/*
The MIT License (MIT)

Copyright (c) 2013-2014 winlin

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef SRS_RTMP_PROTOCOL_HANDSHKAE_HPP
#define SRS_RTMP_PROTOCOL_HANDSHKAE_HPP

/*
#include <srs_protocol_handshake.hpp>
*/

#include <srs_core.hpp>

class ISrsProtocolReaderWriter;
class SrsComplexHandshake;

/**
* try complex handshake, if failed, fallback to simple handshake.
*/
class SrsSimpleHandshake
{
public:
    SrsSimpleHandshake();
    virtual ~SrsSimpleHandshake();
public:
    /**
    * simple handshake.
    * @param complex_hs, try complex handshake first, 
    *         if NULL, use simple handshake.
    *         if failed, rollback to simple handshake.
    */
    virtual int handshake_with_client(ISrsProtocolReaderWriter* io, SrsComplexHandshake* complex_hs);
    virtual int handshake_with_server(ISrsProtocolReaderWriter* io, SrsComplexHandshake* complex_hs);
};

/**
* rtmp complex handshake,
* @see also crtmp(crtmpserver) or librtmp,
* @see also: http://blog.csdn.net/win_lin/article/details/13006803
*/
class SrsComplexHandshake
{
public:
    SrsComplexHandshake();
    virtual ~SrsComplexHandshake();
public:
    /**
    * complex hanshake.
    * @_c1, size of c1 must be 1536.
    * @remark, user must free the c1.
    * @return user must:
    *     continue connect app if success,
    *     try simple handshake if error is ERROR_RTMP_TRY_SIMPLE_HS,
    *     otherwise, disconnect
    */
    virtual int handshake_with_client(ISrsProtocolReaderWriter* io, char* _c1);
    virtual int handshake_with_server(ISrsProtocolReaderWriter* io);
};

namespace srs
{
    /**
    * the schema type.
    */
    enum srs_schema_type {
        srs_schema0 = 0, // key-digest sequence
        srs_schema1 = 1, // digest-key sequence
        srs_schema_invalid = 2,
    };
    
    /**
    * 764bytes key结构
    *     random-data: (offset)bytes
    *     key-data: 128bytes
    *     random-data: (764-offset-128-4)bytes
    *     offset: 4bytes
    * @see also: http://blog.csdn.net/win_lin/article/details/13006803
    */
    struct key_block
    {
        // (offset)bytes
        char* random0;
        int random0_size;
        
        // 128bytes
        char key[128];
        
        // (764-offset-128-4)bytes
        char* random1;
        int random1_size;
        
        // 4bytes
        int32_t offset;
    };
    
    /**
    * 764bytes digest结构
    *     offset: 4bytes
    *     random-data: (offset)bytes
    *     digest-data: 32bytes
    *     random-data: (764-4-offset-32)bytes
    * @see also: http://blog.csdn.net/win_lin/article/details/13006803
    */
    struct digest_block
    {
        // 4bytes
        int32_t offset;
        
        // (offset)bytes
        char* random0;
        int random0_size;
        
        // 32bytes
        char digest[32];
        
        // (764-4-offset-32)bytes
        char* random1;
        int random1_size;
    };
    
    /**
    * c1s1 schema0
    *     time: 4bytes
    *     version: 4bytes
    *     key: 764bytes
    *     digest: 764bytes
    * c1s1 schema1
    *     time: 4bytes
    *     version: 4bytes
    *     digest: 764bytes
    *     key: 764bytes
    * @see also: http://blog.csdn.net/win_lin/article/details/13006803
    */
    struct c1s1
    {
        union block {
            key_block key; 
            digest_block digest; 
        };
        
        // 4bytes
        int32_t time;
        // 4bytes
        int32_t version;
        // 764bytes
        // if schema0, use key
        // if schema1, use digest
        block block0;
        // 764bytes
        // if schema0, use digest
        // if schema1, use key
        block block1;
        
        // the logic schema
        srs_schema_type schema;
        
        c1s1();
        virtual ~c1s1();
        /**
        * get the digest key.
        */
        virtual char* get_digest();
        /**
        * copy to bytes.
        */
        virtual void dump(char* _c1s1);
        
        /**
        * client: create and sign c1 by schema.
        * sign the c1, generate the digest.
        *         calc_c1_digest(c1, schema) {
        *            get c1s1-joined from c1 by specified schema
        *            digest-data = HMACsha256(c1s1-joined, FPKey, 30)
        *            return digest-data;
        *        }
        *        random fill 1536bytes c1 // also fill the c1-128bytes-key
        *        time = time() // c1[0-3]
        *        version = [0x80, 0x00, 0x07, 0x02] // c1[4-7]
        *        schema = choose schema0 or schema1
        *        digest-data = calc_c1_digest(c1, schema)
        *        copy digest-data to c1
        */
        virtual int c1_create(srs_schema_type _schema);
        /**
        * server: parse the c1s1, discovery the key and digest by schema.
        * use the c1_validate_digest() to valid the digest of c1.
        */
        virtual int c1_parse(char* _c1s1, srs_schema_type _schema);
        /**
        * server: validate the parsed schema and c1s1
        */
        virtual int c1_validate_digest(bool& is_valid);
        /**
        * server: create and sign the s1 from c1.
        */
        virtual int s1_create(c1s1* c1);
    private:
        virtual int calc_s1_digest(char*& digest);
        virtual int calc_c1_digest(char*& digest);
        virtual void destroy_blocks();
    };
    
    /**
    * the c2s2 complex handshake structure.
    * random-data: 1504bytes
    * digest-data: 32bytes
    * @see also: http://blog.csdn.net/win_lin/article/details/13006803
    */
    struct c2s2
    {
        char random[1504];
        char digest[32];
        
        c2s2();
        virtual ~c2s2();
        
        /**
        * copy to bytes.
        */
        virtual void dump(char* _c2s2);
    
        /**
        * create c2.
        * random fill c2s2 1536 bytes
        * 
        * // client generate C2, or server valid C2
        * temp-key = HMACsha256(s1-digest, FPKey, 62)
        * c2-digest-data = HMACsha256(c2-random-data, temp-key, 32)
        */
        virtual int c2_create(c1s1* s1);
        
        /**
        * create s2.
        * random fill c2s2 1536 bytes
        * 
        * // server generate S2, or client valid S2
        * temp-key = HMACsha256(c1-digest, FMSKey, 68)
        * s2-digest-data = HMACsha256(s2-random-data, temp-key, 32)
        */
        virtual int s2_create(c1s1* c1);
    };
    
    /**
    * compare the memory in bytes.
    */
    bool srs_bytes_equals(void* pa, void* pb, int size);
    
    /**
    * c1s1 is splited by digest:
    *     c1s1-part1: n bytes (time, version, key and digest-part1).
    *     digest-data: 32bytes
    *     c1s1-part2: (1536-n-32)bytes (digest-part2)
    * @return a new allocated bytes, user must free it.
    */
    char* srs_bytes_join_schema0(int32_t time, int32_t version, key_block* key, digest_block* digest);
    
    /**
    * c1s1 is splited by digest:
    *     c1s1-part1: n bytes (time, version and digest-part1).
    *     digest-data: 32bytes
    *     c1s1-part2: (1536-n-32)bytes (digest-part2 and key)
    * @return a new allocated bytes, user must free it.
    */
    char* srs_bytes_join_schema1(int32_t time, int32_t version, digest_block* digest, key_block* key);
    
    // the digest key generate size.
    #define OpensslHashSize 512
    extern u_int8_t SrsGenuineFMSKey[];
    extern u_int8_t SrsGenuineFPKey[];
    int openssl_HMACsha256(const void* data, int data_size, const void* key, int key_size, void* digest);
}

#endif