Technology Stack

struct ContentView: View {
    @Environment(AppViewModel.self) private var viewModel
    
    var body: some View {
        NavigationSplitView {
            // Sidebar with bucket list
            List(selection: $selection) {
                Section("Buckets") {
                    ForEach(viewModel.credentialsList) { creds in
                        Label(creds.bucketName, systemImage: "externaldrive.fill")
                    }
                }
            }
        } detail: {
            // Main browser view
            BrowserView()
        }
    }
}

import AppKit

@MainActor
final class MenuBarManager: NSObject {
    private var statusItem: NSStatusItem!
    private var popover: NSPopover!
    
    private func setupStatusItem() {
        statusItem = NSStatusBar.system.statusItem(
            withLength: NSStatusItem.squareLength
        )
        if let button = statusItem.button {
            button.image = NSImage(
                systemSymbolName: "arrow.up.to.line.compact",
                accessibilityDescription: "R2 Vault"
            )
            button.action = #selector(togglePopover)
            button.target = self
        }
    }
    
    private func setupPopover() {
        popover = NSPopover()
        popover.contentSize = NSSize(width: 300, height: 400)
        popover.behavior = .applicationDefined  // Never auto-dismiss
        
        let hostingController = NSHostingController(
            rootView: MenuBarView().environment(viewModel)
        )
        popover.contentViewController = hostingController
    }
}

static func upload(
    fileURL: URL,
    credentials: R2Credentials,
    key: String,
    contentType: String,
    onProgress: @MainActor @escaping @Sendable (Int64, Int64) -> Void
) async throws -> UploadResult {
    var request = URLRequest(url: objectURL)
    request.httpMethod = "PUT"
    request.setValue(contentType, forHTTPHeaderField: "Content-Type")
    
    let signedRequest = AWSV4Signer.sign(
        request: request, 
        credentials: credentials
    )
    
    let delegate = UploadProgressDelegate(onProgress: onProgress)
    let session = URLSession(
        configuration: .default, 
        delegate: delegate, 
        delegateQueue: nil
    )
    
    let (data, response) = try await session.upload(
        for: signedRequest, 
        fromFile: fileURL
    )
    
    let statusCode = (response as? HTTPURLResponse)?.statusCode ?? 0
    return UploadResult(httpStatusCode: statusCode, responseBody: data)
}

import CryptoKit

nonisolated enum AWSV4Signer {
    static func sha256Hex(_ string: String) -> String {
        let digest = SHA256.hash(data: Data(string.utf8))
        return digest.map { String(format: "%02x", $0) }.joined()
    }
    
    private static func deriveSigningKey(
        secret: String, 
        date: String, 
        region: String, 
        service: String
    ) -> SymmetricKey {
        let kSecret = SymmetricKey(data: Data(("AWS4" + secret).utf8))
        let kDate = hmac(key: kSecret, data: Data(date.utf8))
        let kRegion = hmac(key: kDate, data: Data(region.utf8))
        let kService = hmac(key: kRegion, data: Data(service.utf8))
        return hmac(key: kService, data: Data("aws4_request".utf8))
    }
    
    private static func hmac(key: SymmetricKey, data: Data) -> SymmetricKey {
        SymmetricKey(data: Data(
            HMAC<SHA256>.authenticationCode(for: data, using: key)
        ))
    }
}

enum KeychainService {
    private static let storageKey = "fiaxe.r2credentials"
    
    static func saveAll(_ credentials: [R2Credentials]) throws {
        let data = try JSONEncoder().encode(credentials)
        UserDefaults.standard.set(data, forKey: storageKey)
    }
    
    static func loadAll() throws -> [R2Credentials] {
        guard let data = UserDefaults.standard.data(forKey: storageKey) 
        else { return [] }
        return try JSONDecoder().decode([R2Credentials].self, from: data)
    }
}

@Observable
final class UploadHistoryStore {
    private static let storageKey = "fiaxe.uploadHistory"
    var items: [UploadItem] = []
    
    private func save() {
        guard let data = try? JSONEncoder().encode(items) else { return }
        UserDefaults.standard.set(data, forKey: Self.storageKey)
    }
    
    private func load() {
        guard let data = UserDefaults.standard.data(forKey: Self.storageKey),
              let decoded = try? JSONDecoder().decode([UploadItem].self, from: data)
        else { return }
        items = decoded
    }
}

actor ThumbnailCache {
    private let diskCacheURL: URL = {
        let caches = FileManager.default.urls(
            for: .cachesDirectory, 
            in: .userDomainMask
        ).first!
        let dir = caches.appendingPathComponent(
            "R2VaultThumbnails", 
            isDirectory: true
        )
        try? FileManager.default.createDirectory(
            at: dir, 
            withIntermediateDirectories: true
        )
        return dir
    }()
    
    private func saveToDisk(_ image: NSImage, key: String) {
        guard let tiff = image.tiffRepresentation,
              let rep = NSBitmapImageRep(data: tiff),
              let png = rep.representation(using: .png, properties: [:])
        else { return }
        try? png.write(to: diskURL(for: key))
    }
}

import UniformTypeIdentifiers

private func mimeType(for url: URL) -> String {
    if let type = UTType(filenameExtension: url.pathExtension) {
        return type.preferredMIMEType ?? "application/octet-stream"
    }
    return "application/octet-stream"
}

import AVFoundation

private func videoThumbnail(url: URL) async -> NSImage? {
    let asset = AVURLAsset(url: url)
    let gen = AVAssetImageGenerator(asset: asset)
    gen.appliesPreferredTrackTransform = true
    gen.maximumSize = CGSize(width: 120, height: 120)
    guard let cgImage = try? await gen.image(at: .zero).image 
    else { return nil }
    return NSImage(cgImage: cgImage, size: NSSize(width: 120, height: 120))
}

import Quartz

final class QuickLookCoordinator: NSObject, QLPreviewPanelDataSource {
    var previewURL: URL?
    
    func numberOfPreviewItems(in panel: QLPreviewPanel!) -> Int {
        previewURL != nil ? 1 : 0
    }
    
    func previewPanel(
        _ panel: QLPreviewPanel!, 
        previewItemAt index: Int
    ) -> QLPreviewItem! {
        previewURL as QLPreviewItem?
    }
}

private final class ListBucketResultParser: NSObject, XMLParserDelegate {
    private var objects: [R2Object] = []
    private var folders: [R2Object] = []
    private var currentElement = ""
    private var currentText = ""
    
    func parser(
        _ parser: XMLParser, 
        didStartElement elementName: String, 
        namespaceURI: String?, 
        qualifiedName qName: String?, 
        attributes attributeDict: [String: String] = [:]
    ) {
        currentElement = elementName
        currentText = ""
        if elementName == "Contents" { inContents = true }
    }
    
    func parser(_ parser: XMLParser, foundCharacters string: String) {
        currentText += string
    }
    
    func parser(
        _ parser: XMLParser, 
        didEndElement elementName: String, 
        namespaceURI: String?, 
        qualifiedName qName: String?
    ) {
        switch elementName {
        case "Key": currentKey = currentText
        case "Size": currentSize = Int64(currentText) ?? 0
        case "LastModified": currentLastModified = iso8601.date(from: currentText)
        default: break
        }
    }
}