/*  Tarlz - Archiver with multimember lzip compression
    Copyright (C) 2013-2018 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/>.
*/
/*
    Exit status: 0 for a normal exit, 1 for environmental problems
    (file not found, invalid flags, I/O errors, etc), 2 to indicate a
    corrupt or invalid input file, 3 for an internal consistency error
    (eg, bug) which caused tarlz to panic.
*/

#define _FILE_OFFSET_BITS 64

#include <cctype>
#include <cerrno>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <fcntl.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/stat.h>
#include <grp.h>
#include <pwd.h>
#if defined(__OS2__)
#include <io.h>
#endif

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

#ifndef O_BINARY
#define O_BINARY 0
#endif

#if CHAR_BIT != 8
#error "Environments where CHAR_BIT != 8 are not supported."
#endif

int verbosity = 0;

namespace {

const char * const Program_name = "Tarlz";
const char * const program_name = "tarlz";
const char * const program_year = "2018";
const char * invocation_name = 0;

enum Mode { m_none, m_append, m_create, m_extract, m_list };


void show_help()
  {
  std::printf( "%s - Archiver with multimember lzip compression.\n", Program_name );
  std::printf( "\nUsage: %s [options] [files]\n", invocation_name );
  std::printf( "\nOptions:\n"
               "  -h, --help                 display this help and exit\n"
               "  -V, --version              output version information and exit\n"
               "  -c, --create               create a new archive\n"
               "  -C, --directory=<dir>      change to directory <dir>\n"
               "  -f, --file=<archive>       use archive file <archive>\n"
               "  -q, --quiet                suppress all messages\n"
               "  -r, --append               append files to the end of an archive\n"
               "  -t, --list                 list the contents of an archive\n"
               "  -v, --verbose              verbosely list files processed\n"
               "  -x, --extract              extract files from an archive\n"
               "  -0 .. -9                   set compression level [default 6]\n"
               "      --asolid               create solidly compressed appendable archive\n"
               "      --dsolid               create per-directory compressed archive\n"
               "      --solid                create solidly compressed archive\n"
               "      --group=<group>        use <group> name/id for added files\n"
               "      --owner=<owner>        use <owner> name/id for added files\n"
               "      --uncompressed         don't compress the created archive\n"
               "\nExit status: 0 for a normal exit, 1 for environmental problems (file\n"
               "not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or\n"
               "invalid input file, 3 for an internal consistency error (eg, bug) which\n"
               "caused tarlz to panic.\n"
               "\nReport bugs to lzip-bug@nongnu.org\n"
               "Tarlz home page: http://www.nongnu.org/lzip/tarlz.html\n" );
  }


void show_version()
  {
  std::printf( "%s %s\n", program_name, PROGVERSION );
  std::printf( "Copyright (C) %s Antonio Diaz Diaz.\n", program_year );
  std::printf( "License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>\n"
               "This is free software: you are free to change and redistribute it.\n"
               "There is NO WARRANTY, to the extent permitted by law.\n" );
  }


unsigned long long getnum( const char * const ptr,
                           const unsigned long long llimit,
                           const unsigned long long ulimit )
  {
  char * tail;
  errno = 0;
  unsigned long long result = strtoull( ptr, &tail, 0 );
  if( tail == ptr )
    {
    show_error( "Bad or missing numerical argument.", 0, true );
    std::exit( 1 );
    }

  if( !errno && tail[0] )
    {
    const unsigned factor = ( tail[1] == 'i' ) ? 1024 : 1000;
    int exponent = 0;				// 0 = bad multiplier
    switch( tail[0] )
      {
      case 'Y': exponent = 8; break;
      case 'Z': exponent = 7; break;
      case 'E': exponent = 6; break;
      case 'P': exponent = 5; break;
      case 'T': exponent = 4; break;
      case 'G': exponent = 3; break;
      case 'M': exponent = 2; break;
      case 'K': if( factor == 1024 ) exponent = 1; break;
      case 'k': if( factor == 1000 ) exponent = 1; break;
      }
    if( exponent <= 0 )
      {
      show_error( "Bad multiplier in numerical argument.", 0, true );
      std::exit( 1 );
      }
    for( int i = 0; i < exponent; ++i )
      {
      if( ulimit / factor >= result ) result *= factor;
      else { errno = ERANGE; break; }
      }
    }
  if( !errno && ( result < llimit || result > ulimit ) ) errno = ERANGE;
  if( errno )
    {
    show_error( "Numerical argument out of limits." );
    std::exit( 1 );
    }
  return result;
  }


void set_mode( Mode & program_mode, const Mode new_mode )
  {
  if( program_mode != m_none && program_mode != new_mode )
    {
    show_error( "Only one operation can be specified.", 0, true );
    std::exit( 1 );
    }
  program_mode = new_mode;
  }


void set_owner( const char * const arg )
  {
  const struct passwd * const pw = getpwnam( arg );
  if( pw ) cl_owner = pw->pw_uid;
  else if( std::isdigit( arg[0] ) ) cl_owner = getnum( arg, 0, INT_MAX );
  else { show_file_error( arg, "Invalid owner" ); std::exit( 1 ); }
  }

void set_group( const char * const arg )
  {
  const struct group * const gr = getgrnam( arg );
  if( gr ) cl_group = gr->gr_gid;
  else if( std::isdigit( arg[0] ) ) cl_group = getnum( arg, 0, INT_MAX );
  else { show_file_error( arg, "Invalid group" ); std::exit( 1 ); }
  }

} // end namespace


int open_instream( const std::string & name )
  {
  const int infd = open( name.c_str(), O_RDONLY | O_BINARY );
  if( infd < 0 )
    show_file_error( name.c_str(), "Can't open for reading", errno );
  return infd;
  }


int open_outstream( const std::string & name, const bool create )
  {
  const int flags = (create ? O_CREAT | O_WRONLY | O_TRUNC : O_RDWR) | O_BINARY;
  const mode_t outfd_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;

  const int outfd = open( name.c_str(), flags, outfd_mode );
  if( outfd < 0 )
    show_file_error( name.c_str(), create ?
                     "Can't create file" : "Error opening file", errno );
  return outfd;
  }


/* Returns the number of bytes really read.
   If (returned value < size) and (errno == 0), means EOF was reached.
*/
int readblock( const int fd, uint8_t * const buf, const int size )
  {
  int sz = 0;
  errno = 0;
  while( sz < size )
    {
    const int n = read( fd, buf + sz, size - sz );
    if( n > 0 ) sz += n;
    else if( n == 0 ) break;				// EOF
    else if( errno != EINTR ) break;
    errno = 0;
    }
  return sz;
  }


/* Returns the number of bytes really written.
   If (returned value < size), it is always an error.
*/
int writeblock( const int fd, const uint8_t * const buf, const int size )
  {
  int sz = 0;
  errno = 0;
  while( sz < size )
    {
    const int n = write( fd, buf + sz, size - sz );
    if( n > 0 ) sz += n;
    else if( n < 0 && errno != EINTR ) break;
    errno = 0;
    }
  return sz;
  }


void show_error( const char * const msg, const int errcode, const bool help )
  {
  if( verbosity < 0 ) return;
  if( msg && msg[0] )
    std::fprintf( stderr, "%s: %s%s%s\n", program_name, msg,
                  ( errcode > 0 ) ? ": " : "",
                  ( errcode > 0 ) ? std::strerror( errcode ) : "" );
  if( help )
    std::fprintf( stderr, "Try '%s --help' for more information.\n",
                  invocation_name );
  }


void show_file_error( const char * const filename, const char * const msg,
                      const int errcode )
  {
  if( verbosity >= 0 )
    std::fprintf( stderr, "%s: %s: %s%s%s\n", program_name, filename, msg,
                  ( errcode > 0 ) ? ": " : "",
                  ( errcode > 0 ) ? std::strerror( errcode ) : "" );
  }


void internal_error( const char * const msg )
  {
  if( verbosity >= 0 )
    std::fprintf( stderr, "%s: internal error: %s\n", program_name, msg );
  std::exit( 3 );
  }


int main( const int argc, const char * const argv[] )
  {
  std::string archive_name;
  Mode program_mode = m_none;
  int level = 6;		// compression level, < 0 = uncompressed
  invocation_name = argv[0];

  enum { opt_aso = 256, opt_dso, opt_grp, opt_own, opt_sol, opt_un };
  const Arg_parser::Option options[] =
    {
    { '0',  0,                Arg_parser::no  },
    { '1',  0,                Arg_parser::no  },
    { '2',  0,                Arg_parser::no  },
    { '3',  0,                Arg_parser::no  },
    { '4',  0,                Arg_parser::no  },
    { '5',  0,                Arg_parser::no  },
    { '6',  0,                Arg_parser::no  },
    { '7',  0,                Arg_parser::no  },
    { '8',  0,                Arg_parser::no  },
    { '9',  0,                Arg_parser::no  },
    { 'c', "create",          Arg_parser::no  },
    { 'C', "directory",       Arg_parser::yes },
    { 'f', "file",            Arg_parser::yes },
    { 'h', "help",            Arg_parser::no  },
    { 'H', "format",          Arg_parser::yes },
    { 'q', "quiet",           Arg_parser::no  },
    { 'r', "append",          Arg_parser::no  },
    { 't', "list",            Arg_parser::no  },
    { 'v', "verbose",         Arg_parser::no  },
    { 'V', "version",         Arg_parser::no  },
    { 'x', "extract",         Arg_parser::no  },
    { opt_aso, "asolid",      Arg_parser::no  },
    { opt_dso, "dsolid",      Arg_parser::no  },
    { opt_grp, "group",       Arg_parser::yes },
    { opt_own, "owner",       Arg_parser::yes },
    { opt_sol, "solid",       Arg_parser::no  },
    { opt_un, "uncompressed", Arg_parser::no  },
    {  0 ,  0,                Arg_parser::no  } };

  const Arg_parser parser( argc, argv, options, true );
  if( parser.error().size() )				// bad option
    { show_error( parser.error().c_str(), 0, true ); return 1; }

  int filenames = 0;
  for( int argind = 0; argind < parser.arguments(); ++argind )
    {
    const int code = parser.code( argind );
    if( !code ) { ++filenames; continue; }		// skip non-options
    const std::string & sarg = parser.argument( argind );
    const char * const arg = sarg.c_str();
    switch( code )
      {
      case '0': case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
                level = code - '0'; break;
      case 'c': set_mode( program_mode, m_create ); break;
      case 'C': break;					// skip chdir
      case 'f': if( sarg != "-" ) archive_name = sarg; break;
      case 'h': show_help(); return 0;
      case 'H': break;					// ignore format
      case 'q': verbosity = -1; break;
      case 'r': set_mode( program_mode, m_append ); break;
      case 't': set_mode( program_mode, m_list ); break;
      case 'v': if( verbosity < 4 ) ++verbosity; break;
      case 'V': show_version(); return 0;
      case 'x': set_mode( program_mode, m_extract ); break;
      case opt_aso: cl_solid = 2; break;
      case opt_dso: cl_solid = 1; break;
      case opt_grp: set_group( arg ); break;
      case opt_own: set_owner( arg ); break;
      case opt_sol: cl_solid = 3; break;
      case opt_un: level = -1; break;
      default : internal_error( "uncaught option" );
      }
    } // end process options

#if defined(__MSVCRT__) || defined(__OS2__)
  setmode( STDIN_FILENO, O_BINARY );
  setmode( STDOUT_FILENO, O_BINARY );
#endif

  switch( program_mode )
    {
    case m_none: show_error( "Missing operation.", 0, true ); return 2;
    case m_append:
    case m_create: return encode( archive_name, parser, filenames, level,
                                  program_mode == m_append );
    case m_extract:
    case m_list:
      return decode( archive_name, parser, filenames, program_mode == m_list );
    }
  }