/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
   It is considered beerware. Prost. Skol. Cheers or whatever.

   $id$ */

#ifdef WANT_FULLSCRAPE

/* System */
#include <sys/param.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include <arpa/inet.h>
#ifdef WANT_COMPRESSION_GZIP
#include <zlib.h>
#endif

/* Libowfat */
#include "byte.h"
#include "io.h"
#include "textcode.h"

/* Opentracker */
#include "trackerlogic.h"
#include "ot_mutex.h"
#include "ot_iovec.h"
#include "ot_fullscrape.h"

/* Fetch full scrape info for all torrents
   Full scrapes usually are huge and one does not want to
   allocate more memory. So lets get them in 512k units
*/
#define OT_SCRAPE_CHUNK_SIZE (512*1024)

/* "d8:completei%zde10:downloadedi%zde10:incompletei%zdee" */
#define OT_SCRAPE_MAXENTRYLEN 256

/* Forward declaration */
static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tasktype mode );
#ifdef WANT_COMPRESSION_GZIP
static void fullscrape_make_gzip( int *iovec_entries, struct iovec **iovector, ot_tasktype mode );
#endif

/* Converter function from memory to human readable hex strings
   XXX - Duplicated from ot_stats. Needs fix. */
static char*to_hex(char*d,uint8_t*s){char*m="0123456789ABCDEF";char *t=d;char*e=d+40;while(d<e){*d++=m[*s>>4];*d++=m[*s++&15];}*d=0;return t;}

/* This is the entry point into this worker thread
   It grabs tasks from mutex_tasklist and delivers results back
*/
static void * fullscrape_worker( void * args ) {
  int iovec_entries;
  struct iovec *iovector;

  (void) args;

  while( g_opentracker_running ) {
    ot_tasktype tasktype = TASK_FULLSCRAPE;
    ot_taskid   taskid   = mutex_workqueue_poptask( &tasktype );
#ifdef WANT_COMPRESSION_GZIP
    if (tasktype & TASK_FLAG_GZIP)
        fullscrape_make_gzip( &iovec_entries, &iovector, tasktype );
    else
#endif
        fullscrape_make( &iovec_entries, &iovector, tasktype );
    if( mutex_workqueue_pushresult( taskid, iovec_entries, iovector ) )
      iovec_free( &iovec_entries, &iovector );
  }
  return NULL;
}

static pthread_t thread_id;
void fullscrape_init( ) {
  pthread_create( &thread_id, NULL, fullscrape_worker, NULL );
}

void fullscrape_deinit( ) {
  pthread_cancel( thread_id );
}

void fullscrape_deliver( int64 sock, ot_tasktype tasktype ) {
  mutex_workqueue_pushtask( sock, tasktype );
}

static char * fullscrape_write_one( ot_tasktype mode, char *r, ot_peerlist *peer_list, ot_hash *hash ) {
  switch( mode & TASK_TASK_MASK ) {
    case TASK_FULLSCRAPE:
    default:
      /* push hash as bencoded string */
      *r++='2'; *r++='0'; *r++=':';
      memcpy( r, hash, sizeof(ot_hash) ); r += sizeof(ot_hash);
      /* push rest of the scrape string */
      r += sprintf( r, "d8:completei%zde10:downloadedi%zde10:incompletei%zdee", peer_list->seed_count, peer_list->down_count, peer_list->peer_count-peer_list->seed_count );

      break;
    case TASK_FULLSCRAPE_TPB_ASCII:
      to_hex( r, *hash ); r+= 2 * sizeof(ot_hash);
      r += sprintf( r, ":%zd:%zd\n", peer_list->seed_count, peer_list->peer_count-peer_list->seed_count );
      break;
    case TASK_FULLSCRAPE_TPB_ASCII_PLUS:
      to_hex( r, *hash ); r+= 2 * sizeof(ot_hash);
      r += sprintf( r, ":%zd:%zd:%zd\n", peer_list->seed_count, peer_list->peer_count-peer_list->seed_count, peer_list->down_count );
      break;
    case TASK_FULLSCRAPE_TPB_BINARY:
      memcpy( r, *hash, sizeof(ot_hash) ); r += sizeof(ot_hash);
      *(uint32_t*)(r+0) = htonl( (uint32_t)  peer_list->seed_count );
      *(uint32_t*)(r+4) = htonl( (uint32_t)( peer_list->peer_count-peer_list->seed_count) );
      r+=8;
      break;
    case TASK_FULLSCRAPE_TPB_URLENCODED:
      r += fmt_urlencoded( r, (char *)*hash, 20 );
      r += sprintf( r, ":%zd:%zd\n", peer_list->seed_count, peer_list->peer_count-peer_list->seed_count );
      break;
    case TASK_FULLSCRAPE_TRACKERSTATE:
      to_hex( r, *hash ); r+= 2 * sizeof(ot_hash);
      r += sprintf( r, ":%zd:%zd\n", peer_list->base, peer_list->down_count );
      break;
    }
    return r;
}

static void fullscrape_make( int *iovec_entries, struct iovec **iovector, ot_tasktype mode ) {
  int      bucket;
  char    *r, *re;

  /* Setup return vector... */
  *iovec_entries = 0;
  *iovector = NULL;
  r = iovec_increase( iovec_entries, iovector, OT_SCRAPE_CHUNK_SIZE );
  if( !r )
    return;

  /* re points to low watermark */
  re = r + OT_SCRAPE_CHUNK_SIZE - OT_SCRAPE_MAXENTRYLEN;

  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE )
    r += sprintf( r, "d5:filesd" );

  /* For each bucket... */
  for( bucket=0; bucket<OT_BUCKET_COUNT; ++bucket ) {
    /* Get exclusive access to that bucket */
    ot_vector *torrents_list = mutex_bucket_lock( bucket );
    ot_torrent *torrents = (ot_torrent*)(torrents_list->data);
    size_t i;

    /* For each torrent in this bucket.. */
    for( i=0; i<torrents_list->size; ++i ) {
      r = fullscrape_write_one( mode, r, torrents[i].peer_list, &torrents[i].hash );

      if( r > re) {
        /* Allocate a fresh output buffer at the end of our buffers list */
        r = iovec_fix_increase_or_free( iovec_entries, iovector, r, OT_SCRAPE_CHUNK_SIZE );
        if( !r )
          return mutex_bucket_unlock( bucket, 0 );

        /* re points to low watermark */
        re = r + OT_SCRAPE_CHUNK_SIZE - OT_SCRAPE_MAXENTRYLEN;
      }
    }

    /* All torrents done: release lock on current bucket */
    mutex_bucket_unlock( bucket, 0 );

    /* Parent thread died? */
    if( !g_opentracker_running )
      return;
  }

  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE )
    r += sprintf( r, "ee" );

  /* Release unused memory in current output buffer */
  iovec_fixlast( iovec_entries, iovector, r );
}

#ifdef WANT_COMPRESSION_GZIP

static void fullscrape_make_gzip( int *iovec_entries, struct iovec **iovector, ot_tasktype mode ) {
  int      bucket;
  char    *r;
  int      zres;
  z_stream strm;

  /* Setup return vector... */
  *iovec_entries = 0;
  *iovector = NULL;
  r = iovec_increase( iovec_entries, iovector, OT_SCRAPE_CHUNK_SIZE );
  if( !r )
    return;

  byte_zero( &strm, sizeof(strm) );
  strm.next_out  = (uint8_t*)r;
  strm.avail_out = OT_SCRAPE_CHUNK_SIZE;
  if( deflateInit2(&strm,7,Z_DEFLATED,31,8,Z_DEFAULT_STRATEGY) != Z_OK )
    fprintf( stderr, "not ok.\n" );

  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE ) {
    strm.next_in   = (uint8_t*)"d5:filesd";
    strm.avail_in  = strlen("d5:filesd");
    zres = deflate( &strm, Z_NO_FLUSH );
  }

  /* For each bucket... */
  for( bucket=0; bucket<OT_BUCKET_COUNT; ++bucket ) {
    /* Get exclusive access to that bucket */
    ot_vector *torrents_list = mutex_bucket_lock( bucket );
    ot_torrent *torrents = (ot_torrent*)(torrents_list->data);
    size_t i;

    /* For each torrent in this bucket.. */
    for( i=0; i<torrents_list->size; ++i ) {
      char compress_buffer[OT_SCRAPE_MAXENTRYLEN];
      r = fullscrape_write_one( mode, compress_buffer, torrents[i].peer_list, &torrents[i].hash );
      strm.next_in   = (uint8_t*)compress_buffer;
      strm.avail_in  = r - compress_buffer;
      zres = deflate( &strm, Z_NO_FLUSH );
      if( ( zres < Z_OK ) && ( zres != Z_BUF_ERROR ) )
        fprintf( stderr, "deflate() failed while in fullscrape_make().\n" );

      /* Check if there still is enough buffer left */
      while( !strm.avail_out ) {
        /* Allocate a fresh output buffer at the end of our buffers list */
        r = iovec_fix_increase_or_free( iovec_entries, iovector, strm.next_out, OT_SCRAPE_CHUNK_SIZE );
        if( !r ) {
          fprintf( stderr, "Problem with iovec_fix_increase_or_free\n" );
          deflateEnd(&strm);
          return mutex_bucket_unlock( bucket, 0 );
        }
        strm.next_out  = (uint8_t*)r;
        strm.avail_out = OT_SCRAPE_CHUNK_SIZE;
        zres = deflate( &strm, Z_NO_FLUSH );
        if( ( zres < Z_OK ) && ( zres != Z_BUF_ERROR ) )
          fprintf( stderr, "deflate() failed while in fullscrape_make().\n" );
      }
    }

    /* All torrents done: release lock on current bucket */
    mutex_bucket_unlock( bucket, 0 );

    /* Parent thread died? */
    if( !g_opentracker_running )
      return;
  }

  if( ( mode & TASK_TASK_MASK ) == TASK_FULLSCRAPE ) {
    strm.next_in = (uint8_t*)"ee";
    strm.avail_in = strlen("ee");
  }

  if( deflate( &strm, Z_FINISH ) < Z_OK )
    fprintf( stderr, "deflate() failed while in fullscrape_make()'s endgame.\n" );

  if( !strm.avail_out ) {
    unsigned int pending;
    int bits;
    deflatePending( &strm, &pending, &bits);
    pending += ( bits ? 1 : 0 );

    /* Allocate a fresh output buffer at the end of our buffers list */
    r = iovec_fix_increase_or_free( iovec_entries, iovector, strm.next_out, pending );
    if( !r ) {
      fprintf( stderr, "Problem with iovec_fix_increase_or_free\n" );
      deflateEnd(&strm);
      return mutex_bucket_unlock( bucket, 0 );
    }
    strm.next_out  = (uint8_t*)r;
    strm.avail_out = pending;
    if( deflate( &strm, Z_FINISH ) < Z_OK )
      fprintf( stderr, "deflate() failed while in fullscrape_make()'s endgame.\n" );
  }

  /* Release unused memory in current output buffer */
  iovec_fixlast( iovec_entries, iovector, strm.next_out );

  deflateEnd(&strm);
}
/* WANT_COMPRESSION_GZIP */
#endif

/* WANT_FULLSCRAPE */
#endif
const char *g_version_fullscrape_c = "$Source$: $Revision$\n";