ObsidianDragon/src/services/history_scan_policy.cpp

// DragonX Wallet - ImGui Edition
// Copyright 2024-2026 The Hush Developers
// Released under the GPLv3

#include "history_scan_policy.h"

#include <algorithm>
#include <cmath>

namespace dragonx {
namespace services {

int historyStaleAfterBlocks(std::size_t addressCount, double perAddressScanMs)
{
    if (addressCount == 0 || !(perAddressScanMs > 0.0)) return kHistoryMinStaleBlocks;
    const double blocks = std::ceil((static_cast<double>(addressCount) * perAddressScanMs / 1000.0) /
                                    (kHistoryBlockSeconds * kHistoryScanDuty));
    if (!(blocks < kHistoryMaxStaleBlocks)) return kHistoryMaxStaleBlocks;   // also NaN / inf
    return std::max(kHistoryMinStaleBlocks, static_cast<int>(blocks));
}

double updateScanCostEstimateMs(double previousMs, double sampleMs)
{
    if (!(sampleMs > 0.0)) return previousMs;
    if (!(previousMs > 0.0) || sampleMs > previousMs) return sampleMs;
    return 0.75 * previousMs + 0.25 * sampleMs;
}

int transparentPageSize(std::size_t previousRowCount)
{
    const std::size_t want = previousRowCount + std::max<std::size_t>(200, previousRowCount / 10);
    return static_cast<int>(std::clamp<std::size_t>(want, kTransparentPageMin, kTransparentPageMax));
}

bool sentSweepIsFull(int tip, int fromHeight)
{
    return tip <= 0 || fromHeight < 0 || fromHeight > tip;
}

nlohmann::json sentSweepParams(const std::string& anyZAddress, int tip, int fromHeight)
{
    nlohmann::json params = nlohmann::json::array();
    params.push_back(anyZAddress);
    params.push_back(0);
    if (sentSweepIsFull(tip, fromHeight)) return params;
    const int maxDepth = (tip - fromHeight) + kSentSweepReorgMarginBlocks;
    params.push_back(2);          // filter type 2: depth
    params.push_back(maxDepth);   // at most this deep (mempool txs, depth 0, always pass)
    return params;
}

long fullSentSweepRetryDelaySec(int consecutiveFailures)
{
    if (consecutiveFailures <= 0) return 0;
    if (consecutiveFailures == 1) return 600;
    if (consecutiveFailures == 2) return 3600;
    return 21600;
}

bool fullSentSweepFailureCounts(rpc::RpcFailureKind kind)
{
    using K = rpc::RpcFailureKind;
    return kind == K::ReplyTimeout || kind == K::AppError || kind == K::Other;
}

std::size_t oldestScannedAddressIndex(const std::vector<std::string>& addresses,
                                      const std::unordered_map<std::string, int>& heights)
{
    std::size_t best = 0;
    int bestHeight = 0;
    bool haveBest = false;
    for (std::size_t i = 0; i < addresses.size(); ++i) {
        const auto it = heights.find(addresses[i]);
        if (it == heights.end()) return i;   // never scanned: first
        if (!haveBest || it->second < bestHeight) {
            best = i;
            bestHeight = it->second;
            haveBest = true;
        }
    }
    return best;
}

std::string ProbeRotation::next(const std::vector<std::string>& addresses,
                                const std::unordered_map<std::string, int>& heights)
{
    std::unordered_set<std::string> listed(addresses.begin(), addresses.end());
    for (auto it = left_.begin(); it != left_.end();) {
        if (listed.count(*it)) ++it;
        else it = left_.erase(it);
    }
    if (left_.empty()) left_ = std::move(listed);
    std::vector<std::string> left;
    for (const auto& address : addresses) {
        if (left_.count(address)) left.push_back(address);
    }
    if (left.empty()) return {};
    return left[oldestScannedAddressIndex(left, heights)];
}

int ShieldedHistoryPass::floorAt(int tip) const
{
    return tip > 0 ? std::min(startHeight_, tip) : startHeight_;
}

ShieldedHistoryPass::Work ShieldedHistoryPass::evaluate(int tip, const std::vector<std::string>& addresses,
                                                        const std::unordered_map<std::string, int>& heights,
                                                        int staleAfter, bool initialComplete) const
{
    Work work;
    work.total = addresses.size();
    const int floor = active_ ? floorAt(tip) : -1;
    std::size_t below = 0;
    bool staleDue = false;
    for (const auto& address : addresses) {
        const auto it = heights.find(address);
        if (it == heights.end()) {
            ++work.missing;
            continue;
        }
        if (active_) {
            if (it->second < floor) ++below;
        } else if (tip > 0 && it->second < tip - staleAfter) {
            staleDue = true;
        }
    }
    work.pending = work.missing + (active_ ? below : (staleDue ? work.total - work.missing : 0));
    work.explicitWork = !stalled() &&
        (work.missing > 0 || (active_ ? (explicit_ && below > 0) : (staleDue && !initialComplete)));
    work.routineWork = !work.explicitWork && work.pending > 0;
    return work;
}

void ShieldedHistoryPass::begin(int tip, const std::vector<std::string>& addresses,
                                const std::unordered_map<std::string, int>& heights, int staleAfter,
                                bool initialComplete, bool routineAllowed)
{
    if (active_) {
        if (tip > 0 && startHeight_ > tip) startHeight_ = tip;   // the chain reorganised below the floor
        return;
    }
    if (tip <= 0 || !(routineAllowed || !initialComplete)) return;
    bool staleDue = false;
    for (const auto& address : addresses) {
        const auto it = heights.find(address);
        if (it != heights.end() && it->second < tip - staleAfter) {
            staleDue = true;
            break;
        }
    }
    if (!staleDue) return;
    active_ = true;
    explicit_ = !initialComplete;
    startHeight_ = tip;
}

int ShieldedHistoryPass::scanFloor(int tip, bool routineAllowed) const
{
    return (active_ && (explicit_ || routineAllowed)) ? floorAt(tip) : -1;
}

void ShieldedHistoryPass::finish(int tip, const std::vector<std::string>& addresses,
                                 const std::unordered_map<std::string, int>& heights, std::size_t attempted,
                                 std::size_t succeeded)
{
    if (attempted > 0) stalledCycles_ = succeeded > 0 ? 0 : stalledCycles_ + 1;
    // An empty list proves nothing (a failed enumeration blanks it); a real wallet change resets the pass.
    if (!active_ || addresses.empty()) return;
    const int floor = floorAt(tip);
    for (const auto& address : addresses) {
        const auto it = heights.find(address);
        if (it == heights.end() || it->second < floor) return;   // still work left in this pass
    }
    active_ = false;
    explicit_ = false;
}

void ShieldedHistoryPass::reset()
{
    *this = ShieldedHistoryPass{};
}

TxCycle decideTxCycle(const TxCycleInputs& in)
{
    const bool wanted = in.neverFetched || in.newTip || in.dirty || in.explicitScanWork || in.routineScanWork;
    const bool scansAllowed = !in.syncing && in.heightKnown;
    if (wanted) {
        if (scansAllowed && (in.explicitScanWork || in.gateOpen)) return TxCycle::Full;
        // Rows now (a mutation, a tracked send at a new tip); wallet-wide scans wait for the throttle.
        if (in.neverFetched || in.dirty || (in.sendTracking && in.newTip)) return TxCycle::Light;
    }
    if (in.recentDue) return (scansAllowed && in.gateOpen) ? TxCycle::RecentWithProbe : TxCycle::Recent;
    return TxCycle::None;
}

}  // namespace services
}  // namespace dragonx