#!/bin/sh

# Thomas Esser, 1999, 2002, 2003. public domain.

# texlinks: script to maintain symlinks from format to engine. Interprets
# the lines given in fmtutil.cnf.

# History:
#   Tue Oct  9 14:23:01 BST 2007
#      Added unlink option (-u) to aid OpenBSD package uninstall
#      Edd Barrett <vext01@gmail.com>
#   Sun Aug 28 21:41:06 CEST 2005
#      remove special cases for csplain,cslatex,pdfcslatex,pdfcsplain
#   Fr Apr  8 19:15:05 CEST 2005
#      cleanup now has an argument for the return code
#   So Mär 27 18:52:06 CEST 2005
#       honor $TMPDIR, $TEMP and $TMP, not just $TMP
#   Mon May 10 20:52:48 CEST 2004
#       kpseaccess instead of access
#   Thu Dec 25 22:11:53 CET 2003, te:
#       add version string
#   Tue Apr  9 22:46:34 CEST 2002, te:
#       do not create symlinks for cont-??, metafun and mptopdf

test -f /bin/sh5 && test -z "$RUNNING_SH5" \
  && { UNAMES=`uname -s`; test "x$UNAMES" = xULTRIX; } 2>/dev/null \
  && { RUNNING_SH5=true; export RUNNING_SH5; exec /bin/sh5 $0 ${1+"$@"}; }
unset RUNNING_SH5

test -f /bin/bsh && test -z "$RUNNING_BSH" \
  && { UNAMES=`uname -s`; test "x$UNAMES" = xAIX; } 2>/dev/null \
  && { RUNNING_BSH=true; export RUNNING_BSH; exec /bin/bsh $0 ${1+"$@"}; }
unset RUNNING_BSH

export PATH

# hack around a bug in zsh:
test -n "${ZSH_VERSION+set}" && alias -g '${1+"$@"}'='"$@"'

cnf=fmtutil.cnf   # name of the config file
version=1192147136 # seconds since `00:00:00 1970-01-01 UTC'
                   # date '+%s' (with GNU date)
progname=texlinks

usage='Usage: texlinks [OPTION]... [DIRECTORY]...

Create symbolic links format -> engine according to fmtutil setup.

Mandatory arguments to long options are mandatory for short options too.
  -h, --help           show this help text
  --version            show version string
  -f, --cnffile FILE   use FILE as config file (default: fmtutil.cnf)
  -v, --verbose        enable verbose messages (default: off)
  -m, --multiplatform  operate in all platform specific directories
                        (default: operate only in directory for this platform)
  -s, --silent         silently skip existing scripts / binaries
                        (default: issue warning)
  -u, --unlink	       remove symlinks created by texlinks

The DIRECTORY arguments are an optional list of directories in which to
operate.  If no directories are specified the list of directories
depends on the --multiplatform option.

Report bugs to tex-k@tug.org.'

###############################################################################
# abort(errmsg)
#   print `errmsg' to stderr and exit with error code 1
###############################################################################
abort() { errmsg "texlinks: $1."; cleanup 1; }

# error message to stderr:
errmsg() { echo "$@" >&2; }

# give message to stderr only if "verbose" mode is on:
verbose_echo() { $verbose && errmsg "$@"; }

# in verbose mode: show command that is executed:
verbose_do() { verbose_echo "$@"; "$@"; }

###############################################################################
# cleanup()
#   clean up the temp area and exit with proper exit status
###############################################################################
cleanup()
{
  rc=$1
  $needsCleanup && test -n "$tmpdir" && test -d "$tmpdir" \
    && { rm -f "$tmpdir"/*; cd /; rmdir "$tmpdir"; }
  exit $rc
}

###############################################################################
# setupTmpDir()
#   set up a temp directory and a trap to remove it
###############################################################################
setupTmpDir()
{
  $needsCleanup && return

  trap 'cleanup 1' 1 2 3 7 13 15
  needsCleanup=true
  (umask 077; mkdir "$tmpdir") \
    || abort "could not create directory \`$tmpdir'"
}


# search a binary along $PATH:
check_for_binary()
{
  testbin=$1
  set x `echo "$PATH" | sed 's/^:/.:/; s/:$/:./; s/::/:.:/g; s/:/ /g'`; shift
  for i
  do
    if [ -x "$i/$testbin" ]; then
      echo "$i/$testbin"
      return 0
    fi
  done
  return 1
}


###############################################################################
# install_link(dest src)
#   create a symlink like ln -s dest src, but make sure that src is not
#   an existing binary
###############################################################################
install_link()
{
  # make symlink    src -> dest
  dest=$1; src=$2

  case $src in
    */mf)
      if test "$dest" = mf-nowin; then
        if test -f $selfautoloc/mfw; then
          dest=mfw  # name for windows-enabled mf, once upon a time
          verbose_echo "both mfw and mf-nowin exists, $src linked to $dest"
        fi
        if test -f $selfautoloc/mf && test -f $selfautoloc/mf-nowin; then
          # have both mf and mf-nowin binaries.  no link.
          verbose_echo "skipped metafont symlink $src -> $dest (special case)"
          return
        fi
      fi
      ;;
  esac

  case $src in
    */cont-??|*/metafun|*/mptopdf)
      verbose_echo "skipped ConTeXtish symlink $src -> $dest (special case)"
      ;;
    *)
      test "x$src" != "x`(ls -ld $src | awk '{print $NF}') 2>/dev/null`" &&
        verbose_do rm -f "$src"
  
      if test -f "$src"; then
        case $silent in
          true)
            ;;
          *)
            errmsg "install_link $src -> $dest failed: file already exists."
            ;;
        esac
      else
        verbose_do ln -s "$dest" "$src"
      fi
      ;;
   esac
}

###############################################################################
# search_symlinkdir()
#   look if $PATH has only symlinks to the real binaries and find that
#   directory. Also check if this directory is writable.
###############################################################################
search_symlinkdir()
{
  kpsewhich=`check_for_binary kpsewhich`
  test -z "$kpsewhich" && return 1
  symlinkdir=`echo $kpsewhich | sed 's@/*kpsewhich$@@'`
  kpseaccess -w "$symlinkdir" || return 1
  touch "$symlinkdir/tl$$"
  if test -f "$selfautoloc/tl$$"; then
    rm -f "$symlinkdir/tl$$"
    return 1
  else
    rm -f "$symlinkdir/tl$$"
    return 0
  fi
}

###############################################################################
# upd_symlinkdir()
#   if $PATH has only symlinks to the real binaries, update that directory
#   that holds the symlinks
###############################################################################
upd_symlinkdir()
{
  search_symlinkdir || return 0
  for i in `sed 's@ .*@@' cnf_file_ln.$$`; do
    install_link "$selfautoloc/$i" "$symlinkdir/$i"
  done
}

###############################################################################
# rm_link()
#   Delete a previously installed link
###############################################################################
rm_link()
{
  link=$1;
  if test -e $link; then
    if test -h $link; then
      verbose_do rm -Rf $link
    else
      verbose_echo "kept $link, since not a symlink"
    fi
  else
    verbose_echo "skipped $link, non-existent"
  fi
}

###############################################################################
# main()
#   parse commandline arguments, initialize variables,
#   switch into temp. direcrory, execute desired command
###############################################################################
main()
{
  cnf_file=    # global variable: full name of the config file
  dirs=
  needsCleanup=false

  multiplatform=false
  verbose=false
  unlink=false
  silent=false
  thisdir=`pwd`
  : ${KPSE_DOT=$thisdir}; export KPSE_DOT
  selfautoloc=`kpsewhich --expand-var='$SELFAUTOLOC'`
  while 
    case $1 in
      --h*|-h)
          echo "$usage"; exit 0;;
      --version)
          echo "$progname version $version."; exit 0;;
      --cnffile|-f)
          shift; cnf_file=$1;;
      --v*|-v) verbose=true;;
      --s*|-s) silent=true;;
      --m*|-m) multiplatform=true;;
      --u*|-u) unlink=true;;
      -*) errmsg "fmtutil: unknown option \`$1' ignored.";;
      *)  break;;
    esac
  do test $# -gt 0 && shift; done
  dirs="$*"

  # if no cnf_file from command-line, look it up with kpsewhich:
  test -z "$cnf_file" && cnf_file=`kpsewhich --format='web2c files' $cnf`
  test -f "$cnf_file" || abort "config file \`$cnf' not found"


  tmpdir=${TMPDIR-${TEMP-${TMP-/tmp}}}/texlinks.$$
  setupTmpDir
  cd "$tmpdir" || cleanup 1

  sed '/^[ 	]*#/d; /^[ 	]*$/d' $cnf_file \
    | awk '{print $1, $2}' > cnf_file_ln.$$

  if test -z "$dirs"; then
    if test $multiplatform = true; then
      case $selfautoloc in
        */bin) dirs=$selfautoloc;;
        *)     parent=`kpsewhich --expand-var='$SELFAUTODIR'`
               dirs=`find $parent -type f -name kpsewhich -print \
                       | sed 's@/kpsewhich$@@'`;;
      esac
    else
      dirs=$selfautoloc
    fi
  fi
  
  for d in $dirs; do
    kpseaccess -w $d \
      || { errmsg "$d: no write permissions. Skipping..."; continue; }
    # cnf_file_ln.$$ has lines with "format engine" pairs
    set x `cat cnf_file_ln.$$`; shift
    while test $# != 0; do
      fmt=$1; engine=$2; shift; shift

      # Some broken shells destroy the positional arguments when calling a
      # shellfunction. Therefore, we save and restore them "by hand" in the
      # main_args_while variable.
      main_args_while="$@"

      test "x$fmt" = "x$engine" && continue
      if test -f "$d/$engine"; then
        case $unlink in
        true)
          rm_link "$d/$fmt";;
        *)
          install_link "$engine" "$d/$fmt";;
        esac
      else
        verbose_echo "skipped $d/$engine, engine does not exist"
      fi

      # restore positional arguments:
      set x $main_args_while; shift

    done
  done
  upd_symlinkdir
}

main ${1+"$@"}

# set successful return code
cleanup 0
