wip

DB/Sources/DB/Entities/Composition.swift

@@ -19,20 +19,6 @@ public class Composition {
 
 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/CompositionAttachmentsDataSource.swift

@@ -0,0 +1,13 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Mastodon
+import UIKit
+import ViewModels
+
+final class CompositionAttachmentsDataSource: UICollectionViewDiffableDataSource<Int, Attachment> {
+//    init(collectionView: UICollectionView, composition: Composition) {
+//        super.init(collectionView: collectionView) { collectionView, indexPath, attachment in
+//
+//        }
+//    }
+}

HTTP/Sources/HTTP/HTTPClient.swift

@@ -19,14 +19,14 @@ open class HTTPClient {
     }
 
     open func dataTaskPublisher<T: DecodableTarget>(
-        _ target: T) -> AnyPublisher<(data: Data, response: HTTPURLResponse), Error> {
+        _ target: T, progress: Progress? = nil) -> AnyPublisher<(data: Data, response: HTTPURLResponse), Error> {
         if let protocolClasses = session.configuration.protocolClasses {
             for protocolClass in protocolClasses {
                 (protocolClass as? TargetProcessing.Type)?.process(target: target)
             }
         }
 
-        return session.dataTaskPublisher(for: target.urlRequest())
+        return session.dataTaskPublisher(for: target.urlRequest(), progress: progress)
             .tryMap { data, response in
                 guard let httpResponse = response as? HTTPURLResponse else {
                     throw HTTPError.nonHTTPURLResponse(data: data, response: response)
@@ -41,8 +41,8 @@ open class HTTPClient {
             .eraseToAnyPublisher()
     }
 
-    open func request<T: DecodableTarget>(_ target: T) -> AnyPublisher<T.ResultType, Error> {
+    open func request<T: DecodableTarget>(_ target: T, progress: Progress? = nil) -> AnyPublisher<T.ResultType, Error> {
-        dataTaskPublisher(target)
+        dataTaskPublisher(target, progress: progress)
             .map(\.data)
             .decode(type: T.ResultType.self, decoder: decoder)
             .eraseToAnyPublisher()

HTTP/Sources/HTTP/URLSession+Extensions.swift

@@ -0,0 +1,29 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import Foundation
+
+extension URLSession {
+    func dataTaskPublisher(for request: URLRequest, progress: Progress?)
+    -> AnyPublisher<DataTaskPublisher.Output, Error> {
+        if let progress = progress {
+            return Deferred {
+                Future<DataTaskPublisher.Output, Error> { promise in
+                    let dataTask = self.dataTask(with: request) { data, response, error in
+                        if let error = error {
+                            promise(.failure(error))
+                        } else if let data = data, let response = response {
+                            promise(.success((data, response)))
+                        }
+                    }
+
+                    progress.addChild(dataTask.progress, withPendingUnitCount: 1)
+                    dataTask.resume()
+                }
+            }
+            .eraseToAnyPublisher()
+        } else {
+            return dataTaskPublisher(for: request).mapError { $0 as Error }.eraseToAnyPublisher()
+        }
+    }
+}

MastodonAPI/Sources/MastodonAPI/MastodonAPIClient.swift

@@ -15,8 +15,8 @@ public final class MastodonAPIClient: HTTPClient {
     }
 
     public override func dataTaskPublisher<T: DecodableTarget>(
-        _ target: T) -> AnyPublisher<(data: Data, response: HTTPURLResponse), Error> {
+        _ target: T, progress: Progress? = nil) -> AnyPublisher<(data: Data, response: HTTPURLResponse), Error> {
-        super.dataTaskPublisher(target)
+        super.dataTaskPublisher(target, progress: progress)
             .mapError { [weak self] error -> Error in
                 if case let HTTPError.invalidStatusCode(data, _) = error,
                    let apiError = try? self?.decoder.decode(APIError.self, from: data) {
@@ -30,8 +30,8 @@ public final class MastodonAPIClient: HTTPClient {
 }
 
 extension MastodonAPIClient {
-    public func request<E: Endpoint>(_ endpoint: E) -> AnyPublisher<E.ResultType, Error> {
+    public func request<E: Endpoint>(_ endpoint: E, progress: Progress? = nil) -> AnyPublisher<E.ResultType, Error> {
-        dataTaskPublisher(target(endpoint: endpoint))
+        dataTaskPublisher(target(endpoint: endpoint), progress: progress)
             .map(\.data)
             .decode(type: E.ResultType.self, decoder: decoder)
             .eraseToAnyPublisher()
@@ -42,9 +42,10 @@ extension MastodonAPIClient {
         maxId: String? = nil,
         minId: String? = nil,
         sinceId: String? = nil,
-        limit: Int? = nil) -> AnyPublisher<PagedResult<E.ResultType>, Error> {
+        limit: Int? = nil,
+        progress: Progress? = nil) -> AnyPublisher<PagedResult<E.ResultType>, Error> {
         let pagedTarget = target(endpoint: Paged(endpoint, maxId: maxId, minId: minId, sinceId: sinceId, limit: limit))
-        let dataTask = dataTaskPublisher(pagedTarget).share()
+        let dataTask = dataTaskPublisher(pagedTarget, progress: progress).share()
         let decoded = dataTask.map(\.data).decode(type: E.ResultType.self, decoder: decoder)
         let info = dataTask.map { _, response -> PagedResult<E.ResultType>.Info in
             var maxId: String?

Metatext.xcodeproj/project.pbxproj

@@ -27,6 +27,10 @@
 		D04226FD2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04226FC2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift */; };
 		D0625E59250F092900502611 /* StatusListCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0625E58250F092900502611 /* StatusListCell.swift */; };
 		D0625E5D250F0B5C00502611 /* StatusContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0625E5C250F0B5C00502611 /* StatusContentConfiguration.swift */; };
+		D065965B25899DAE0096AC5D /* CompositionAttachmentsDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D065965A25899DAE0096AC5D /* CompositionAttachmentsDataSource.swift */; };
+		D065966125899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D065966025899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift */; };
+		D065966225899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D065966025899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift */; };
+		D065966725899E910096AC5D /* CompositionAttachmentsDataSource.swift in Sources */ = {isa = PBXBuildFile; fileRef = D065965A25899DAE0096AC5D /* CompositionAttachmentsDataSource.swift */; };
 		D06B492324D4611300642749 /* KingfisherSwiftUI in Frameworks */ = {isa = PBXBuildFile; productRef = D06B492224D4611300642749 /* KingfisherSwiftUI */; };
 		D06BC5E625202AD90079541D /* ProfileViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D06BC5E525202AD90079541D /* ProfileViewController.swift */; };
 		D08B8D3D253F929E00B1EBEF /* ImageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */; };
@@ -91,6 +95,8 @@
 		D0C7D4D724F7616A001EBDBB /* UIColor+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0C7D46C24F76169001EBDBB /* UIColor+Extensions.swift */; };
 		D0C7D4D924F7616A001EBDBB /* KingfisherOptionsInfo+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0C7D46E24F76169001EBDBB /* KingfisherOptionsInfo+Extensions.swift */; };
 		D0C7D4DA24F7616A001EBDBB /* View+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0C7D46F24F76169001EBDBB /* View+Extensions.swift */; };
+		D0CE9F87258B076900E3A6B6 /* AttachmentUploadView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CE9F86258B076900E3A6B6 /* AttachmentUploadView.swift */; };
+		D0CE9F88258B076900E3A6B6 /* AttachmentUploadView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CE9F86258B076900E3A6B6 /* AttachmentUploadView.swift */; };
 		D0DD50CB256B1F24004A04F7 /* ReportView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DD50CA256B1F24004A04F7 /* ReportView.swift */; };
 		D0E1F583251F13EC00D45315 /* WebfingerIndicatorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0E1F582251F13EC00D45315 /* WebfingerIndicatorView.swift */; };
 		D0E2C1D124FD97F000854680 /* ViewModels in Frameworks */ = {isa = PBXBuildFile; productRef = D0E2C1D024FD97F000854680 /* ViewModels */; };
@@ -180,6 +186,8 @@
 		D047FA8C24C3E21200AF17C5 /* Metatext.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Metatext.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		D0625E58250F092900502611 /* StatusListCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StatusListCell.swift; sourceTree = "<group>"; };
 		D0625E5C250F0B5C00502611 /* StatusContentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StatusContentConfiguration.swift; sourceTree = "<group>"; };
+		D065965A25899DAE0096AC5D /* CompositionAttachmentsDataSource.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CompositionAttachmentsDataSource.swift; sourceTree = "<group>"; };
+		D065966025899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CompositionAttachmentCollectionViewCell.swift; sourceTree = "<group>"; };
 		D0666A2124C677B400F3F04B /* Tests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = Tests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		D0666A2524C677B400F3F04B /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		D06BC5E525202AD90079541D /* ProfileViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProfileViewController.swift; sourceTree = "<group>"; };
@@ -245,6 +253,7 @@
 		D0C7D46C24F76169001EBDBB /* UIColor+Extensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "UIColor+Extensions.swift"; sourceTree = "<group>"; };
 		D0C7D46E24F76169001EBDBB /* KingfisherOptionsInfo+Extensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "KingfisherOptionsInfo+Extensions.swift"; sourceTree = "<group>"; };
 		D0C7D46F24F76169001EBDBB /* View+Extensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "View+Extensions.swift"; sourceTree = "<group>"; };
+		D0CE9F86258B076900E3A6B6 /* AttachmentUploadView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AttachmentUploadView.swift; sourceTree = "<group>"; };
 		D0D7C013250440610039AD6F /* CodableBloomFilter */ = {isa = PBXFileReference; lastKnownFileType = folder; path = CodableBloomFilter; sourceTree = "<group>"; };
 		D0DD50CA256B1F24004A04F7 /* ReportView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ReportView.swift; sourceTree = "<group>"; };
 		D0E0F1E424FC49FC002C04BF /* Mastodon */ = {isa = PBXFileReference; lastKnownFileType = folder; path = Mastodon; sourceTree = "<group>"; };
@@ -410,6 +419,7 @@
 			children = (
 				D0A1F4F6252E7D4B004435BF /* TableViewDataSource.swift */,
 				D0F2D4D0257EE84400986197 /* NewStatusDataSource.swift */,
+				D065965A25899DAE0096AC5D /* CompositionAttachmentsDataSource.swift */,
 			);
 			path = "Data Sources";
 			sourceTree = "<group>";
@@ -432,6 +442,8 @@
 				D0F0B125251A90F400942152 /* AccountListCell.swift */,
 				D0F0B10D251A868200942152 /* AccountView.swift */,
 				D0C7D42424F76169001EBDBB /* AddIdentityView.swift */,
+				D0CE9F86258B076900E3A6B6 /* AttachmentUploadView.swift */,
+				D065966025899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift */,
 				D08E52E2257D747400FA2C5F /* CompositionContentConfiguration.swift */,
 				D0E9F9A9258450B300EF503D /* CompositionInputAccessoryView.swift */,
 				D08E52DB257D742B00FA2C5F /* CompositionListCell.swift */,
@@ -772,6 +784,7 @@
 				D0F0B12E251A97E400942152 /* TableViewController.swift in Sources */,
 				D0DD50CB256B1F24004A04F7 /* ReportView.swift in Sources */,
 				D0FE1C8F253686F9003EF1EB /* PlayerView.swift in Sources */,
+				D0CE9F87258B076900E3A6B6 /* AttachmentUploadView.swift in Sources */,
 				D0F0B113251A86A000942152 /* AccountContentConfiguration.swift in Sources */,
 				D036AA02254B6101009094DF /* NotificationListCell.swift in Sources */,
 				D08B8D42253F92B600B1EBEF /* ImagePageViewController.swift in Sources */,
@@ -806,6 +819,7 @@
 				D036AA17254CA824009094DF /* StatusBodyView.swift in Sources */,
 				D08E512125786A6600FA2C5F /* UIButton+Extensions.swift in Sources */,
 				D0EA59482522B8B600804347 /* ViewConstants.swift in Sources */,
+				D065965B25899DAE0096AC5D /* CompositionAttachmentsDataSource.swift in Sources */,
 				D04226FD2546AC0B000980A3 /* StartupAndSyncingPreferencesView.swift in Sources */,
 				D036AA0C254B612B009094DF /* NotificationContentConfiguration.swift in Sources */,
 				D0C7D49824F7616A001EBDBB /* CustomEmojiText.swift in Sources */,
@@ -814,6 +828,7 @@
 				D08E52612579D2E100FA2C5F /* DomainBlocksView.swift in Sources */,
 				D01F41E424F8889700D55A2D /* StatusAttachmentsView.swift in Sources */,
 				D00702312555F4AE00F38136 /* ConversationView.swift in Sources */,
+				D065966125899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift in Sources */,
 				D0BEB21124FA2A91001B0F04 /* EditFilterView.swift in Sources */,
 				D08B8D4A253FC36500B1EBEF /* ImageNavigationController.swift in Sources */,
 				D0070252255921B100F38136 /* AccountFieldView.swift in Sources */,
@@ -851,12 +866,15 @@
 				D08E52DD257D742B00FA2C5F /* CompositionListCell.swift in Sources */,
 				D0E7AD4225870C79005F5E2D /* UIVIewController+Extensions.swift in Sources */,
 				D08E52EF257D757100FA2C5F /* CompositionView.swift in Sources */,
+				D0CE9F88258B076900E3A6B6 /* AttachmentUploadView.swift in Sources */,
 				D0F2D5452581ABAB00986197 /* KingfisherOptionsInfo+Extensions.swift in Sources */,
 				D08E52C7257C7AEE00FA2C5F /* ShareErrorViewController.swift in Sources */,
 				D08E52F8257D78BE00FA2C5F /* ViewConstants.swift in Sources */,
 				D0F2D4D6257EED6100986197 /* NewStatusDataSource.swift in Sources */,
+				D065966725899E910096AC5D /* CompositionAttachmentsDataSource.swift in Sources */,
 				D08E52FD257D78CB00FA2C5F /* UIColor+Extensions.swift in Sources */,
 				D08E52E4257D747400FA2C5F /* CompositionContentConfiguration.swift in Sources */,
+				D065966225899E890096AC5D /* CompositionAttachmentCollectionViewCell.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

ServiceLayer/Sources/ServiceLayer/Services/IdentityService.swift

@@ -206,17 +206,26 @@ public extension IdentityService {
             .eraseToAnyPublisher()
     }
 
+    func uploadAttachment(data: Data, mimeType: String, progress: Progress) -> AnyPublisher<Attachment, Error> {
+        mastodonAPIClient.request(
+            AttachmentEndpoint.create(data: data, mimeType: mimeType, description: nil, focus: nil),
+            progress: progress)
+    }
+
     func post(compositions: [Composition]) -> AnyPublisher<Never, Error> {
-        guard let composition = compositions.first else { fatalError() }
+        fatalError()
-        guard let attachment = composition.attachments.first else { fatalError() }
+//        guard let composition = compositions.first else { fatalError() }
-        return mastodonAPIClient.request(AttachmentEndpoint.create(
+
-                                            data: attachment.data,
+//        guard let attachment = composition.attachments.first else { fatalError() }
-                                            mimeType: attachment.mimeType,
+//        return mastodonAPIClient.request(AttachmentEndpoint.create(
-                                            description: attachment.description,
+//                                            data: attachment.data,
-                                            focus: attachment.focus))
+//                                            mimeType: attachment.mimeType,
-            .print()
+//                                            description: attachment.description,
-            .ignoreOutput()
+//                                            focus: attachment.focus))
-            .eraseToAnyPublisher()
+//            .print()
+//            .ignoreOutput()
+//            .eraseToAnyPublisher()
+
 //        var components = StatusEndpoint.Components()
 //
 //        if !composition.text.isEmpty {

ServiceLayer/Sources/ServiceLayer/Services/MediaProcessingService.swift

@@ -3,7 +3,6 @@
 import Combine
 import Foundation
 import ImageIO
-import Mastodon
 import UniformTypeIdentifiers
 
 enum MediaProcessingError: Error {
@@ -18,32 +17,18 @@ enum MediaProcessingError: Error {
 public struct MediaProcessingService {}
 
 public extension MediaProcessingService {
-    static func attachment(itemProvider: NSItemProvider) -> AnyPublisher<Composition.Attachment, Error> {
+    static func dataAndMimeType(itemProvider: NSItemProvider) -> AnyPublisher<(data: Data, mimeType: String), 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)
+            return Self.uploadableMimeTypes.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 {
@@ -63,13 +48,23 @@ public extension MediaProcessingService {
                 }
             }
         }
-        .map { Composition.Attachment(data: $0, type: type, mimeType: mimeType) }
+        .map { (data: $0, mimeType: mimeType) }
         .eraseToAnyPublisher()
     }
 }
 
 private extension MediaProcessingService {
-    static let unuploadableMimeTypes: Set<String> = [UTType.heic.preferredMIMEType!]
+
+    static let uploadableMimeTypes = Set(
+        [UTType.png,
+         UTType.jpeg,
+         UTType.gif,
+         UTType.webP,
+         UTType.mpeg4Movie,
+         UTType.quickTimeMovie,
+         UTType.mp3,
+         UTType.wav]
+            .compactMap(\.preferredMIMEType))
     static let imageSourceOptions =  [kCGImageSourceShouldCache: false] as CFDictionary
     static let thumbnailOptions = [
         kCGImageSourceCreateThumbnailFromImageAlways: true,

View Controllers/NewStatusViewController.swift

@@ -73,9 +73,14 @@ class NewStatusViewController: UICollectionViewController {
         }
         .store(in: &cancellables)
 
+        // Invalidate the collection view layout on anything that could change the height of a cell
         viewModel.$compositionViewModels
             .flatMap { Publishers.MergeMany($0.map(\.composition.$text)) }
-            .sink { [weak self] _ in self?.collectionView.collectionViewLayout.invalidateLayout() }
+            .map { _ in () }
+            .merge(with: viewModel.$compositionViewModels
+                    .flatMap { Publishers.MergeMany($0.map(\.objectWillChange)) }
+                    .map { _ in () })
+            .sink { [weak self] in self?.collectionView.collectionViewLayout.invalidateLayout() }
             .store(in: &cancellables)
 
         viewModel.$canPost.sink { [weak self] in self?.postButton.isEnabled = $0 }.store(in: &cancellables)

ViewModels/Sources/ViewModels/CompositionAttachmentViewModel.swift

@@ -0,0 +1,14 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import Foundation
+import Mastodon
+import ServiceLayer
+
+public final class CompositionAttachmentViewModel: ObservableObject {
+    public var attachment: Attachment
+
+    init(attachment: Attachment) {
+        self.attachment = attachment
+    }
+}

ViewModels/Sources/ViewModels/CompositionViewModel.swift

@@ -9,8 +9,10 @@ public final class CompositionViewModel: ObservableObject {
     public let composition: Composition
     @Published public private(set) var isPostable = false
     @Published public private(set) var identification: Identification
+    @Published public private(set) var attachmentUpload: AttachmentUpload?
 
     private let eventsSubject: PassthroughSubject<Event, Never>
+    private var cancellables = Set<AnyCancellable>()
 
     init(composition: Composition,
          identification: Identification,
@@ -28,7 +30,13 @@ public extension CompositionViewModel {
     enum Event {
         case insertAfter(CompositionViewModel)
         case presentMediaPicker(CompositionViewModel)
-        case attach(itemProvider: NSItemProvider, viewModel: CompositionViewModel)
+        case error(Error)
+    }
+
+    struct AttachmentUpload {
+        public let progress: Progress
+        public let data: Data
+        public let mimeType: String
     }
 
     func presentMediaPicker() {
@@ -40,6 +48,30 @@ public extension CompositionViewModel {
     }
 
     func attach(itemProvider: NSItemProvider) {
-        eventsSubject.send(.attach(itemProvider: itemProvider, viewModel: self))
+        let progress = Progress(totalUnitCount: 1)
+
+        MediaProcessingService.dataAndMimeType(itemProvider: itemProvider)
+            .flatMap { [weak self] data, mimeType -> AnyPublisher<Attachment, Error> in
+                guard let self = self else { return Empty().eraseToAnyPublisher() }
+
+                DispatchQueue.main.async {
+                    self.attachmentUpload = AttachmentUpload(progress: progress, data: data, mimeType: mimeType)
+                }
+
+                return self.identification.service.uploadAttachment(data: data, mimeType: mimeType, progress: progress)
+            }
+            .print()
+            .sink { [weak self] in
+                DispatchQueue.main.async {
+                    self?.attachmentUpload = nil
+                }
+
+                if case let .failure(error) = $0 {
+                    self?.eventsSubject.send(.error(error))
+                }
+            } receiveValue: { [weak self] in
+                self?.composition.attachments.append($0)
+            }
+            .store(in: &cancellables)
     }
 }

ViewModels/Sources/ViewModels/NewStatusViewModel.swift

@@ -99,11 +99,8 @@ private extension NewStatusViewModel {
             } else {
                 compositionViewModels.insert(newViewModel, at: index + 1)
             }
-        case let .attach(itemProvider, viewModel):
+        case let .error(error):
-            MediaProcessingService.attachment(itemProvider: itemProvider)
+            alertItem = AlertItem(error: error)
-                .assignErrorsToAlertItem(to: \.alertItem, on: self)
-                .sink { viewModel.composition.attachments.append($0) }
-                .store(in: &cancellables)
         default:
             eventsSubject.send(event)
         }

Views/AttachmentUploadView.swift

@@ -0,0 +1,41 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+import UIKit
+import ViewModels
+
+final class AttachmentUploadView: UIView {
+    let progressView = UIProgressView(progressViewStyle: .default)
+    private var progressCancellable: AnyCancellable?
+
+    var attachmentUpload: CompositionViewModel.AttachmentUpload? {
+        didSet {
+            if let attachmentUpload = attachmentUpload {
+                progressCancellable = attachmentUpload.progress.publisher(for: \.fractionCompleted)
+                    .receive(on: DispatchQueue.main)
+                    .sink { [weak self] in self?.progressView.progress = Float($0) }
+                isHidden = false
+            } else {
+                isHidden = true
+            }
+        }
+    }
+
+    init() {
+        super.init(frame: .zero)
+
+        addSubview(progressView)
+        progressView.translatesAutoresizingMaskIntoConstraints = false
+
+        NSLayoutConstraint.activate([
+            progressView.leadingAnchor.constraint(equalTo: layoutMarginsGuide.leadingAnchor),
+            progressView.trailingAnchor.constraint(equalTo: layoutMarginsGuide.trailingAnchor),
+            progressView.centerYAnchor.constraint(equalTo: centerYAnchor)
+        ])
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}

Views/CompositionAttachmentCollectionViewCell.swift

@@ -0,0 +1,7 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import UIKit
+
+class CompositionAttachmentCollectionViewCell: UICollectionViewCell {
+    
+}

Views/CompositionView.swift

@@ -7,6 +7,8 @@ import UIKit
 class CompositionView: UIView {
     let avatarImageView = UIImageView()
     let textView = UITextView()
+    let attachmentUploadView = AttachmentUploadView()
+//    let attachmentsCollectionView = UICollectionView()
 
     private var compositionConfiguration: CompositionContentConfiguration
     private var cancellables = Set<AnyCancellable>()
@@ -46,6 +48,8 @@ extension CompositionView: UITextViewDelegate {
 }
 
 private extension CompositionView {
+    static let attachmentsCollectionViewHeight: CGFloat = 100
+
     func initialSetup() {
         addSubview(avatarImageView)
         avatarImageView.translatesAutoresizingMaskIntoConstraints = false
@@ -67,6 +71,10 @@ private extension CompositionView {
         textView.inputAccessoryView?.sizeToFit()
         textView.delegate = self
 
+//        stackView.addArrangedSubview(attachmentsCollectionView)
+
+        stackView.addArrangedSubview(attachmentUploadView)
+
         let constraints = [
             avatarImageView.heightAnchor.constraint(equalToConstant: .avatarDimension),
             avatarImageView.widthAnchor.constraint(equalToConstant: .avatarDimension),
@@ -76,7 +84,9 @@ private extension CompositionView {
             stackView.leadingAnchor.constraint(equalTo: avatarImageView.trailingAnchor, constant: .defaultSpacing),
             stackView.topAnchor.constraint(equalTo: readableContentGuide.topAnchor),
             stackView.trailingAnchor.constraint(equalTo: readableContentGuide.trailingAnchor),
-            stackView.bottomAnchor.constraint(equalTo: readableContentGuide.bottomAnchor)
+            stackView.bottomAnchor.constraint(equalTo: readableContentGuide.bottomAnchor),
+//            attachmentsCollectionView.heightAnchor.constraint(equalToConstant: Self.attachmentsCollectionViewHeight)
+            attachmentUploadView.heightAnchor.constraint(equalToConstant: Self.attachmentsCollectionViewHeight)
         ]
 
         for constraint in constraints {
@@ -88,6 +98,10 @@ private extension CompositionView {
         compositionConfiguration.viewModel.$identification.map(\.identity.image)
             .sink { [weak self] in self?.avatarImageView.kf.setImage(with: $0) }
             .store(in: &cancellables)
+
+        compositionConfiguration.viewModel.$attachmentUpload
+            .sink { [weak self] in self?.attachmentUploadView.attachmentUpload = $0 }
+            .store(in: &cancellables)
     }
 
     func applyCompositionConfiguration() {