import Combine import Foundation import UIKit final class FileMiddleware { static let shared = FileMiddleware() private var downloadingMessageIDs = ThreadSafeSet() func middleware(state _: AppState, action: AppAction) -> AnyPublisher { switch action { case .conversationAction(.messagesUpdated(let messages)): return Future { [weak self] promise in guard let wSelf = self else { promise(.success(.empty)) return } for message in messages where message.attachmentRemotePath != nil && message.attachmentLocalPath == nil { if wSelf.downloadingMessageIDs.contains(message.id) { continue } wSelf.downloadingMessageIDs.insert(message.id) DispatchQueue.main.async { // swiftlint:disable:next force_unwrapping store.dispatch(.fileAction(.downloadAttachmentFile(messageId: message.id, attachmentRemotePath: message.attachmentRemotePath!))) } } promise(.success(.empty)) }.eraseToAnyPublisher() case .fileAction(.downloadAttachmentFile(let id, let attachmentRemotePath)): return Future { promise in let localName = "\(id)_\(UUID().uuidString)\(attachmentRemotePath.lastPathComponent)" let localUrl = FileProcessing.fileFolder.appendingPathComponent(localName) DownloadManager.shared.enqueueDownload(from: attachmentRemotePath, to: localUrl) { error in DispatchQueue.main.async { if let error { store.dispatch(.fileAction(.downloadingAttachmentFileFailed(messageId: id, reason: error.localizedDescription))) } else { store.dispatch(.fileAction(.attachmentFileDownloaded(messageId: id, localName: localName))) } } } promise(.success(.empty)) }.eraseToAnyPublisher() case .fileAction(.attachmentFileDownloaded(let id, let localName)): return Future { [weak self] promise in self?.downloadingMessageIDs.remove(id) promise(.success(.fileAction(.createAttachmentThumbnail(messageId: id, localName: localName)))) } .eraseToAnyPublisher() case .fileAction(.createAttachmentThumbnail(let id, let localName)): return Future { [weak self] promise in if let thumbnailName = FileProcessing.shared.createThumbnail(localName: localName) { self?.downloadingMessageIDs.remove(id) promise(.success(.fileAction(.attachmentThumbnailCreated(messageId: id, thumbnailName: thumbnailName)))) } else { self?.downloadingMessageIDs.remove(id) promise(.success(.empty)) } } .eraseToAnyPublisher() case .fileAction(.copyFileForUploading(let messageId, let data, let thumbnail)): print("=====") print("copyFileForUploading") print(data.count) print(thumbnail?.count) print("=====") return Empty().eraseToAnyPublisher() default: return Empty().eraseToAnyPublisher() } } }