==========================================================================================================
// *** RELAY POLICY FILTER ***
// Place in src/policy/policy.cpp, and call from within IsStandardTx() before returning:
//     if (IsBulkDust(tx, reason))
//         return false;   // reject as nonstandard
// ==========================================================================================================

bool IsBulkDust(const CTransaction& tx, std::string& reason)
{
    static constexpr int     MAX_TINY_OUTPUTS        = 100;     // >=100 tiny outputs triggers ratio check
    static constexpr double  TINY_RATIO_THRESHOLD    = 0.6;     // >=60% of all outputs tiny → reject
    static constexpr CAmount BASE_TINY_THRESHOLD     = 4096;    // starting tiny threshold (sats)
    static constexpr int64_t FIRST_TINY_HALVING_H    = 1260000; // first halving of tiny threshold
    static constexpr int64_t HALVING_INTERVAL        = 210000;  // blocks per subsequent halving
    static constexpr CAmount MIN_TINY_FLOOR          = 1;       // never below 1 sat

    const int total = tx.vout.size();
    if (total == 0) return false;

    int currentHeight = chainActive.Tip() ? chainActive.Tip()->nHeight : 0;

    // Era index for TinyTx threshold, anchored at FIRST_TINY_HALVING_H (not subsidy eras)
    int era = 0;
    if (currentHeight >= FIRST_TINY_HALVING_H) {
        era = 1 + static_cast<int>((currentHeight - FIRST_TINY_HALVING_H) / HALVING_INTERVAL);
    }

    CAmount tinyThresh = BASE_TINY_THRESHOLD >> era;      // halve per era
    if (tinyThresh < MIN_TINY_FLOOR) tinyThresh = MIN_TINY_FLOOR;

    int tiny = 0;
    for (const auto& out : tx.vout) {
        if (out.nValue < tinyThresh) ++tiny;
    }

    if (tiny >= MAX_TINY_OUTPUTS && (static_cast<double>(tiny) / total) >= TINY_RATIO_THRESHOLD) {
        reason = strprintf("too-many-tiny-outputs(%d of %d, %.2f%%, tiny<%d)",
                           tiny, total, 100.0 * tiny / total, tinyThresh);
        return true; // flag as bulk dust (nonstandard)
    }
    return false;
}


// ==========================================================================================================
// *** CONSENSUS (soft-fork, hybrid activation) ***
// Helpers in src/consensus/tx_check.cpp; activation/enforcement in src/validation.cpp
// Also define deployment in: src/consensus/params.h, src/chainparams.cpp, src/versionbits.*
// ==========================================================================================================

// -----------------------------------------------------------------------
// --- In src/consensus/tx_check.cpp (helper only; no params needed) ---
// -----------------------------------------------------------------------

static constexpr CAmount BASE_TINY_THRESHOLD     = 4096;
static constexpr int64_t FIRST_TINY_HALVING_H    = 1260000;
static constexpr int64_t HALVING_INTERVAL        = 210000;
static constexpr int     MAX_TINY_OUTPUTS        = 100;
static constexpr double  TINY_RATIO_THRESHOLD    = 0.6;
static constexpr CAmount MIN_TINY_FLOOR          = 1;

bool IsBulkDust(const CTransaction& tx, int currentHeight) // expose via tx_check.h if needed
{
    const int total = tx.vout.size();
    if (total == 0) return false;

    int era = 0;
    if (currentHeight >= FIRST_TINY_HALVING_H) {
        era = 1 + static_cast<int>((currentHeight - FIRST_TINY_HALVING_H) / HALVING_INTERVAL);
    }

    CAmount tinyThresh = BASE_TINY_THRESHOLD >> era;
    if (tinyThresh < MIN_TINY_FLOOR) tinyThresh = MIN_TINY_FLOOR;

    int tiny = 0;
    for (const auto& out : tx.vout) {
        if (out.nValue < tinyThresh) ++tiny;
    }

    if (tiny >= MAX_TINY_OUTPUTS && (static_cast<double>(tiny) / total) >= TINY_RATIO_THRESHOLD)
        return true;

    return false;
}


// -----------------------------------------------------------------------
// --- In src/validation.cpp (enforcement with hybrid activation) ---
// -----------------------------------------------------------------------

#include <consensus/tx_check.h>
#include <versionbits.h>

const Consensus::Params& params = chainparams.GetConsensus();
int currentHeight = chainActive.Tip() ? chainActive.Tip()->nHeight : 0;

const bool bulk_dust_active =
    DeploymentActiveAtTip(params, Consensus::DEPLOYMENT_BULK_DUST_LIMIT) ||
    (currentHeight >= params.BulkDustActivationHeight);

if (bulk_dust_active) {
    if (IsBulkDust(tx, currentHeight)) {
        return state.Invalid(TxValidationResult::TX_CONSENSUS, "too-many-tiny-outputs");
    }
}


// -----------------------------------------------------------------------
// --- In src/consensus/params.h ---
// -----------------------------------------------------------------------

enum DeploymentPos {
    // ...
    DEPLOYMENT_BULK_DUST_LIMIT,
    MAX_VERSION_BITS_DEPLOYMENTS
};

struct Params {
    // ...
    int BulkDustActivationHeight; // height flag-day fallback
};


// -----------------------------------------------------------------------
// --- In src/chainparams.cpp (per-network values; examples only) ---
// -----------------------------------------------------------------------

consensus.vDeployments[Consensus::DEPLOYMENT_BULK_DUST_LIMIT].bit = 12;
consensus.vDeployments[Consensus::DEPLOYMENT_BULK_DUST_LIMIT].nStartTime = 1767225600;  // 2026-01-01 UTC
consensus.vDeployments[Consensus::DEPLOYMENT_BULK_DUST_LIMIT].nTimeout   = 1838160000;  // 2028-04-01 UTC
consensus.vDeployments[Consensus::DEPLOYMENT_BULK_DUST_LIMIT].min_activation_height = 969696;

consensus.BulkDustActivationHeight = 1021021; // flag-day fallback