// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2012 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_DB_H
#define BITCOIN_DB_H

#include "key.h"

#include <map>
#include <string>
#include <vector>

#include <db_cxx.h>

class CAccount;
class CAccountingEntry;
class CAddress;
class CAddrMan;
class CBlockLocator;
class CDiskBlockIndex;
class CDiskTxPos;
class CMasterKey;
class COutPoint;
class CTxIndex;
class CWallet;
class CWalletTx;

extern unsigned int nWalletDBUpdated;
extern DbEnv dbenv;

extern void DBFlush(bool fShutdown);
void ThreadFlushWalletDB(void* parg);
bool BackupWallet(const CWallet& wallet, const std::string& strDest);


/** RAII class that provides access to a Berkeley database */
class CDB
{
protected:
    Db* pdb;
    std::string strFile;
    std::vector<DbTxn*> vTxn;
    bool fReadOnly;

    explicit CDB(const char* pszFile, const char* pszMode="r+");
    ~CDB() { Close(); }
public:
    void Close();
private:
    CDB(const CDB&);
    void operator=(const CDB&);

protected:
    template<typename K, typename T>
    bool Read(const K& key, T& value)
    {
        if (!pdb)
            return false;

        // Key
        CDataStream ssKey(SER_DISK);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(&ssKey[0], ssKey.size());

        // Read
        Dbt datValue;
        datValue.set_flags(DB_DBT_MALLOC);
        int ret = pdb->get(GetTxn(), &datKey, &datValue, 0);
        memset(datKey.get_data(), 0, datKey.get_size());
        if (datValue.get_data() == NULL)
            return false;

        // Unserialize value
        CDataStream ssValue((char*)datValue.get_data(), (char*)datValue.get_data() + datValue.get_size(), SER_DISK);
        ssValue >> value;

        // Clear and free memory
        memset(datValue.get_data(), 0, datValue.get_size());
        free(datValue.get_data());
        return (ret == 0);
    }

    template<typename K, typename T>
    bool Write(const K& key, const T& value, bool fOverwrite=true)
    {
        if (!pdb)
            return false;
        if (fReadOnly)
            assert(!"Write called on database in read-only mode");

        // Key
        CDataStream ssKey(SER_DISK);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(&ssKey[0], ssKey.size());

        // Value
        CDataStream ssValue(SER_DISK);
        ssValue.reserve(10000);
        ssValue << value;
        Dbt datValue(&ssValue[0], ssValue.size());

        // Write
        int ret = pdb->put(GetTxn(), &datKey, &datValue, (fOverwrite ? 0 : DB_NOOVERWRITE));

        // Clear memory in case it was a private key
        memset(datKey.get_data(), 0, datKey.get_size());
        memset(datValue.get_data(), 0, datValue.get_size());
        return (ret == 0);
    }

    template<typename K>
    bool Erase(const K& key)
    {
        if (!pdb)
            return false;
        if (fReadOnly)
            assert(!"Erase called on database in read-only mode");

        // Key
        CDataStream ssKey(SER_DISK);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(&ssKey[0], ssKey.size());

        // Erase
        int ret = pdb->del(GetTxn(), &datKey, 0);

        // Clear memory
        memset(datKey.get_data(), 0, datKey.get_size());
        return (ret == 0 || ret == DB_NOTFOUND);
    }

    template<typename K>
    bool Exists(const K& key)
    {
        if (!pdb)
            return false;

        // Key
        CDataStream ssKey(SER_DISK);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(&ssKey[0], ssKey.size());

        // Exists
        int ret = pdb->exists(GetTxn(), &datKey, 0);

        // Clear memory
        memset(datKey.get_data(), 0, datKey.get_size());
        return (ret == 0);
    }

    Dbc* GetCursor()
    {
        if (!pdb)
            return NULL;
        Dbc* pcursor = NULL;
        int ret = pdb->cursor(NULL, &pcursor, 0);
        if (ret != 0)
            return NULL;
        return pcursor;
    }

    int ReadAtCursor(Dbc* pcursor, CDataStream& ssKey, CDataStream& ssValue, unsigned int fFlags=DB_NEXT)
    {
        // Read at cursor
        Dbt datKey;
        if (fFlags == DB_SET || fFlags == DB_SET_RANGE || fFlags == DB_GET_BOTH || fFlags == DB_GET_BOTH_RANGE)
        {
            datKey.set_data(&ssKey[0]);
            datKey.set_size(ssKey.size());
        }
        Dbt datValue;
        if (fFlags == DB_GET_BOTH || fFlags == DB_GET_BOTH_RANGE)
        {
            datValue.set_data(&ssValue[0]);
            datValue.set_size(ssValue.size());
        }
        datKey.set_flags(DB_DBT_MALLOC);
        datValue.set_flags(DB_DBT_MALLOC);
        int ret = pcursor->get(&datKey, &datValue, fFlags);
        if (ret != 0)
            return ret;
        else if (datKey.get_data() == NULL || datValue.get_data() == NULL)
            return 99999;

        // Convert to streams
        ssKey.SetType(SER_DISK);
        ssKey.clear();
        ssKey.write((char*)datKey.get_data(), datKey.get_size());
        ssValue.SetType(SER_DISK);
        ssValue.clear();
        ssValue.write((char*)datValue.get_data(), datValue.get_size());

        // Clear and free memory
        memset(datKey.get_data(), 0, datKey.get_size());
        memset(datValue.get_data(), 0, datValue.get_size());
        free(datKey.get_data());
        free(datValue.get_data());
        return 0;
    }

    DbTxn* GetTxn()
    {
        if (!vTxn.empty())
            return vTxn.back();
        else
            return NULL;
    }

public:
    bool TxnBegin()
    {
        if (!pdb)
            return false;
        DbTxn* ptxn = NULL;
        int ret = dbenv.txn_begin(GetTxn(), &ptxn, DB_TXN_NOSYNC);
        if (!ptxn || ret != 0)
            return false;
        vTxn.push_back(ptxn);
        return true;
    }

    bool TxnCommit()
    {
        if (!pdb)
            return false;
        if (vTxn.empty())
            return false;
        int ret = vTxn.back()->commit(0);
        vTxn.pop_back();
        return (ret == 0);
    }

    bool TxnAbort()
    {
        if (!pdb)
            return false;
        if (vTxn.empty())
            return false;
        int ret = vTxn.back()->abort();
        vTxn.pop_back();
        return (ret == 0);
    }

    bool ReadVersion(int& nVersion)
    {
        nVersion = 0;
        return Read(std::string("version"), nVersion);
    }

    bool WriteVersion(int nVersion)
    {
        return Write(std::string("version"), nVersion);
    }

    bool static Rewrite(const std::string& strFile, const char* pszSkip = NULL);
};







/** Access to the transaction database (blkindex.dat) */
class CTxDB : public CDB
{
public:
    CTxDB(const char* pszMode="r+") : CDB("blkindex.dat", pszMode) { }
private:
    CTxDB(const CTxDB&);
    void operator=(const CTxDB&);
public:
    bool ReadTxIndex(uint256 hash, CTxIndex& txindex);
    bool UpdateTxIndex(uint256 hash, const CTxIndex& txindex);
    bool AddTxIndex(const CTransaction& tx, const CDiskTxPos& pos, int nHeight);
    bool EraseTxIndex(const CTransaction& tx);
    bool ContainsTx(uint256 hash);
    bool ReadOwnerTxes(uint160 hash160, int nHeight, std::vector<CTransaction>& vtx);
    bool ReadDiskTx(uint256 hash, CTransaction& tx, CTxIndex& txindex);
    bool ReadDiskTx(uint256 hash, CTransaction& tx);
    bool ReadDiskTx(COutPoint outpoint, CTransaction& tx, CTxIndex& txindex);
    bool ReadDiskTx(COutPoint outpoint, CTransaction& tx);
    bool WriteBlockIndex(const CDiskBlockIndex& blockindex);
    bool EraseBlockIndex(uint256 hash);
    bool ReadHashBestChain(uint256& hashBestChain);
    bool WriteHashBestChain(uint256 hashBestChain);
    bool ReadBestInvalidWork(CBigNum& bnBestInvalidWork);
    bool WriteBestInvalidWork(CBigNum bnBestInvalidWork);
    bool LoadBlockIndex();
};




/** Access to the (IP) address database (addr.dat) */
class CAddrDB : public CDB
{
public:
    CAddrDB(const char* pszMode="r+") : CDB("addr.dat", pszMode) { }
private:
    CAddrDB(const CAddrDB&);
    void operator=(const CAddrDB&);
public:
    bool WriteAddrman(const CAddrMan& addr);
    bool LoadAddresses();
};

bool LoadAddresses();


/** A key pool entry */
class CKeyPool
{
public:
    int64 nTime;
    std::vector<unsigned char> vchPubKey;

    CKeyPool()
    {
        nTime = GetTime();
    }

    CKeyPool(const std::vector<unsigned char>& vchPubKeyIn)
    {
        nTime = GetTime();
        vchPubKey = vchPubKeyIn;
    }

    IMPLEMENT_SERIALIZE
    (
        if (!(nType & SER_GETHASH))
            READWRITE(nVersion);
        READWRITE(nTime);
        READWRITE(vchPubKey);
    )
};



/** Error statuses for the wallet database */
enum DBErrors
{
    DB_LOAD_OK,
    DB_CORRUPT,
    DB_TOO_NEW,
    DB_LOAD_FAIL,
    DB_NEED_REWRITE
};

/** Access to the wallet database (wallet.dat) */
class CWalletDB : public CDB
{
public:
    CWalletDB(std::string strFilename, const char* pszMode="r+") : CDB(strFilename.c_str(), pszMode)
    {
    }
private:
    CWalletDB(const CWalletDB&);
    void operator=(const CWalletDB&);
public:
    bool ReadName(const std::string& strAddress, std::string& strName)
    {
        strName = "";
        return Read(std::make_pair(std::string("name"), strAddress), strName);
    }

    bool WriteName(const std::string& strAddress, const std::string& strName);

    bool EraseName(const std::string& strAddress);

    bool ReadTx(uint256 hash, CWalletTx& wtx)
    {
        return Read(std::make_pair(std::string("tx"), hash), wtx);
    }

    bool WriteTx(uint256 hash, const CWalletTx& wtx)
    {
        nWalletDBUpdated++;
        return Write(std::make_pair(std::string("tx"), hash), wtx);
    }

    bool EraseTx(uint256 hash)
    {
        nWalletDBUpdated++;
        return Erase(std::make_pair(std::string("tx"), hash));
    }

    bool ReadKey(const std::vector<unsigned char>& vchPubKey, CPrivKey& vchPrivKey)
    {
        vchPrivKey.clear();
        return Read(std::make_pair(std::string("key"), vchPubKey), vchPrivKey);
    }

    bool WriteKey(const std::vector<unsigned char>& vchPubKey, const CPrivKey& vchPrivKey)
    {
        nWalletDBUpdated++;
        return Write(std::make_pair(std::string("key"), vchPubKey), vchPrivKey, false);
    }

    bool WriteCryptedKey(const std::vector<unsigned char>& vchPubKey, const std::vector<unsigned char>& vchCryptedSecret, bool fEraseUnencryptedKey = true)
    {
        nWalletDBUpdated++;
        if (!Write(std::make_pair(std::string("ckey"), vchPubKey), vchCryptedSecret, false))
            return false;
        if (fEraseUnencryptedKey)
        {
            Erase(std::make_pair(std::string("key"), vchPubKey));
            Erase(std::make_pair(std::string("wkey"), vchPubKey));
        }
        return true;
    }

    bool WriteMasterKey(unsigned int nID, const CMasterKey& kMasterKey)
    {
        nWalletDBUpdated++;
        return Write(std::make_pair(std::string("mkey"), nID), kMasterKey, true);
    }

    // Support for BIP 0013 : see https://en.bitcoin.it/wiki/BIP_0013
    bool ReadCScript(const uint160 &hash, CScript& redeemScript)
    {
        redeemScript.clear();
        return Read(std::make_pair(std::string("cscript"), hash), redeemScript);
    }

    bool WriteCScript(const uint160& hash, const CScript& redeemScript)
    {
        nWalletDBUpdated++;
        return Write(std::make_pair(std::string("cscript"), hash), redeemScript, false);
    }

    bool WriteBestBlock(const CBlockLocator& locator)
    {
        nWalletDBUpdated++;
        return Write(std::string("bestblock"), locator);
    }

    bool ReadBestBlock(CBlockLocator& locator)
    {
        return Read(std::string("bestblock"), locator);
    }

    bool ReadDefaultKey(std::vector<unsigned char>& vchPubKey)
    {
        vchPubKey.clear();
        return Read(std::string("defaultkey"), vchPubKey);
    }

    bool WriteDefaultKey(const std::vector<unsigned char>& vchPubKey)
    {
        nWalletDBUpdated++;
        return Write(std::string("defaultkey"), vchPubKey);
    }

    bool ReadPool(int64 nPool, CKeyPool& keypool)
    {
        return Read(std::make_pair(std::string("pool"), nPool), keypool);
    }

    bool WritePool(int64 nPool, const CKeyPool& keypool)
    {
        nWalletDBUpdated++;
        return Write(std::make_pair(std::string("pool"), nPool), keypool);
    }

    bool ErasePool(int64 nPool)
    {
        nWalletDBUpdated++;
        return Erase(std::make_pair(std::string("pool"), nPool));
    }

    // Settings are no longer stored in wallet.dat; these are
    // used only for backwards compatibility:
    template<typename T>
    bool ReadSetting(const std::string& strKey, T& value)
    {
        return Read(std::make_pair(std::string("setting"), strKey), value);
    }
    template<typename T>
    bool WriteSetting(const std::string& strKey, const T& value)
    {
        nWalletDBUpdated++;
        return Write(std::make_pair(std::string("setting"), strKey), value);
    }
    bool EraseSetting(const std::string& strKey)
    {
        nWalletDBUpdated++;
        return Erase(std::make_pair(std::string("setting"), strKey));
    }

    bool WriteMinVersion(int nVersion)
    {
        return Write(std::string("minversion"), nVersion);
    }

    bool ReadAccount(const std::string& strAccount, CAccount& account);
    bool WriteAccount(const std::string& strAccount, const CAccount& account);
    bool WriteAccountingEntry(const CAccountingEntry& acentry);
    int64 GetAccountCreditDebit(const std::string& strAccount);
    void ListAccountCreditDebit(const std::string& strAccount, std::list<CAccountingEntry>& acentries);

    int LoadWallet(CWallet* pwallet);
};

#endif
