Add Qt6 desktop uploader

A native Qt6/C++ desktop client for the gallery's POST /upload API, in
desktop/ with its own flake (kept separate from the Go server module the
same way android/ is). Single-photo parity with the Android app:

- multipart upload with preemptive HTTP Basic auth and retry-aware outcome
  classification (uploadclient)
- JPEG/PNG metadata stripped byte-for-byte to drop embedded GPS, EXIF
  orientation baked in, and a quality/scale valve for the 20M nginx cap;
  HEIC decodes via the qtimageformats plugin (imageprep)
- base URL / username in QSettings, password in the system keychain via
  qtkeychain; https required and a trailing /upload stripped (settings)
- settings and post screens in a QStackedWidget (mainwindow)

Native Wayland or xcb is selected at runtime. Bulk upload, EXIF
capture-date prefill, and moving image prep off the UI thread are left as
follow-ups.

desktop/.gitignore

@@ -0,0 +1,3 @@
+/build/
+/.direnv/
+.envrc

desktop/CMakeLists.txt

@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.20)
+project(photogallery_uploader LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_AUTOMOC ON)
+
+find_package(Qt6 REQUIRED COMPONENTS Widgets Network)
+find_package(Qt6Keychain REQUIRED)
+
+add_executable(uploader
+    main.cpp
+    mainwindow.cpp
+    settings.cpp
+    uploadclient.cpp
+    imageprep.cpp
+)
+
+target_link_libraries(uploader PRIVATE
+    Qt6::Widgets
+    Qt6::Network
+    Qt6Keychain::Qt6Keychain
+)

desktop/flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1787498568,
+        "narHash": "sha256-9i/VTdusq/+NM/tz+J1Re+ojkMB8MBf0QshnYfzHz30=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "56c02bc00adcf003215cc4bd996d6efaf4cff188",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

desktop/flake.nix

@@ -0,0 +1,38 @@
+{
+  description = "photogallery uploader — Qt6 C++ desktop app";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+
+        qtPlugins = pkgs.lib.makeSearchPathOutput "out" "lib/qt-6/plugins" [
+          pkgs.qt6.qtbase
+          pkgs.qt6.qtwayland
+          pkgs.qt6.qtimageformats
+        ];
+      in {
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            cmake
+            ninja
+            pkg-config
+            qt6.qtbase
+            qt6.qtwayland       # native Wayland QPA plugin
+            qt6.qtimageformats  # HEIF/HEIC + others, read by QImage
+            qt6Packages.qtkeychain # password → libsecret / kwallet
+          ];
+
+          shellHook = ''
+            # Let a binary run straight from the build dir find Qt's platform
+            # (xcb + wayland) and image-format plugins without wrapQtAppsHook.
+            export QT_PLUGIN_PATH="${qtPlugins}''${QT_PLUGIN_PATH:+:$QT_PLUGIN_PATH}"
+          '';
+        };
+      });
+}

desktop/imageprep.cpp

@@ -0,0 +1,237 @@
+#include "imageprep.h"
+
+#include <QBuffer>
+#include <QDir>
+#include <QFile>
+#include <QImage>
+#include <QImageReader>
+#include <QImageWriter>
+
+namespace {
+// nginx is configured with client_max_body_size 20M; leave headroom.
+constexpr qint64 kMaxUploadBytes = 18LL * 1024 * 1024;
+constexpr int kJpegQuality = 92;
+const int kQualityLadder[] = {92, 85, 75};
+
+// Encodes to JPEG in memory at the given quality.
+QByteArray encodeJpeg(const QImage &image, int quality)
+{
+    QByteArray out;
+    QBuffer buffer(&out);
+    buffer.open(QIODevice::WriteOnly);
+    QImageWriter writer(&buffer, "jpeg");
+    writer.setQuality(quality);
+    writer.write(image);
+    return out;
+}
+
+// Decodes with EXIF orientation baked into the pixels. Works for HEIC too, via
+// the qtimageformats plugin.
+QImage decodeOriented(const QString &path)
+{
+    QImageReader reader(path);
+    reader.setAutoTransform(true);
+    return reader.read();
+}
+} // namespace
+
+ImagePrep::Prepared ImagePrep::prepare(const QString &sourcePath, const QString &cacheDir,
+                                       const QString &baseName)
+{
+    Prepared result;
+
+    QFile in(sourcePath);
+    if (!in.open(QIODevice::ReadOnly)) {
+        result.error = QStringLiteral("Could not read the selected image");
+        return result;
+    }
+    const QByteArray source = in.readAll();
+    in.close();
+
+    QStringList notes;
+
+    // A rotation flag cannot survive metadata stripping, so bake it into the
+    // pixels instead, which costs a re-encode.
+    QImageReader orientationReader(sourcePath);
+    const bool mustRotate =
+        orientationReader.transformation() != QImageIOHandler::TransformationNone;
+
+    QByteArray bytes;
+    QString extension;
+
+    if (!mustRotate && isJpeg(source)) {
+        bytes = stripJpegSegments(source);
+        extension = QStringLiteral("jpg");
+    } else if (!mustRotate && isPng(source)) {
+        bytes = stripPngChunks(source);
+        extension = QStringLiteral("png");
+    }
+
+    if (bytes.isEmpty()) {
+        // Re-encode path: rotated originals, HEIC, or a JPEG/PNG whose marker
+        // structure did not parse.
+        const QImage image = decodeOriented(sourcePath);
+        if (image.isNull()) {
+            result.error = QStringLiteral("Could not decode the selected image");
+            return result;
+        }
+        if (mustRotate)
+            notes << QStringLiteral("rotated to match its EXIF orientation");
+        else if (!isJpeg(source) && !isPng(source))
+            notes << QStringLiteral("converted to JPEG");
+        bytes = encodeJpeg(image, kJpegQuality);
+        extension = QStringLiteral("jpg");
+    }
+
+    // Size valve. Only trips on genuinely huge originals; quality is stepped
+    // before touching resolution.
+    if (bytes.size() > kMaxUploadBytes) {
+        QImage image = decodeOriented(sourcePath);
+        if (image.isNull()) {
+            result.error = QStringLiteral("Could not decode the selected image");
+            return result;
+        }
+        QByteArray shrunk;
+        for (int quality : kQualityLadder) {
+            const QByteArray attempt = encodeJpeg(image, quality);
+            if (attempt.size() <= kMaxUploadBytes) {
+                shrunk = attempt;
+                notes << QStringLiteral("re-encoded at quality %1 to fit the 20M upload limit").arg(quality);
+                break;
+            }
+        }
+        if (shrunk.isEmpty()) {
+            double factor = 1.0;
+            while (factor > 0.2) {
+                factor *= 0.75;
+                const QImage scaled = image.scaledToWidth(
+                    qMax(1, int(image.width() * factor)), Qt::SmoothTransformation);
+                const QByteArray attempt = encodeJpeg(scaled, kQualityLadder[2]);
+                if (attempt.size() <= kMaxUploadBytes) {
+                    shrunk = attempt;
+                    notes << QStringLiteral("scaled to %1×%2 to fit the 20M upload limit")
+                                 .arg(scaled.width()).arg(scaled.height());
+                    break;
+                }
+            }
+        }
+        if (shrunk.isEmpty()) {
+            result.error = QStringLiteral("Image is too large to upload even after downscaling");
+            return result;
+        }
+        bytes = shrunk;
+        extension = QStringLiteral("jpg");
+    }
+
+    const QString outPath = QDir(cacheDir).filePath(baseName + QLatin1Char('.') + extension);
+    QFile out(outPath);
+    if (!out.open(QIODevice::WriteOnly) || out.write(bytes) != bytes.size()) {
+        result.error = QStringLiteral("Could not write the prepared image");
+        return result;
+    }
+    out.close();
+
+    result.filePath = outPath;
+    result.note = notes.join(QStringLiteral("; "));
+    return result;
+}
+
+bool ImagePrep::isJpeg(const QByteArray &b)
+{
+    return b.size() > 3 && quint8(b[0]) == 0xFF && quint8(b[1]) == 0xD8 && quint8(b[2]) == 0xFF;
+}
+
+bool ImagePrep::isPng(const QByteArray &b)
+{
+    return b.size() > 8 && quint8(b[0]) == 0x89 && quint8(b[1]) == 0x50 && quint8(b[2]) == 0x4E
+        && quint8(b[3]) == 0x47;
+}
+
+// Drops APP1 (EXIF and XMP) and COM segments, keeping the compressed scan data
+// byte-for-byte. APP0/JFIF and APP2/ICC stay: removing the colour profile would
+// shift the rendered colours. Returns an empty array if the marker structure
+// does not parse, so the caller falls back to a re-encode.
+QByteArray ImagePrep::stripJpegSegments(const QByteArray &src)
+{
+    const auto u8 = [&](int i) { return quint8(src[i]); };
+    QByteArray out;
+    out.append(char(0xFF));
+    out.append(char(0xD8));
+
+    int i = 2;
+    while (i + 1 < src.size()) {
+        if (u8(i) != 0xFF)
+            return {};
+        const int marker = u8(i + 1);
+
+        // Standalone markers: no length field, no payload.
+        if (marker == 0x01 || (marker >= 0xD0 && marker <= 0xD7)) {
+            out.append(char(0xFF));
+            out.append(char(marker));
+            i += 2;
+            continue;
+        }
+
+        // Start of scan: entropy-coded data runs to the end of the file.
+        if (marker == 0xDA) {
+            out.append(src.mid(i));
+            return out;
+        }
+
+        if (i + 3 >= src.size())
+            return {};
+        const int length = (u8(i + 2) << 8) | u8(i + 3);
+        if (length < 2 || i + 2 + length > src.size())
+            return {};
+
+        const bool isExifOrXmp = marker == 0xE1;
+        const bool isComment = marker == 0xFE;
+        if (!isExifOrXmp && !isComment)
+            out.append(src.mid(i, 2 + length));
+
+        i += 2 + length;
+    }
+    return {};
+}
+
+// Drops the metadata chunks, keeps everything else including the critical
+// IHDR/PLTE/IDAT/IEND run and colour chunks (iCCP, sRGB). Whole chunks go, so no
+// CRC needs recomputing.
+QByteArray ImagePrep::stripPngChunks(const QByteArray &src)
+{
+    static const QByteArray drop[] = {"eXIf", "tEXt", "zTXt", "iTXt", "tIME"};
+    const auto u8 = [&](int i) { return quint8(src[i]); };
+    if (src.size() < 8)
+        return {};
+
+    QByteArray out;
+    out.append(src.mid(0, 8));
+
+    int i = 8;
+    while (i + 8 <= src.size()) {
+        const qint64 length =
+            (qint64(u8(i)) << 24) | (qint64(u8(i + 1)) << 16) | (qint64(u8(i + 2)) << 8) | qint64(u8(i + 3));
+        if (length < 0)
+            return {};
+
+        const QByteArray type = src.mid(i + 4, 4);
+        const qint64 total = 12 + length;
+        if (i + total > src.size())
+            return {};
+
+        bool dropped = false;
+        for (const QByteArray &d : drop) {
+            if (type == d) {
+                dropped = true;
+                break;
+            }
+        }
+        if (!dropped)
+            out.append(src.mid(i, int(total)));
+        i += int(total);
+
+        if (type == "IEND")
+            return out;
+    }
+    return {};
+}

desktop/imageprep.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <QByteArray>
+#include <QString>
+
+// Turns a picked image into a file the gallery's upload API accepts.
+//
+// Three things must be true of the result: no EXIF (the gallery publishes the
+// uploaded file verbatim as its full-size download, so embedded GPS would be
+// public), a .jpg or .png extension (server.go rejects anything else, HEIC
+// included), and under nginx's 20M body cap.
+//
+// JPEG and PNG take a lossless route — whole metadata segments are dropped
+// without touching the compressed image data — so the published file keeps the
+// original sensor pixels. Anything else, or a file whose EXIF orientation must
+// be baked in, is decoded and re-encoded as JPEG (HEIC via Qt's qtimageformats
+// plugin). The strippers are a direct port of the Android app's.
+class ImagePrep
+{
+public:
+    struct Prepared {
+        QString filePath;
+        QString note; // non-empty when the app departed from a byte-exact copy
+        QString error;
+        bool ok() const { return error.isEmpty(); }
+    };
+
+    // Writes the upload-ready file into cacheDir as baseName.(jpg|png).
+    static Prepared prepare(const QString &sourcePath, const QString &cacheDir,
+                            const QString &baseName);
+
+private:
+    static QByteArray stripJpegSegments(const QByteArray &src); // empty on parse failure
+    static QByteArray stripPngChunks(const QByteArray &src);
+    static bool isJpeg(const QByteArray &b);
+    static bool isPng(const QByteArray &b);
+};

desktop/main.cpp

@@ -0,0 +1,15 @@
+#include <QApplication>
+
+#include "mainwindow.h"
+
+int main(int argc, char **argv)
+{
+    QApplication app(argc, argv);
+    app.setApplicationName(QStringLiteral("photogallery-uploader"));
+    app.setOrganizationName(QStringLiteral("inflo.ws"));
+
+    MainWindow window;
+    window.resize(440, 680);
+    window.show();
+    return app.exec();
+}

desktop/mainwindow.cpp

@@ -0,0 +1,257 @@
+#include "mainwindow.h"
+
+#include "imageprep.h"
+
+#include <QDateEdit>
+#include <QDateTime>
+#include <QDesktopServices>
+#include <QFileDialog>
+#include <QFileInfo>
+#include <QFormLayout>
+#include <QFrame>
+#include <QImageReader>
+#include <QLabel>
+#include <QLineEdit>
+#include <QPixmap>
+#include <QPushButton>
+#include <QStackedWidget>
+#include <QStandardPaths>
+#include <QUrl>
+#include <QVBoxLayout>
+
+namespace {
+constexpr int kPreviewSize = 360;
+}
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent)
+{
+    setWindowTitle(QStringLiteral("Photo Gallery Uploader"));
+
+    m_stack = new QStackedWidget(this);
+    m_stack->addWidget(buildSettingsPage()); // index 0
+    m_stack->addWidget(buildPostPage());     // index 1
+    setCentralWidget(m_stack);
+
+    // Land on settings until there is somewhere to post to.
+    if (m_settings.isConfigured())
+        showPost();
+    else
+        showSettings();
+}
+
+QWidget *MainWindow::buildSettingsPage()
+{
+    auto *page = new QWidget;
+    auto *layout = new QVBoxLayout(page);
+    layout->setContentsMargins(24, 24, 24, 24);
+
+    auto *form = new QFormLayout;
+    m_baseUrl = new QLineEdit;
+    m_baseUrl->setPlaceholderText(QStringLiteral("https://photos.example.com"));
+    m_username = new QLineEdit;
+    m_password = new QLineEdit;
+    m_password->setEchoMode(QLineEdit::Password);
+    form->addRow(QStringLiteral("Base URL"), m_baseUrl);
+    form->addRow(QStringLiteral("Username"), m_username);
+    form->addRow(QStringLiteral("Password"), m_password);
+    layout->addLayout(form);
+
+    m_saveButton = new QPushButton(QStringLiteral("Save && test connection"));
+    connect(m_saveButton, &QPushButton::clicked, this, &MainWindow::saveAndTest);
+    layout->addWidget(m_saveButton);
+
+    m_settingsStatus = new QLabel;
+    m_settingsStatus->setWordWrap(true);
+    layout->addWidget(m_settingsStatus);
+
+    m_settingsBack = new QPushButton(QStringLiteral("Back"));
+    connect(m_settingsBack, &QPushButton::clicked, this, &MainWindow::showPost);
+    layout->addWidget(m_settingsBack);
+
+    layout->addWidget(new QLabel(QStringLiteral(
+        "The password is stored in your system keychain, never in plain text. "
+        "https is required — Basic auth would otherwise send it in the clear.")));
+    layout->addStretch();
+    return page;
+}
+
+QWidget *MainWindow::buildPostPage()
+{
+    auto *page = new QWidget;
+    auto *layout = new QVBoxLayout(page);
+    layout->setContentsMargins(24, 24, 24, 24);
+
+    m_preview = new QLabel(QStringLiteral("No photo selected"));
+    m_preview->setAlignment(Qt::AlignCenter);
+    m_preview->setFixedSize(kPreviewSize, kPreviewSize);
+    m_preview->setFrameShape(QFrame::Box);
+    layout->addWidget(m_preview, 0, Qt::AlignHCenter);
+
+    m_chooseButton = new QPushButton(QStringLiteral("Choose a photo…"));
+    connect(m_chooseButton, &QPushButton::clicked, this, &MainWindow::chooseImage);
+    layout->addWidget(m_chooseButton);
+
+    auto *form = new QFormLayout;
+    m_caption = new QLineEdit;
+    m_date = new QDateEdit(QDate::currentDate());
+    m_date->setCalendarPopup(true);
+    m_date->setDisplayFormat(QStringLiteral("yyyy-MM-dd"));
+    form->addRow(QStringLiteral("Caption"), m_caption);
+    form->addRow(QStringLiteral("Date"), m_date);
+    layout->addLayout(form);
+
+    m_postButton = new QPushButton(QStringLiteral("Post"));
+    m_postButton->setEnabled(false);
+    connect(m_postButton, &QPushButton::clicked, this, &MainWindow::submit);
+    layout->addWidget(m_postButton);
+
+    m_postStatus = new QLabel;
+    m_postStatus->setWordWrap(true);
+    layout->addWidget(m_postStatus);
+
+    m_lastPost = new QLabel;
+    m_lastPost->setOpenExternalLinks(true);
+    m_lastPost->setWordWrap(true);
+    layout->addWidget(m_lastPost);
+
+    auto *settingsButton = new QPushButton(QStringLiteral("Settings"));
+    connect(settingsButton, &QPushButton::clicked, this, &MainWindow::showSettings);
+    layout->addWidget(settingsButton);
+
+    layout->addStretch();
+    return page;
+}
+
+void MainWindow::showSettings()
+{
+    m_baseUrl->setText(m_settings.baseUrl());
+    m_username->setText(m_settings.username());
+    m_password->setText(m_settings.readPassword());
+    m_settingsStatus->clear();
+    m_settingsBack->setVisible(m_settings.isConfigured());
+    m_stack->setCurrentIndex(0);
+}
+
+void MainWindow::showPost()
+{
+    const Settings::LastPost last = m_settings.lastPost();
+    if (last.valid()) {
+        m_lastPost->setText(QStringLiteral("Last post: <a href=\"%1\">%2</a>")
+                                .arg(last.url, last.caption.isEmpty() ? last.slug : last.caption));
+    } else {
+        m_lastPost->clear();
+    }
+    m_stack->setCurrentIndex(1);
+}
+
+void MainWindow::saveAndTest()
+{
+    const QString urlError = Settings::validateBaseUrl(m_baseUrl->text());
+    if (!urlError.isEmpty()) {
+        m_settingsStatus->setText(urlError);
+        return;
+    }
+    if (m_username->text().trimmed().isEmpty() || m_password->text().isEmpty()) {
+        m_settingsStatus->setText(QStringLiteral("Username and password are required"));
+        return;
+    }
+
+    m_settings.setBaseUrl(m_baseUrl->text());
+    m_settings.setUsername(m_username->text());
+    m_settings.writePassword(m_password->text());
+    m_baseUrl->setText(m_settings.baseUrl()); // show normalised value
+
+    m_saveButton->setEnabled(false);
+    m_settingsStatus->setText(QStringLiteral("Testing…"));
+
+    auto *client = new UploadClient(m_settings.baseUrl(), m_settings.username(),
+                                    m_settings.readPassword(), this);
+    connect(client, &UploadClient::testFinished, this, [this, client](const QString &error) {
+        m_saveButton->setEnabled(true);
+        m_settingsBack->setVisible(m_settings.isConfigured());
+        m_settingsStatus->setText(error.isEmpty()
+                                      ? QStringLiteral("Saved — server reachable and credentials accepted")
+                                      : error);
+        client->deleteLater();
+    });
+    client->testConnection();
+}
+
+void MainWindow::chooseImage()
+{
+    const QString path = QFileDialog::getOpenFileName(
+        this, QStringLiteral("Choose a photo"), QString(),
+        QStringLiteral("Images (*.jpg *.jpeg *.png *.heic *.heif *.webp *.tif *.tiff *.bmp);;All files (*)"));
+    if (path.isEmpty())
+        return;
+
+    m_imagePath = path;
+
+    QImageReader reader(path);
+    reader.setAutoTransform(true);
+    const QImage image = reader.read();
+    if (image.isNull()) {
+        m_preview->setText(QStringLiteral("Could not preview this image"));
+    } else {
+        m_preview->setPixmap(QPixmap::fromImage(image).scaled(
+            kPreviewSize, kPreviewSize, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+    }
+    m_postStatus->clear();
+    m_postButton->setEnabled(true);
+}
+
+void MainWindow::submit()
+{
+    if (m_imagePath.isEmpty())
+        return;
+    if (!m_settings.isConfigured()) {
+        m_postStatus->setText(QStringLiteral("Set the server URL and credentials first"));
+        return;
+    }
+
+    m_postButton->setEnabled(false);
+    m_postStatus->setText(QStringLiteral("Preparing…"));
+
+    // Slug from wall-clock time: posts are made one at a time, so this cannot
+    // collide, and re-sending the same filename overwrites the same post. The
+    // real capture date still travels in the date field.
+    const QString slug = QDateTime::currentDateTime().toString(QStringLiteral("yyyy-MM-dd-HHmmss"));
+    const QString cacheDir = QStandardPaths::writableLocation(QStandardPaths::TempLocation);
+
+    const ImagePrep::Prepared prepared = ImagePrep::prepare(m_imagePath, cacheDir, slug);
+    if (!prepared.ok()) {
+        m_postStatus->setText(prepared.error);
+        m_postButton->setEnabled(true);
+        return;
+    }
+
+    m_postStatus->setText(QStringLiteral("Uploading…"));
+
+    const QString caption = m_caption->text();
+    const QString date = m_date->date().toString(QStringLiteral("yyyy-MM-dd"));
+    const QString fileName = QFileInfo(prepared.filePath).fileName();
+
+    auto *client = new UploadClient(m_settings.baseUrl(), m_settings.username(),
+                                    m_settings.readPassword(), this);
+    connect(client, &UploadClient::uploadFinished, this,
+            [this, client, prepared, caption](UploadClient::Result result, const QString &slug,
+                                              const QString &url, const QString &message) {
+                QFile::remove(prepared.filePath); // no retry queue in this MVP
+                m_postButton->setEnabled(true);
+
+                if (result == UploadClient::Result::Success) {
+                    Settings::LastPost last{slug, url, caption, QDateTime::currentDateTime()};
+                    m_settings.setLastPost(last);
+                    QString msg = QStringLiteral("Posted. <a href=\"%1\">View</a>").arg(url);
+                    if (!prepared.note.isEmpty())
+                        msg += QStringLiteral("<br><span>%1</span>").arg(prepared.note);
+                    m_postStatus->setText(msg);
+                    m_postStatus->setOpenExternalLinks(true);
+                } else {
+                    m_postStatus->setText(message);
+                }
+                client->deleteLater();
+            });
+    client->upload(prepared.filePath, fileName, caption, date);
+}

desktop/mainwindow.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <QMainWindow>
+
+#include "settings.h"
+#include "uploadclient.h"
+
+class QDateEdit;
+class QLabel;
+class QLineEdit;
+class QPushButton;
+class QStackedWidget;
+
+class MainWindow : public QMainWindow
+{
+    Q_OBJECT
+public:
+    explicit MainWindow(QWidget *parent = nullptr);
+
+private:
+    QWidget *buildSettingsPage();
+    QWidget *buildPostPage();
+
+    void showSettings();
+    void showPost();
+
+    void saveAndTest();
+    void chooseImage();
+    void submit();
+
+    Settings m_settings;
+
+    QStackedWidget *m_stack = nullptr;
+
+    // Settings page
+    QLineEdit *m_baseUrl = nullptr;
+    QLineEdit *m_username = nullptr;
+    QLineEdit *m_password = nullptr;
+    QPushButton *m_saveButton = nullptr;
+    QPushButton *m_settingsBack = nullptr;
+    QLabel *m_settingsStatus = nullptr;
+
+    // Post page
+    QLabel *m_preview = nullptr;
+    QLineEdit *m_caption = nullptr;
+    QDateEdit *m_date = nullptr;
+    QPushButton *m_chooseButton = nullptr;
+    QPushButton *m_postButton = nullptr;
+    QLabel *m_postStatus = nullptr;
+    QLabel *m_lastPost = nullptr;
+
+    QString m_imagePath; // currently selected source image
+};

desktop/settings.cpp

@@ -0,0 +1,113 @@
+#include "settings.h"
+
+#include <QEventLoop>
+#include <QUrl>
+
+#include <qt6keychain/keychain.h>
+
+namespace {
+const QLatin1String kService("photogallery-uploader");
+const QLatin1String kPasswordKey("password");
+} // namespace
+
+Settings::Settings()
+    : m_settings(QStringLiteral("inflo.ws"), QStringLiteral("photogallery-uploader"))
+{
+}
+
+QString Settings::baseUrl() const
+{
+    return m_settings.value(QStringLiteral("baseUrl")).toString();
+}
+
+void Settings::setBaseUrl(const QString &value)
+{
+    m_settings.setValue(QStringLiteral("baseUrl"), normalizeBaseUrl(value));
+}
+
+QString Settings::username() const
+{
+    return m_settings.value(QStringLiteral("username")).toString();
+}
+
+void Settings::setUsername(const QString &value)
+{
+    m_settings.setValue(QStringLiteral("username"), value.trimmed());
+}
+
+QString Settings::readPassword() const
+{
+    QKeychain::ReadPasswordJob job(kService);
+    job.setAutoDelete(false);
+    job.setKey(kPasswordKey);
+
+    QEventLoop loop;
+    QObject::connect(&job, &QKeychain::Job::finished, &loop, &QEventLoop::quit);
+    job.start();
+    loop.exec();
+
+    if (job.error() != QKeychain::NoError)
+        return QString();
+    return job.textData();
+}
+
+void Settings::writePassword(const QString &value) const
+{
+    QKeychain::WritePasswordJob job(kService);
+    job.setAutoDelete(false);
+    job.setKey(kPasswordKey);
+    job.setTextData(value);
+
+    QEventLoop loop;
+    QObject::connect(&job, &QKeychain::Job::finished, &loop, &QEventLoop::quit);
+    job.start();
+    loop.exec();
+}
+
+bool Settings::isConfigured() const
+{
+    return !baseUrl().isEmpty() && !username().isEmpty() && !readPassword().isEmpty();
+}
+
+Settings::LastPost Settings::lastPost() const
+{
+    LastPost p;
+    p.slug = m_settings.value(QStringLiteral("last/slug")).toString();
+    p.url = m_settings.value(QStringLiteral("last/url")).toString();
+    p.caption = m_settings.value(QStringLiteral("last/caption")).toString();
+    p.postedAt = m_settings.value(QStringLiteral("last/postedAt")).toDateTime();
+    return p;
+}
+
+void Settings::setLastPost(const LastPost &value)
+{
+    m_settings.setValue(QStringLiteral("last/slug"), value.slug);
+    m_settings.setValue(QStringLiteral("last/url"), value.url);
+    m_settings.setValue(QStringLiteral("last/caption"), value.caption);
+    m_settings.setValue(QStringLiteral("last/postedAt"), value.postedAt);
+}
+
+QString Settings::validateBaseUrl(const QString &raw)
+{
+    const QString trimmed = raw.trimmed();
+    if (trimmed.isEmpty())
+        return QStringLiteral("Base URL is required");
+    const QUrl url(trimmed);
+    if (!url.isValid() || url.host().isEmpty())
+        return QStringLiteral("Not a valid URL");
+    if (url.scheme() != QStringLiteral("https"))
+        return QStringLiteral("Must be https — plain http sends your password in the clear");
+    return QString();
+}
+
+QString Settings::normalizeBaseUrl(const QString &raw)
+{
+    QString v = raw.trimmed();
+    while (v.endsWith(QLatin1Char('/')))
+        v.chop(1);
+    if (v.endsWith(QStringLiteral("/upload"), Qt::CaseInsensitive))
+        v.chop(QStringLiteral("/upload").size());
+    while (v.endsWith(QLatin1Char('/')))
+        v.chop(1);
+    return v;
+}

desktop/settings.h

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <QDateTime>
+#include <QSettings>
+#include <QString>
+
+// Persists the non-secret settings (base URL, username, last post) in a
+// QSettings INI under ~/.config, and the password in the system keychain
+// (libsecret / kwallet via QtKeychain). The password never lands on disk in the
+// clear, mirroring the Android app's Keystore sealing.
+class Settings
+{
+public:
+    struct LastPost {
+        QString slug;
+        QString url;
+        QString caption;
+        QDateTime postedAt;
+        bool valid() const { return !slug.isEmpty(); }
+    };
+
+    Settings();
+
+    QString baseUrl() const;
+    void setBaseUrl(const QString &value);
+
+    QString username() const;
+    void setUsername(const QString &value);
+
+    // Keychain access is synchronous here (a local event loop): the app does
+    // nothing until the credential is in hand, and there is no background retry
+    // worker as on Android that would need it off the UI thread.
+    QString readPassword() const;
+    void writePassword(const QString &value) const;
+
+    bool isConfigured() const;
+
+    LastPost lastPost() const;
+    void setLastPost(const LastPost &value);
+
+    // Returns an error message, or an empty string when the URL is usable.
+    // https is required: Basic auth would otherwise send the password in the
+    // clear.
+    static QString validateBaseUrl(const QString &raw);
+
+    // Trims trailing slashes and a trailing "/upload" (the endpoint path a user
+    // pasting the upload URL would leave on — the client appends it itself).
+    static QString normalizeBaseUrl(const QString &raw);
+
+private:
+    mutable QSettings m_settings;
+};

desktop/uploadclient.cpp

@@ -0,0 +1,126 @@
+#include "uploadclient.h"
+
+#include <QFile>
+#include <QFileInfo>
+#include <QHttpMultiPart>
+#include <QHttpPart>
+#include <QNetworkAccessManager>
+#include <QNetworkReply>
+#include <QNetworkRequest>
+
+UploadClient::UploadClient(QString baseUrl, QString username, QString password, QObject *parent)
+    : QObject(parent)
+    , m_base(std::move(baseUrl))
+    , m_username(std::move(username))
+    , m_password(std::move(password))
+    , m_net(new QNetworkAccessManager(this))
+{
+    while (m_base.endsWith(QLatin1Char('/')))
+        m_base.chop(1);
+}
+
+QByteArray UploadClient::authHeader() const
+{
+    const QByteArray raw = (m_username + QLatin1Char(':') + m_password).toUtf8();
+    return "Basic " + raw.toBase64();
+}
+
+void UploadClient::upload(const QString &filePath, const QString &fileName,
+                          const QString &caption, const QString &date)
+{
+    auto *file = new QFile(filePath);
+    if (!file->open(QIODevice::ReadOnly)) {
+        delete file;
+        emit uploadFinished(Result::Rejected, {}, {}, QStringLiteral("Could not read the prepared image"));
+        return;
+    }
+
+    auto *multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);
+
+    const QByteArray contentType =
+        fileName.endsWith(QStringLiteral(".png"), Qt::CaseInsensitive) ? "image/png" : "image/jpeg";
+
+    QHttpPart imagePart;
+    imagePart.setHeader(QNetworkRequest::ContentTypeHeader, QVariant(contentType));
+    imagePart.setHeader(QNetworkRequest::ContentDispositionHeader,
+                        QVariant(QStringLiteral("form-data; name=\"image\"; filename=\"%1\"").arg(fileName)));
+    file->setParent(multiPart);
+    imagePart.setBodyDevice(file);
+    multiPart->append(imagePart);
+
+    const auto textPart = [](const QString &name, const QString &value) {
+        QHttpPart part;
+        part.setHeader(QNetworkRequest::ContentDispositionHeader,
+                       QVariant(QStringLiteral("form-data; name=\"%1\"").arg(name)));
+        part.setBody(value.toUtf8());
+        return part;
+    };
+    multiPart->append(textPart(QStringLiteral("caption"), caption));
+    multiPart->append(textPart(QStringLiteral("date"), date));
+
+    QNetworkRequest request(QUrl(m_base + QStringLiteral("/upload")));
+    request.setRawHeader("Authorization", authHeader());
+
+    QNetworkReply *reply = m_net->post(request, multiPart);
+    multiPart->setParent(reply);
+
+    const QString fallbackSlug = QFileInfo(fileName).completeBaseName();
+
+    connect(reply, &QNetworkReply::finished, this, [this, reply, fallbackSlug]() {
+        reply->deleteLater();
+        const int status = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
+        const QString body = QString::fromUtf8(reply->readAll()).trimmed();
+
+        if (reply->error() == QNetworkReply::NoError && status >= 200 && status < 300) {
+            // Server replies "uploaded slug.ext"; recover the slug.
+            QString name = body;
+            if (name.startsWith(QStringLiteral("uploaded ")))
+                name = name.mid(QStringLiteral("uploaded ").size()).trimmed();
+            const int dot = name.lastIndexOf(QLatin1Char('.'));
+            QString slug = dot > 0 ? name.left(dot) : name;
+            if (slug.isEmpty())
+                slug = fallbackSlug;
+            emit uploadFinished(Result::Success, slug, m_base + QStringLiteral("/photo/") + slug + QLatin1Char('/'), {});
+            return;
+        }
+        if (status == 401 || status == 403) {
+            emit uploadFinished(Result::AuthFailed, {}, {}, QStringLiteral("Wrong username or password"));
+            return;
+        }
+        if (status >= 500 && status < 600) {
+            emit uploadFinished(Result::Transient, {}, {}, QStringLiteral("Server error %1").arg(status));
+            return;
+        }
+        if (status == 0) {
+            // No HTTP response — a socket/TLS failure. Worth retrying.
+            emit uploadFinished(Result::Transient, {}, {}, reply->errorString());
+            return;
+        }
+        emit uploadFinished(Result::Rejected, {}, {}, body.isEmpty() ? QStringLiteral("Upload rejected") : body);
+    });
+}
+
+void UploadClient::testConnection()
+{
+    QNetworkRequest request(QUrl(m_base + QStringLiteral("/upload")));
+    request.setRawHeader("Authorization", authHeader());
+
+    QNetworkReply *reply = m_net->get(request);
+    connect(reply, &QNetworkReply::finished, this, [this, reply]() {
+        reply->deleteLater();
+        const int status = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
+        if (reply->error() == QNetworkReply::NoError && status >= 200 && status < 300) {
+            emit testFinished(QString());
+            return;
+        }
+        if (status == 401 || status == 403) {
+            emit testFinished(QStringLiteral("Wrong username or password"));
+            return;
+        }
+        if (status == 0) {
+            emit testFinished(reply->errorString());
+            return;
+        }
+        emit testFinished(QStringLiteral("Server returned %1").arg(status));
+    });
+}

desktop/uploadclient.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#include <QObject>
+#include <QString>
+
+class QNetworkAccessManager;
+
+// Talks to the gallery's POST /upload endpoint, which sits behind nginx HTTP
+// Basic auth. The credentials go out preemptively in the Authorization header
+// on every request (never via QNetworkAccessManager's authenticationRequired
+// signal, which only fires on a 401 and would replay a multipart body already
+// streamed off disk).
+//
+// Asynchronous: results arrive via signals so the UI stays responsive during an
+// upload over a slow link.
+class UploadClient : public QObject
+{
+    Q_OBJECT
+public:
+    enum class Result {
+        Success,     // uploaded; slug/url populated
+        AuthFailed,  // wrong credentials — a retry will not help
+        Rejected,    // server said no for a reason a retry won't change
+        Transient,   // network trouble or a 5xx — worth retrying
+    };
+
+    UploadClient(QString baseUrl, QString username, QString password, QObject *parent = nullptr);
+
+    // The filename matters: server.go derives the slug from it, so re-sending
+    // the same name overwrites the same post instead of duplicating it.
+    void upload(const QString &filePath, const QString &fileName,
+                const QString &caption, const QString &date);
+
+    // Credential check via GET /upload (same Basic-auth gate the POST uses).
+    // /health is not usable: nginx only proxies location /upload.
+    void testConnection();
+
+signals:
+    void uploadFinished(UploadClient::Result result, const QString &slug,
+                        const QString &url, const QString &message);
+    // errorMessage is empty on success.
+    void testFinished(const QString &errorMessage);
+
+private:
+    QByteArray authHeader() const;
+
+    QString m_base;
+    QString m_username;
+    QString m_password;
+    QNetworkAccessManager *m_net;
+};