Posting media WIP

DB/Sources/DB/Entities/Composition.swift

@@ -1,20 +1,38 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
+import Combine
 import Foundation
 import GRDB
+import Mastodon
 
 public class Composition {
     public let id: Id
-    public var text: String
+    @Published public var text: String
+    @Published public var attachments: [Attachment]
 
     public init(id: Id, text: String) {
         self.id = id
         self.text = text
+        attachments = []
     }
 }
 
 public extension Composition {
     typealias Id = UUID
+
+    struct Attachment {
+        public let data: Data
+        public let type: Mastodon.Attachment.AttachmentType
+        public let mimeType: String
+        public var description: String?
+        public var focus: Mastodon.Attachment.Meta.Focus?
+
+        public init(data: Data, type: Mastodon.Attachment.AttachmentType, mimeType: String) {
+            self.data = data
+            self.type = type
+            self.mimeType = mimeType
+        }
+    }
 }
 
 extension Composition {

Data Sources/NewStatusDataSource.swift

@@ -4,6 +4,9 @@ import UIKit
 import ViewModels
 
 final class NewStatusDataSource: UICollectionViewDiffableDataSource<Int, Composition.Id> {
+    private let updateQueue =
+        DispatchQueue(label: "com.metabolist.metatext.new-status-data-source.update-queue")
+
     init(collectionView: UICollectionView, viewModelProvider: @escaping (IndexPath) -> CompositionViewModel) {
         let registration = UICollectionView.CellRegistration<CompositionListCell, CompositionViewModel> {
             $0.viewModel = $2
@@ -16,4 +19,12 @@ final class NewStatusDataSource: UICollectionViewDiffableDataSource<Int, Composi
                 item: viewModelProvider(indexPath))
         }
     }
+
+    override func apply(_ snapshot: NSDiffableDataSourceSnapshot<Int, Composition.Id>,
+                        animatingDifferences: Bool = true,
+                        completion: (() -> Void)? = nil) {
+        updateQueue.async {
+            super.apply(snapshot, animatingDifferences: animatingDifferences, completion: completion)
+        }
+    }
 }

Extensions/UIVIewController+Extensions.swift

@@ -0,0 +1,19 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+extension UIViewController {
+    func present(alertItem: AlertItem) {
+        let alertController = UIAlertController(
+            title: nil,
+            message: alertItem.error.localizedDescription,
+            preferredStyle: .alert)
+
+        let okAction = UIAlertAction(title: NSLocalizedString("ok", comment: ""), style: .default) { _ in }
+
+        alertController.addAction(okAction)
+
+        present(alertController, animated: true)
+    }
+}

HTTP/Sources/HTTP/MultipartFormValue.swift

@@ -0,0 +1,27 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+public enum MultipartFormValue {
+    case string(String)
+    case data(Data, filename: String, mimeType: String)
+}
+
+extension MultipartFormValue {
+    func httpBodyComponent(boundary: String, key: String) -> Data {
+        switch self {
+        case let .string(value):
+            return Data("--\(boundary)\r\nContent-Disposition: form-data; name=\"\(key)\"\r\n\r\n\(value)\r\n".utf8)
+        case let .data(data, filename, mimeType):
+            var component = Data()
+
+            component.append(Data("--\(boundary)\r\n".utf8))
+            component.append(Data("Content-Disposition: form-data; name=\"\(key)\"; filename=\"\(filename)\"\r\n".utf8))
+            component.append(Data("Content-Type: \(mimeType)\r\n\r\n".utf8))
+            component.append(data)
+            component.append(Data("\r\n".utf8))
+
+            return component
+        }
+    }
+}

HTTP/Sources/HTTP/Target.swift

@@ -8,6 +8,7 @@ public protocol Target {
     var method: HTTPMethod { get }
     var queryParameters: [URLQueryItem] { get }
     var jsonBody: [String: Any]? { get }
+    var multipartFormData: [String: MultipartFormValue]? { get }
     var headers: [String: String]? { get }
 }
 
@@ -35,6 +36,17 @@ public extension Target {
         if let jsonBody = jsonBody {
             urlRequest.httpBody = try? JSONSerialization.data(withJSONObject: jsonBody)
             urlRequest.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
+        } else if let multipartFormData = multipartFormData {
+            let boundary = "Boundary-\(UUID().uuidString)"
+            var httpBody = Data()
+
+            for (key, value) in multipartFormData {
+                httpBody.append(value.httpBodyComponent(boundary: boundary, key: key))
+            }
+
+            httpBody.append(Data("--\(boundary)--".utf8))
+            urlRequest.httpBody = httpBody
+            urlRequest.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
         }
 
         return urlRequest

Localizations/Localizable.strings

@@ -58,6 +58,7 @@
 "messages" = "Messages";
 "ok" = "OK";
 "pending.pending-confirmation" = "Your account is pending confirmation";
+"post" = "Post";
 "preferences" = "Preferences";
 "preferences.app" = "App Preferences";
 "preferences.blocked-domains" = "Blocked Domains";

MastodonAPI/Sources/MastodonAPI/Endpoint.swift

@@ -11,6 +11,7 @@ public protocol Endpoint {
     var method: HTTPMethod { get }
     var queryParameters: [URLQueryItem] { get }
     var jsonBody: [String: Any]? { get }
+    var multipartFormData: [String: MultipartFormValue]? { get }
     var headers: [String: String]? { get }
 }
 
@@ -33,5 +34,7 @@ public extension Endpoint {
 
     var jsonBody: [String: Any]? { nil }
 
+    var multipartFormData: [String: MultipartFormValue]? { nil }
+
     var headers: [String: String]? { nil }
 }

MastodonAPI/Sources/MastodonAPI/Endpoints/AttachmentEndpoint.swift

@@ -0,0 +1,50 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import HTTP
+import Mastodon
+
+public enum AttachmentEndpoint {
+    case create(data: Data, mimeType: String, description: String?, focus: Attachment.Meta.Focus?)
+}
+
+extension AttachmentEndpoint: Endpoint {
+    public typealias ResultType = Attachment
+
+    public var context: [String] {
+        defaultContext + ["media"]
+    }
+
+    public var pathComponentsInContext: [String] {
+        switch self {
+        case .create:
+            return []
+        }
+    }
+
+    public var multipartFormData: [String: MultipartFormValue]? {
+        switch self {
+        case let .create(data, mimeType, description, focus):
+            var params = [String: MultipartFormValue]()
+
+            params["file"] = .data(data, filename: UUID().uuidString, mimeType: mimeType)
+
+            if let description = description {
+                params["description"] = .string(description)
+            }
+
+            if let focus = focus {
+                params["focus"] = .string("\(focus.x),\(focus.y)")
+            }
+
+            return params
+        }
+    }
+
+    public var method: HTTPMethod {
+        switch self {
+        case .create:
+            return .post
+        }
+    }
+}

MastodonAPI/Sources/MastodonAPI/Endpoints/StatusEndpoint.swift

@@ -10,6 +10,25 @@ public enum StatusEndpoint {
     case unfavourite(id: Status.Id)
     case bookmark(id: Status.Id)
     case unbookmark(id: Status.Id)
+    case post(Components)
+}
+
+public extension StatusEndpoint {
+    struct Components {
+        public var text: String?
+
+        public init() {}
+    }
+}
+
+extension StatusEndpoint.Components {
+    var jsonBody: [String: Any]? {
+        var params = [String: Any]()
+
+        params["status"] = text
+
+        return params
+    }
 }
 
 extension StatusEndpoint: Endpoint {
@@ -31,6 +50,17 @@ extension StatusEndpoint: Endpoint {
             return [id, "bookmark"]
         case let .unbookmark(id):
             return [id, "unbookmark"]
+        case .post:
+            return []
+        }
+    }
+
+    public var jsonBody: [String: Any]? {
+        switch self {
+        case let .post(components):
+            return components.jsonBody
+        default:
+            return nil
         }
     }
 
@@ -38,7 +68,7 @@ extension StatusEndpoint: Endpoint {
         switch self {
         case .status:
             return .get
-        case .favourite, .unfavourite, .bookmark, .unbookmark:
+        case .favourite, .unfavourite, .bookmark, .unbookmark, .post:
             return .post
         }
     }

MastodonAPI/Sources/MastodonAPI/MastodonAPITarget.swift

@@ -26,6 +26,8 @@ extension MastodonAPITarget: DecodableTarget {
 
     public var jsonBody: [String: Any]? { endpoint.jsonBody }
 
+    public var multipartFormData: [String: MultipartFormValue]? { endpoint.multipartFormData }
+
     public var headers: [String: String]? {
         var headers = endpoint.headers
 

Metatext.xcodeproj/project.pbxproj

@@ -98,6 +98,10 @@
 		D0E5362024E3EB4D00FB1CE1 /* Notification Service Extension.appex in Embed App Extensions */ = {isa = PBXBuildFile; fileRef = D0E5361924E3EB4D00FB1CE1 /* Notification Service Extension.appex */; settings = {ATTRIBUTES = (RemoveHeadersOnCopy, ); }; };
 		D0E569DB2529319100FA1D72 /* LoadMoreView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E569DA2529319100FA1D72 /* LoadMoreView.swift */; };
 		D0E569E0252931B100FA1D72 /* LoadMoreContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E569DF252931B100FA1D72 /* LoadMoreContentConfiguration.swift */; };
+		D0E7AD3925870B13005F5E2D /* UIVIewController+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E7AD3825870B13005F5E2D /* UIVIewController+Extensions.swift */; };
+		D0E7AD4225870C79005F5E2D /* UIVIewController+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E7AD3825870B13005F5E2D /* UIVIewController+Extensions.swift */; };
+		D0E9F9AA258450B300EF503D /* CompositionInputAccessoryView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E9F9A9258450B300EF503D /* CompositionInputAccessoryView.swift */; };
+		D0E9F9AB258450B300EF503D /* CompositionInputAccessoryView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E9F9A9258450B300EF503D /* CompositionInputAccessoryView.swift */; };
 		D0EA59402522AC8700804347 /* CardView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0EA593F2522AC8700804347 /* CardView.swift */; };
 		D0EA59482522B8B600804347 /* ViewConstants.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0EA59472522B8B600804347 /* ViewConstants.swift */; };
 		D0F0B10E251A868200942152 /* AccountView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0F0B10D251A868200942152 /* AccountView.swift */; };
@@ -252,6 +256,8 @@
 		D0E5362824E4A06B00FB1CE1 /* Notification Service Extension.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = "Notification Service Extension.entitlements"; sourceTree = "<group>"; };
 		D0E569DA2529319100FA1D72 /* LoadMoreView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoadMoreView.swift; sourceTree = "<group>"; };
 		D0E569DF252931B100FA1D72 /* LoadMoreContentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoadMoreContentConfiguration.swift; sourceTree = "<group>"; };
+		D0E7AD3825870B13005F5E2D /* UIVIewController+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIVIewController+Extensions.swift"; sourceTree = "<group>"; };
+		D0E9F9A9258450B300EF503D /* CompositionInputAccessoryView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CompositionInputAccessoryView.swift; sourceTree = "<group>"; };
 		D0EA593F2522AC8700804347 /* CardView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CardView.swift; sourceTree = "<group>"; };
 		D0EA59472522B8B600804347 /* ViewConstants.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewConstants.swift; sourceTree = "<group>"; };
 		D0F0B10D251A868200942152 /* AccountView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AccountView.swift; sourceTree = "<group>"; };
@@ -427,6 +433,7 @@
 				D0F0B10D251A868200942152 /* AccountView.swift */,
 				D0C7D42424F76169001EBDBB /* AddIdentityView.swift */,
 				D08E52E2257D747400FA2C5F /* CompositionContentConfiguration.swift */,
+				D0E9F9A9258450B300EF503D /* CompositionInputAccessoryView.swift */,
 				D08E52DB257D742B00FA2C5F /* CompositionListCell.swift */,
 				D08E52ED257D757100FA2C5F /* CompositionView.swift */,
 				D007023D25562A2800F38136 /* ConversationAvatarsView.swift */,
@@ -514,6 +521,7 @@
 				D0C7D46A24F76169001EBDBB /* String+Extensions.swift */,
 				D08E512025786A6600FA2C5F /* UIButton+Extensions.swift */,
 				D0C7D46C24F76169001EBDBB /* UIColor+Extensions.swift */,
+				D0E7AD3825870B13005F5E2D /* UIVIewController+Extensions.swift */,
 				D0030981250C6C8500EACB32 /* URL+Extensions.swift */,
 				D0C7D46F24F76169001EBDBB /* View+Extensions.swift */,
 			);
@@ -755,6 +763,7 @@
 				D08E52E3257D747400FA2C5F /* CompositionContentConfiguration.swift in Sources */,
 				D0F0B136251AA12700942152 /* CollectionItem+Extensions.swift in Sources */,
 				D007023E25562A2800F38136 /* ConversationAvatarsView.swift in Sources */,
+				D0E7AD3925870B13005F5E2D /* UIVIewController+Extensions.swift in Sources */,
 				D0625E5D250F0B5C00502611 /* StatusContentConfiguration.swift in Sources */,
 				D0BEB1F324F8EE8C001B0F04 /* StatusAttachmentView.swift in Sources */,
 				D0C7D49A24F7616A001EBDBB /* TableView.swift in Sources */,
@@ -768,6 +777,7 @@
 				D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */,
 				D01F41D924F880C400D55A2D /* TouchFallthroughTextView.swift in Sources */,
 				D0C7D4D624F7616A001EBDBB /* NSMutableAttributedString+Extensions.swift in Sources */,
+				D0E9F9AA258450B300EF503D /* CompositionInputAccessoryView.swift in Sources */,
 				D0625E59250F092900502611 /* StatusListCell.swift in Sources */,
 				D0E569DB2529319100FA1D72 /* LoadMoreView.swift in Sources */,
 				D0C7D49D24F7616A001EBDBB /* PostingReadingPreferencesView.swift in Sources */,
@@ -836,8 +846,10 @@
 				D08E52A6257C61C000FA2C5F /* ShareExtensionNavigationViewController.swift in Sources */,
 				D08E52BD257C635800FA2C5F /* NewStatusViewController.swift in Sources */,
 				D08E52D2257C811200FA2C5F /* ShareExtensionError+Extensions.swift in Sources */,
+				D0E9F9AB258450B300EF503D /* CompositionInputAccessoryView.swift in Sources */,
 				D0F2D4DB257F018300986197 /* Array+Extensions.swift in Sources */,
 				D08E52DD257D742B00FA2C5F /* CompositionListCell.swift in Sources */,
+				D0E7AD4225870C79005F5E2D /* UIVIewController+Extensions.swift in Sources */,
 				D08E52EF257D757100FA2C5F /* CompositionView.swift in Sources */,
 				D0F2D5452581ABAB00986197 /* KingfisherOptionsInfo+Extensions.swift in Sources */,
 				D08E52C7257C7AEE00FA2C5F /* ShareErrorViewController.swift in Sources */,

ServiceLayer/Sources/ServiceLayer/Services/IdentityService.swift

@@ -206,6 +206,28 @@ public extension IdentityService {
             .eraseToAnyPublisher()
     }
 
+    func post(compositions: [Composition]) -> AnyPublisher<Never, Error> {
+        guard let composition = compositions.first else { fatalError() }
+        guard let attachment = composition.attachments.first else { fatalError() }
+        return mastodonAPIClient.request(AttachmentEndpoint.create(
+                                            data: attachment.data,
+                                            mimeType: attachment.mimeType,
+                                            description: attachment.description,
+                                            focus: attachment.focus))
+            .print()
+            .ignoreOutput()
+            .eraseToAnyPublisher()
+//        var components = StatusEndpoint.Components()
+//
+//        if !composition.text.isEmpty {
+//            components.text = composition.text
+//        }
+//
+//        return mastodonAPIClient.request(StatusEndpoint.post(components))
+//            .ignoreOutput()
+//            .eraseToAnyPublisher()
+    }
+
     func service(timeline: Timeline) -> TimelineService {
         TimelineService(timeline: timeline, mastodonAPIClient: mastodonAPIClient, contentDatabase: contentDatabase)
     }

ServiceLayer/Sources/ServiceLayer/Services/InstanceURLService.swift

@@ -75,6 +75,7 @@ private struct UpdatedFilterTarget: DecodableTarget {
     let method = HTTPMethod.get
     let queryParameters: [URLQueryItem] = []
     let jsonBody: [String: Any]? = nil
+    let multipartFormData: [String: MultipartFormValue]? = nil
     let headers: [String: String]? = nil
 }
 

ServiceLayer/Sources/ServiceLayer/Services/MediaProcessingService.swift

@@ -0,0 +1,100 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import Foundation
+import ImageIO
+import Mastodon
+import UniformTypeIdentifiers
+
+enum MediaProcessingError: Error {
+    case invalidMimeType
+    case fileURLNotFound
+    case unsupportedType
+    case unableToCreateImageSource
+    case unableToDownsample
+    case unableToCreateImageDataDestination
+}
+
+public struct MediaProcessingService {}
+
+public extension MediaProcessingService {
+    static func attachment(itemProvider: NSItemProvider) -> AnyPublisher<Composition.Attachment, Error> {
+        let registeredTypes = itemProvider.registeredTypeIdentifiers.compactMap(UTType.init)
+
+        guard let uniformType = registeredTypes.first(where: {
+            guard let mimeType = $0.preferredMIMEType else { return false }
+
+            return !Self.unuploadableMimeTypes.contains(mimeType)
+        }),
+              let mimeType = uniformType.preferredMIMEType else {
+            return Fail(error: MediaProcessingError.invalidMimeType).eraseToAnyPublisher()
+        }
+
+        let type: Attachment.AttachmentType
+
+        if uniformType.conforms(to: .image) {
+            type = .image
+        } else if uniformType.conforms(to: .movie) {
+            type = .video
+        } else if uniformType.conforms(to: .audio) {
+            type = .audio
+        } else if uniformType.conforms(to: .video), uniformType == .mpeg4Movie {
+            type = .gifv
+        } else {
+            type = .unknown
+        }
+
+        return Future<Data, Error> { promise in
+            itemProvider.loadFileRepresentation(forTypeIdentifier: uniformType.identifier) { url, error in
+                if let error = error {
+                    return promise(.failure(error))
+                }
+
+                guard let url = url else { return promise(.failure(MediaProcessingError.fileURLNotFound)) }
+
+                if uniformType.conforms(to: .image) {
+                    return promise(imageData(url: url, type: uniformType))
+                } else {
+                    do {
+                        return try promise(.success(Data(contentsOf: url)))
+                    } catch {
+                        return promise(.failure(error))
+                    }
+                }
+            }
+        }
+        .map { Composition.Attachment(data: $0, type: type, mimeType: mimeType) }
+        .eraseToAnyPublisher()
+    }
+}
+
+private extension MediaProcessingService {
+    static let unuploadableMimeTypes: Set<String> = [UTType.heic.preferredMIMEType!]
+    static let imageSourceOptions =  [kCGImageSourceShouldCache: false] as CFDictionary
+    static let thumbnailOptions = [
+        kCGImageSourceCreateThumbnailFromImageAlways: true,
+        kCGImageSourceCreateThumbnailWithTransform: true,
+        kCGImageSourceThumbnailMaxPixelSize: 1280
+    ] as CFDictionary
+
+    static func imageData(url: URL, type: UTType) -> Result<Data, Error> {
+        guard let source = CGImageSourceCreateWithURL(url as CFURL, Self.imageSourceOptions) else {
+            return .failure(MediaProcessingError.unableToCreateImageSource)
+        }
+
+        guard let image = CGImageSourceCreateThumbnailAtIndex(source, 0, thumbnailOptions) else {
+            return .failure(MediaProcessingError.unableToDownsample)
+        }
+
+        let data = NSMutableData()
+
+        guard let imageDestination = CGImageDestinationCreateWithData(data, type.identifier as CFString, 1, nil) else {
+            return .failure(MediaProcessingError.unableToCreateImageDataDestination)
+        }
+
+        CGImageDestinationAddImage(imageDestination, image, nil)
+        CGImageDestinationFinalize(imageDestination)
+
+        return .success(data as Data)
+    }
+}

View Controllers/NewStatusViewController.swift

@@ -2,12 +2,19 @@
 
 import Combine
 import Kingfisher
+import PhotosUI
 import UIKit
 import ViewModels
 
 class NewStatusViewController: UICollectionViewController {
     private let viewModel: NewStatusViewModel
     private let isShareExtension: Bool
+    private let postButton = UIBarButtonItem(
+        title: NSLocalizedString("post", comment: ""),
+        style: .done,
+        target: nil,
+        action: nil)
+    private var attachMediaTo: CompositionViewModel?
     private var cancellables = Set<AnyCancellable>()
 
     private lazy var dataSource: NewStatusDataSource = {
@@ -22,14 +29,6 @@ class NewStatusViewController: UICollectionViewController {
         let layout = UICollectionViewCompositionalLayout.list(using: configuration)
 
         super.init(collectionViewLayout: layout)
-
-        viewModel.$identification
-            .sink { [weak self] in
-                guard let self = self else { return }
-
-                self.setupBarButtonItems(identification: $0)
-            }
-            .store(in: &cancellables)
     }
 
     @available(*, unavailable)
@@ -44,22 +43,49 @@ class NewStatusViewController: UICollectionViewController {
 
         view.backgroundColor = .systemBackground
 
+        postButton.primaryAction = UIAction(title: NSLocalizedString("post", comment: "")) { [weak self] _ in
+            self?.viewModel.post()
+        }
+
         setupBarButtonItems(identification: viewModel.identification)
 
+        viewModel.$identification
+            .sink { [weak self] in
+                guard let self = self else { return }
+
+                self.setupBarButtonItems(identification: $0)
+            }
+            .store(in: &cancellables)
+
         viewModel.$compositionViewModels.sink { [weak self] in
-            self?.dataSource.apply([$0.map(\.composition.id)].snapshot()) {
+            guard let self = self else { return }
-                DispatchQueue.main.async {
+
-                    if let collectionView = self?.collectionView,
+            let oldSnapshot = self.dataSource.snapshot()
-                       collectionView.indexPathsForSelectedItems?.isEmpty ?? false {
+            let newSnapshot = [$0.map(\.composition.id)].snapshot()
-                        collectionView.selectItem(
+            let diff = newSnapshot.itemIdentifiers.difference(from: oldSnapshot.itemIdentifiers)
-                            at: collectionView.indexPathsForVisibleItems.first,
+
-                            animated: false,
+            self.dataSource.apply(newSnapshot) {
-                            scrollPosition: .top)
+                if case let .insert(_, id, _) = diff.insertions.first,
-                    }
+                   let indexPath = self.dataSource.indexPath(for: id) {
+                    self.collectionView.selectItem(at: indexPath, animated: false, scrollPosition: .top)
                 }
             }
         }
         .store(in: &cancellables)
+
+        viewModel.$compositionViewModels
+            .flatMap { Publishers.MergeMany($0.map(\.composition.$text)) }
+            .sink { [weak self] _ in self?.collectionView.collectionViewLayout.invalidateLayout() }
+            .store(in: &cancellables)
+
+        viewModel.$canPost.sink { [weak self] in self?.postButton.isEnabled = $0 }.store(in: &cancellables)
+
+        viewModel.events.sink { [weak self] in self?.handle(event: $0) }.store(in: &cancellables)
+
+        viewModel.$alertItem
+            .compactMap { $0 }
+            .sink { [weak self] in self?.present(alertItem: $0) }
+            .store(in: &cancellables)
     }
 
     override func didMove(toParent parent: UIViewController?) {
@@ -68,12 +94,6 @@ class NewStatusViewController: UICollectionViewController {
         setupBarButtonItems(identification: viewModel.identification)
     }
 
-    override func collectionView(_ collectionView: UICollectionView,
-                                 willDisplay cell: UICollectionViewCell,
-                                 forItemAt indexPath: IndexPath) {
-        ((cell as? CompositionListCell)?.contentView as? CompositionView)?.textView.delegate = self
-    }
-
     func setupBarButtonItems(identification: Identification) {
         let target = isShareExtension ? self : parent
         let closeButton = UIBarButtonItem(
@@ -84,6 +104,7 @@ class NewStatusViewController: UICollectionViewController {
         target?.navigationItem.titleView = viewModel.canChangeIdentity
             ? changeIdentityButton(identification: identification)
             : nil
+        target?.navigationItem.rightBarButtonItem = postButton
     }
 
     func dismiss() {
@@ -95,9 +116,14 @@ class NewStatusViewController: UICollectionViewController {
     }
 }
 
-extension NewStatusViewController: UITextViewDelegate {
+extension NewStatusViewController: PHPickerViewControllerDelegate {
-    func textViewDidChange(_ textView: UITextView) {
+    func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
-        collectionView.collectionViewLayout.invalidateLayout()
+        dismiss(animated: true)
+
+        guard let result = results.first else { return }
+
+        attachMediaTo?.attach(itemProvider: result.itemProvider)
+        attachMediaTo = nil
     }
 }
 
@@ -139,4 +165,22 @@ private extension NewStatusViewController {
 
         return changeIdentityButton
     }
+
+    func handle(event: CompositionViewModel.Event) {
+        switch event {
+        case let .presentMediaPicker(compositionViewModel):
+            attachMediaTo = compositionViewModel
+
+            var configuration = PHPickerConfiguration()
+
+            configuration.preferredAssetRepresentationMode = .current
+
+            let picker = PHPickerViewController(configuration: configuration)
+
+            picker.delegate = self
+            present(picker, animated: true)
+        default:
+            break
+        }
+    }
 }

ViewModels/Sources/ViewModels/CompositionViewModel.swift

@@ -7,13 +7,39 @@ import ServiceLayer
 
 public final class CompositionViewModel: ObservableObject {
     public let composition: Composition
+    @Published public private(set) var isPostable = false
     @Published public private(set) var identification: Identification
 
+    private let eventsSubject: PassthroughSubject<Event, Never>
+
     init(composition: Composition,
          identification: Identification,
-         identificationPublisher: AnyPublisher<Identification, Never>) {
+         identificationPublisher: AnyPublisher<Identification, Never>,
+         eventsSubject: PassthroughSubject<Event, Never>) {
         self.composition = composition
         self.identification = identification
+        self.eventsSubject = eventsSubject
         identificationPublisher.assign(to: &$identification)
+        composition.$text.map { !$0.isEmpty }.removeDuplicates().assign(to: &$isPostable)
+    }
+}
+
+public extension CompositionViewModel {
+    enum Event {
+        case insertAfter(CompositionViewModel)
+        case presentMediaPicker(CompositionViewModel)
+        case attach(itemProvider: NSItemProvider, viewModel: CompositionViewModel)
+    }
+
+    func presentMediaPicker() {
+        eventsSubject.send(.presentMediaPicker(self))
+    }
+
+    func insert() {
+        eventsSubject.send(.insertAfter(self))
+    }
+
+    func attach(itemProvider: NSItemProvider) {
+        eventsSubject.send(.attach(itemProvider: itemProvider, viewModel: self))
     }
 }

ViewModels/Sources/ViewModels/NewStatusViewModel.swift

@@ -9,11 +9,16 @@ public final class NewStatusViewModel: ObservableObject {
     @Published public private(set) var compositionViewModels = [CompositionViewModel]()
     @Published public private(set) var identification: Identification
     @Published public private(set) var authenticatedIdentities = [Identity]()
+    @Published public var canPost = false
     @Published public var canChangeIdentity = true
     @Published public var alertItem: AlertItem?
+    @Published public private(set) var loading = false
+    public let events: AnyPublisher<CompositionViewModel.Event, Never>
 
     private let allIdentitiesService: AllIdentitiesService
     private let environment: AppEnvironment
+    private let eventsSubject = PassthroughSubject<CompositionViewModel.Event, Never>()
+    private let itemEventsSubject = PassthroughSubject<CompositionViewModel.Event, Never>()
     private var cancellables = Set<AnyCancellable>()
 
     public init(allIdentitiesService: AllIdentitiesService,
@@ -22,13 +27,18 @@ public final class NewStatusViewModel: ObservableObject {
         self.allIdentitiesService = allIdentitiesService
         self.identification = identification
         self.environment = environment
-        compositionViewModels = [CompositionViewModel(
+        events = eventsSubject.eraseToAnyPublisher()
-                                    composition: .init(id: environment.uuid(), text: ""),
+        compositionViewModels = [newCompositionViewModel()]
-                                    identification: identification,
+        itemEventsSubject.sink { [weak self] in self?.handle(event: $0) }.store(in: &cancellables)
-                                    identificationPublisher: $identification.eraseToAnyPublisher())]
         allIdentitiesService.authenticatedIdentitiesPublisher()
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
             .assign(to: &$authenticatedIdentities)
+        $compositionViewModels.flatMap { Publishers.MergeMany($0.map(\.$isPostable)) }
+            .receive(on: DispatchQueue.main) // hack to punt to next run loop, consider refactoring
+            .compactMap { [weak self] _ in self?.compositionViewModels.allSatisfy(\.isPostable) }
+            .combineLatest($loading)
+            .map { $0 && !$1 }
+            .assign(to: &$canPost)
     }
 }
 
@@ -55,4 +65,47 @@ public extension NewStatusViewModel {
             service: identityService,
             environment: environment)
     }
+
+    func post() {
+        identification.service.post(compositions: compositionViewModels.map(\.composition))
+            .receive(on: DispatchQueue.main)
+            .handleEvents(
+                receiveSubscription: { [weak self] _ in self?.loading = true },
+                receiveCompletion: { [weak self] _ in self?.loading = false })
+            .assignErrorsToAlertItem(to: \.alertItem, on: self)
+            .sink { _ in }
+            .store(in: &cancellables)
+    }
+}
+
+private extension NewStatusViewModel {
+    func newCompositionViewModel() -> CompositionViewModel {
+        CompositionViewModel(
+            composition: .init(id: environment.uuid(), text: ""),
+            identification: identification,
+            identificationPublisher: $identification.eraseToAnyPublisher(),
+            eventsSubject: itemEventsSubject)
+    }
+
+    func handle(event: CompositionViewModel.Event) {
+        switch event {
+        case let .insertAfter(viewModel):
+            guard let index = compositionViewModels.firstIndex(where: { $0 === viewModel }) else { return }
+
+            let newViewModel = newCompositionViewModel()
+
+            if index >= compositionViewModels.count - 1 {
+                compositionViewModels.append(newViewModel)
+            } else {
+                compositionViewModels.insert(newViewModel, at: index + 1)
+            }
+        case let .attach(itemProvider, viewModel):
+            MediaProcessingService.attachment(itemProvider: itemProvider)
+                .assignErrorsToAlertItem(to: \.alertItem, on: self)
+                .sink { viewModel.composition.attachments.append($0) }
+                .store(in: &cancellables)
+        default:
+            eventsSubject.send(event)
+        }
+    }
 }

Views/CompositionInputAccessoryView.swift

@@ -0,0 +1,84 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import UIKit
+import ViewModels
+
+class CompositionInputAccessoryView: UIView {
+    private let stackView = UIStackView()
+    private let viewModel: CompositionViewModel
+    private var cancellables = Set<AnyCancellable>()
+
+    init(viewModel: CompositionViewModel) {
+        self.viewModel = viewModel
+
+        super.init(frame: .zero)
+
+        initialSetup()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override var intrinsicContentSize: CGSize {
+        stackView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
+    }
+}
+
+private extension CompositionInputAccessoryView {
+    func initialSetup() {
+        autoresizingMask = .flexibleHeight
+        backgroundColor = .secondarySystemFill
+
+        addSubview(stackView)
+        stackView.translatesAutoresizingMaskIntoConstraints = false
+        stackView.spacing = .defaultSpacing
+
+        let mediaButton = UIButton()
+
+        stackView.addArrangedSubview(mediaButton)
+        mediaButton.setImage(
+            UIImage(
+                systemName: "photo",
+                withConfiguration: UIImage.SymbolConfiguration(scale: .medium)),
+            for: .normal)
+        mediaButton.addAction(UIAction { [weak self] _ in self?.viewModel.presentMediaPicker() }, for: .touchUpInside)
+
+        let pollButton = UIButton()
+
+        stackView.addArrangedSubview(pollButton)
+        pollButton.setImage(
+            UIImage(
+                systemName: "chart.bar.xaxis",
+                withConfiguration: UIImage.SymbolConfiguration(scale: .medium)),
+            for: .normal)
+
+        stackView.addArrangedSubview(UIView())
+
+        let addButton = UIButton()
+
+        stackView.addArrangedSubview(addButton)
+        addButton.setImage(
+            UIImage(
+                systemName: "plus.circle.fill",
+                withConfiguration: UIImage.SymbolConfiguration(scale: .medium)),
+            for: .normal)
+        addButton.addAction(UIAction { [weak self] _ in self?.viewModel.insert() }, for: .touchUpInside)
+
+        for button in [mediaButton, pollButton, addButton] {
+            button.heightAnchor.constraint(greaterThanOrEqualToConstant: .minimumButtonDimension).isActive = true
+            button.widthAnchor.constraint(greaterThanOrEqualToConstant: .minimumButtonDimension).isActive = true
+        }
+
+        NSLayoutConstraint.activate([
+            stackView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            stackView.topAnchor.constraint(equalTo: topAnchor),
+            stackView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            stackView.bottomAnchor.constraint(equalTo: bottomAnchor)
+        ])
+
+        viewModel.$isPostable.sink { addButton.isEnabled = $0 }.store(in: &cancellables)
+    }
+}

Views/CompositionView.swift

@@ -39,6 +39,12 @@ extension CompositionView: UIContentView {
     }
 }
 
+extension CompositionView: UITextViewDelegate {
+    func textViewDidChange(_ textView: UITextView) {
+        compositionConfiguration.viewModel.composition.text = textView.text
+    }
+}
+
 private extension CompositionView {
     func initialSetup() {
         addSubview(avatarImageView)
@@ -57,6 +63,9 @@ private extension CompositionView {
         textView.adjustsFontForContentSizeCategory = true
         textView.font = .preferredFont(forTextStyle: .body)
         textView.textContainer.lineFragmentPadding = 0
+        textView.inputAccessoryView = CompositionInputAccessoryView(viewModel: compositionConfiguration.viewModel)
+        textView.inputAccessoryView?.sizeToFit()
+        textView.delegate = self
 
         let constraints = [
             avatarImageView.heightAnchor.constraint(equalToConstant: .avatarDimension),