[Client] DeckSyncProfile + sidecar + DeckDiff with tests

cockatrice/src/interface/deck_sync/deck_sync_sidecar.h

@@ -0,0 +1,52 @@
+/**
+ * @file deck_sync_sidecar.h
+ * @brief Per-profile local bookkeeping for deck collection sync.
+ */
+
+#ifndef DECK_SYNC_SIDECAR_H
+#define DECK_SYNC_SIDECAR_H
+
+#include <QMap>
+#include <QString>
+
+/** @brief Sync bookkeeping for one local deck file. */
+struct DeckSyncRecord
+{
+    QString guid;            ///< Stable deck identity shared with the server.
+    int remoteId = -1;       ///< Server row id, -1 when never uploaded.
+    QString baseHash;        ///< Deck hash at the last successful sync.
+    qint64 lastSyncSecs = 0; ///< Last sync time, seconds since Unix epoch.
+    bool deleted = false;    ///< Local tombstone waiting to be pushed.
+};
+
+/**
+ * @class DeckSyncSidecar
+ * @brief Loads and stores sync records as JSON next to the deck folder.
+ *
+ * One sidecar file per DeckSyncProfile (named by profile key), mapping paths
+ * relative to the deck folder to their last-synced state. Comparing the live
+ * file hash against baseHash tells clean apart from locally modified.
+ */
+class DeckSyncSidecar
+{
+public:
+    QString filePath; ///< Full path of the sidecar JSON file.
+
+    explicit DeckSyncSidecar(const QString &_filePath);
+
+    /** @brief Loads records; a missing file loads as empty and returns true. */
+    bool load();
+    /** @brief Stores records, creating parent folders as needed. */
+    bool save() const;
+    [[nodiscard]] bool contains(const QString &relativePath) const;
+    /** @brief Returns the record, or a default record when unknown. */
+    [[nodiscard]] DeckSyncRecord get(const QString &relativePath) const;
+    void set(const QString &relativePath, const DeckSyncRecord &record);
+    void remove(const QString &relativePath);
+    [[nodiscard]] QMap<QString, DeckSyncRecord> records() const;
+
+private:
+    QMap<QString, DeckSyncRecord> recordMap;
+};
+
+#endif // DECK_SYNC_SIDECAR_H