#ifndef IDENTITY_H__
#define IDENTITY_H__

#include <inttypes.h>
#include <string.h>
#include <string>
#include <memory>
#include "util/base64.h"
#include "crypto/ElGamal.h"

namespace i2p {

// Forward declaration to avoid include
namespace crypto {
    class Signer;
    class Verifier;
}

namespace data {
    template<int sz>
    class Tag
    {
        public:

            Tag (const uint8_t * buf) { memcpy (m_Buf, buf, sz); };
            Tag (const Tag<sz>& ) = default;
#ifndef _WIN32 // FIXME!!! msvs 2013 can't compile it
            Tag (Tag<sz>&& ) = default;
#endif
            Tag () = default;
            
            Tag<sz>& operator= (const Tag<sz>& ) = default;
#ifndef _WIN32
            Tag<sz>& operator= (Tag<sz>&& ) = default;
#endif
            
            uint8_t * operator()() { return m_Buf; };
            const uint8_t * operator()() const { return m_Buf; };

            operator uint8_t * () { return m_Buf; };
            operator const uint8_t * () const { return m_Buf; };
            
            const uint64_t * GetLL () const { return ll; };

            bool operator== (const Tag<sz>& other) const { return !memcmp (m_Buf, other.m_Buf, sz); };
            bool operator< (const Tag<sz>& other) const { return memcmp (m_Buf, other.m_Buf, sz) < 0; };

            bool IsZero () const
            {
                for (int i = 0; i < sz/8; i++)
                    if (ll[i]) return false;
                return true;
            }
            
            std::string ToBase64 () const
            {
                char str[sz*2];
                int l = i2p::util::ByteStreamToBase64 (m_Buf, sz, str, sz*2);
                str[l] = 0;
                return std::string (str);
            }

            std::string ToBase32 () const
            {
                char str[sz*2];
                int l = i2p::util::ByteStreamToBase32 (m_Buf, sz, str, sz*2);
                str[l] = 0;
                return std::string (str);
            }   

            void FromBase32 (const std::string& s)
            {
                i2p::util::Base32ToByteStream (s.c_str (), s.length (), m_Buf, sz);
            }

            void FromBase64 (const std::string& s)
            {
                i2p::util::Base64ToByteStream (s.c_str (), s.length (), m_Buf, sz);
            }

        private:

            union // 8 bytes alignment
            {   
                uint8_t m_Buf[sz];
                uint64_t ll[sz/8];
            };      
    };  
    typedef Tag<32> IdentHash;

#pragma pack(1)
    struct Keys
    {
        uint8_t privateKey[256];
        uint8_t signingPrivateKey[20];
        uint8_t publicKey[256];
        uint8_t signingKey[128];
    };
    
    const uint8_t CERTIFICATE_TYPE_NULL = 0;
    const uint8_t CERTIFICATE_TYPE_HASHCASH = 1;
    const uint8_t CERTIFICATE_TYPE_HIDDEN = 2;
    const uint8_t CERTIFICATE_TYPE_SIGNED = 3;  
    const uint8_t CERTIFICATE_TYPE_MULTIPLE = 4;    
    const uint8_t CERTIFICATE_TYPE_KEY = 5;

    struct Identity
    {
        uint8_t publicKey[256];
        uint8_t signingKey[128];
        struct
        {
            uint8_t type;
            uint16_t length;
        } certificate;  

        Identity () = default;
        Identity (const Keys& keys) { *this = keys; };
        Identity& operator=(const Keys& keys);
        size_t FromBuffer (const uint8_t * buf, size_t len);
        IdentHash Hash () const;
    };
#pragma pack()
    Keys CreateRandomKeys ();
    
    const size_t DEFAULT_IDENTITY_SIZE = sizeof (Identity); // 387 bytes
    
    const uint16_t CRYPTO_KEY_TYPE_ELGAMAL = 0;
    const uint16_t SIGNING_KEY_TYPE_DSA_SHA1 = 0;
    const uint16_t SIGNING_KEY_TYPE_ECDSA_SHA256_P256 = 1;
    const uint16_t SIGNING_KEY_TYPE_ECDSA_SHA384_P384 = 2;
    const uint16_t SIGNING_KEY_TYPE_ECDSA_SHA512_P521 = 3;
    const uint16_t SIGNING_KEY_TYPE_RSA_SHA256_2048 = 4;
    const uint16_t SIGNING_KEY_TYPE_RSA_SHA384_3072 = 5;
    const uint16_t SIGNING_KEY_TYPE_RSA_SHA512_4096 = 6;
    const uint16_t SIGNING_KEY_TYPE_EDDSA_SHA512_ED25519 = 7;
    typedef uint16_t SigningKeyType;
    typedef uint16_t CryptoKeyType; 
    
    class IdentityEx
    {
        public:

            IdentityEx ();
            IdentityEx (const uint8_t * publicKey, const uint8_t * signingKey,
                SigningKeyType type = SIGNING_KEY_TYPE_DSA_SHA1);
            IdentityEx (const uint8_t * buf, size_t len);
            IdentityEx (const IdentityEx& other);
            ~IdentityEx ();
            IdentityEx& operator=(const IdentityEx& other);
            IdentityEx& operator=(const Identity& standard);

            size_t FromBuffer (const uint8_t * buf, size_t len);
            size_t ToBuffer (uint8_t * buf, size_t len) const;
            size_t FromBase64(const std::string& s);
            std::string ToBase64 () const;
            const Identity& GetStandardIdentity () const { return m_StandardIdentity; };
            const IdentHash& GetIdentHash () const { return m_IdentHash; };
            size_t GetFullLen () const { return m_ExtendedLen + DEFAULT_IDENTITY_SIZE; };
            size_t GetSigningPublicKeyLen () const;
            size_t GetSigningPrivateKeyLen () const;
            size_t GetSignatureLen () const;
            bool Verify (const uint8_t * buf, size_t len, const uint8_t * signature) const;
            SigningKeyType GetSigningKeyType () const;
            CryptoKeyType GetCryptoKeyType () const;
            void DropVerifier (); // to save memory         

        private:

            void CreateVerifier () const;
            
        private:

            Identity m_StandardIdentity;
            IdentHash m_IdentHash;
            mutable i2p::crypto::Verifier * m_Verifier; 
            size_t m_ExtendedLen;
            uint8_t * m_ExtendedBuffer;
    };  
    
    class PrivateKeys // for eepsites
    {
        public:
            
            PrivateKeys (): m_Signer (nullptr) {};
            PrivateKeys (const PrivateKeys& other): m_Signer (nullptr) { *this = other; };
            PrivateKeys (const Keys& keys): m_Signer (nullptr) { *this = keys; };
            PrivateKeys& operator=(const Keys& keys);
            PrivateKeys& operator=(const PrivateKeys& other);
            ~PrivateKeys ();
            
            const IdentityEx& GetPublic () const { return m_Public; };
            const uint8_t * GetPrivateKey () const { return m_PrivateKey; };
            const uint8_t * GetSigningPrivateKey () const { return m_SigningPrivateKey; };
            void Sign (const uint8_t * buf, int len, uint8_t * signature) const;

            size_t GetFullLen () const { return m_Public.GetFullLen () + 256 + m_Public.GetSigningPrivateKeyLen (); };      
            size_t FromBuffer (const uint8_t * buf, size_t len);
            size_t ToBuffer (uint8_t * buf, size_t len) const;

            size_t FromBase64(const std::string& s);
            std::string ToBase64 () const;

            static PrivateKeys CreateRandomKeys (SigningKeyType type = SIGNING_KEY_TYPE_DSA_SHA1);
    
        private:

            void CreateSigner ();
            
        private:

            IdentityEx m_Public;
            uint8_t m_PrivateKey[256];
            uint8_t m_SigningPrivateKey[1024]; // assume private key doesn't exceed 1024 bytes
            i2p::crypto::Signer * m_Signer;
    };

    // kademlia
    struct XORMetric
    {
        union
        {   
            uint8_t metric[32];
            uint64_t metric_ll[4];  
        };  

        void SetMin () { memset (metric, 0, 32); };
        void SetMax () { memset (metric, 0xFF, 32); };
        bool operator< (const XORMetric& other) const { return memcmp (metric, other.metric, 32) < 0; };
    };  

    IdentHash CreateRoutingKey (const IdentHash& ident);
    XORMetric operator^(const IdentHash& key1, const IdentHash& key2);  
    
    // destination for delivery instructions
    class RoutingDestination
    {
        public:

            RoutingDestination () {};
            virtual ~RoutingDestination () {};
            
            virtual const IdentHash& GetIdentHash () const = 0;
            virtual const uint8_t * GetEncryptionPublicKey () const = 0;
            virtual bool IsDestination () const = 0; // for garlic 

            std::unique_ptr<const i2p::crypto::ElGamalEncryption>& GetElGamalEncryption () const
            {
                if (!m_ElGamalEncryption)
                    m_ElGamalEncryption.reset (new i2p::crypto::ElGamalEncryption (GetEncryptionPublicKey ()));
                return m_ElGamalEncryption;
            }
            
        private:

            mutable std::unique_ptr<const i2p::crypto::ElGamalEncryption> m_ElGamalEncryption; // use lazy initialization
    };  

    class LocalDestination 
    {
        public:

            virtual ~LocalDestination() {};
            virtual const PrivateKeys& GetPrivateKeys () const = 0;
            virtual const uint8_t * GetEncryptionPrivateKey () const = 0; 
            virtual const uint8_t * GetEncryptionPublicKey () const = 0; 

            const IdentityEx& GetIdentity () const { return GetPrivateKeys ().GetPublic (); };
            const IdentHash& GetIdentHash () const { return GetIdentity ().GetIdentHash (); };  
            void Sign (const uint8_t * buf, int len, uint8_t * signature) const 
            { 
                GetPrivateKeys ().Sign (buf, len, signature); 
            };
    };  
}
}


#endif