[DeckShare] Open shared decks via links with a gated preview flow (#7244)

* [DeckShare] Open shared decks via links with a gated preview flow

- Serialized url-chain dispatcher in IntentUrlParser; queue-drained
  urlChainFinished(bool) drives the startup auto-connect fallback
- Open-shared-deck intent with sequential download state machine,
  15s per-item timeout, partial-success offer, livable Cancel via
  ApplicationModal dlg_login_prompt interactive fallback
- Preview dialog: download progress label, share vocab sweep,
  palette-highlight selection frame, Space/Enter keyboard toggle,
  NoFocus checkbox, double-click tile opens immediately
- Confirm-before-server-migration with one-shot restore to the
  previous server on failed/cancelled chains (statusChanged settle
  deferral), hostname-only identity comparisons
- Skip credential link when already connected; arrow-key navigation
  in FlowWidget; card glows use palette highlight
- Address code-review M1-M4 and UI/UX QA blockers 1-2

* [DeckShare] End the open-shared-deck files with a trailing newline

* [DeckShare] Forward a dependency's cancellation as the owner's own

* [DeckShare] Let intent chains opt into the link sign-in dialog

* [DeckShare] Track link-intent chains per-run so each can restore its own session

* [Settings] Match a server on the exact host and port when adding it

* [DeckShare] Confirm the share link's target server before opening a deck

* [DeckShare] Reformat the link sign-in intent constructor

* [DeckShare] Time the share-list round trip and backstop silently-destroyed intent chains

* [Client] Drain a single-instance payload before its handlers read the socket again

* [Client] Treat a busy single-instance primary as alive instead of stealing its socket

* [DeckShare] Keep arrow-key navigation between flow items inside a scroll area

* [Client] Skip the startup connection when a macOS URL launch owns the connection

* [Client] Redact share secrets from activation URL logs

* [Client] Make the link-connection gates port-aware and keyboard-safe

Second-pass review notes for the shared-deck link flow (Cockatrice#7244):

- FlowWidget arrow-key navigation is opt-in via addNavigableWidget, so
  combo/spin controls on the analytics flows keep their own arrow keys
- isConnectedTo and the open-deck/join-game preconditions compare the
  configured server port alongside the host, so a same-host/different-port
  link cannot resolve its share token or game id on the wrong instance
- the link sign-in dialog reuses an existing server entry's saved name
  instead of renaming it to the raw hostname
- skipStartupAutoConnect is cleared once the launch chain connects, so a
  later mid-session declined link cannot fire the startup fallback
- the plain-launch path of SingleInstanceManager no longer blocks on the
  primary's ACK
- link- and server-supplied text is html-escaped in the confirm prompts and
  shared-deck preview so markup cannot spoof the shown messages

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

cockatrice/src/interface/widgets/dialogs/dlg_login_prompt.cpp

@@ -0,0 +1,50 @@
+#include "dlg_login_prompt.h"
+
+#include <QCheckBox>
+#include <QDialogButtonBox>
+#include <QFormLayout>
+#include <QLabel>
+#include <QLineEdit>
+#include <QVBoxLayout>
+
+DlgLoginPrompt::DlgLoginPrompt(const QString &serverText, QWidget *parent) : QDialog(parent)
+{
+    setWindowTitle(tr("Sign in"));
+
+    auto *mainLayout = new QVBoxLayout(this);
+    mainLayout->addWidget(
+        new QLabel(tr("This link requires you to be signed in.\nSign in to %1:").arg(serverText), this));
+
+    auto *formLayout = new QFormLayout;
+    usernameEdit = new QLineEdit(this);
+    passwordEdit = new QLineEdit(this);
+    passwordEdit->setEchoMode(QLineEdit::Password);
+    formLayout->addRow(tr("Username:"), usernameEdit);
+    formLayout->addRow(tr("Password:"), passwordEdit);
+    mainLayout->addLayout(formLayout);
+
+    savePasswordCheckBox = new QCheckBox(tr("Save password for this server"), this);
+    mainLayout->addWidget(savePasswordCheckBox);
+
+    auto *buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, this);
+    connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
+    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
+    mainLayout->addWidget(buttonBox);
+
+    usernameEdit->setFocus();
+}
+
+QString DlgLoginPrompt::username() const
+{
+    return usernameEdit->text().trimmed();
+}
+
+QString DlgLoginPrompt::password() const
+{
+    return passwordEdit->text();
+}
+
+bool DlgLoginPrompt::savePassword() const
+{
+    return savePasswordCheckBox->isChecked();
+}

cockatrice/src/interface/widgets/dialogs/dlg_login_prompt.h

@@ -0,0 +1,40 @@
+/**
+ * @file dlg_login_prompt.h
+ * @ingroup ConnectionDialogs
+ */
+//! \todo Document this file.
+
+#ifndef DLG_LOGIN_PROMPT_H
+#define DLG_LOGIN_PROMPT_H
+
+#include <QDialog>
+
+class QCheckBox;
+class QLineEdit;
+
+/**
+ * @brief Small sign-in dialog used when a cockatrice:// link needs credentials
+ * that are not saved for the target server.
+ *
+ * The entered name and password are handed to the intent chain; when the user
+ * opts to save them, they are stored in the server settings so that later links
+ * to the same server connect seamlessly.
+ */
+class DlgLoginPrompt : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit DlgLoginPrompt(const QString &serverText, QWidget *parent = nullptr);
+
+    [[nodiscard]] QString username() const;
+    [[nodiscard]] QString password() const;
+    [[nodiscard]] bool savePassword() const;
+
+private:
+    QLineEdit *usernameEdit;
+    QLineEdit *passwordEdit;
+    QCheckBox *savePasswordCheckBox;
+};
+
+#endif // DLG_LOGIN_PROMPT_H

cockatrice/src/interface/widgets/dialogs/dlg_shared_decks_preview.cpp

@@ -0,0 +1,181 @@
+#include "dlg_shared_decks_preview.h"
+
+#include "../deck_share/shared_deck_preview_widget.h"
+#include "../general/layout_containers/flow_widget.h"
+
+#include <QCloseEvent>
+#include <QDateTime>
+#include <QDialogButtonBox>
+#include <QLabel>
+#include <QPushButton>
+#include <QVBoxLayout>
+#include <libcockatrice/card/database/card_database_querier.h>
+#include <libcockatrice/protocol/pb/serverinfo_deck_share_item.pb.h>
+
+DlgSharedDecksPreview::DlgSharedDecksPreview(QWidget *parent,
+                                             const CardDatabaseQuerier *querier,
+                                             const QString &shareName,
+                                             qint64 expiresAt,
+                                             const QString &serverText,
+                                             const QList<ServerInfo_DeckShareItem> &items)
+    : QDialog(parent)
+{
+    setWindowTitle(tr("Open shared decks"));
+    resize(700, 500);
+
+    auto *mainLayout = new QVBoxLayout(this);
+
+    // shareName and serverText come from the share server, so escape them: the
+    // QLabels render AutoText and markup would otherwise be shown as rich text.
+    auto *titleLabel =
+        new QLabel(tr("Share: %1").arg((shareName.isEmpty() ? tr("Untitled") : shareName).toHtmlEscaped()), this);
+    QFont titleFont = titleLabel->font();
+    titleFont.setBold(true);
+    titleFont.setPointSize(titleFont.pointSize() + 2);
+    titleLabel->setFont(titleFont);
+    mainLayout->addWidget(titleLabel);
+
+    if (!serverText.isEmpty()) {
+        mainLayout->addWidget(new QLabel(tr("From %1").arg(serverText.toHtmlEscaped()), this));
+    }
+
+    if (expiresAt > 0) {
+        const QString expiryText = QDateTime::fromSecsSinceEpoch(expiresAt).toLocalTime().toString(Qt::TextDate);
+        mainLayout->addWidget(new QLabel(tr("This share link expires on %1").arg(expiryText), this));
+    }
+
+    downloadStatusLabel = new QLabel(this);
+    downloadStatusLabel->setVisible(false);
+    mainLayout->addWidget(downloadStatusLabel);
+
+    flowWidget = new FlowWidget(this, Qt::Horizontal, Qt::ScrollBarAlwaysOff, Qt::ScrollBarAsNeeded);
+    mainLayout->addWidget(flowWidget, 1);
+
+    for (const ServerInfo_DeckShareItem &item : items) {
+        QStringList tags;
+        for (const auto &tag : item.tags()) {
+            tags.append(QString::fromStdString(tag));
+        }
+
+        auto *tile = new SharedDeckPreviewWidget(
+            this, querier, QString::fromStdString(item.name()), QString::fromStdString(item.banner_card()),
+            QString::fromStdString(item.color_identity()), QString::fromStdString(item.game_format()), tags.join(", "));
+        flowWidget->addNavigableWidget(tile);
+        tiles.append(tile);
+        itemIds.append(item.id());
+    }
+
+    if (tiles.size() == 1) {
+        tiles.first()->setSelected(true);
+    }
+
+    auto *buttonBox = new QDialogButtonBox(this);
+    openSelectedButton = buttonBox->addButton(tr("Open selected"), QDialogButtonBox::AcceptRole);
+    openAllButton = buttonBox->addButton(tr("Open all"), QDialogButtonBox::ActionRole);
+    buttonBox->addButton(tr("Cancel"), QDialogButtonBox::RejectRole);
+    mainLayout->addWidget(buttonBox);
+
+    connect(buttonBox, &QDialogButtonBox::rejected, this, [this]() {
+        onCancel();
+        close();
+    });
+
+    // Esc calls QDialog::reject() directly (which hides the dialog without a
+    // close event), so route it through the same guarded cancel as the button.
+    connect(this, &QDialog::rejected, this, [this]() {
+        onCancel();
+        close();
+    });
+
+    connect(openSelectedButton, &QPushButton::clicked, this, &DlgSharedDecksPreview::openSelected);
+    connect(buttonBox, &QDialogButtonBox::clicked, this, [this, buttonBox](QAbstractButton *button) {
+        if (buttonBox->buttonRole(button) == QDialogButtonBox::ActionRole) {
+            openAll();
+        }
+    });
+
+    for (SharedDeckPreviewWidget *tile : tiles) {
+        connect(tile, &SharedDeckPreviewWidget::selectionToggled, this,
+                &DlgSharedDecksPreview::updateOpenSelectedEnabled);
+    }
+    for (int i = 0; i < tiles.size(); ++i) {
+        const int itemId = itemIds.at(i);
+        // Double-clicking a tile selects it and opens just that deck.
+        connect(tiles.at(i), &SharedDeckPreviewWidget::activated, this, [this, itemId]() {
+            resultEmitted = true;
+            setDownloading(true);
+            emit openRequested(QList<int>{itemId});
+        });
+    }
+    updateOpenSelectedEnabled();
+}
+
+QList<int> DlgSharedDecksPreview::selectedItemIds() const
+{
+    QList<int> selectedIds;
+    for (int i = 0; i < tiles.size(); ++i) {
+        if (tiles.at(i)->isSelected()) {
+            selectedIds.append(itemIds.at(i));
+        }
+    }
+    return selectedIds;
+}
+
+void DlgSharedDecksPreview::openSelected()
+{
+    const QList<int> selectedIds = selectedItemIds();
+    if (selectedIds.isEmpty()) {
+        return;
+    }
+    resultEmitted = true;
+    setDownloading(true);
+    emit openRequested(selectedIds);
+}
+
+void DlgSharedDecksPreview::openAll()
+{
+    resultEmitted = true;
+    setDownloading(true);
+    emit openRequested(itemIds);
+}
+
+void DlgSharedDecksPreview::setDownloading(bool downloading)
+{
+    if (downloadInProgress == downloading) {
+        return;
+    }
+    downloadInProgress = downloading;
+    downloadStatusLabel->setVisible(downloading);
+    for (SharedDeckPreviewWidget *tile : tiles) {
+        tile->setEnabled(!downloading);
+    }
+    openSelectedButton->setEnabled(!downloading);
+    openAllButton->setEnabled(!downloading);
+}
+
+void DlgSharedDecksPreview::setDownloadProgress(int done, int total, const QString &currentDeckName)
+{
+    if (!downloadInProgress) {
+        return;
+    }
+    downloadStatusLabel->setText(tr("Downloading deck %1 of %2: %3").arg(done).arg(total).arg(currentDeckName));
+}
+
+void DlgSharedDecksPreview::updateOpenSelectedEnabled()
+{
+    openSelectedButton->setEnabled(!selectedItemIds().isEmpty());
+}
+
+void DlgSharedDecksPreview::onCancel()
+{
+    if (!resultEmitted || downloadInProgress) {
+        resultEmitted = true;
+        emit cancelled();
+    }
+}
+
+void DlgSharedDecksPreview::closeEvent(QCloseEvent *event)
+{
+    onCancel();
+    QDialog::closeEvent(event);
+}

cockatrice/src/interface/widgets/dialogs/dlg_shared_decks_preview.h

@@ -0,0 +1,68 @@
+#ifndef COCKATRICE_DLG_SHARED_DECKS_PREVIEW_H
+#define COCKATRICE_DLG_SHARED_DECKS_PREVIEW_H
+
+#include <QDialog>
+#include <QList>
+
+class FlowWidget;
+class QCloseEvent;
+class QLabel;
+class QPushButton;
+class ServerInfo_DeckShareItem;
+class SharedDeckPreviewWidget;
+class CardDatabaseQuerier;
+
+/**
+ * @brief Non-modal preview of the decks contained in a shared-deck link.
+ *
+ * Lets the user pick which of the shared decks to open before anything is
+ * downloaded. Emits openRequested with the ids of the chosen decks, or
+ * cancelled when the user closes the dialog without choosing. Once the user
+ * picks, the dialog switches into a "downloading" state: the tiles and open
+ * buttons are disabled, a progress label shows the current download and Cancel
+ * stays functional so the download can be aborted.
+ */
+class DlgSharedDecksPreview : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit DlgSharedDecksPreview(QWidget *parent,
+                                   const CardDatabaseQuerier *querier,
+                                   const QString &shareName,
+                                   qint64 expiresAt,
+                                   const QString &serverText,
+                                   const QList<ServerInfo_DeckShareItem> &items);
+
+    void setDownloadProgress(int done, int total, const QString &currentDeckName);
+
+public slots:
+    void setDownloading(bool downloading);
+
+signals:
+    void openRequested(const QList<int> &itemIds);
+    void cancelled();
+
+protected:
+    void closeEvent(QCloseEvent *event) override;
+
+private slots:
+    void openSelected();
+    void openAll();
+    void updateOpenSelectedEnabled();
+    void onCancel();
+
+private:
+    QList<int> selectedItemIds() const;
+
+    FlowWidget *flowWidget;
+    QList<SharedDeckPreviewWidget *> tiles;
+    QList<int> itemIds;
+    QPushButton *openSelectedButton;
+    QPushButton *openAllButton;
+    QLabel *downloadStatusLabel;
+    bool resultEmitted = false;
+    bool downloadInProgress = false;
+};
+
+#endif // COCKATRICE_DLG_SHARED_DECKS_PREVIEW_H