/* Tarlz - Archiver with multimember lzip compression
   Copyright (C) 2013-2022 Antonio Diaz Diaz.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#define _FILE_OFFSET_BITS 64

#include <cerrno>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <sys/stat.h>

#include "tarlz.h"
#include "arg_parser.h"


namespace {

enum { mode_string_size = 10,
       group_string_size = 1 + uname_l + 1 + gname_l + 1 };	// 67

void format_mode_string( const Tar_header header, char buf[mode_string_size] )
  {
  const Typeflag typeflag = (Typeflag)header[typeflag_o];

  std::memcpy( buf, "----------", mode_string_size );
  switch( typeflag )
    {
    case tf_regular: break;
    case tf_link: buf[0] = 'h'; break;
    case tf_symlink: buf[0] = 'l'; break;
    case tf_chardev: buf[0] = 'c'; break;
    case tf_blockdev: buf[0] = 'b'; break;
    case tf_directory: buf[0] = 'd'; break;
    case tf_fifo: buf[0] = 'p'; break;
    case tf_hiperf: buf[0] = 'C'; break;
    default: buf[0] = '?';
    }
  const mode_t mode = parse_octal( header + mode_o, mode_l );	// 12 bits
  const bool setuid = mode & S_ISUID;
  const bool setgid = mode & S_ISGID;
  const bool sticky = mode & S_ISVTX;
  if( mode & S_IRUSR ) buf[1] = 'r';
  if( mode & S_IWUSR ) buf[2] = 'w';
  if( mode & S_IXUSR ) buf[3] = setuid ? 's' : 'x';
  else if( setuid ) buf[3] = 'S';
  if( mode & S_IRGRP ) buf[4] = 'r';
  if( mode & S_IWGRP ) buf[5] = 'w';
  if( mode & S_IXGRP ) buf[6] = setgid ? 's' : 'x';
  else if( setgid ) buf[6] = 'S';
  if( mode & S_IROTH ) buf[7] = 'r';
  if( mode & S_IWOTH ) buf[8] = 'w';
  if( mode & S_IXOTH ) buf[9] = sticky ? 't' : 'x';
  else if( sticky ) buf[9] = 'T';
  }


int format_user_group_string( const Tar_header header,
                              char buf[group_string_size] )
  {
  int len;
  if( header[uname_o] && header[gname_o] )
    len = snprintf( buf, group_string_size,
                    " %.32s/%.32s", header + uname_o, header + gname_o );
  else
    {
    const unsigned uid = parse_octal( header + uid_o, uid_l );
    const unsigned gid = parse_octal( header + gid_o, gid_l );
    len = snprintf( buf, group_string_size, " %u/%u", uid, gid );
    }
  return len;
  }


// return true if dir is a parent directory of name
bool compare_prefix_dir( const char * const dir, const char * const name )
  {
  int len = 0;
  while( dir[len] && dir[len] == name[len] ) ++len;
  return ( !dir[len] && len > 0 && ( dir[len-1] == '/' || name[len] == '/' ) );
  }


// compare two file names ignoring trailing slashes
bool compare_tslash( const char * const name1, const char * const name2 )
  {
  const char * p = name1;
  const char * q = name2;
  while( *p && *p == *q ) { ++p; ++q; }
  while( *p == '/' ) ++p;
  while( *q == '/' ) ++q;
  return ( !*p && !*q );
  }

} // end namespace


bool block_is_zero( const uint8_t * const buf, const int size )
  {
  for( int i = 0; i < size; ++i ) if( buf[i] != 0 ) return false;
  return true;
  }


bool format_member_name( const Extended & extended, const Tar_header header,
                         Resizable_buffer & rbuf, const bool long_format )
  {
  if( long_format )
    {
    format_mode_string( header, rbuf() );
    const int group_string_len =
      format_user_group_string( header, rbuf() + mode_string_size );
    int offset = mode_string_size + group_string_len;
    const time_t mtime = parse_octal( header + mtime_o, mtime_l ); // 33 bits
    struct tm tms;
    const struct tm * tm = localtime_r( &mtime, &tms );
    if( !tm )
      { time_t z = 0; tm = localtime_r( &z, &tms ); if( !tm ) tm = &tms; }
    const Typeflag typeflag = (Typeflag)header[typeflag_o];
    const bool islink = ( typeflag == tf_link || typeflag == tf_symlink );
    const char * const link_string = !islink ? "" :
                         ( ( typeflag == tf_link ) ? " link to " : " -> " );
    if( typeflag == tf_chardev || typeflag == tf_blockdev )
      offset += snprintf( rbuf() + offset, rbuf.size() - offset, " %5u,%u",
                  (unsigned)parse_octal( header + devmajor_o, devmajor_l ),
                  (unsigned)parse_octal( header + devminor_o, devminor_l ) );
    else
      offset += snprintf( rbuf() + offset, rbuf.size() - offset, " %9llu",
                          extended.file_size() );
    for( int i = 0; i < 2; ++i )	// resize rbuf if not large enough
      {
      const int len = snprintf( rbuf() + offset, rbuf.size() - offset,
                " %4d-%02u-%02u %02u:%02u %s%s%s\n",
                1900 + tm->tm_year, 1 + tm->tm_mon, tm->tm_mday,
                tm->tm_hour, tm->tm_min, extended.path().c_str(),
                link_string, islink ? extended.linkpath().c_str() : "" );
      if( (int)rbuf.size() > len + offset ) break;
      if( !rbuf.resize( len + offset + 1 ) ) return false;
      }
    }
  else
    {
    if( rbuf.size() < extended.path().size() + 2 &&
        !rbuf.resize( extended.path().size() + 2 ) ) return false;
    snprintf( rbuf(), rbuf.size(), "%s\n", extended.path().c_str() );
    }
  return true;
  }


bool show_member_name( const Extended & extended, const Tar_header header,
                       const int vlevel, Resizable_buffer & rbuf )
  {
  if( verbosity >= vlevel )
    {
    if( !format_member_name( extended, header, rbuf, verbosity > vlevel ) )
      { show_error( mem_msg ); return false; }
    std::fputs( rbuf(), stdout );
    std::fflush( stdout );
    }
  return true;
  }


bool check_skip_filename( const Cl_options & cl_opts,
                          std::vector< char > & name_pending,
                          const char * const filename )
  {
  if( Exclude::excluded( filename ) ) return true;	// skip excluded files
  bool skip = cl_opts.num_files > 0;
  if( skip )
    for( int i = 0; i < cl_opts.parser.arguments(); ++i )
      if( nonempty_arg( cl_opts.parser, i ) )
        {
        const char * const name =
          remove_leading_dotslash( cl_opts.parser.argument( i ).c_str() );
        if( compare_prefix_dir( name, filename ) ||
            compare_tslash( name, filename ) )
          { skip = false; name_pending[i] = false; break; }
        }
  return skip;
  }


mode_t get_umask()
  {
  static mode_t mask = 0;		// read once, cache the result
  static bool first_call = true;
  if( first_call ) { first_call = false; mask = umask( 0 ); umask( mask );
                     mask &= S_IRWXU | S_IRWXG | S_IRWXO; }
  return mask;
  }


bool make_path( const std::string & name )
  {
  const mode_t mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
  unsigned end = name.size();	// first slash before last component

  while( end > 0 && name[end-1] == '/' ) --end;	// remove trailing slashes
  while( end > 0 && name[end-1] != '/' ) --end;	// remove last component
  while( end > 0 && name[end-1] == '/' ) --end;	// remove more slashes

  unsigned index = 0;
  while( index < end )
    {
    while( index < end && name[index] == '/' ) ++index;
    unsigned first = index;
    while( index < end && name[index] != '/' ) ++index;
    if( first < index )
      {
      const std::string partial( name, 0, index );
      struct stat st;
      if( stat( partial.c_str(), &st ) == 0 )
        { if( !S_ISDIR( st.st_mode ) ) return false; }
      else if( mkdir( partial.c_str(), mode ) != 0 && errno != EEXIST )
        return false;
      }
    }
  return true;
  }