uri
+  }
+
+  get hasContent() {
+    return this.createdAt !== ''
+  }
+
+  get hasError() {
+    return this.error !== ''
+  }
+
+  get isEmpty() {
+    return this.hasLoaded && !this.hasContent
+  }
+
+  // public api
+  // =
+
+  async setup() {
+    await this._load()
+  }
+
+  // state transitions
+  // =
+
+  _xLoading() {
+    this.isLoading = true
+    this.error = ''
+  }
+
+  _xIdle(err?: any) {
+    this.isLoading = false
+    this.hasLoaded = true
+    this.error = cleanError(err)
+    if (err) {
+      this.rootStore.log.error('Failed to fetch post', err)
+    }
+  }
+
+  // loader functions
+  // =
+
+  async _load() {
+    this._xLoading()
+    try {
+      const urip = new AtUri(this.uri)
+      const res = await this.rootStore.agent.getPost({
+        repo: urip.host,
+        rkey: urip.rkey,
+      })
+      // TODO
+      // if (!res.valid) {
+      //   throw new Error(res.error)
+      // }
+      this._replaceAll(res.value)
+      this._xIdle()
+    } catch (e: any) {
+      this._xIdle(e)
+    }
+  }
+
+  _replaceAll(res: Post.Record) {
+    this.text = res.text
+    this.entities = res.entities
+    this.reply = res.reply
+    this.createdAt = res.createdAt
+  }
+}