[APP-705] Metrics revamp pt2 (#896)

* export track function from analytics.tsx

* fix create account tracking

* fix tracking sign in

* add custom feed events

* fix type errors

* refactor create post event

* add profile follow & unfollow events

* refactor PostsFeedSliceModel into its own file

* refactor PostThreadItemModel into its own file

* reorganize code a lil bit

* refactor post-thread-item to use post-feed-item model under the hood

* add post events

* add post reply tracking

* track custom feed load more

* track list subscribe and unsubscribe

1 files changed, 78 insertions, 0 deletions

diff --git a/src/state/models/feeds/posts-slice.ts b/src/state/models/feeds/posts-slice.ts
new file mode 100644
index 000000000..239bc5b6a
--- /dev/null
+++ b/src/state/models/feeds/posts-slice.ts
@@ -0,0 +1,78 @@
+import {makeAutoObservable} from 'mobx'
+import {RootStoreModel} from '../root-store'
+import {FeedViewPostsSlice} from 'lib/api/feed-manip'
+import {mergePostModerations} from 'lib/labeling/helpers'
+import {PostsFeedItemModel} from './post'
+
+let _idCounter = 0
+
+export class PostsFeedSliceModel {
+  // ui state
+  _reactKey: string = ''
+
+  // data
+  items: PostsFeedItemModel[] = []
+
+  constructor(
+    public rootStore: RootStoreModel,
+    reactKey: string,
+    slice: FeedViewPostsSlice,
+  ) {
+    this._reactKey = reactKey
+    for (const item of slice.items) {
+      this.items.push(
+        new PostsFeedItemModel(rootStore, `slice-${_idCounter++}`, item),
+      )
+    }
+    makeAutoObservable(this, {rootStore: false})
+  }
+
+  get uri() {
+    if (this.isReply) {
+      return this.items[1].post.uri
+    }
+    return this.items[0].post.uri
+  }
+
+  get isThread() {
+    return (
+      this.items.length > 1 &&
+      this.items.every(
+        item => item.post.author.did === this.items[0].post.author.did,
+      )
+    )
+  }
+
+  get isReply() {
+    return this.items.length > 1 && !this.isThread
+  }
+
+  get rootItem() {
+    if (this.isReply) {
+      return this.items[1]
+    }
+    return this.items[0]
+  }
+
+  get moderation() {
+    return mergePostModerations(this.items.map(item => item.moderation))
+  }
+
+  containsUri(uri: string) {
+    return !!this.items.find(item => item.post.uri === uri)
+  }
+
+  isThreadParentAt(i: number) {
+    if (this.items.length === 1) {
+      return false
+    }
+    return i < this.items.length - 1
+  }
+
+  isThreadChildAt(i: number) {
+    if (this.items.length === 1) {
+      return false
+    }
+    return i > 0
+  }
+}