Promote the paid app when no ad fills the slot

OpenDocumentReader.xcodeproj/project.pbxproj

@@ -20,6 +20,7 @@
 		AC384BCF23B4FFA700C7BF47 /* PageViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = AC384BCB23B4FFA700C7BF47 /* PageViewController.swift */; };
 		ACA46529244E403900A5DA7A /* AppType.swift in Sources */ = {isa = PBXBuildFile; fileRef = ACA46528244E403900A5DA7A /* AppType.swift */; };
 		ACD9BE3C2444A371009014E6 /* ConfigurationManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = ACD9BE2D2444A371009014E6 /* ConfigurationManager.swift */; };
+		C0A5E1200000000000000001 /* HouseAdView.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0A5E1200000000000000002 /* HouseAdView.swift */; };
 		BFFB694BE9E3E744FD4F92E0 /* CrashManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 25ACB597DDB073F3AFC74345 /* CrashManager.swift */; };
 		C43B65A97E4029F7790DA729 /* CoreWrapper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 02C00CD0A89EF1F64FF879A1 /* CoreWrapper.swift */; };
 		D2DCD7104EBCC0F1A784E116 /* GoogleMobileAds in Frameworks */ = {isa = PBXBuildFile; productRef = B5F033C5AA89A6E9C19EA27D /* GoogleMobileAds */; };
@@ -87,6 +88,7 @@
 		AC73790F2438E52B00F9F3B5 /* sl */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = sl; path = sl.lproj/Localizable.strings; sourceTree = "<group>"; };
 		ACA46528244E403900A5DA7A /* AppType.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppType.swift; sourceTree = "<group>"; };
 		ACD9BE2D2444A371009014E6 /* ConfigurationManager.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ConfigurationManager.swift; sourceTree = "<group>"; };
+		C0A5E1200000000000000002 /* HouseAdView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HouseAdView.swift; sourceTree = "<group>"; };
 		ACF1A3E42469F8DE000BA420 /* Info-Lite.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-Lite.plist"; sourceTree = "<group>"; };
 		B01C1B2BA00A7917FF7D7726 /* PrivacyInfo.xcprivacy */ = {isa = PBXFileReference; includeInIndex = 1; path = PrivacyInfo.xcprivacy; sourceTree = "<group>"; };
 		B94897965C815527C6C06996 /* PrivacyInfo.xcprivacy */ = {isa = PBXFileReference; includeInIndex = 1; path = PrivacyInfo.xcprivacy; sourceTree = "<group>"; };
@@ -244,6 +246,7 @@
 				AC384BC923B4FFA700C7BF47 /* ContentViewController.swift */,
 				AC384BCB23B4FFA700C7BF47 /* PageViewController.swift */,
 				ACD9BE2D2444A371009014E6 /* ConfigurationManager.swift */,
+				C0A5E1200000000000000002 /* HouseAdView.swift */,
 				E22EB717226B633500053B86 /* Document.swift */,
 				E22EB71B226B66B300053B86 /* Main.storyboard */,
 				E2F7ED5D220B54D700D63515 /* Assets.xcassets */,
@@ -410,6 +413,7 @@
 				E22EB716226B621200053B86 /* DocumentBrowserTransitioningDelegate.swift in Sources */,
 				ACA46529244E403900A5DA7A /* AppType.swift in Sources */,
 				ACD9BE3C2444A371009014E6 /* ConfigurationManager.swift in Sources */,
+				C0A5E1200000000000000001 /* HouseAdView.swift in Sources */,
 				AC384BCE23B4FFA700C7BF47 /* Constants.swift in Sources */,
 				E2F7ED55220B54D600D63515 /* DocumentBrowserViewController.swift in Sources */,
 				E2F7ED53220B54D600D63515 /* AppDelegate.swift in Sources */,

OpenDocumentReader/Assets.xcassets/house_ad_icon.imageset/Contents.json

@@ -0,0 +1,8 @@
+{
+  "images" : [
+    { "filename" : "icon.png", "idiom" : "universal", "scale" : "1x" },
+    { "filename" : "icon@2x.png", "idiom" : "universal", "scale" : "2x" },
+    { "filename" : "icon@3x.png", "idiom" : "universal", "scale" : "3x" }
+  ],
+  "info" : { "author" : "xcode", "version" : 1 }
+}

OpenDocumentReader/Constants.swift

@@ -12,4 +12,11 @@ enum Constants {
     static let onboardingImages = ["onboard1", "onboard2", "onboard3"]
 
     static let key_was_intro_watched = "wasIntroWatched"
+
+    /// Which of the house ad's rotations comes next.
+    static let key_house_ad_index = "houseAdIndex"
+
+    /// ODR Pro on the App Store. This is the *paid* app: on iOS that is `at.tomtasche.reader`,
+    /// while on Android the same bundle id names the free one.
+    static let proAppStoreId = 1_452_061_743
 }

OpenDocumentReader/DocumentViewController.swift

@@ -8,13 +8,14 @@ A view controller for displaying and editing documents.
 import AdSupport
 import AppTrackingTransparency
 import GoogleMobileAds
+import StoreKit
 import UIKit
 import UIKit.UIPrinter
 import WebKit
 
 // taken from: https://developer.apple.com/documentation/uikit/view_controllers/building_a_document_browser-based_app
 class DocumentViewController: UIViewController, DocumentDelegate, BannerViewDelegate, UISearchBarDelegate,
-    WKNavigationDelegate
+    SKStoreProductViewControllerDelegate, WKNavigationDelegate
 {
 
     private var browserTransition: DocumentBrowserTransitioningDelegate?
@@ -52,6 +53,10 @@ class DocumentViewController: UIViewController, DocumentDelegate, BannerViewDele
     @IBOutlet weak var barButtonItem: UIBarButtonItem!
     @IBOutlet weak var searchButton: UIBarButtonItem!
 
+    /// Fills the banner slot when no ad does. Sits on top of `bannerView` rather than in the
+    /// layout chain, so the slot keeps its height and nothing below it moves.
+    private let houseAdView = HouseAdView()
+
     private var searchBarHeightWhenShown: NSLayoutConstraint?
     private var searchBarHeightWhenHidden: NSLayoutConstraint?
     private lazy var pageTabBarHeight = pageTabBar.heightAnchor.constraint(equalToConstant: 0)
@@ -74,6 +79,27 @@ class DocumentViewController: UIViewController, DocumentDelegate, BannerViewDele
         pageTabBar.addTarget(self, action: #selector(pageSelected(sender:)), for: .valueChanged)
 
         webview.navigationDelegate = self
+
+        setUpHouseAd()
+    }
+
+    /// Here rather than in `setVCconstraints`, which runs on every appearance and would stack up a
+    /// fresh set of constraints each time.
+    private func setUpHouseAd() {
+        houseAdView.isHidden = true
+        houseAdView.translatesAutoresizingMaskIntoConstraints = false
+        houseAdView.onTap = { [weak self] in
+            self?.openProOnAppStore()
+        }
+
+        view.addSubview(houseAdView)
+
+        NSLayoutConstraint.activate([
+            houseAdView.leadingAnchor.constraint(equalTo: bannerView.leadingAnchor),
+            houseAdView.trailingAnchor.constraint(equalTo: bannerView.trailingAnchor),
+            houseAdView.topAnchor.constraint(equalTo: bannerView.topAnchor),
+            houseAdView.bottomAnchor.constraint(equalTo: bannerView.bottomAnchor),
+        ])
     }
 
     /// odrcore renders a page when this web view asks for it, so a document
@@ -185,11 +211,57 @@ class DocumentViewController: UIViewController, DocumentDelegate, BannerViewDele
 
     func hideBannerView() {
         bannerView.isHidden = true
+        houseAdView.isHidden = true
         bannerViewHeight.constant = 0.0
     }
 
+    /// No ad to show, so the slot promotes the paid app instead of collapsing.
+    ///
+    /// This is our own view - nothing is fetched and no identifier is read - so it is as valid on
+    /// the path where the user refused consent as on the one where an ad request merely came back
+    /// empty.
+    private func showHouseAd() {
+        houseAdView.rotate()
+
+        bannerView.isHidden = true
+        houseAdView.isHidden = false
+
+        AnalyticsManager.shared.report("house_ad_shown")
+    }
+
     func bannerView(_ bannerView: BannerView, didFailToReceiveAdWithError error: Error) {
-        hideBannerView()
+        showHouseAd()
+    }
+
+    /// An ad did arrive after all - on a later document, or once the network came back.
+    func bannerViewDidReceiveAd(_ bannerView: BannerView) {
+        houseAdView.isHidden = true
+        bannerView.isHidden = false
+    }
+
+    private func openProOnAppStore() {
+        AnalyticsManager.shared.report("house_ad_tapped")
+
+        let store = SKStoreProductViewController()
+        store.delegate = self
+
+        // presented over the document rather than sending the user out to the App Store app
+        store.loadProduct(withParameters: [SKStoreProductParameterITunesItemIdentifier: Constants.proAppStoreId]) {
+            loaded, error in
+            if let error {
+                CrashManager.shared.log(error)
+            }
+
+            guard loaded else { return }
+
+            DispatchQueue.main.async {
+                self.present(store, animated: true)
+            }
+        }
+    }
+
+    func productViewControllerDidFinish(_ viewController: SKStoreProductViewController) {
+        viewController.dismiss(animated: true)
     }
 
     override func viewDidAppear(_ animated: Bool) {

OpenDocumentReader/HouseAdView.swift

@@ -0,0 +1,223 @@
+import StoreKit
+import UIKit
+
+/// The promotion for the paid app that takes the banner's place when no ad arrives.
+///
+/// This is our own content, not an ad: nothing is fetched, no identifier is read and no storage is
+/// touched. That is what makes it usable on every no-fill path, including the one where the user
+/// refused consent outright and Google is serving limited ads or nothing at all.
+///
+/// One layout, sized to whatever the slot gives it - the banner height is fixed by the ad slot and
+/// cannot grow, so parts drop out instead of wrapping.
+final class HouseAdView: UIView {
+
+    /// One rotation of the promotion. `shortHeadline` is what a phone-width slot can actually fit.
+    private struct Creative {
+        let shortHeadline: String
+        let headline: String
+        let subline: String
+        let callToAction: String
+    }
+
+    private static let creatives = [
+        Creative(
+            shortHeadline: NSLocalizedString(
+                "house_ad_support_short", value: "Support us", comment: ""),
+            headline: NSLocalizedString(
+                "house_ad_support_headline", value: "Support OpenDocument Reader", comment: ""),
+            subline: NSLocalizedString(
+                "house_ad_support_subline", value: "Get Pro — no ads, ever", comment: ""),
+            callToAction: NSLocalizedString(
+                "house_ad_cta_go_pro", value: "Go Pro", comment: "")),
+        Creative(
+            shortHeadline: NSLocalizedString(
+                "house_ad_adfree_short", value: "Read without ads", comment: ""),
+            headline: NSLocalizedString(
+                "house_ad_adfree_headline", value: "Read without ads", comment: ""),
+            subline: NSLocalizedString(
+                "house_ad_adfree_subline", value: "ODR Pro — a one-time purchase", comment: ""),
+            callToAction: NSLocalizedString(
+                "house_ad_cta_get_pro", value: "Get Pro", comment: "")),
+        Creative(
+            shortHeadline: NSLocalizedString(
+                "house_ad_source_short", value: "Open source", comment: ""),
+            headline: NSLocalizedString(
+                "house_ad_source_headline", value: "Open source, kept free", comment: ""),
+            subline: NSLocalizedString(
+                "house_ad_source_subline", value: "Pro pays for it — and drops the ads", comment: ""),
+            callToAction: NSLocalizedString(
+                "house_ad_cta_go_pro", value: "Go Pro", comment: "")),
+    ]
+
+    /// Round-robin rather than random, so the three are seen evenly and a session does not repeat
+    /// the same one. Advanced once per presentation, not once per layout pass.
+    private static func nextCreative() -> Creative {
+        let defaults = UserDefaults.standard
+        let index = defaults.integer(forKey: Constants.key_house_ad_index)
+
+        defaults.set((index + 1) % creatives.count, forKey: Constants.key_house_ad_index)
+
+        return creatives[index % creatives.count]
+    }
+
+    // its own imageset rather than the app icon: UIImage(named:) cannot reliably reach an
+    // AppIcon.appiconset at runtime
+    private let iconView = UIImageView(image: UIImage(named: "house_ad_icon"))
+    private lazy var iconWidth = iconView.widthAnchor.constraint(equalToConstant: 34)
+    private lazy var iconHeight = iconView.heightAnchor.constraint(equalToConstant: 34)
+    private let headlineLabel = UILabel()
+    private let sublineLabel = UILabel()
+    private let callToActionLabel = PaddedLabel()
+    private let textStack = UIStackView()
+    private let stack = UIStackView()
+
+    private var creative = HouseAdView.nextCreative()
+
+    /// Called when the promotion is tapped, so the controller can present the store.
+    var onTap: (() -> Void)?
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+
+        setUp()
+    }
+
+    required init?(coder: NSCoder) {
+        super.init(coder: coder)
+
+        setUp()
+    }
+
+    private func setUp() {
+        backgroundColor = .secondarySystemBackground
+        isAccessibilityElement = true
+        accessibilityTraits = .button
+
+        iconView.contentMode = .scaleAspectFit
+        iconView.layer.cornerRadius = 6
+        iconView.clipsToBounds = true
+        iconView.setContentHuggingPriority(.required, for: .horizontal)
+
+        headlineLabel.font = .preferredFont(forTextStyle: .footnote).bold()
+        headlineLabel.adjustsFontForContentSizeCategory = true
+        // truncate rather than wrap: a long translation must shorten, not break the fixed height
+        headlineLabel.lineBreakMode = .byTruncatingTail
+
+        sublineLabel.font = .preferredFont(forTextStyle: .caption2)
+        sublineLabel.adjustsFontForContentSizeCategory = true
+        sublineLabel.textColor = .secondaryLabel
+        sublineLabel.lineBreakMode = .byTruncatingTail
+
+        callToActionLabel.font = .preferredFont(forTextStyle: .caption1).bold()
+        callToActionLabel.adjustsFontForContentSizeCategory = true
+        callToActionLabel.textColor = .systemBackground
+        callToActionLabel.backgroundColor = .tintColor
+        callToActionLabel.textAlignment = .center
+        callToActionLabel.clipsToBounds = true
+        callToActionLabel.setContentHuggingPriority(.required, for: .horizontal)
+        callToActionLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
+
+        textStack.axis = .vertical
+        textStack.alignment = .fill
+        textStack.addArrangedSubview(headlineLabel)
+        textStack.addArrangedSubview(sublineLabel)
+
+        stack.axis = .horizontal
+        stack.alignment = .center
+        stack.spacing = 10
+        stack.isLayoutMarginsRelativeArrangement = true
+        stack.directionalLayoutMargins = .init(top: 4, leading: 10, bottom: 4, trailing: 10)
+        stack.addArrangedSubview(iconView)
+        stack.addArrangedSubview(textStack)
+        stack.addArrangedSubview(callToActionLabel)
+        stack.translatesAutoresizingMaskIntoConstraints = false
+
+        addSubview(stack)
+
+        NSLayoutConstraint.activate([
+            stack.leadingAnchor.constraint(equalTo: leadingAnchor),
+            stack.trailingAnchor.constraint(equalTo: trailingAnchor),
+            stack.topAnchor.constraint(equalTo: topAnchor),
+            stack.bottomAnchor.constraint(equalTo: bottomAnchor),
+            iconWidth,
+            iconHeight,
+        ])
+
+        addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(tapped)))
+
+        apply(creative)
+    }
+
+    /// Picks the next rotation. Called when the promotion is about to be shown, not on every layout
+    /// pass, so it does not change under the user while they are looking at it.
+    func rotate() {
+        creative = HouseAdView.nextCreative()
+
+        apply(creative)
+        setNeedsLayout()
+    }
+
+    private func apply(_ creative: Creative) {
+        sublineLabel.text = creative.subline
+        callToActionLabel.text = creative.callToAction
+
+        accessibilityLabel = "\(creative.headline). \(creative.subline)"
+        accessibilityHint = creative.callToAction
+    }
+
+    override func layoutSubviews() {
+        super.layoutSubviews()
+
+        let width = bounds.width
+        let isTall = bounds.height >= 70
+
+        // the slot is 50pt on a phone and 90pt on a tablet, and everything here has to fit inside
+        // that; each of these is dropped at the width where it stops fitting
+        iconView.isHidden = width < 300
+        sublineLabel.isHidden = width < 360
+        headlineLabel.text = width < 360 ? creative.shortHeadline : creative.headline
+
+        headlineLabel.font =
+            isTall ? .preferredFont(forTextStyle: .headline) : .preferredFont(forTextStyle: .footnote).bold()
+        sublineLabel.font =
+            isTall ? .preferredFont(forTextStyle: .footnote) : .preferredFont(forTextStyle: .caption2)
+
+        // updated, never re-created: activating a fresh pair here would leak one per layout pass
+        iconWidth.constant = isTall ? 58 : 34
+        iconHeight.constant = isTall ? 58 : 34
+        stack.spacing = isTall ? 14 : 10
+
+        callToActionLabel.layer.cornerRadius = callToActionLabel.bounds.height / 2
+    }
+
+    @objc private func tapped() {
+        onTap?()
+    }
+}
+
+/// A label with room around its text, for the call-to-action pill.
+private final class PaddedLabel: UILabel {
+
+    private let insets = UIEdgeInsets(top: 5, left: 12, bottom: 5, right: 12)
+
+    override func drawText(in rect: CGRect) {
+        super.drawText(in: rect.inset(by: insets))
+    }
+
+    override var intrinsicContentSize: CGSize {
+        let size = super.intrinsicContentSize
+
+        return CGSize(
+            width: size.width + insets.left + insets.right,
+            height: size.height + insets.top + insets.bottom)
+    }
+}
+
+extension UIFont {
+
+    fileprivate func bold() -> UIFont {
+        guard let descriptor = fontDescriptor.withSymbolicTraits(.traitBold) else { return self }
+
+        return UIFont(descriptor: descriptor, size: 0)
+    }
+}