/*
 * This file is part of the Flowee project
 * Copyright (C) 2021 Tom Zander <tom@flowee.org>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef HDMASTERKEY_H
#define HDMASTERKEY_H

#include "primitives/key.h"
#include <string>

/**
 * Hierarchically Deterministic wallet Master key.
 * This class stores a HD wallet masterkey and allow you to derive any child key
 * from it.
 * This implements BIP32 and combined with the fromMnemonic() method this supports BIP39 based wallets.
 */
class HDMasterKey
{
public:
    /// Adding this value to a path-element makes it 'hardened'
    static const uint32_t Hardened = 0x80000000;

    HDMasterKey(const HDMasterKey &other) = default;

    /**
     * Convert a string based derivation path into a vector of fields.
     * This throws an exception when the string is not a fully valid derivation path.
     */
    static std::vector<uint32_t> deriveFromString(const std::string &path);

    /**
     * Create a masterkey from a known-good mnemonic.
     * @see Mnemonic::validateMnemonic() to make sure the string is good.
     * @param phrase a UTF8-encoded multi-word mnemonic phrase
     */
    static HDMasterKey fromMnemonic(const std::string &phrase, const std::string &password = std::string());
    static HDMasterKey fromSeed(const std::vector<uint8_t> &seed);

    /**
     * Used in the string output methods.
     */
    enum Chain {
        Testnet,
        MainChain
    };
    /// returns true if the key is valid.
    bool isValid() const;

    std::string toString(Chain chain = MainChain) const; ///< output xpub pubkey key as text
    std::string privToString(Chain chain = MainChain) const; ///< output xprv private key as text

    CKey derive(const std::vector<uint32_t> &path) const;
    CKey derive(const std::string &path) const;

    HDMasterKey &operator=(const HDMasterKey &other) = default;
    friend bool operator==(const HDMasterKey &a, const HDMasterKey &b) {
        return memcmp(&a.m_fingerprint[0], &b.m_fingerprint[0], 4) == 0 && a.m_chaincode == b.m_chaincode && a.m_key == b.m_key;
    }

protected:
    HDMasterKey();

private:
    uint8_t m_fingerprint[4];
    ChainCode m_chaincode;
    CKey m_key;
};

#endif