/* XMRig - Hush/DragonX HAC Support
 * Copyright (c) 2024 XMRig       <https://github.com/xmrig>
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 */

#ifndef XMRIG_HUSHCLIENT_H
#define XMRIG_HUSHCLIENT_H

#include "base/kernel/interfaces/IHttpListener.h"
#include "base/kernel/interfaces/ITimerListener.h"
#include "base/net/stratum/BaseClient.h"
#include "base/net/stratum/SubmitResult.h"

#include <map>
#include <memory>
#include <vector>

namespace xmrig {

class Timer;

/**
 * Client for Hush Asset Chains (HAC) that use RandomX PoW.
 * Handles BIP22-style getblocktemplate RPC format used by hushd/dragonxd.
 */
class HushClient : public BaseClient, public ITimerListener, public IHttpListener
{
public:
    XMRIG_DISABLE_COPY_MOVE_DEFAULT(HushClient)

    HushClient(int id, IClientListener *listener);
    ~HushClient() override;

protected:
    // BaseClient interface
    bool disconnect() override;
    bool isTLS() const override;
    int64_t submit(const JobResult &result) override;
    void connect() override;
    void connect(const Pool &pool) override;
    void setPool(const Pool &pool) override;
    void deleteLater() override;

    // IHttpListener
    void onHttpData(const HttpData &data) override;

    // ITimerListener
    void onTimer(const Timer *timer) override;

    inline bool hasExtension(Extension) const noexcept override         { return false; }
    inline const char *mode() const override                            { return "hush-daemon"; }
    inline const char *tlsFingerprint() const override                  { return m_tlsFingerprint; }
    inline const char *tlsVersion() const override                      { return m_tlsVersion; }
    inline int64_t send(const rapidjson::Value &, Callback) override    { return -1; }
    inline int64_t send(const rapidjson::Value &) override              { return -1; }
    inline void tick(uint64_t) override                                 {}

private:
    // RPC methods
    int64_t getBlockTemplate();
    int64_t getBlockHash(uint64_t height);
    int64_t submitBlock(const std::string &blockHex);
    int64_t rpcSend(const rapidjson::Document &doc);

    // Job handling
    bool parseBlockTemplate(const rapidjson::Value &result);
    bool parseResponse(int64_t id, const rapidjson::Value &result, const rapidjson::Value &error);
    void retry();
    void setState(SocketState state);

    // RandomX key management
    uint64_t getKeyHeight(uint64_t height) const;
    
    // Block serialization
    std::vector<uint8_t> serializeBlock(uint32_t nonce, uint64_t extraNonce) const;
    std::vector<uint8_t> serializeHeader(const uint8_t* nonce32, const uint8_t* solution) const;
    std::string serializeBlockHex(const uint8_t* nonce32, const uint8_t* solution) const;
    
    // PoW verification (SHA256D of header with solution)
    bool checkPow(const uint8_t* nonce32, const uint8_t* solution) const;
    static void sha256d(const uint8_t* data, size_t len, uint8_t* out);

    // Target/difficulty conversion
    uint64_t targetToDiff(const char *target) const;

    // Constants for RandomX key derivation
    static constexpr int RANDOMX_INTERVAL = 1024;
    static constexpr int RANDOMX_LAG = 64;

    // Block template data
    int32_t m_version = 4;
    uint64_t m_height = 0;
    uint64_t m_curtime = 0;
    String m_prevHash;
    String m_merkleRoot;        // coinbasetxn.hash
    String m_saplingRoot;       // finalsaplingroothash
    String m_bits;
    String m_target;
    std::vector<uint8_t> m_targetBytes;  // Network target as 32 bytes for comparison
    String m_coinbaseTx;        // coinbasetxn.data
    std::vector<String> m_transactions;

    // RandomX key tracking
    uint64_t m_keyHeight = 0;
    String m_keyBlockHash;
    
    // Job state
    String m_currentJobId;
    String m_prevJobHash;
    uint64_t m_jobSteadyMs = 0;
    
    // Cached block blob for submission (full block with header + txs)
    std::vector<uint8_t> m_headerBlob;
    size_t m_nonceOffset = 0;  // Offset of nNonce field in the block blob

    // Cached binary header fields for block serialization (avoids re-parsing hex each submit)
    uint8_t m_headerPrevHash[32] = {};
    uint8_t m_headerMerkleRoot[32] = {};
    uint8_t m_headerSaplingRoot[32] = {};
    uint32_t m_headerTime = 0;
    uint32_t m_headerBits = 0;

    // Request tracking
    enum RequestType { REQ_NONE, REQ_TEMPLATE, REQ_KEYHASH, REQ_SUBMIT };
    RequestType m_pendingRequest = REQ_NONE;
    uint64_t m_pendingKeyHeight = 0;

    Timer *m_timer;
    std::shared_ptr<IHttpListener> m_httpListener;
    std::map<int64_t, SubmitResult> m_results;

    char m_tlsFingerprint[64] = { 0 };
    char m_tlsVersion[32] = { 0 };
};

} // namespace xmrig

#endif // XMRIG_HUSHCLIENT_H