ObsidianDragon - DragonX ImGui Wallet

Full-node GUI wallet for DragonX cryptocurrency.
Built with Dear ImGui, SDL3, and OpenGL3/DX11.

Features:
- Send/receive shielded and transparent transactions
- Autoshield with merged transaction display
- Built-in CPU mining (xmrig)
- Peer management and network monitoring
- Wallet encryption with PIN lock
- QR code generation for receive addresses
- Transaction history with pagination
- Console for direct RPC commands
- Cross-platform (Linux, Windows)

src/util/bootstrap.h

@@ -0,0 +1,116 @@
+// DragonX Wallet - ImGui Edition
+// Copyright 2024-2026 The Hush Developers
+// Released under the GPLv3
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include <mutex>
+#include <atomic>
+#include <thread>
+
+namespace dragonx {
+namespace util {
+
+/**
+ * @brief Bootstrap downloader + extractor for DRAGONX blockchain data.
+ *
+ * Downloads a blockchain snapshot zip from bootstrap.dragonx.is, verifies
+ * SHA-256 / MD5 checksums, extracts it into the DRAGONX data directory
+ * (skipping wallet.dat), and cleans old chain data before extraction.
+ * All work runs on a background thread; progress is queried thread-safely
+ * from the UI thread.
+ */
+class Bootstrap {
+public:
+    enum class State {
+        Idle,
+        Downloading,
+        Extracting,
+        Completed,
+        Failed
+    };
+
+    struct Progress {
+        State   state          = State::Idle;
+        double  downloaded_bytes = 0;
+        double  total_bytes    = 0;       // 0 if server doesn't send Content-Length
+        float   percent        = 0.0f;    // 0..100
+        std::string status_text;          // human-readable status
+        std::string error;                // non-empty on failure
+    };
+
+    Bootstrap() = default;
+    ~Bootstrap();
+
+    // Non-copyable
+    Bootstrap(const Bootstrap&) = delete;
+    Bootstrap& operator=(const Bootstrap&) = delete;
+
+    /// Base URL for bootstrap downloads (zip + checksum files).
+    static constexpr const char* kBaseUrl = "https://bootstrap.dragonx.is";
+    static constexpr const char* kZipName = "DRAGONX.zip";
+
+    /// Start the bootstrap process on a background thread.
+    /// @param dataDir  Path to DRAGONX data dir (e.g. ~/.hush/DRAGONX/)
+    /// @param url      Bootstrap zip URL
+    void start(const std::string& dataDir,
+               const std::string& url = "https://bootstrap.dragonx.is/DRAGONX.zip");
+
+    /// Cancel an in-progress download/extract.
+    void cancel();
+
+    /// Thread-safe read of current progress.
+    Progress getProgress() const;
+
+    /// Whether the operation is finished (success or failure).
+    bool isDone() const;
+
+    /// Format a byte count as human-readable string (e.g. "1.24 GB")
+    static std::string formatSize(double bytes);
+
+private:
+    mutable std::mutex mutex_;
+    Progress progress_;
+    std::atomic<bool> cancel_requested_{false};
+    std::thread worker_;
+    std::atomic<bool> worker_running_{false};
+
+    bool download(const std::string& url, const std::string& destZip);
+    bool extract(const std::string& zipPath, const std::string& dataDir);
+    void cleanChainData(const std::string& dataDir);
+    void setProgress(State state, const std::string& text, double downloaded = 0, double total = 0);
+
+    /// Download a small text file (checksum) into a string. Returns empty on failure.
+    std::string downloadSmallFile(const std::string& url);
+
+    /// Compute SHA-256 of a file, return lowercase hex digest.
+    /// Updates progress with "Verifying SHA-256..." status during computation.
+    std::string computeSHA256(const std::string& filePath);
+
+    /// Compute MD5 of a file, return lowercase hex digest.
+    /// Updates progress with "Verifying MD5..." status during computation.
+    std::string computeMD5(const std::string& filePath);
+
+    /// Parse the first hex token from a checksum file (handles "<hash>  <filename>" format).
+    static std::string parseChecksumFile(const std::string& content);
+
+    /// Verify downloaded zip against remote checksums. Returns true if valid.
+    bool verifyChecksums(const std::string& zipPath, const std::string& baseUrl);
+
+    /// Perform a HEAD request to get remote file size.
+    /// Returns -1 on failure.
+    long long getRemoteFileSize(const std::string& url);
+
+    /// Byte offset of the partial file when resuming a download.
+    /// Added to dlnow in progress reports so the bar reflects true total.
+    double resume_offset_{0};
+
+    // libcurl progress callback (static → calls into instance via clientp)
+    static int progressCallback(void* clientp, long long dltotal, long long dlnow,
+                                long long ultotal, long long ulnow);
+};
+
+} // namespace util
+} // namespace dragonx