//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.

    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.

    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

#ifndef RIPPLE_SHAMAP_SHAMAPTREENODE_H_INCLUDED
#define RIPPLE_SHAMAP_SHAMAPTREENODE_H_INCLUDED

#include <ripple/shamap/SHAMapItem.h>
#include <ripple/shamap/SHAMapNodeID.h>
#include <ripple/basics/TaggedCache.h>
#include <beast/utility/Journal.h>

#include <cstdint>
#include <memory>
#include <mutex>
#include <string>

namespace ripple {

enum SHANodeFormat
{
    snfPREFIX   = 1, // Form that hashes to its official hash
    snfWIRE     = 2, // Compressed form used on the wire
    snfHASH     = 3, // just the hash
};

class SHAMapAbstractNode
{
public:
    enum TNType
    {
        tnERROR             = 0,
        tnINNER             = 1,
        tnTRANSACTION_NM    = 2, // transaction, no metadata
        tnTRANSACTION_MD    = 3, // transaction, with metadata
        tnACCOUNT_STATE     = 4
    };

protected:
    TNType                          mType;
    uint256                         mHash;
    std::uint32_t                   mSeq;

protected:
    virtual ~SHAMapAbstractNode() = 0;
    SHAMapAbstractNode(SHAMapAbstractNode const&) = delete;
    SHAMapAbstractNode& operator=(SHAMapAbstractNode const&) = delete;

    SHAMapAbstractNode(TNType type, std::uint32_t seq);
    SHAMapAbstractNode(TNType type, std::uint32_t seq, uint256 const& hash);

public:
    std::uint32_t getSeq () const;
    void setSeq (std::uint32_t s);
    uint256 const& getNodeHash () const;
    TNType getType () const;
    bool isLeaf () const;
    bool isInner () const;
    bool isValid () const;
    bool isInBounds (SHAMapNodeID const &id) const;

    virtual bool updateHash () = 0;
    virtual void addRaw (Serializer&, SHANodeFormat format) const = 0;
    virtual std::string getString (SHAMapNodeID const&) const;
    virtual std::shared_ptr<SHAMapAbstractNode> clone(std::uint32_t seq) const = 0;

    static std::shared_ptr<SHAMapAbstractNode>
        make(Blob const& rawNode, std::uint32_t seq, SHANodeFormat format,
             uint256 const& hash, bool hashValid);

    // debugging
#ifdef BEAST_DEBUG
    static void dump (SHAMapNodeID const&, beast::Journal journal);
#endif
};

class SHAMapInnerNode
    : public SHAMapAbstractNode
{
    uint256                         mHashes[16];
    std::shared_ptr<SHAMapAbstractNode> mChildren[16];
    int                             mIsBranch = 0;
    std::uint32_t                   mFullBelowGen = 0;

    static std::mutex               childLock;
public:
    SHAMapInnerNode(std::uint32_t seq = 0);
    std::shared_ptr<SHAMapAbstractNode> clone(std::uint32_t seq) const override;

    bool isEmpty () const;
    bool isEmptyBranch (int m) const;
    int getBranchCount () const;
    uint256 const& getChildHash (int m) const;

    void setChild(int m, std::shared_ptr<SHAMapAbstractNode> const& child);
    void shareChild (int m, std::shared_ptr<SHAMapAbstractNode> const& child);
    SHAMapAbstractNode* getChildPointer (int branch);
    std::shared_ptr<SHAMapAbstractNode> getChild (int branch);
    std::shared_ptr<SHAMapAbstractNode>
        canonicalizeChild (int branch, std::shared_ptr<SHAMapAbstractNode> node);

    // sync functions
    bool isFullBelow (std::uint32_t generation) const;
    void setFullBelowGen (std::uint32_t gen);

    bool updateHash () override;
    void updateHashDeep();
    void addRaw (Serializer&, SHANodeFormat format) const override;
    std::string getString (SHAMapNodeID const&) const override;

    friend std::shared_ptr<SHAMapAbstractNode>
        SHAMapAbstractNode::make(Blob const& rawNode, std::uint32_t seq,
             SHANodeFormat format, uint256 const& hash, bool hashValid);
};

// SHAMapTreeNode represents a leaf, and may eventually be renamed to reflect that.
class SHAMapTreeNode
    : public SHAMapAbstractNode
{
private:
    std::shared_ptr<SHAMapItem const> mItem;

public:
    SHAMapTreeNode (const SHAMapTreeNode&) = delete;
    SHAMapTreeNode& operator= (const SHAMapTreeNode&) = delete;

    SHAMapTreeNode (std::shared_ptr<SHAMapItem const> const& item,
                    TNType type, std::uint32_t seq);
    SHAMapTreeNode(std::shared_ptr<SHAMapItem const> const& item, TNType type,
                   std::uint32_t seq, uint256 const& hash);
    std::shared_ptr<SHAMapAbstractNode> clone(std::uint32_t seq) const override;

    void addRaw (Serializer&, SHANodeFormat format) const override;

public:  // public only to SHAMap

    // inner node functions
    bool isInnerNode () const;

    // item node function
    bool hasItem () const;
    std::shared_ptr<SHAMapItem const> const& peekItem () const;
    bool setItem (std::shared_ptr<SHAMapItem const> const& i, TNType type);

    std::string getString (SHAMapNodeID const&) const override;
    bool updateHash () override;
};

// SHAMapAbstractNode

inline
SHAMapAbstractNode::SHAMapAbstractNode(TNType type, std::uint32_t seq)
    : mType(type)
    , mSeq(seq)
{
}

inline
SHAMapAbstractNode::SHAMapAbstractNode(TNType type, std::uint32_t seq,
                                       uint256 const& hash)
    : mType(type)
    , mHash(hash)
    , mSeq(seq)
{
}

inline
std::uint32_t
SHAMapAbstractNode::getSeq () const
{
    return mSeq;
}

inline
void
SHAMapAbstractNode::setSeq (std::uint32_t s)
{
    mSeq = s;
}

inline
uint256 const&
SHAMapAbstractNode::getNodeHash () const
{
    return mHash;
}

inline
SHAMapAbstractNode::TNType
SHAMapAbstractNode::getType () const
{
    return mType;
}

inline
bool
SHAMapAbstractNode::isLeaf () const
{
    return (mType == tnTRANSACTION_NM) || (mType == tnTRANSACTION_MD) ||
           (mType == tnACCOUNT_STATE);
}

inline
bool
SHAMapAbstractNode::isInner () const
{
    return mType == tnINNER;
}

inline
bool
SHAMapAbstractNode::isValid () const
{
    return mType != tnERROR;
}

inline
bool
SHAMapAbstractNode::isInBounds (SHAMapNodeID const &id) const
{
    // Nodes at depth 64 must be leaves
    return (!isInner() || (id.getDepth() < 64));
}

// SHAMapInnerNode

inline
SHAMapInnerNode::SHAMapInnerNode(std::uint32_t seq)
    : SHAMapAbstractNode(tnINNER, seq)
{
}

inline
bool
SHAMapInnerNode::isEmptyBranch (int m) const
{
    return (mIsBranch & (1 << m)) == 0;
}

inline
uint256 const&
SHAMapInnerNode::getChildHash (int m) const
{
    assert ((m >= 0) && (m < 16) && (getType() == tnINNER));
    return mHashes[m];
}

inline
bool
SHAMapInnerNode::isFullBelow (std::uint32_t generation) const
{
    return mFullBelowGen == generation;
}

inline
void
SHAMapInnerNode::setFullBelowGen (std::uint32_t gen)
{
    mFullBelowGen = gen;
}

// SHAMapTreeNode

inline
bool
SHAMapTreeNode::isInnerNode () const
{
    return !mItem;
}

inline
bool
SHAMapTreeNode::hasItem () const
{
    return bool(mItem);
}

inline
std::shared_ptr<SHAMapItem const> const&
SHAMapTreeNode::peekItem () const
{
    return mItem;
}

} // ripple

#endif