Estimate more cell heights

Extensions/CollectionItem+Extensions.swift

@@ -34,8 +34,21 @@ extension CollectionItem {
                 identification: identification,
                 status: status,
                 configuration: configuration)
-        default:
-            return UITableView.automaticDimension
+        case let .account(account):
+            return AccountView.estimatedHeight(width: width, account: account)
+        case .loadMore:
+            return LoadMoreView.estimatedHeight
+        case let .notification(notification, configuration):
+            return NotificationView.estimatedHeight(
+                width: width,
+                identification: identification,
+                notification: notification,
+                configuration: configuration)
+        case let .conversation(conversation):
+            return ConversationView.estimatedHeight(
+                width: width,
+                identification: identification,
+                conversation: conversation)
         }
     }
 }

Views/AccountView.swift

@@ -1,6 +1,7 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
 import Kingfisher
+import Mastodon
 import UIKit
 
 final class AccountView: UIView {
@@ -26,6 +27,16 @@ final class AccountView: UIView {
     }
 }
 
+extension AccountView {
+    static func estimatedHeight(width: CGFloat, account: Account) -> CGFloat {
+        .defaultSpacing * 2
+            + .compactSpacing * 2
+            + account.displayName.height(width: width, font: .preferredFont(forTextStyle: .headline))
+            + account.acct.height(width: width, font: .preferredFont(forTextStyle: .subheadline))
+            + account.note.attributed.string.height(width: width, font: .preferredFont(forTextStyle: .callout))
+    }
+}
+
 extension AccountView: UIContentView {
     var configuration: UIContentConfiguration {
         get { accountConfiguration }

Views/ConversationView.swift

@@ -1,6 +1,8 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
+import Mastodon
 import UIKit
+import ViewModels
 
 final class ConversationView: UIView {
     let avatarsView = ConversationAvatarsView()
@@ -24,6 +26,24 @@ final class ConversationView: UIView {
     }
 }
 
+extension ConversationView {
+    static func estimatedHeight(width: CGFloat,
+                                identification: Identification,
+                                conversation: Conversation) -> CGFloat {
+        guard let status = conversation.lastStatus else { return UITableView.automaticDimension }
+
+        let bodyWidth = width - .defaultSpacing - .avatarDimension
+
+        return .defaultSpacing * 2
+            + UIFont.preferredFont(forTextStyle: .headline).lineHeight
+            + StatusBodyView.estimatedHeight(
+                width: bodyWidth,
+                identification: identification,
+                status: status,
+                configuration: .default)
+    }
+}
+
 extension ConversationView: UIContentView {
     var configuration: UIContentConfiguration {
         get { conversationConfiguration }

Views/LoadMoreView.swift

@@ -28,6 +28,10 @@ final class LoadMoreView: UIView {
 }
 
 extension LoadMoreView {
+    static var estimatedHeight: CGFloat {
+        .defaultSpacing * 2 + UIFont.preferredFont(forTextStyle: .title2).lineHeight
+    }
+
     func directionChanged(up: Bool) {
         guard !loadMoreConfiguration.viewModel.loading else { return }
 

Views/NotificationView.swift

@@ -3,6 +3,7 @@
 import Kingfisher
 import Mastodon
 import UIKit
+import ViewModels
 
 final class NotificationView: UIView {
     private let iconImageView = UIImageView()
@@ -29,6 +30,33 @@ final class NotificationView: UIView {
     }
 }
 
+extension NotificationView {
+    static func estimatedHeight(width: CGFloat,
+                                identification: Identification,
+                                notification: MastodonNotification,
+                                configuration: CollectionItem.StatusConfiguration?) -> CGFloat {
+        let bodyWidth = width - .defaultSpacing - .avatarDimension
+
+        var height = CGFloat.defaultSpacing * 2
+            + UIFont.preferredFont(forTextStyle: .headline).lineHeight
+            + .compactSpacing
+
+        if let status = notification.status {
+            height += StatusBodyView.estimatedHeight(
+                width: bodyWidth,
+                identification: identification,
+                status: status,
+                configuration: configuration ?? .default)
+        } else {
+            height += UIFont.preferredFont(forTextStyle: .headline).lineHeight
+                + .compactSpacing
+                + UIFont.preferredFont(forTextStyle: .subheadline).lineHeight
+        }
+
+        return height
+    }
+}
+
 extension NotificationView: UIContentView {
     var configuration: UIContentConfiguration {
         get { notificationConfiguration }