// DragonX Wallet - ImGui Edition
// Copyright 2024-2026 The Hush Developers
// Released under the GPLv3
//
// DaemonUpdater — fetch + verify + install the latest dragonxd full node from the DragonX Gitea.
//
// Sibling of util::XmrigUpdater (the miner updater): same query → download → verify → extract →
// install pipeline on a background thread, but for the full-node binaries instead of the miner.
// Flow: query the Gitea releases API for the latest dragonx release, pick the archive matching this
// platform (dragonx-<ver>-linux-amd64.zip / -win64.zip / -macos.zip), download it, verify it, then
// extract the daemon executables (dragonxd / dragonx-cli / dragonx-tx, flattening the versioned
// subdir the archive nests them in) into the daemon directory and chmod them executable.
//
// Security: download-and-execute, so verification is mandatory. TLS is verified (libcurl defaults),
// the host is the project's own Gitea over HTTPS, the archive's SHA-256 is checked against the
// checksum table published in the release body, AND a detached ed25519 signature over the archive
// bytes is verified against the key pinned below (kDaemonRequireSignature enforces it: an install
// is refused when no valid .sig is published). The inner binaries are trusted by transitivity once
// the whole archive is authenticated. The generic SHA-256 / ed25519 primitives are shared with the
// miner updater (util::sha256Hex / util::verifyXmrigSignature in xmrig_updater_core.cpp).

#pragma once

#include <atomic>
#include <cstddef>
#include <map>
#include <mutex>
#include <string>
#include <thread>
#include <vector>

namespace dragonx {
namespace util {

struct DaemonReleaseAsset {
    std::string name;
    std::string downloadUrl;
    long long   size = 0;
};

struct DaemonRelease {
    bool ok = false;
    std::string tag;                        // e.g. "v1.0.2"
    std::string name;                       // human title (e.g. "Dragonx v1.0.2")
    std::string body;                       // release notes markdown (holds the checksum table)
    bool prerelease = false;                // marked pre-release on the Gitea release
    std::string publishedAt;                // ISO-8601 publish timestamp (date shown in the UI)
    std::vector<DaemonReleaseAsset> assets;
    std::string error;
};

// ── Release signature (supply-chain hardening, mandatory for the daemon) ──────
//
// Pinned ed25519 public key (base64, 32 bytes) used to verify a detached signature over the
// downloaded archive. With kDaemonRequireSignature=true an install is refused unless the release
// publishes a "<archive-name>.sig" asset (base64 of, or raw, a 64-byte ed25519 signature over the
// archive bytes) that verifies against this key — see scripts/sign-daemon-release.sh. To rotate the
// key, regenerate with that script and replace the value below. If the key is set empty AND
// kDaemonRequireSignature=false, verification falls back to TLS + the published SHA-256 only.
inline constexpr const char* kDaemonSignaturePublicKeyBase64 =
    "d59hosHzh2LtHypgGvsMBlgrRGBhOfS0Xl40D/fEjzQ=";
inline constexpr bool        kDaemonRequireSignature = true;   // enforced: refuse installs without a valid .sig

// ── Pure helpers (no I/O; unit-tested) ───────────────────────────────────────

// Parse the Gitea GET /releases/latest JSON into a DaemonRelease (ok=false + error on failure).
DaemonRelease parseDaemonRelease(const std::string& json);

// Parse the Gitea GET /releases (array) JSON into the list of releases, newest first, skipping
// drafts. Empty on parse failure. Lets the user browse + pin a specific (or pre-release) version.
std::vector<DaemonRelease> parseDaemonReleaseList(const std::string& json);

// The asset-name token for the host platform: "linux-amd64", "win64", "macos", or "" if
// unknown/unsupported (e.g. linux-arm64, for which no build is published -> Unavailable).
std::string currentDaemonPlatformToken();

// Index of the asset whose name matches the platform token (e.g. ends with "-linux-amd64.zip"),
// or -1 if none.
int selectDaemonAsset(const DaemonRelease& release, const std::string& platformToken);

// Parse the release-body markdown checksum table ( "| <archive>.zip | `<sha256hex>` |" rows ) into
// { archive-name -> lowercase-hex }. Header/separator/prose rows (no 64-hex token) are ignored.
std::map<std::string, std::string> parseDaemonChecksums(const std::string& body);

// The binary file basenames to extract for a platform: {"dragonxd","dragonx-cli","dragonx-tx"} on
// POSIX, the ".exe" variants on Windows. The first entry is always the daemon itself.
std::vector<std::string> daemonExtractBasenames(const std::string& platformToken);

// Index of the detached-signature asset for a given archive (name "<archive>.sig" or
// "<archive>.minisig"), or -1 if none is published.
int selectDaemonSignatureAsset(const DaemonRelease& release, const std::string& archiveName);

// Reduce a version string to its "vMAJOR.MINOR.PATCH" core, dropping any "-<commit>" suffix the
// binary scanner appends, so an installed "v1.0.2-ddd851dc1" compares equal to a release "v1.0.2".
// Returns the input unchanged if it holds no vN.N.N pattern.
std::string daemonVersionCore(const std::string& version);

// ── Background worker ────────────────────────────────────────────────────────

class DaemonUpdater {
public:
    enum class State {
        Idle,
        Checking,
        UpToDate,
        UpdateAvailable,
        Unavailable,    // no daemon build is published for this platform (terminal, not an error)
        Listing,        // fetching the full release list (Browse all releases)
        ReleaseList,    // release list fetched; awaiting the user's pick
        Downloading,
        Verifying,
        Extracting,
        Done,
        Failed
    };

    struct Progress {
        State       state = State::Idle;
        double      downloaded_bytes = 0;
        double      total_bytes = 0;
        float       percent = 0.0f;
        std::string status_text;
        std::string error;            // non-empty on Failed
        std::string latest_tag;       // tag reported by the API (once checked)
        std::string installed_tag;    // caller-supplied current install (for update detection)
        bool        update_available = false;
    };

    // Gitea releases API for the dragonx full node.
    static constexpr const char* kApiUrl =
        "https://git.dragonx.is/api/v1/repos/DragonX/dragonx/releases/latest";
    // Full release list (newest first, includes pre-releases) for the "Browse all releases" picker.
    static constexpr const char* kReleasesUrl =
        "https://git.dragonx.is/api/v1/repos/DragonX/dragonx/releases?limit=50";

    DaemonUpdater() = default;
    ~DaemonUpdater();
    DaemonUpdater(const DaemonUpdater&) = delete;
    DaemonUpdater& operator=(const DaemonUpdater&) = delete;

    // Query the latest release on a background thread. `installedVersion` (may be empty/unknown) is
    // compared (by vN.N.N core) to the API tag to set Progress.update_available. End state:
    // UpToDate / UpdateAvailable / Failed.
    void startCheck(const std::string& installedVersion);

    // Download → verify archive → extract (flatten) → install into `targetDir` on a background
    // thread. Re-fetches the latest release so it is self-contained. End state: Done / Failed. The
    // new binary takes effect on the next daemon start (the caller offers a restart).
    void startInstall(const std::string& targetDir);

    // Fetch the full release list on a background thread (for "Browse all releases"). End state:
    // ReleaseList (then getReleases() holds the list, newest first) / Failed.
    void startListReleases();

    // Snapshot of the release list fetched by startListReleases().
    std::vector<DaemonRelease> getReleases() const;

    // Install a SPECIFIC release (chosen from the browse list) into `targetDir` — same verify/extract
    // path as startInstall, but pinned to `release` instead of latest. End state: Done / Failed.
    void startInstallRelease(const std::string& targetDir, DaemonRelease release);

    void cancel();
    Progress getProgress() const;
    bool isDone() const;   // true once the worker reached a terminal state (Done/Failed/Unavailable)

    // Internal: called by the libcurl progress callback. Publishes live download bytes and returns
    // false to ask curl to abort (when cancel() was requested). Public only so the C callback in the
    // .cpp can reach it without leaking curl types into this header.
    bool onDownloadProgress(double downloadedBytes, double totalBytes);

private:
    void runCheck(std::string installedVersion);
    void runListReleases();
    void runInstall(std::string targetDir);
    void installResolved(const std::string& targetDir, const DaemonRelease& rel);  // shared install body
    void setProgress(State state, const std::string& text, double done = 0, double total = 0);
    bool downloadToFile(const std::string& url, const std::string& destPath);
    std::string httpGet(const std::string& url);

    mutable std::mutex mutex_;
    Progress progress_;
    std::vector<DaemonRelease> releases_;
    std::atomic<bool> cancel_requested_{false};
    std::atomic<bool> worker_running_{false};
    std::thread worker_;
};

} // namespace util
} // namespace dragonx