Reorganize state models for clarity (#378)

src/state/models/lists/user-followers.ts

@@ -0,0 +1,120 @@
+import {makeAutoObservable} from 'mobx'
+import {
+  AppBskyGraphGetFollowers as GetFollowers,
+  AppBskyActorDefs as ActorDefs,
+} from '@atproto/api'
+import {RootStoreModel} from '../root-store'
+import {cleanError} from 'lib/strings/errors'
+import {bundleAsync} from 'lib/async/bundle'
+
+const PAGE_SIZE = 30
+
+export type FollowerItem = ActorDefs.ProfileViewBasic
+
+export class UserFollowersModel {
+  // state
+  isLoading = false
+  isRefreshing = false
+  hasLoaded = false
+  error = ''
+  params: GetFollowers.QueryParams
+  hasMore = true
+  loadMoreCursor?: string
+
+  // data
+  subject: ActorDefs.ProfileViewBasic = {
+    did: '',
+    handle: '',
+  }
+  followers: FollowerItem[] = []
+
+  constructor(
+    public rootStore: RootStoreModel,
+    params: GetFollowers.QueryParams,
+  ) {
+    makeAutoObservable(
+      this,
+      {
+        rootStore: false,
+        params: false,
+      },
+      {autoBind: true},
+    )
+    this.params = params
+  }
+
+  get hasContent() {
+    return this.subject.did !== ''
+  }
+
+  get hasError() {
+    return this.error !== ''
+  }
+
+  get isEmpty() {
+    return this.hasLoaded && !this.hasContent
+  }
+
+  // public api
+  // =
+
+  async refresh() {
+    return this.loadMore(true)
+  }
+
+  loadMore = bundleAsync(async (replace: boolean = false) => {
+    if (!replace && !this.hasMore) {
+      return
+    }
+    this._xLoading(replace)
+    try {
+      const params = Object.assign({}, this.params, {
+        limit: PAGE_SIZE,
+        cursor: replace ? undefined : this.loadMoreCursor,
+      })
+      const res = await this.rootStore.agent.getFollowers(params)
+      if (replace) {
+        this._replaceAll(res)
+      } else {
+        this._appendAll(res)
+      }
+      this._xIdle()
+    } catch (e: any) {
+      this._xIdle(e)
+    }
+  })
+
+  // state transitions
+  // =
+
+  _xLoading(isRefreshing = false) {
+    this.isLoading = true
+    this.isRefreshing = isRefreshing
+    this.error = ''
+  }
+
+  _xIdle(err?: any) {
+    this.isLoading = false
+    this.isRefreshing = false
+    this.hasLoaded = true
+    this.error = cleanError(err)
+    if (err) {
+      this.rootStore.log.error('Failed to fetch user followers', err)
+    }
+  }
+
+  // helper functions
+  // =
+
+  _replaceAll(res: GetFollowers.Response) {
+    this.followers = []
+    this._appendAll(res)
+  }
+
+  _appendAll(res: GetFollowers.Response) {
+    this.loadMoreCursor = res.data.cursor
+    this.hasMore = !!this.loadMoreCursor
+    this.followers = this.followers.concat(res.data.followers)
+    this.rootStore.me.follows.hydrateProfiles(res.data.followers)
+  }
+}