Notifications wip

DB/Sources/DB/Content/ContentDatabase+Migration.swift

@@ -110,6 +110,13 @@ extension ContentDatabase {
                 t.column("id", .text).notNull()
             }
 
+            try db.create(table: "notificationRecord") { t in
+                t.column("id", .text).primaryKey(onConflict: .replace)
+                t.column("type", .text).notNull()
+                t.column("accountId", .text).notNull().references("accountRecord")
+                t.column("statusId").references("statusRecord")
+            }
+
             try db.create(table: "statusAncestorJoin") { t in
                 t.column("parentId", .text).indexed().notNull()
                     .references("statusRecord", onDelete: .cascade)

DB/Sources/DB/Content/ContentDatabase.swift

@@ -292,6 +292,16 @@ public extension ContentDatabase {
             .eraseToAnyPublisher()
     }
 
+    func insert(notifications: [MastodonNotification]) -> AnyPublisher<Never, Error> {
+        databaseWriter.writePublisher {
+            for notification in notifications {
+                try notification.save($0)
+            }
+        }
+        .ignoreOutput()
+        .eraseToAnyPublisher()
+    }
+
     func timelinePublisher(_ timeline: Timeline) -> AnyPublisher<[[CollectionItem]], Error> {
         ValueObservation.tracking(
             TimelineItemsInfo.request(TimelineRecord.filter(TimelineRecord.Columns.id == timeline.id)).fetchOne)
@@ -346,6 +356,28 @@ public extension ContentDatabase {
             .eraseToAnyPublisher()
     }
 
+    func notificationsPublisher() -> AnyPublisher<[[CollectionItem]], Error> {
+        ValueObservation.tracking(
+            NotificationInfo.request(
+                NotificationRecord.order(NotificationRecord.Columns.id.desc)).fetchAll)
+            .removeDuplicates()
+            .publisher(in: databaseWriter)
+            .map { [$0.map {
+                let configuration: CollectionItem.StatusConfiguration?
+
+                if $0.record.type == .mention, let statusInfo = $0.statusInfo {
+                    configuration = CollectionItem.StatusConfiguration(
+                        showContentToggled: statusInfo.showContentToggled,
+                        showAttachmentsToggled: statusInfo.showAttachmentsToggled)
+                } else {
+                    configuration = nil
+                }
+
+                return .notification(MastodonNotification(info: $0), configuration)
+            }] }
+            .eraseToAnyPublisher()
+    }
+
     func lastReadId(_ markerTimeline: Marker.Timeline) -> String? {
         try? databaseWriter.read {
             try String.fetchOne(
@@ -366,6 +398,8 @@ private extension ContentDatabase {
                       useHomeTimelineLastReadId: Bool,
                       useNotificationsLastReadId: Bool) throws {
         try databaseWriter.write {
+            try NotificationRecord.deleteAll($0)
+
             if useHomeTimelineLastReadId {
                 try TimelineRecord.filter(TimelineRecord.Columns.id != Timeline.home.id).deleteAll($0)
                 var statusIds = try Status.Id.fetchAll(

DB/Sources/DB/Content/NotificationInfo.swift

@@ -0,0 +1,23 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import GRDB
+
+struct NotificationInfo: Codable, Hashable, FetchableRecord {
+    let record: NotificationRecord
+    let accountInfo: AccountInfo
+    let statusInfo: StatusInfo?
+}
+
+extension NotificationInfo {
+    static func addingIncludes<T: DerivableRequest>(_ request: T) -> T where T.RowDecoder == NotificationRecord {
+        request.including(required: AccountInfo.addingIncludes(NotificationRecord.account)
+                            .forKey(CodingKeys.accountInfo))
+            .including(optional: StatusInfo.addingIncludesForNotificationInfo(NotificationRecord.status)
+                        .forKey(CodingKeys.statusInfo))
+    }
+
+    static func request(_ request: QueryInterfaceRequest<NotificationRecord>) -> QueryInterfaceRequest<Self> {
+        addingIncludes(request).asRequest(of: self)
+    }
+}

DB/Sources/DB/Content/NotificationRecord.swift

@@ -0,0 +1,31 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import GRDB
+import Mastodon
+
+struct NotificationRecord: ContentDatabaseRecord, Hashable {
+    let id: String
+    let type: MastodonNotification.NotificationType
+    let accountId: Account.Id
+    let statusId: Status.Id?
+}
+
+extension NotificationRecord {
+    enum Columns {
+        static let id = Column(NotificationRecord.CodingKeys.id)
+        static let type = Column(NotificationRecord.CodingKeys.type)
+        static let accountId = Column(NotificationRecord.CodingKeys.accountId)
+        static let statusId = Column(NotificationRecord.CodingKeys.statusId)
+    }
+
+    static let account = belongsTo(AccountRecord.self)
+    static let status = belongsTo(StatusRecord.self)
+
+    init(notification: MastodonNotification) {
+        id = notification.id
+        type = notification.type
+        accountId = notification.account.id
+        statusId = notification.status?.id
+    }
+}

DB/Sources/DB/Content/StatusInfo.swift

@@ -16,15 +16,17 @@ struct StatusInfo: Codable, Hashable, FetchableRecord {
 
 extension StatusInfo {
     static func addingIncludes<T: DerivableRequest>(_ request: T) -> T where T.RowDecoder == StatusRecord {
-        request.including(required: AccountInfo.addingIncludes(StatusRecord.account).forKey(CodingKeys.accountInfo))
+        addingOptionalIncludes(
-            .including(optional: AccountInfo.addingIncludes(StatusRecord.reblogAccount)
+            request
-                        .forKey(CodingKeys.reblogAccountInfo))
+                .including(required: AccountInfo.addingIncludes(StatusRecord.account).forKey(CodingKeys.accountInfo)))
-            .including(optional: StatusRecord.reblog.forKey(CodingKeys.reblogRecord))
+    }
-            .including(optional: StatusRecord.showContentToggle.forKey(CodingKeys.showContentToggle))
+
-            .including(optional: StatusRecord.reblogShowContentToggle.forKey(CodingKeys.reblogShowContentToggle))
+    // Hack, remove once GRDB supports chaining a required association behind an optional association
-            .including(optional: StatusRecord.showAttachmentsToggle.forKey(CodingKeys.showAttachmentsToggle))
+    static func addingIncludesForNotificationInfo<T: DerivableRequest>(
-            .including(optional: StatusRecord.reblogShowAttachmentsToggle
+        _ request: T) -> T where T.RowDecoder == StatusRecord {
-                        .forKey(CodingKeys.reblogShowAttachmentsToggle))
+        addingOptionalIncludes(
+            request
+                .including(optional: AccountInfo.addingIncludes(StatusRecord.account).forKey(CodingKeys.accountInfo)))
     }
 
     static func request(_ request: QueryInterfaceRequest<StatusRecord>) -> QueryInterfaceRequest<Self> {
@@ -43,3 +45,16 @@ extension StatusInfo {
         showAttachmentsToggle != nil || reblogShowAttachmentsToggle != nil
     }
 }
+
+private extension StatusInfo {
+    static func addingOptionalIncludes<T: DerivableRequest>(_ request: T) -> T where T.RowDecoder == StatusRecord {
+        request.including(optional: AccountInfo.addingIncludes(StatusRecord.reblogAccount)
+                            .forKey(CodingKeys.reblogAccountInfo))
+            .including(optional: StatusRecord.reblog.forKey(CodingKeys.reblogRecord))
+            .including(optional: StatusRecord.showContentToggle.forKey(CodingKeys.showContentToggle))
+            .including(optional: StatusRecord.reblogShowContentToggle.forKey(CodingKeys.reblogShowContentToggle))
+            .including(optional: StatusRecord.showAttachmentsToggle.forKey(CodingKeys.showAttachmentsToggle))
+            .including(optional: StatusRecord.reblogShowAttachmentsToggle
+                        .forKey(CodingKeys.reblogShowAttachmentsToggle))
+    }
+}

DB/Sources/DB/Entities/CollectionItem.swift

@@ -6,6 +6,7 @@ public enum CollectionItem: Hashable {
     case status(Status, StatusConfiguration)
     case loadMore(LoadMore)
     case account(Account)
+    case notification(MastodonNotification, StatusConfiguration?)
 }
 
 public extension CollectionItem {

DB/Sources/DB/Extensions/MastodonNotification+Extensions.swift

@@ -0,0 +1,29 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import GRDB
+import Mastodon
+
+extension MastodonNotification {
+    func save(_ db: Database) throws {
+        try account.save(db)
+        try status?.save(db)
+        try NotificationRecord(notification: self).save(db)
+    }
+
+    init(info: NotificationInfo) {
+        let status: Status?
+
+        if let statusInfo = info.statusInfo {
+            status = .init(info: statusInfo)
+        } else {
+            status = nil
+        }
+
+        self.init(
+            id: info.record.id,
+            type: info.record.type,
+            account: .init(info: info.accountInfo),
+            status: status)
+    }
+}

Data Sources/TableViewDataSource.swift

@@ -24,6 +24,8 @@ final class TableViewDataSource: UITableViewDiffableDataSource<Int, CollectionIt
                 accountListCell.viewModel = accountViewModel
             case let (loadMoreCell as LoadMoreCell, loadMoreViewModel as LoadMoreViewModel):
                 loadMoreCell.viewModel = loadMoreViewModel
+            case let (notificationListCell as NotificationListCell, notificationViewModel as NotificationViewModel):
+                notificationListCell.viewModel = notificationViewModel
             default:
                 break
             }

Extensions/CollectionItem+Extensions.swift

@@ -1,9 +1,14 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
+import UIKit
 import ViewModels
 
 extension CollectionItem {
-    static let cellClasses = [StatusListCell.self, AccountListCell.self, LoadMoreCell.self]
+    static let cellClasses = [
+        StatusListCell.self,
+        AccountListCell.self,
+        LoadMoreCell.self,
+        NotificationListCell.self]
 
     var cellClass: AnyClass {
         switch self {
@@ -13,6 +18,8 @@ extension CollectionItem {
             return AccountListCell.self
         case .loadMore:
             return LoadMoreCell.self
+        case let .notification(_, statusConfiguration):
+            return statusConfiguration == nil ? NotificationListCell.self : StatusListCell.self
         }
     }
 }

Extensions/String+Extensions.swift

@@ -1,5 +1,6 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
+import Mastodon
 import UIKit
 
 extension String {
@@ -21,4 +22,25 @@ extension String {
 
         return attributed
     }
+
+    func localizedBolding(displayName: String, emoji: [Emoji], label: UILabel) -> NSAttributedString {
+        let mutableString = NSMutableAttributedString(
+            string: String.localizedStringWithFormat(
+                NSLocalizedString(self, comment: ""),
+                displayName))
+
+        let range = (mutableString.string as NSString).range(of: displayName)
+
+        if range.location != NSNotFound,
+           let boldFontDescriptor = label.font.fontDescriptor.withSymbolicTraits([.traitBold]) {
+            let boldFont = UIFont(descriptor: boldFontDescriptor, size: label.font.pointSize)
+
+            mutableString.setAttributes([NSAttributedString.Key.font: boldFont], range: range)
+        }
+
+        mutableString.insert(emoji: emoji, view: label)
+        mutableString.resizeAttachments(toLineHeight: label.font.lineHeight)
+
+        return mutableString
+    }
 }

Localizations/Localizable.strings

@@ -93,6 +93,13 @@
 "filter.context.thread" = "Conversations";
 "filter.context.account" = "Profiles";
 "filter.context.unknown" = "Unknown context";
+"notifications" = "Notifications";
+"notifications.reblogged-your-status" = "%@ boosted your status";
+"notifications.favourited-your-status" = "%@ favorited your status";
+"notifications.followed-you" = "%@ followed you";
+"notifications.poll-ended" = "A poll you have voted in has ended";
+"notifications.your-poll-ended" = "Your poll has ended";
+"notifications.unknown" = "Notification from %@";
 "status.reblogged-by" = "%@ boosted";
 "status.pinned-post" = "Pinned post";
 "status.show-more" = "Show More";

Mastodon/Sources/Mastodon/Entities/MastodonNotification.swift

@@ -0,0 +1,31 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+public struct MastodonNotification: Codable, Hashable {
+    public let id: String
+    public let type: NotificationType
+    public let account: Account
+    public let status: Status?
+
+    public init(id: String, type: MastodonNotification.NotificationType, account: Account, status: Status?) {
+        self.id = id
+        self.type = type
+        self.account = account
+        self.status = status
+    }
+}
+
+extension MastodonNotification {
+    public enum NotificationType: String, Codable, Unknowable {
+        case follow
+        case mention
+        case reblog
+        case favourite
+        case poll
+        case followRequest = "follow_request"
+        case unknown
+
+        public static var unknownCase: Self { .unknown }
+    }
+}

MastodonAPI/Sources/MastodonAPI/Endpoints/NotificationsEndpoint.swift

@@ -0,0 +1,24 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import HTTP
+import Mastodon
+
+public enum NotificationsEndpoint {
+    case notifications
+}
+
+extension NotificationsEndpoint: Endpoint {
+    public typealias ResultType = [MastodonNotification]
+
+    public var pathComponentsInContext: [String] {
+        ["notifications"]
+    }
+
+    public var method: HTTPMethod {
+        switch self {
+        case .notifications:
+            return .get
+        }
+    }
+}

Metatext.xcodeproj/project.pbxproj

@@ -14,6 +14,9 @@
 		D01F41D924F880C400D55A2D /* TouchFallthroughTextView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D01F41D624F880C400D55A2D /* TouchFallthroughTextView.swift */; };
 		D01F41E424F8889700D55A2D /* StatusAttachmentsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D01F41E224F8889700D55A2D /* StatusAttachmentsView.swift */; };
 		D02E1F95250B13210071AD56 /* SafariView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D02E1F94250B13210071AD56 /* SafariView.swift */; };
+		D036AA02254B6101009094DF /* NotificationListCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D036AA01254B6101009094DF /* NotificationListCell.swift */; };
+		D036AA07254B6118009094DF /* NotificationView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D036AA06254B6118009094DF /* NotificationView.swift */; };
+		D036AA0C254B612B009094DF /* NotificationContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D036AA0B254B612B009094DF /* NotificationContentConfiguration.swift */; };
 		D03B1B2A253818F3008F964B /* MediaPreferencesView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D03B1B29253818F3008F964B /* MediaPreferencesView.swift */; };
 		D04226FD2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04226FC2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift */; };
 		D0625E59250F092900502611 /* StatusListCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0625E58250F092900502611 /* StatusListCell.swift */; };
@@ -118,6 +121,9 @@
 		D01F41D624F880C400D55A2D /* TouchFallthroughTextView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TouchFallthroughTextView.swift; sourceTree = "<group>"; };
 		D01F41E224F8889700D55A2D /* StatusAttachmentsView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = StatusAttachmentsView.swift; sourceTree = "<group>"; };
 		D02E1F94250B13210071AD56 /* SafariView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SafariView.swift; sourceTree = "<group>"; };
+		D036AA01254B6101009094DF /* NotificationListCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationListCell.swift; sourceTree = "<group>"; };
+		D036AA06254B6118009094DF /* NotificationView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationView.swift; sourceTree = "<group>"; };
+		D036AA0B254B612B009094DF /* NotificationContentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationContentConfiguration.swift; sourceTree = "<group>"; };
 		D03B1B29253818F3008F964B /* MediaPreferencesView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MediaPreferencesView.swift; sourceTree = "<group>"; };
 		D04226FC2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StartupAndSyncingPreferencesView.swift; sourceTree = "<group>"; };
 		D047FA8C24C3E21200AF17C5 /* Metatext.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Metatext.app; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -339,7 +345,10 @@
 				D0E569DF252931B100FA1D72 /* LoadMoreContentConfiguration.swift */,
 				D0E569DA2529319100FA1D72 /* LoadMoreView.swift */,
 				D03B1B29253818F3008F964B /* MediaPreferencesView.swift */,
+				D036AA0B254B612B009094DF /* NotificationContentConfiguration.swift */,
+				D036AA01254B6101009094DF /* NotificationListCell.swift */,
 				D0C7D42D24F76169001EBDBB /* NotificationTypesPreferencesView.swift */,
+				D036AA06254B6118009094DF /* NotificationView.swift */,
 				D0FE1C8E253686F9003EF1EB /* PlayerView.swift */,
 				D08B8D812544D80000B1EBEF /* PollOptionButton.swift */,
 				D08B8D8C2544E6EC00B1EBEF /* PollResultView.swift */,
@@ -599,6 +608,7 @@
 				D0F0B126251A90F400942152 /* AccountListCell.swift in Sources */,
 				D0B32F50250B373600311912 /* RegistrationView.swift in Sources */,
 				D08B8D612540DE3B00B1EBEF /* ZoomDismissalInteractionController.swift in Sources */,
+				D036AA07254B6118009094DF /* NotificationView.swift in Sources */,
 				D0E569E0252931B100FA1D72 /* LoadMoreContentConfiguration.swift in Sources */,
 				D0FE1C9825368A9D003EF1EB /* PlayerCache.swift in Sources */,
 				D0F0B136251AA12700942152 /* CollectionItem+Extensions.swift in Sources */,
@@ -609,6 +619,7 @@
 				D0F0B12E251A97E400942152 /* TableViewController.swift in Sources */,
 				D0FE1C8F253686F9003EF1EB /* PlayerView.swift in Sources */,
 				D0F0B113251A86A000942152 /* AccountContentConfiguration.swift in Sources */,
+				D036AA02254B6101009094DF /* NotificationListCell.swift in Sources */,
 				D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */,
 				D01F41D924F880C400D55A2D /* TouchFallthroughTextView.swift in Sources */,
 				D0C7D4D624F7616A001EBDBB /* NSMutableAttributedString+Extensions.swift in Sources */,
@@ -636,6 +647,7 @@
 				D01EF22425182B1F00650C6B /* AccountHeaderView.swift in Sources */,
 				D0EA59482522B8B600804347 /* ViewConstants.swift in Sources */,
 				D04226FD2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift in Sources */,
+				D036AA0C254B612B009094DF /* NotificationContentConfiguration.swift in Sources */,
 				D0C7D49824F7616A001EBDBB /* CustomEmojiText.swift in Sources */,
 				D08B8D3D253F929E00B1EBEF /* ImageViewController.swift in Sources */,
 				D0B8510C25259E56004E0744 /* LoadMoreCell.swift in Sources */,

ServiceLayer/Sources/ServiceLayer/Services/IdentityService.swift

@@ -208,6 +208,10 @@ public extension IdentityService {
     func service(timeline: Timeline) -> TimelineService {
         TimelineService(timeline: timeline, mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
     }
+
+    func notificationsService() -> NotificationsService {
+        NotificationsService(mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
+    }
 }
 
 private extension IdentityService {

ServiceLayer/Sources/ServiceLayer/Services/NavigationService.swift

@@ -72,6 +72,13 @@ public extension NavigationService {
     func loadMoreService(loadMore: LoadMore) -> LoadMoreService {
         LoadMoreService(loadMore: loadMore, mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
     }
+
+    func notificationService(notification: MastodonNotification) -> NotificationService {
+        NotificationService(
+            notification: notification,
+            mastodonAPIClient: mastodonAPIClient,
+            contentDatabase: contentDatabase)
+    }
 }
 
 private extension NavigationService {

ServiceLayer/Sources/ServiceLayer/Services/NotificationService.swift

@@ -0,0 +1,24 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import DB
+import Foundation
+import Mastodon
+import MastodonAPI
+
+public struct NotificationService {
+    public let notification: MastodonNotification
+    public let navigationService: NavigationService
+    private let mastodonAPIClient: MastodonAPIClient
+    private let contentDatabase: ContentDatabase
+
+    init(notification: MastodonNotification, mastodonAPIClient: MastodonAPIClient, contentDatabase: ContentDatabase) {
+        self.notification = notification
+        self.navigationService = NavigationService(
+            mastodonAPIClient: mastodonAPIClient,
+            contentDatabase: contentDatabase,
+            status: nil)
+        self.mastodonAPIClient = mastodonAPIClient
+        self.contentDatabase = contentDatabase
+    }
+}

ServiceLayer/Sources/ServiceLayer/Services/NotificationsService.swift

@@ -0,0 +1,50 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import DB
+import Foundation
+import Mastodon
+import MastodonAPI
+
+public struct NotificationsService {
+    public let sections: AnyPublisher<[[CollectionItem]], Error>
+    public let nextPageMaxId: AnyPublisher<String, Never>
+    public let navigationService: NavigationService
+
+    private let mastodonAPIClient: MastodonAPIClient
+    private let contentDatabase: ContentDatabase
+    private let nextPageMaxIdSubject: CurrentValueSubject<String, Never>
+
+    init(mastodonAPIClient: MastodonAPIClient, contentDatabase: ContentDatabase) {
+        self.mastodonAPIClient = mastodonAPIClient
+        self.contentDatabase = contentDatabase
+
+        let nextPageMaxIdSubject = CurrentValueSubject<String, Never>(String(Int.max))
+
+        self.nextPageMaxIdSubject  = nextPageMaxIdSubject
+        sections = contentDatabase.notificationsPublisher()
+            .handleEvents(receiveOutput: {
+                guard case let .notification(notification, _) = $0.last?.last,
+                      notification.id < nextPageMaxIdSubject.value
+                else { return }
+
+                nextPageMaxIdSubject.send(notification.id)
+            })
+            .eraseToAnyPublisher()
+        nextPageMaxId = nextPageMaxIdSubject.eraseToAnyPublisher()
+        navigationService = NavigationService(mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
+    }
+}
+
+extension NotificationsService: CollectionService {
+    public func request(maxId: String?, minId: String?) -> AnyPublisher<Never, Error> {
+        mastodonAPIClient.pagedRequest(NotificationsEndpoint.notifications, maxId: maxId, minId: minId)
+            .handleEvents(receiveOutput: {
+                guard let maxId = $0.info.maxId, maxId < nextPageMaxIdSubject.value else { return }
+
+                nextPageMaxIdSubject.send(maxId)
+            })
+            .flatMap { contentDatabase.insert(notifications: $0.result) }
+            .eraseToAnyPublisher()
+    }
+}

ViewModels/Sources/ViewModels/AccountViewModel.swift

@@ -28,7 +28,9 @@ public extension AccountViewModel {
         }
     }
 
-    var displayName: String { accountService.account.displayName }
+    var displayName: String {
+        accountService.account.displayName.isEmpty ? accountService.account.acct : accountService.account.displayName
+    }
 
     var accountName: String { "@".appending(accountService.account.acct) }
 
@@ -36,6 +38,8 @@ public extension AccountViewModel {
 
     var emoji: [Emoji] { accountService.account.emojis }
 
+    var isSelf: Bool { accountService.account.id == identification.identity.account?.id }
+
     func avatarURL(profile: Bool = false) -> URL {
         if !identification.appPreferences.shouldReduceMotion,
            (identification.appPreferences.animateAvatars == .everywhere

ViewModels/Sources/ViewModels/CollectionItemsViewModel.swift

@@ -126,6 +126,18 @@ extension CollectionItemsViewModel: CollectionViewModel {
                 .navigation(.profile(collectionService
                                         .navigationService
                                         .profileService(account: account))))
+        case let .notification(notification, _):
+            if let status = notification.status {
+                eventsSubject.send(
+                    .navigation(.collection(collectionService
+                                                .navigationService
+                                                .contextService(id: status.displayStatus.id))))
+            } else {
+                eventsSubject.send(
+                    .navigation(.profile(collectionService
+                                            .navigationService
+                                            .profileService(account: notification.account))))
+            }
         }
     }
 
@@ -195,6 +207,27 @@ extension CollectionItemsViewModel: CollectionViewModel {
 
             cache(viewModel: viewModel, forItem: item)
 
+            return viewModel
+        case let .notification(notification, statusConfiguration):
+            let viewModel: CollectionItemViewModel
+
+            if let cachedViewModel = cachedViewModel {
+                viewModel = cachedViewModel
+            } else if let status = notification.status, let statusConfiguration = statusConfiguration {
+                let statusViewModel = StatusViewModel(
+                    statusService: collectionService.navigationService.statusService(status: status),
+                    identification: identification)
+                statusViewModel.configuration = statusConfiguration
+                viewModel = statusViewModel
+                cache(viewModel: viewModel, forItem: item)
+            } else {
+                viewModel = NotificationViewModel(
+                    notificationService: collectionService.navigationService.notificationService(
+                        notification: notification),
+                    identification: identification)
+                cache(viewModel: viewModel, forItem: item)
+            }
+
             return viewModel
         }
     }

ViewModels/Sources/ViewModels/NavigationViewModel.swift

@@ -18,9 +18,23 @@ public final class NavigationViewModel: ObservableObject {
     @Published public private(set) var timelinesAndLists: [Timeline]
     @Published public var presentingSecondaryNavigation = false
     @Published public var alertItem: AlertItem?
-    public var selectedTab: Tab? = .timelines
     public private(set) var timelineViewModel: CollectionItemsViewModel
 
+    public var notificationsViewModel: CollectionViewModel? {
+        if identification.identity.authenticated {
+            if _notificationsViewModel == nil {
+                _notificationsViewModel = CollectionItemsViewModel(
+                    collectionService: identification.service.notificationsService(),
+                    identification: identification)
+            }
+
+            return _notificationsViewModel
+        } else {
+            return nil
+        }
+    }
+
+    private var _notificationsViewModel: CollectionViewModel?
     private var cancellables = Set<AnyCancellable>()
 
     public init(identification: Identification) {

ViewModels/Sources/ViewModels/NotificationViewModel.swift

@@ -0,0 +1,31 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import Foundation
+import Mastodon
+import ServiceLayer
+
+public final class NotificationViewModel: CollectionItemViewModel, ObservableObject {
+    public let accountViewModel: AccountViewModel
+    public let events: AnyPublisher<AnyPublisher<CollectionItemEvent, Error>, Never>
+
+    private let notificationService: NotificationService
+    private let identification: Identification
+    private let eventsSubject = PassthroughSubject<AnyPublisher<CollectionItemEvent, Error>, Never>()
+
+    init(notificationService: NotificationService, identification: Identification) {
+        self.notificationService = notificationService
+        self.identification = identification
+        self.accountViewModel = AccountViewModel(
+            accountService: notificationService.navigationService.accountService(
+                account: notificationService.notification.account),
+            identification: identification)
+        self.events = eventsSubject.eraseToAnyPublisher()
+    }
+}
+
+public extension NotificationViewModel {
+    var type: MastodonNotification.NotificationType {
+        notificationService.notification.type
+    }
+}

Views/NotificationContentConfiguration.swift

@@ -0,0 +1,18 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+struct NotificationContentConfiguration {
+    let viewModel: NotificationViewModel
+}
+
+extension NotificationContentConfiguration: UIContentConfiguration {
+    func makeContentView() -> UIView & UIContentView {
+        NotificationView(configuration: self)
+    }
+
+    func updated(for state: UIConfigurationState) -> NotificationContentConfiguration {
+        self
+    }
+}

Views/NotificationListCell.swift

@@ -0,0 +1,26 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+class NotificationListCell: UITableViewCell {
+    var viewModel: NotificationViewModel?
+
+    override func updateConfiguration(using state: UICellConfigurationState) {
+        guard let viewModel = viewModel else { return }
+
+        contentConfiguration = NotificationContentConfiguration(viewModel: viewModel).updated(for: state)
+    }
+
+    override func layoutSubviews() {
+        super.layoutSubviews()
+
+        if UIDevice.current.userInterfaceIdiom == .phone {
+            separatorInset.left = 0
+            separatorInset.right = 0
+        } else {
+            separatorInset.left = layoutMargins.left
+            separatorInset.right = layoutMargins.right
+        }
+    }
+}

Views/NotificationView.swift

@@ -0,0 +1,120 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Mastodon
+import UIKit
+
+class NotificationView: UIView {
+    private let iconImageView = UIImageView()
+    private let typeLabel = UILabel()
+    private var notificationConfiguration: NotificationContentConfiguration
+
+    init(configuration: NotificationContentConfiguration) {
+        notificationConfiguration = configuration
+
+        super.init(frame: .zero)
+
+        initialSetup()
+        applyNotificationConfiguration()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+extension NotificationView: UIContentView {
+    var configuration: UIContentConfiguration {
+        get { notificationConfiguration }
+        set {
+            guard let notificationConfiguration = newValue as? NotificationContentConfiguration else { return }
+
+            self.notificationConfiguration = notificationConfiguration
+
+            applyNotificationConfiguration()
+        }
+    }
+}
+
+private extension NotificationView {
+    func initialSetup() {
+        let stackView = UIStackView()
+
+        addSubview(stackView)
+        stackView.translatesAutoresizingMaskIntoConstraints = false
+        stackView.spacing = .compactSpacing
+
+        stackView.addArrangedSubview(iconImageView)
+        iconImageView.setContentHuggingPriority(.required, for: .horizontal)
+
+        stackView.addArrangedSubview(typeLabel)
+        typeLabel.font = .preferredFont(forTextStyle: .body)
+        typeLabel.adjustsFontForContentSizeCategory = true
+
+        NSLayoutConstraint.activate([
+            stackView.leadingAnchor.constraint(equalTo: readableContentGuide.leadingAnchor),
+            stackView.topAnchor.constraint(equalTo: readableContentGuide.topAnchor),
+            stackView.trailingAnchor.constraint(equalTo: readableContentGuide.trailingAnchor),
+            stackView.bottomAnchor.constraint(equalTo: readableContentGuide.bottomAnchor)
+        ])
+    }
+
+    func applyNotificationConfiguration() {
+        let viewModel = notificationConfiguration.viewModel
+
+        switch viewModel.type {
+        case .follow:
+            typeLabel.attributedText = "notifications.followed-you".localizedBolding(
+                displayName: viewModel.accountViewModel.displayName,
+                emoji: viewModel.accountViewModel.emoji,
+                label: typeLabel)
+            iconImageView.tintColor = nil
+        case .reblog:
+            typeLabel.attributedText = "notifications.reblogged-your-status".localizedBolding(
+                displayName: viewModel.accountViewModel.displayName,
+                emoji: viewModel.accountViewModel.emoji,
+                label: typeLabel)
+            iconImageView.tintColor = .systemGreen
+        case .favourite:
+            typeLabel.attributedText = "notifications.favourited-your-status".localizedBolding(
+                displayName: viewModel.accountViewModel.displayName,
+                emoji: viewModel.accountViewModel.emoji,
+                label: typeLabel)
+            iconImageView.tintColor = .systemYellow
+        case .poll:
+            typeLabel.text = NSLocalizedString(
+                viewModel.accountViewModel.isSelf
+                    ? "notifications.your-poll-ended"
+                    : "notifications.poll-ended",
+                comment: "")
+            iconImageView.tintColor = nil
+        default:
+            typeLabel.attributedText = "notifications.unknown".localizedBolding(
+                displayName: viewModel.accountViewModel.displayName,
+                emoji: viewModel.accountViewModel.emoji,
+                label: typeLabel)
+            iconImageView.tintColor = nil
+        }
+
+        iconImageView.image = UIImage(
+            systemName: viewModel.type.systemImageName,
+            withConfiguration: UIImage.SymbolConfiguration(scale: .medium))
+    }
+}
+
+extension MastodonNotification.NotificationType {
+    var systemImageName: String {
+        switch self {
+        case .follow, .followRequest:
+            return "person.badge.plus"
+        case .reblog:
+            return "arrow.2.squarepath"
+        case .favourite:
+            return "star.fill"
+        case .poll:
+            return "chart.bar.doc.horizontal"
+        case .mention, .unknown:
+            return "at"
+        }
+    }
+}

Views/TabNavigationView.swift

@@ -8,13 +8,14 @@ struct TabNavigationView: View {
     @ObservedObject var viewModel: NavigationViewModel
     @EnvironmentObject var rootViewModel: RootViewModel
     @Environment(\.displayScale) var displayScale: CGFloat
+    @State var selectedTab = NavigationViewModel.Tab.timelines
 
     var body: some View {
         Group {
             if viewModel.identification.identity.pending {
                 pendingView
             } else {
-                TabView(selection: $viewModel.selectedTab) {
+                TabView(selection: $selectedTab) {
                     ForEach(viewModel.tabs) { tab in
                         NavigationView {
                             view(tab: tab)
@@ -91,6 +92,15 @@ private extension TabNavigationView {
                         Image(systemName: viewModel.timeline.systemImageName)
                             .padding([.leading, .top, .bottom])
                     })
+        case .notifications:
+            if let notificationsViewModel = viewModel.notificationsViewModel {
+                TableView(viewModel: notificationsViewModel)
+                    .id(tab)
+                    .edgesIgnoringSafeArea(.all)
+                    .navigationTitle("notifications")
+                    .navigationBarTitleDisplayMode(.inline)
+                    .navigationBarItems(leading: secondaryNavigationButton)
+            }
         default: Text(tab.title)
         }
     }