WP-5b: FSEvents ReturnWatcher per SPEC-A1c with review corrections

Sources/ShotdeckCore/Returns/AnnotationInspector.swift

@@ -0,0 +1,110 @@
+import Foundation
+import PDFKit
+
+public struct ReturnedDocument: Codable, Sendable, Identifiable, Equatable {
+    public var id: URL { fileURL }
+    public let fileURL: URL
+    /// Session UUID recovered from the PDF's subject attribute, when present and valid.
+    public let sessionID: UUID?
+    public let pageCount: Int
+    /// 1-based page numbers that carry at least one human mark, ascending, no duplicates.
+    public let annotatedPages: [Int]
+    public let detectedAt: Date
+    public var isCommented: Bool { !annotatedPages.isEmpty }
+
+    public init(
+        fileURL: URL,
+        sessionID: UUID?,
+        pageCount: Int,
+        annotatedPages: [Int],
+        detectedAt: Date
+    ) {
+        self.fileURL = fileURL
+        self.sessionID = sessionID
+        self.pageCount = pageCount
+        self.annotatedPages = annotatedPages
+        self.detectedAt = detectedAt
+    }
+}
+
+public enum AnnotationInspector {
+    private static let humanMarkTypes: Set<String> = [
+        PDFAnnotationSubtype.ink.rawValue,
+        PDFAnnotationSubtype.highlight.rawValue,
+        PDFAnnotationSubtype.underline.rawValue,
+        PDFAnnotationSubtype.strikeOut.rawValue,
+        // PDFKit has no PDFAnnotationSubtype.squiggly member (unsupported renderer),
+        // but Apple Markup still writes Adobe /Squiggly objects that we must count.
+        PDFAnnotationSubtype(rawValue: "/Squiggly").rawValue,
+        PDFAnnotationSubtype.freeText.rawValue,
+        PDFAnnotationSubtype.square.rawValue,
+        PDFAnnotationSubtype.circle.rawValue,
+        PDFAnnotationSubtype.line.rawValue,
+        PDFAnnotationSubtype.stamp.rawValue,
+        PDFAnnotationSubtype.text.rawValue,
+    ]
+
+    // .link ignored: a PDF hyperlink is structural, not a human mark.
+    // .popup ignored: it is always the companion of another annotation; counting it
+    //   would double-count a single human mark as two.
+    // .widget ignored: a form field. Shotdeck's own PASS/FAIL boxes are page content
+    //   (drawn by WP-2), never PDFAnnotation objects — a widget seen here can only be
+    //   introduced by a third-party tool flattening/reopening the file, and is not a
+    //   human mark either way.
+
+    /// PDFKit's `PDFAnnotation.type` may omit the leading slash that
+    /// `PDFAnnotationSubtype.rawValue` includes; compare against the slash form.
+    private static func pdfTypeName(_ type: String) -> String {
+        type.hasPrefix("/") ? type : "/" + type
+    }
+
+    private static func isHumanMark(_ annotation: PDFAnnotation) -> Bool {
+        guard let raw = annotation.type else { return false }
+        let type = pdfTypeName(raw)
+        guard humanMarkTypes.contains(type) else { return false }
+        if type == PDFAnnotationSubtype.ink.rawValue {
+            let b = annotation.bounds
+            return b.width > 0 && b.height > 0   // zero-area ink = an undone stroke, not a mark
+        }
+        return true
+    }
+
+    /// Opens the PDF at fileURL and reports which pages carry a genuine human mark.
+    /// Throws ShotdeckError.manifestCorrupt(path: fileURL.path) if PDFDocument cannot open it.
+    /// File modification date is never consulted; only persisted PDFAnnotation objects count.
+    public static func inspect(fileURL: URL) throws -> ReturnedDocument {
+        guard let document = PDFDocument(url: fileURL) else {
+            throw ShotdeckError.manifestCorrupt(path: fileURL.path)
+        }
+        var annotatedPages: [Int] = []
+        for index in 0..<document.pageCount {
+            guard let page = document.page(at: index) else { continue }
+            if page.annotations.contains(where: isHumanMark) {
+                annotatedPages.append(index + 1)   // 1-based
+            }
+        }
+        var sessionID: UUID?
+        if let subject = document.documentAttributes?[PDFDocumentAttribute.subjectAttribute] as? String {
+            sessionID = UUID(uuidString: subject)   // nil (not thrown) if it doesn't parse
+        }
+        return ReturnedDocument(
+            fileURL: fileURL, sessionID: sessionID, pageCount: document.pageCount,
+            annotatedPages: annotatedPages, detectedAt: Date()
+        )
+    }
+
+    /// True when this PDF was produced by Shotdeck. Creator attribute is authoritative;
+    /// the filename fallback applies ONLY when the creator attribute is absent.
+    public static func isShotdeckDocument(_ document: PDFDocument) -> Bool {
+        if let creator = document.documentAttributes?[PDFDocumentAttribute.creatorAttribute] as? String {
+            return creator == "Shotdeck"          // present creator is authoritative, full stop
+        }
+        // Creator ABSENT (some apps rewrite metadata on save) -> filename fallback only here.
+        guard let name = document.documentURL?.lastPathComponent else { return false }
+        // .lastPathComponent on a file URL is already percent-decoded; do not use .absoluteString.
+        return name.wholeMatch(of: /^Shotdeck-\d{8}-\d{6}( \d+)?\.pdf$/) != nil
+        // Case-sensitive by construction (Swift Regex literals are case-sensitive by default).
+        // The optional "( \d+)?" is macOS's duplicate-name suffix AirDrop adds when a file of
+        // the same name already exists in the watch folder — the normal case for a return.
+    }
+}

Sources/ShotdeckCore/Returns/ReturnLedger.swift

@@ -0,0 +1,60 @@
+import Foundation
+
+public actor ReturnLedger {
+    private let fileURL: URL
+    private var entries: [URL: ReturnedDocument]
+
+    /// Loads `returns.json` under paths.root if it exists; starts empty otherwise.
+    /// A file that cannot be decoded is renamed (never deleted) and the ledger starts empty.
+    public init(paths: AppSupportPaths) throws {
+        self.fileURL = paths.root.appendingPathComponent("returns.json")
+        if FileManager.default.fileExists(atPath: fileURL.path) {
+            let data = try Data(contentsOf: fileURL)
+            do {
+                let decoded = try JSONDecoder().decode([ReturnedDocument].self, from: data)
+                entries = Dictionary(decoded.map { ($0.fileURL, $0) }, uniquingKeysWith: { _, new in new })
+            } catch {
+                let stamp = DubaiTime.fileStamp(Date())
+                let corruptURL = fileURL.deletingLastPathComponent()
+                    .appendingPathComponent("returns.json.corrupt-\(stamp)")
+                try FileManager.default.moveItem(at: fileURL, to: corruptURL)
+                Log.returns.error(
+                    "returns.json could not be decoded; moved to \(corruptURL.path, privacy: .public): \(error.localizedDescription, privacy: .public)"
+                )
+                entries = [:]
+            }
+        } else {
+            entries = [:]
+        }
+    }
+
+    /// Upserts by fileURL — recording the same URL again replaces the prior entry
+    /// (the most recently recorded call wins, regardless of its detectedAt value).
+    public func record(_ document: ReturnedDocument) throws {
+        entries[document.fileURL] = document
+        try persist()
+    }
+
+    /// Every recorded return, newest detectedAt first.
+    public func all() throws -> [ReturnedDocument] {
+        entries.values.sorted { $0.detectedAt > $1.detectedAt }
+    }
+
+    /// Commented returns (isCommented == true), newest detectedAt first.
+    public func commented() throws -> [ReturnedDocument] {
+        try all().filter(\.isCommented)
+    }
+
+    /// Absolute POSIX paths of commented returns, newest first, one per line, no
+    /// trailing newline. Throws ShotdeckError.noCommentedReturns when commented() is empty.
+    public func clipboardText() throws -> String {
+        let paths = try commented().map { $0.fileURL.path }
+        guard !paths.isEmpty else { throw ShotdeckError.noCommentedReturns }
+        return paths.joined(separator: "\n")
+    }
+
+    private func persist() throws {
+        let data = try JSONEncoder().encode(Array(entries.values))
+        try AtomicFile.write(data, to: fileURL)
+    }
+}

Sources/ShotdeckCore/Returns/ReturnWatcher.swift

@@ -0,0 +1,154 @@
+import Foundation
+import PDFKit
+import CoreServices   // FSEventStream* APIs; system framework, no Package.swift change needed
+
+public actor ReturnWatcher {
+    private let ledger: ReturnLedger
+    private var watchFolder: URL
+    private var onChange: (@Sendable ([ReturnedDocument]) -> Void)?
+    private var stream: FSEventStreamRef?
+    private var bridge: FSEventBridge?
+    private var pendingScanTask: Task<Void, Never>?
+    private let eventQueue = DispatchQueue(label: "ai.flowmaster.shotdeck.returns.fsevents")
+
+    /// Watch folder is `paths.watchFolder`, which production constructs from
+    /// `FolderSettings.resolve().watch`. This type never calls FolderSettings;
+    /// `updateWatchFolder` is invoked by the UI layer only.
+    public init(paths: AppSupportPaths, ledger: ReturnLedger) {
+        self.ledger = ledger
+        self.watchFolder = paths.watchFolder   // never a literal "~/Downloads" here
+    }
+
+    /// Starts watching paths.watchFolder for returned PDFs. Performs one immediate
+    /// scanNow() before returning, then calls onChange after every subsequent debounced
+    /// batch (even if that batch's result is empty — the caller decides what to do).
+    public func start(onChange: @escaping @Sendable ([ReturnedDocument]) -> Void) async throws {
+        self.onChange = onChange
+        try startStream(on: watchFolder)
+        let found = try await scanNow()
+        onChange(found)
+    }
+
+    /// Idempotent. Stops and releases the FSEventStream if one is running; safe to call
+    /// when never started or already stopped. Cancels any pending debounced scan.
+    public func stop() {
+        // Idempotent: nil stream / already-stopped is a no-op; never started is the same.
+        pendingScanTask?.cancel()
+        pendingScanTask = nil
+        if let stream {
+            FSEventStreamStop(stream)
+            FSEventStreamInvalidate(stream)
+            FSEventStreamRelease(stream)
+        }
+        stream = nil
+        bridge = nil
+    }
+
+    /// Called by whoever owns the Settings "Choose..." folder action (WP-4c) after the user
+    /// picks a new watch folder. If the watcher was running, stops the old FSEventStream,
+    /// switches to the new folder, restarts, and performs one immediate scanNow (reporting
+    /// through the same onChange callback given to start()). If the watcher was never
+    /// started, only updates the stored folder for the next start() call.
+    public func updateWatchFolder(_ url: URL) async throws {
+        let wasRunning = stream != nil
+        stop()
+        watchFolder = url
+        guard wasRunning else { return }
+        try startStream(on: url)
+        let found = try await scanNow()
+        onChange?(found)
+    }
+
+    /// Scans the watch folder once, immediately, without waiting for an event. Every
+    /// recognized, stable, openable Shotdeck PDF present is (re-)inspected and (re-)recorded
+    /// into the ledger; returns exactly the documents processed in this call.
+    @discardableResult
+    public func scanNow() async throws -> [ReturnedDocument] {
+        let fm = FileManager.default
+        let candidates = (try? fm.contentsOfDirectory(
+            at: watchFolder, includingPropertiesForKeys: nil
+        )) ?? []
+        var results: [ReturnedDocument] = []
+        for url in candidates.sorted(by: { $0.lastPathComponent < $1.lastPathComponent }) {
+            let name = url.lastPathComponent
+            // ".pdf.inprogress" already fails hasSuffix(".pdf") -> naturally skipped.
+            guard name.hasSuffix(".pdf"), !name.hasPrefix(".") else { continue }
+            guard await isStableAndReadable(url) else { continue }   // leave for next event
+            guard let document = PDFDocument(url: url),
+                  AnnotationInspector.isShotdeckDocument(document) else { continue }
+            guard let inspected = try? AnnotationInspector.inspect(fileURL: url) else { continue }
+            try await ledger.record(inspected)
+            results.append(inspected)
+        }
+        return results
+    }
+
+    /// Size-stable: two equal byte counts 250 ms apart AND PDFDocument opens;
+    /// otherwise leave the file for the next event.
+    private func isStableAndReadable(_ url: URL) async -> Bool {
+        let fm = FileManager.default
+        guard let size1 = try? fm.attributesOfItem(atPath: url.path)[.size] as? Int else { return false }
+        try? await Task.sleep(for: .milliseconds(250))
+        guard let size2 = try? fm.attributesOfItem(atPath: url.path)[.size] as? Int else { return false }
+        guard size1 == size2, size1 > 0 else { return false }
+        return PDFDocument(url: url) != nil
+    }
+
+    private func startStream(on folder: URL) throws {
+        let bridge = FSEventBridge { [weak self] in
+            guard let self else { return }
+            Task { await self.scheduleDebouncedScan() }
+        }
+        self.bridge = bridge
+        var context = FSEventStreamContext()
+        context.version = 0
+        context.info = Unmanaged.passUnretained(bridge).toOpaque()
+        context.retain = nil
+        context.release = nil
+        context.copyDescription = nil
+        guard let stream = FSEventStreamCreate(
+            kCFAllocatorDefault, shotdeckFSEventsCallback, &context,
+            [folder.path] as CFArray, FSEventStreamEventId(kFSEventStreamEventIdSinceNow),
+            0.0,
+            FSEventStreamCreateFlags(kFSEventStreamCreateFlagFileEvents | kFSEventStreamCreateFlagNoDefer)
+        ) else {
+            throw ShotdeckError.captureFailed(underlying: "could not create FSEventStream for \(folder.path)")
+        }
+        // Dispatch queue, not a run loop: this actor has no run loop of its own, and
+        // FSEventStreamSetDispatchQueue is the modern replacement for
+        // FSEventStreamScheduleWithRunLoop. One dedicated serial queue per watcher.
+        FSEventStreamSetDispatchQueue(stream, eventQueue)
+        guard FSEventStreamStart(stream) else {
+            FSEventStreamInvalidate(stream)
+            FSEventStreamRelease(stream)
+            throw ShotdeckError.captureFailed(underlying: "FSEventStreamStart failed for \(folder.path)")
+        }
+        self.stream = stream
+    }
+
+    private func scheduleDebouncedScan() async {
+        pendingScanTask?.cancel()
+        pendingScanTask = Task {
+            try? await Task.sleep(for: .milliseconds(400))   // coalesce AirDrop's write+rename burst
+            guard !Task.isCancelled else { return }
+            guard let found = try? await self.scanNow() else { return }
+            // One in-flight debounced callback may land after stop(); it is a
+            // harmless read-only rescan (ledger upsert, no watch-folder mutation).
+            self.onChange?(found)
+        }
+    }
+}
+
+/// Non-actor bridge because FSEventStreamCallback is a @convention(c) function pointer and
+/// cannot capture actor-isolated state directly; it hops back onto the actor via Task.
+private final class FSEventBridge: @unchecked Sendable {
+    // @unchecked is safe: `notify` is a let, set once at init, never mutated after — the
+    // type is immutable for its entire lifetime.
+    let notify: @Sendable () -> Void
+    init(notify: @escaping @Sendable () -> Void) { self.notify = notify }
+}
+
+private let shotdeckFSEventsCallback: FSEventStreamCallback = { _, info, _, _, _, _ in
+    guard let info else { return }
+    Unmanaged<FSEventBridge>.fromOpaque(info).takeUnretainedValue().notify()
+}

Tests/ShotdeckCoreTests/AnnotationInspectorTests.swift

@@ -0,0 +1,412 @@
+import AppKit
+import Foundation
+import PDFKit
+import Testing
+import ShotdeckCore
+
+private let pageBounds = CGRect(x: 0, y: 0, width: 600, height: 800)
+
+private func makeAnnotation(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect = CGRect(x: 100, y: 100, width: 80, height: 40),
+    contents: String? = nil
+) -> PDFAnnotation {
+    let annotation = PDFAnnotation(
+        bounds: bounds,
+        forType: subtype,
+        withProperties: nil
+    )
+    annotation.contents = contents
+    return annotation
+}
+
+private func makePDF(
+    at url: URL,
+    pageCount: Int,
+    creator: String? = "Shotdeck",
+    subject: String? = nil,
+    annotations: [(page: Int, annotation: PDFAnnotation)] = []
+) throws {
+    let document = PDFDocument()
+    for index in 0..<pageCount {
+        let page = PDFPage()
+        page.setBounds(pageBounds, for: .mediaBox)
+        document.insert(page, at: index)
+    }
+
+    var attributes = [PDFDocumentAttribute: Any]()
+    if let creator { attributes[.creatorAttribute] = creator }
+    if let subject { attributes[.subjectAttribute] = subject }
+    document.documentAttributes = attributes
+
+    for item in annotations {
+        guard let page = document.page(at: item.page) else {
+            throw NSError(domain: "WP5Test", code: 1)
+        }
+        page.addAnnotation(item.annotation)
+    }
+
+    guard document.write(to: url) else {
+        throw NSError(domain: "WP5Test", code: 2)
+    }
+}
+
+private func makeCasePaths() throws -> (paths: AppSupportPaths, cleanup: URL) {
+    let cleanup = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-wp5a-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: cleanup.appendingPathComponent("root", isDirectory: true),
+        outbox: cleanup.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: cleanup.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (paths, cleanup)
+}
+
+@Test("I-1 Untouched PDF is clean")
+func i1_untouchedPDFIsClean() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134200.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        creator: "Shotdeck",
+        subject: "11111111-1111-1111-1111-111111111111"
+    )
+
+    var calendar = Calendar(identifier: .gregorian)
+    calendar.timeZone = try #require(TimeZone(identifier: "Asia/Dubai"))
+    let firstMTime = try #require(calendar.date(from: DateComponents(
+        year: 2026, month: 8, day: 30, hour: 13, minute: 42, second: 0
+    )))
+    let secondMTime = try #require(calendar.date(from: DateComponents(
+        year: 2026, month: 8, day: 30, hour: 13, minute: 43, second: 0
+    )))
+    try FileManager.default.setAttributes([.modificationDate: firstMTime], ofItemAtPath: pdfURL.path)
+    try FileManager.default.setAttributes([.modificationDate: secondMTime], ofItemAtPath: pdfURL.path)
+
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.fileURL == pdfURL)
+    #expect(inspected.sessionID == UUID(uuidString: "11111111-1111-1111-1111-111111111111"))
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [])
+    #expect(inspected.isCommented == false)
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(inspected)
+    let all = try await ledger.all()
+    #expect(all.count == 1)
+    #expect(all[0].fileURL == pdfURL)
+    #expect(try await ledger.commented() == [])
+    let clipboardError = try await #require(throws: ShotdeckError.self) {
+        try await ledger.clipboardText()
+    }
+    guard case .noCommentedReturns = clipboardError else {
+        Issue.record("expected noCommentedReturns, got \(clipboardError)")
+        return
+    }
+}
+
+@Test("I-2 Ink is a mark")
+func i2_inkIsAMark() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134201.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        annotations: [(page: 1, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 120, y: 240, width: 140, height: 60)
+        ))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [2])
+    #expect(inspected.isCommented == true)
+}
+
+@Test("I-3 Highlight is a mark")
+func i3_highlightIsAMark() throws {
+    try expectSinglePageMark(
+        .highlight,
+        bounds: CGRect(x: 80, y: 500, width: 300, height: 24),
+        fileName: "Shotdeck-20260830-134202.pdf"
+    )
+}
+
+@Test("I-4 Underline is a mark")
+func i4_underlineIsAMark() throws {
+    try expectSinglePageMark(
+        .underline,
+        bounds: CGRect(x: 90, y: 460, width: 280, height: 18),
+        fileName: "Shotdeck-20260830-134203.pdf"
+    )
+}
+
+@Test("I-5 Strike-out is a mark")
+func i5_strikeOutIsAMark() throws {
+    try expectSinglePageMark(
+        .strikeOut,
+        bounds: CGRect(x: 90, y: 430, width: 280, height: 18),
+        fileName: "Shotdeck-20260830-134204.pdf"
+    )
+}
+
+@Test("I-6 Squiggly is a mark")
+func i6_squigglyIsAMark() throws {
+    try expectSinglePageMark(
+        PDFAnnotationSubtype(rawValue: "/Squiggly"),
+        bounds: CGRect(x: 90, y: 400, width: 280, height: 18),
+        fileName: "Shotdeck-20260830-134205.pdf"
+    )
+}
+
+@Test("I-7 Free-text is a mark")
+func i7_freeTextIsAMark() throws {
+    try expectSinglePageMark(
+        .freeText,
+        bounds: CGRect(x: 140, y: 300, width: 220, height: 80),
+        contents: "Typed review note",
+        fileName: "Shotdeck-20260830-134206.pdf"
+    )
+}
+
+@Test("I-8 Square is a mark")
+func i8_squareIsAMark() throws {
+    try expectSinglePageMark(
+        .square,
+        bounds: CGRect(x: 160, y: 250, width: 100, height: 100),
+        fileName: "Shotdeck-20260830-134207.pdf"
+    )
+}
+
+@Test("I-9 Circle is a mark")
+func i9_circleIsAMark() throws {
+    try expectSinglePageMark(
+        .circle,
+        bounds: CGRect(x: 280, y: 250, width: 100, height: 100),
+        fileName: "Shotdeck-20260830-134208.pdf"
+    )
+}
+
+@Test("I-10 Line is a mark")
+func i10_lineIsAMark() throws {
+    try expectSinglePageMark(
+        .line,
+        bounds: CGRect(x: 100, y: 180, width: 320, height: 8),
+        fileName: "Shotdeck-20260830-134209.pdf"
+    )
+}
+
+@Test("I-11 Stamp is a mark")
+func i11_stampIsAMark() throws {
+    try expectSinglePageMark(
+        .stamp,
+        bounds: CGRect(x: 180, y: 500, width: 120, height: 60),
+        contents: "Approved",
+        fileName: "Shotdeck-20260830-134210.pdf"
+    )
+}
+
+@Test("I-12 Sticky text is a mark")
+func i12_stickyTextIsAMark() throws {
+    try expectSinglePageMark(
+        .text,
+        bounds: CGRect(x: 420, y: 620, width: 28, height: 28),
+        contents: "Look here",
+        fileName: "Shotdeck-20260830-134211.pdf"
+    )
+}
+
+@Test("I-13 Link alone is not a mark")
+func i13_linkAloneIsNotAMark() throws {
+    try expectSinglePageIgnored(
+        .link,
+        bounds: CGRect(x: 80, y: 700, width: 160, height: 20),
+        fileName: "Shotdeck-20260830-134212.pdf"
+    )
+}
+
+@Test("I-14 Popup alone is not a mark")
+func i14_popupAloneIsNotAMark() throws {
+    try expectSinglePageIgnored(
+        .popup,
+        bounds: CGRect(x: 450, y: 600, width: 100, height: 60),
+        fileName: "Shotdeck-20260830-134213.pdf"
+    )
+}
+
+@Test("I-15 Widget alone is not a mark")
+func i15_widgetAloneIsNotAMark() throws {
+    try expectSinglePageIgnored(
+        .widget,
+        bounds: CGRect(x: 100, y: 100, width: 140, height: 32),
+        fileName: "Shotdeck-20260830-134214.pdf"
+    )
+}
+
+@Test("I-16 Zero-area ink is not a mark")
+func i16_zeroAreaInkIsNotAMark() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134215.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 240, y: 240, width: 0, height: 0)
+        ))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.annotatedPages == [])
+    #expect(inspected.isCommented == false)
+}
+
+@Test("I-17 Ignored objects plus one real mark count once")
+func i17_ignoredObjectsPlusOneRealMarkCountOnce() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134216.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        annotations: [
+            (page: 1, annotation: makeAnnotation(.link, bounds: CGRect(x: 20, y: 20, width: 40, height: 20))),
+            (page: 1, annotation: makeAnnotation(.popup, bounds: CGRect(x: 70, y: 20, width: 40, height: 20))),
+            (page: 1, annotation: makeAnnotation(.widget, bounds: CGRect(x: 120, y: 20, width: 40, height: 20))),
+            (page: 1, annotation: makeAnnotation(.ink, bounds: CGRect(x: 200, y: 200, width: 120, height: 50))),
+        ]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [2])
+    #expect(inspected.isCommented == true)
+}
+
+@Test("I-18 Page numbers are 1-based and ascending")
+func i18_pageNumbersAre1BasedAndAscending() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134217.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        annotations: [
+            (page: 0, annotation: makeAnnotation(.circle, bounds: CGRect(x: 260, y: 200, width: 70, height: 70))),
+            (page: 1, annotation: makeAnnotation(.link, bounds: CGRect(x: 80, y: 700, width: 160, height: 20))),
+            (page: 2, annotation: makeAnnotation(.ink, bounds: CGRect(x: 100, y: 100, width: 90, height: 40))),
+        ]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [1, 3])
+    #expect(inspected.isCommented == true)
+}
+
+@Test("I-19 Session UUID recovery and invalid-subject tolerance")
+func i19_sessionUUIDRecoveryAndInvalidSubjectTolerance() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let validURL = paths.watchFolder.appendingPathComponent("valid-subject.pdf")
+    let invalidURL = paths.watchFolder.appendingPathComponent("invalid-subject.pdf")
+    let missingURL = paths.watchFolder.appendingPathComponent("missing-subject.pdf")
+
+    try makePDF(
+        at: validURL,
+        pageCount: 1,
+        creator: "Shotdeck",
+        subject: "22222222-2222-2222-2222-222222222222"
+    )
+    try makePDF(
+        at: invalidURL,
+        pageCount: 1,
+        creator: "Shotdeck",
+        subject: "not-a-uuid"
+    )
+    try makePDF(
+        at: missingURL,
+        pageCount: 1,
+        creator: "Shotdeck",
+        subject: nil
+    )
+
+    let valid = try AnnotationInspector.inspect(fileURL: validURL)
+    #expect(valid.sessionID == UUID(uuidString: "22222222-2222-2222-2222-222222222222"))
+    #expect(valid.pageCount == 1)
+    #expect(valid.annotatedPages == [])
+    #expect(valid.isCommented == false)
+
+    let invalid = try AnnotationInspector.inspect(fileURL: invalidURL)
+    #expect(invalid.sessionID == nil)
+    #expect(invalid.annotatedPages == [])
+    #expect(invalid.isCommented == false)
+
+    let missing = try AnnotationInspector.inspect(fileURL: missingURL)
+    #expect(missing.sessionID == nil)
+    #expect(missing.annotatedPages == [])
+    #expect(missing.isCommented == false)
+}
+
+@Test("I-19b Present non-Shotdeck creator beats a matching filename")
+func i19b_presentNonShotdeckCreatorBeatsMatchingFilename() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134218.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        creator: "Preview",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+    let reopened = try #require(PDFDocument(url: pdfURL))
+    #expect(AnnotationInspector.isShotdeckDocument(reopened) == false)
+}
+
+private func expectSinglePageMark(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect,
+    contents: String? = nil,
+    fileName: String
+) throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent(fileName)
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        annotations: [(page: 0, annotation: makeAnnotation(subtype, bounds: bounds, contents: contents))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 1)
+    #expect(inspected.annotatedPages == [1])
+    #expect(inspected.isCommented == true)
+}
+
+private func expectSinglePageIgnored(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect,
+    fileName: String
+) throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent(fileName)
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        annotations: [(page: 0, annotation: makeAnnotation(subtype, bounds: bounds))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.annotatedPages == [])
+    #expect(inspected.isCommented == false)
+}

Tests/ShotdeckCoreTests/ReturnLedgerTests.swift

@@ -0,0 +1,200 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+private func makeCasePaths() throws -> (paths: AppSupportPaths, cleanup: URL) {
+    let cleanup = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-wp5a-ledger-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: cleanup.appendingPathComponent("root", isDirectory: true),
+        outbox: cleanup.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: cleanup.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (paths, cleanup)
+}
+
+private func document(
+    path: String,
+    annotatedPages: [Int],
+    detectedAt: Date,
+    sessionID: UUID? = nil,
+    pageCount: Int = 1
+) -> ReturnedDocument {
+    ReturnedDocument(
+        fileURL: URL(fileURLWithPath: path),
+        sessionID: sessionID,
+        pageCount: pageCount,
+        annotatedPages: annotatedPages,
+        detectedAt: detectedAt
+    )
+}
+
+@Test("L-1 commented() returns only commented entries, newest first")
+func l1_commentedReturnsOnlyCommentedNewestFirst() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let newer = document(
+        path: "/tmp/shotdeck-returns/newer.pdf",
+        annotatedPages: [1, 2],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_200)
+    )
+    let older = document(
+        path: "/tmp/shotdeck-returns/older.pdf",
+        annotatedPages: [3],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_100)
+    )
+    let clean = document(
+        path: "/tmp/shotdeck-returns/clean.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_300)
+    )
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(older)
+    try await ledger.record(newer)
+    try await ledger.record(clean)
+
+    let commented = try await ledger.commented()
+    #expect(commented.map(\.fileURL) == [newer.fileURL, older.fileURL])
+    #expect(commented.map(\.annotatedPages) == [[1, 2], [3]])
+}
+
+@Test("L-2 clipboardText() exact format")
+func l2_clipboardTextExactFormat() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let newer = document(
+        path: "/tmp/shotdeck-returns/newer.pdf",
+        annotatedPages: [1, 2],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_200)
+    )
+    let older = document(
+        path: "/tmp/shotdeck-returns/older.pdf",
+        annotatedPages: [3],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_100)
+    )
+    let clean = document(
+        path: "/tmp/shotdeck-returns/clean.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_300)
+    )
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(older)
+    try await ledger.record(newer)
+    try await ledger.record(clean)
+
+    let text = try await ledger.clipboardText()
+    #expect(text == newer.fileURL.path + "\n" + older.fileURL.path)
+    #expect(text.hasSuffix("\n") == false)
+}
+
+@Test("L-3 Re-recording the same URL upserts")
+func l3_rerecordingTheSameURLUpserts() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let url = URL(fileURLWithPath: "/tmp/shotdeck-returns/same.pdf")
+    let first = ReturnedDocument(
+        fileURL: url,
+        sessionID: nil,
+        pageCount: 1,
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_400)
+    )
+    let second = ReturnedDocument(
+        fileURL: url,
+        sessionID: UUID(uuidString: "11111111-1111-1111-1111-111111111111"),
+        pageCount: 1,
+        annotatedPages: [1],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_100)
+    )
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(first)
+    try await ledger.record(second)
+
+    let all = try await ledger.all()
+    #expect(all.count == 1)
+    #expect(all[0].fileURL == url)
+    #expect(all[0].annotatedPages == [1])
+    #expect(all[0].isCommented == true)
+    #expect(all[0].sessionID == UUID(uuidString: "11111111-1111-1111-1111-111111111111"))
+}
+
+@Test("L-4 clipboardText() throws when nothing is commented")
+func l4_clipboardTextThrowsWhenNothingIsCommented() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let emptyError = try await #require(throws: ShotdeckError.self) {
+        try await ledger.clipboardText()
+    }
+    guard case .noCommentedReturns = emptyError else {
+        Issue.record("expected noCommentedReturns on an empty ledger, got \(emptyError)")
+        return
+    }
+
+    try await ledger.record(document(
+        path: "/tmp/shotdeck-returns/clean-only.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_500)
+    ))
+    let cleanError = try await #require(throws: ShotdeckError.self) {
+        try await ledger.clipboardText()
+    }
+    guard case .noCommentedReturns = cleanError else {
+        Issue.record("expected noCommentedReturns with only clean returns, got \(cleanError)")
+        return
+    }
+}
+
+@Test("L-5 Ledger survives reopening from disk")
+func l5_ledgerSurvivesReopeningFromDisk() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let first = document(
+        path: "/tmp/shotdeck-returns/a.pdf",
+        annotatedPages: [1],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_700),
+        sessionID: UUID(uuidString: "11111111-1111-1111-1111-111111111111")
+    )
+    let second = document(
+        path: "/tmp/shotdeck-returns/b.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_600)
+    )
+
+    do {
+        let ledger = try ReturnLedger(paths: paths)
+        try await ledger.record(first)
+        try await ledger.record(second)
+    }
+
+    let reopened = try ReturnLedger(paths: paths)
+    let all = try await reopened.all()
+    #expect(all == [first, second])
+}
+
+@Test("L-6 Corrupt returns.json is renamed and the ledger starts empty")
+func l6_corruptReturnsJSONIsRenamedAndStartsEmpty() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let returnsURL = paths.root.appendingPathComponent("returns.json")
+    try Data("{not-json".utf8).write(to: returnsURL)
+    #expect(FileManager.default.fileExists(atPath: returnsURL.path))
+
+    let ledger = try ReturnLedger(paths: paths)
+    #expect(try await ledger.all() == [])
+    #expect(FileManager.default.fileExists(atPath: returnsURL.path) == false)
+
+    let names = try FileManager.default.contentsOfDirectory(atPath: paths.root.path)
+    let corrupt = names.filter { $0.hasPrefix("returns.json.corrupt-") }
+    #expect(corrupt.count == 1)
+    #expect(corrupt[0].contains(DubaiTime.fileStamp(Date()).prefix(8)))
+}

Tests/ShotdeckCoreTests/ReturnWatcherTests.swift

@@ -0,0 +1,173 @@
+import AppKit
+import Foundation
+import PDFKit
+import Testing
+import ShotdeckCore
+
+private let pageBounds = CGRect(x: 0, y: 0, width: 600, height: 800)
+
+private func makeAnnotation(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect = CGRect(x: 100, y: 100, width: 80, height: 40),
+    contents: String? = nil
+) -> PDFAnnotation {
+    let annotation = PDFAnnotation(
+        bounds: bounds,
+        forType: subtype,
+        withProperties: nil
+    )
+    annotation.contents = contents
+    return annotation
+}
+
+private func makePDF(
+    at url: URL,
+    pageCount: Int,
+    creator: String? = "Shotdeck",
+    subject: String? = nil,
+    annotations: [(page: Int, annotation: PDFAnnotation)] = []
+) throws {
+    let document = PDFDocument()
+    for index in 0..<pageCount {
+        let page = PDFPage()
+        page.setBounds(pageBounds, for: .mediaBox)
+        document.insert(page, at: index)
+    }
+
+    var attributes = [PDFDocumentAttribute: Any]()
+    if let creator { attributes[.creatorAttribute] = creator }
+    if let subject { attributes[.subjectAttribute] = subject }
+    document.documentAttributes = attributes
+
+    for item in annotations {
+        guard let page = document.page(at: item.page) else {
+            throw NSError(domain: "WP5Test", code: 1)
+        }
+        page.addAnnotation(item.annotation)
+    }
+
+    guard document.write(to: url) else {
+        throw NSError(domain: "WP5Test", code: 2)
+    }
+}
+
+private func makeCasePaths() throws -> (paths: AppSupportPaths, cleanup: URL) {
+    let cleanup = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-wp5b-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: cleanup.appendingPathComponent("root", isDirectory: true),
+        outbox: cleanup.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: cleanup.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (paths, cleanup)
+}
+
+/// Guards `confirmation(expectedCount: 1)` against a create+rename double-event.
+private final class ConfirmOnce: @unchecked Sendable {
+    private let lock = NSLock()
+    private var fired = false
+    func run(_ body: () -> Void) {
+        lock.lock()
+        defer { lock.unlock() }
+        guard !fired else { return }
+        fired = true
+        body()
+    }
+}
+
+@Test("W-25 Duplicate-name suffix is the normal AirDrop return (scanNow)")
+func w25_duplicateNameSuffixIsRecognizedByScanNow() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134205 2.pdf")
+
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        creator: nil,
+        subject: "33333333-3333-3333-3333-333333333333",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+
+    let found = try await watcher.scanNow()
+    #expect(found.count == 1)
+    let doc = try #require(found.first)
+    #expect(doc.fileURL.lastPathComponent == "Shotdeck-20260830-134205 2.pdf")
+    #expect(doc.fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path)
+    #expect(doc.pageCount == 1)
+    #expect(doc.annotatedPages == [1])
+    #expect(doc.isCommented == true)
+
+    let commented = try await ledger.commented()
+    #expect(commented.count == 1)
+    #expect(commented[0].fileURL.lastPathComponent == pdfURL.lastPathComponent)
+    #expect(commented[0].fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path)
+}
+
+@Test("W-26 Creator provenance negative at the scan level")
+func w26_presentNonShotdeckCreatorIsIgnoredByScanNow() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134218.pdf")
+
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        creator: "Preview",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+
+    let found = try await watcher.scanNow()
+    #expect(found.isEmpty)
+    let all = try await ledger.all()
+    #expect(all.isEmpty)
+}
+
+@Test("W-27 FSEvents live callback fires on a real file arrival")
+func w27_fsEventsCallbackFiresOnRealArrival() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-140000.pdf")
+    let once = ConfirmOnce()
+
+    try await confirmation("watcher reports the arrived PDF", expectedCount: 1) { confirm in
+        do {
+            try await watcher.start { docs in
+                if docs.contains(where: { $0.fileURL.lastPathComponent == pdfURL.lastPathComponent }) {
+                    once.run { confirm() }
+                }
+            }
+            // Simulate AirDrop's own write-then-rename so the watcher must survive that pattern.
+            let tmpURL = pdfURL.appendingPathExtension("inprogress")
+            try makePDF(
+                at: tmpURL, pageCount: 1, creator: "Shotdeck",
+                annotations: [(page: 0, annotation: makeAnnotation(
+                    .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+                ))]
+            )
+            try FileManager.default.moveItem(at: tmpURL, to: pdfURL)
+        } catch {
+            print("fsEventsCallbackFiresOnRealArrival error: \(error)")
+            await watcher.stop()
+            throw error
+        }
+        // Budget: 400ms debounce + FS latency + the 250ms stability re-read + PDFKit open.
+        // 5s is a generous, fixed ceiling — never a "some time" wait.
+        try await Task.sleep(for: .seconds(5))
+        await watcher.stop()
+        await watcher.stop()
+    }
+}