/*
 * This file Copyright (C) 2007 Charles Kerr <charles@rebelbase.com>
 *
 * This file is licensed by the GPL version 2.  Works owned by the
 * Transmission project are granted a special exemption to clause 2(b)
 * so that the bulk of its code can remain under the MIT license. 
 * This exemption does not extend to derived works not owned by
 * the Transmission project.
 *
 * $Id$
 */

#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <event.h>
#include "transmission.h"
#include "crypto.h"
#include "net.h"
#include "peer-io.h"
#include "ratecontrol.h"
#include "trevent.h"
#include "utils.h"

/**
***
**/

struct tr_peerIo
{
    struct tr_handle * handle;

    struct in_addr in_addr;
    int port;
    int socket;
    int extensions;
    int encryptionMode;
    struct bufferevent * bufev;
    uint8_t peerId[20];

    unsigned int isEncrypted : 1;
    unsigned int isIncoming : 1;
    unsigned int peerIdIsSet : 1;

    tr_ratecontrol   * rateToPeer;
    tr_ratecontrol   * rateToClient;

    tr_can_read_cb     canRead;
    tr_did_write_cb    didWrite;
    tr_net_error_cb    gotError;
    void             * userData;

    tr_crypto * crypto;
};

/**
***
**/

static void
didWriteWrapper( struct bufferevent * e, void * userData )
{
    tr_peerIo * c = (tr_peerIo *) userData;
    if( c->didWrite != NULL )
        (*c->didWrite)( e, c->userData );
}

static void
canReadWrapper( struct bufferevent * e, void * userData )
{
    tr_peerIo * c = (tr_peerIo *) userData;

    if( c->canRead == NULL )
        return;

    for( ;; ) {
        const int ret = (*c->canRead)( e, c->userData );
        switch( ret ) {
            case READ_AGAIN: if( EVBUFFER_LENGTH( e->input ) ) continue; /* note fall-through */
            case READ_MORE: tr_peerIoSetIOMode( c, EV_READ, 0 ); return; break;
            case READ_DONE: return;
        }
    }
}

static void
gotErrorWrapper( struct bufferevent * e, short what, void * userData )
{
    tr_peerIo * c = (tr_peerIo *) userData;
    if( c->gotError != NULL )
        (*c->gotError)( e, what, c->userData );
}

/**
***
**/

//static int total_io = 0;

static tr_peerIo*
tr_peerIoNew( struct tr_handle  * handle,
              struct in_addr    * in_addr,
              const uint8_t     * torrentHash,
              int                 isIncoming,
              int                 socket )
{
    tr_peerIo * c;
    c = tr_new0( tr_peerIo, 1 );
    c->crypto = tr_cryptoNew( torrentHash, isIncoming );
    c->handle = handle;
    c->in_addr = *in_addr;
    c->socket = socket;
    c->rateToPeer = tr_rcInit( );
    c->rateToClient = tr_rcInit( );
    c->isIncoming = isIncoming ? 1 : 0;
    c->bufev = bufferevent_new( c->socket,
                                canReadWrapper,
                                didWriteWrapper,
                                gotErrorWrapper,
                                c );
    bufferevent_enable( c->bufev, EV_READ|EV_WRITE );
    return c;
}

tr_peerIo*
tr_peerIoNewIncoming( struct tr_handle  * handle,
                      struct in_addr    * in_addr,
                      int                 socket )
{
    tr_peerIo * c;

    assert( handle != NULL );
    assert( in_addr != NULL );
    assert( socket >= 0 );

    c = tr_peerIoNew( handle, in_addr, NULL, 1, socket );
    c->port = -1;
    return c;
}

tr_peerIo*
tr_peerIoNewOutgoing( struct tr_handle  * handle,
                      struct in_addr    * in_addr,
                      int                 port,
                      const uint8_t     * torrentHash )
{
    tr_peerIo * c;

    assert( handle != NULL );
    assert( in_addr != NULL );
    assert( port >= 0 );
    assert( torrentHash != NULL );

    c = tr_peerIoNew( handle, in_addr, torrentHash, 0,
                      tr_netOpenTCP( in_addr, port, 0 ) );
    c->port = port;
    return c;
}

void
tr_peerIoFree( tr_peerIo * c )
{
    if( c != NULL )
    {
        c->canRead = NULL;
        c->didWrite = NULL;
        c->gotError = NULL;
        tr_bufferevent_free( c->handle, c->bufev );
        tr_netClose( c->socket );

        tr_rcClose( c->rateToClient );
        tr_rcClose( c->rateToPeer );

        tr_cryptoFree( c->crypto );

        tr_free( c );
    }
}

tr_handle*
tr_peerIoGetHandle( tr_peerIo * io )
{
    assert( io != NULL );
    assert( io->handle != NULL );

    return io->handle;
}

const struct in_addr*
tr_peerIoGetAddress( const tr_peerIo * io, uint16_t * port )
{
    assert( io != NULL );

    if( port != NULL )
       *port = io->port;

    return &io->in_addr;
}

const char*
tr_peerIoGetAddrStr( const tr_peerIo * io )
{
    static char buf[512];
    assert( io != NULL );
    snprintf( buf, sizeof(buf), "%s:%u", inet_ntoa( io->in_addr ), (unsigned int)io->port );
    return buf;
}

void 
tr_peerIoSetIOFuncs( tr_peerIo          * io,
                     tr_can_read_cb       readcb,
                     tr_did_write_cb      writecb,
                     tr_net_error_cb      errcb,
                     void               * userData )
{
    io->canRead = readcb;
    io->didWrite = writecb;
    io->gotError = errcb;
    io->userData = userData;

    if( EVBUFFER_LENGTH( io->bufev->input ) )
        canReadWrapper( io->bufev, io );
}

void
tr_peerIoSetIOMode( tr_peerIo * c, short enable, short disable )
{
    tr_setBufferEventMode( c->handle, c->bufev, enable, disable );
}

int
tr_peerIoIsIncoming( const tr_peerIo * c )
{
    return c->isIncoming ? 1 : 0;
}

int
tr_peerIoReconnect( tr_peerIo * io )
{
    assert( !tr_peerIoIsIncoming( io ) );

    if( io->socket >= 0 )
        tr_netClose( io->socket );

    io->socket = tr_netOpenTCP( &io->in_addr, io->port, 0 );
  
    if( io->socket >= 0 )
    {
        bufferevent_free( io->bufev );

        io->bufev = bufferevent_new( io->socket,
                                     canReadWrapper,
                                     didWriteWrapper,
                                     gotErrorWrapper,
                                     io );
        bufferevent_enable( io->bufev, EV_READ|EV_WRITE );

        return 0;
    }
 
    return -1;
}

/**
***
**/

void
tr_peerIoSetTorrentHash( tr_peerIo     * io,
                         const uint8_t * hash )
{
    assert( io != NULL );

    tr_cryptoSetTorrentHash( io->crypto, hash );
}

const uint8_t*
tr_peerIoGetTorrentHash( tr_peerIo * io )
{
    assert( io != NULL );
    assert( io->crypto != NULL );

    return tr_cryptoGetTorrentHash( io->crypto );
}

int
tr_peerIoHasTorrentHash( const tr_peerIo * io )
{
    assert( io != NULL );
    assert( io->crypto != NULL );

    return tr_cryptoHasTorrentHash( io->crypto );
}

/**
***
**/

void
tr_peerIoSetPeersId( tr_peerIo     * io,
                     const uint8_t * peer_id )
{
    assert( io != NULL );

    if(( io->peerIdIsSet = peer_id != NULL ))
        memcpy( io->peerId, peer_id, 20 );
    else
        memset( io->peerId, 0, 20 );
}

const uint8_t* 
tr_peerIoGetPeersId( const tr_peerIo * io )
{
    assert( io != NULL );
    assert( io->peerIdIsSet );

    return io->peerId;
}

/**
***
**/

void
tr_peerIoSetExtension( tr_peerIo   * io,
                       int           extensions )
{
    assert( io != NULL );
    assert( ( extensions == LT_EXTENSIONS_NONE )
         || ( extensions == LT_EXTENSIONS_LTEP )
         || ( extensions == LT_EXTENSIONS_AZMP ) );

    io->extensions = extensions;
}

int
tr_peerIoGetExtension( const tr_peerIo * io )
{
    assert( io != NULL );

    return io->extensions;
}

/**
***
**/

size_t
tr_peerIoWriteBytesWaiting( const tr_peerIo * io )
{
    return EVBUFFER_LENGTH( EVBUFFER_OUTPUT( io->bufev ) );
}
 
void
tr_peerIoWrite( tr_peerIo   * io,
                const void  * writeme,
                int           writeme_len )
{
    tr_bufferevent_write( io->handle, io->bufev, writeme, writeme_len );
    tr_rcTransferred( io->rateToPeer, writeme_len );
}

void
tr_peerIoWriteBuf( tr_peerIo       * io,
                   struct evbuffer * buf )
{
    tr_peerIoWrite( io, EVBUFFER_DATA(buf), EVBUFFER_LENGTH(buf) );
    evbuffer_drain( buf, ~0 );
}

/**
***
**/

tr_crypto* 
tr_peerIoGetCrypto( tr_peerIo * c )
{
    return c->crypto;
}

void 
tr_peerIoSetEncryption( tr_peerIo * io,
                        int         encryptionMode )
{
    assert( io != NULL );
    assert( encryptionMode==PEER_ENCRYPTION_NONE || encryptionMode==PEER_ENCRYPTION_RC4 );

    io->encryptionMode = encryptionMode;
}

int
tr_peerIoIsEncrypted( const tr_peerIo * io )
{
    return io!=NULL && io->encryptionMode==PEER_ENCRYPTION_RC4;
}

void
tr_peerIoWriteBytes( tr_peerIo        * io,
                     struct evbuffer  * outbuf,
                     const void       * bytes,
                     int                byteCount )
{
    uint8_t * tmp;

    switch( io->encryptionMode )
    {
        case PEER_ENCRYPTION_NONE:
            /*fprintf( stderr, "writing %d plaintext bytes to outbuf...\n", byteCount );*/
            evbuffer_add( outbuf, bytes, byteCount );
            break;

        case PEER_ENCRYPTION_RC4:
            /*fprintf( stderr, "encrypting and writing %d bytes to outbuf...\n", byteCount );*/
            tmp = tr_new( uint8_t, byteCount );
            tr_cryptoEncrypt( io->crypto, byteCount, bytes, tmp );
            tr_bufferevent_write( io->handle, io->bufev, tmp, byteCount );
            tr_free( tmp );
            break;

        default:
            assert( 0 );
    }
}

void
tr_peerIoWriteUint16( tr_peerIo        * io,
                      struct evbuffer  * outbuf,
                      uint16_t           writeme )
{
    uint16_t tmp = htons( writeme );
    tr_peerIoWriteBytes( io, outbuf, &tmp, sizeof(uint16_t) );
}

void
tr_peerIoWriteUint32( tr_peerIo        * io,
                      struct evbuffer  * outbuf,
                      uint32_t           writeme )
{
    uint32_t tmp = htonl( writeme );
    tr_peerIoWriteBytes( io, outbuf, &tmp, sizeof(uint32_t) );
}

void
tr_peerIoReadBytes( tr_peerIo        * io,
                    struct evbuffer  * inbuf,
                    void             * bytes,
                    int                byteCount )
{
    assert( (int)EVBUFFER_LENGTH( inbuf ) >= byteCount );

    switch( io->encryptionMode )
    {
        case PEER_ENCRYPTION_NONE:
            /*fprintf( stderr, "reading %d plaintext bytes from inbuf...\n", byteCount );*/
            evbuffer_remove(  inbuf, bytes, byteCount );
            tr_rcTransferred( io->rateToClient, byteCount );
            break;

        case PEER_ENCRYPTION_RC4:
            /*fprintf( stderr, "reading AND DECRYPTING %d bytes from inbuf...\n", byteCount );*/
            evbuffer_remove(  inbuf, bytes, byteCount );
            tr_cryptoDecrypt( io->crypto, byteCount, bytes, bytes );
            tr_rcTransferred( io->rateToClient, byteCount );
            break;

        default:
            assert( 0 );
    }
}

void
tr_peerIoReadUint16( tr_peerIo         * io,
                     struct evbuffer   * inbuf,
                     uint16_t          * setme )
{
    uint16_t tmp;
    tr_peerIoReadBytes( io, inbuf, &tmp, sizeof(uint16_t) );
    *setme = ntohs( tmp );
}

void
tr_peerIoReadUint32( tr_peerIo         * io,
                     struct evbuffer   * inbuf,
                     uint32_t          * setme )
{
    uint32_t tmp;
    tr_peerIoReadBytes( io, inbuf, &tmp, sizeof(uint32_t) );
    *setme = ntohl( tmp );
}

void
tr_peerIoDrain( tr_peerIo        * io,
                struct evbuffer  * inbuf,
                int                byteCount )
{
    uint8_t * tmp = tr_new( uint8_t, byteCount );
    tr_peerIoReadBytes( io, inbuf, tmp, byteCount );
    tr_free( tmp );
}

/**
***
**/

float
tr_peerIoGetRateToClient( const tr_peerIo * io )
{
    return io==NULL ? 0.0f : tr_rcRate( io->rateToClient );

}

float
tr_peerIoGetRateToPeer( const tr_peerIo * io )
{
    return io==NULL ? 0.0f : tr_rcRate( io->rateToPeer );
}