#!/usr/bin/env bash

set -e

LD=
AR=
INSTALL=
infile=
outfile=
libdir=
bindir=
install=false
windowsdll=false
msvc=false
msvclibmode=false
libprefix=
libsuffix=
LIBS=

topdir=$(pwd)
tmpdir=$topdir/make-shared-from-static.$$

#trap "cd $topdir; rm -rf $tmpdir" 1 2 15

for arg
do
  case "$1" in
    --install)
      install=true
      shift
      if [ $# -gt 0 ]; then
        INSTALL="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --install option" 1>&2
        exit 1
      fi
    ;;
    --windowsdll)
      shift
      windowsdll=true
    ;;
    --msvc)
      shift
      msvc=true
    ;;
    --bindir)
      shift
      if [ $# -gt 0 ]; then
        bindir="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --bindir option" 1>&2
        exit 1
      fi
    ;;
    --libdir)
      shift
      if [ $# -gt 0 ]; then
        libdir="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --libdir option" 1>&2
        exit 1
      fi
    ;;
    --ld)
      shift
      if [ $# -gt 0 ]; then
        LD="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --ld option" 1>&2
        exit 1
      fi
    ;;
    --ar)
      shift
      if [ $# -gt 0 ]; then
        AR="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --ar option" 1>&2
        exit 1
      fi
    ;;
    --libprefix)
      shift
      if [ $# -gt 0 ]; then
        libprefix="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --libprefix option" 1>&2
        exit 1
      fi
    ;;
    --libsuffix)
      shift
      if [ $# -gt 0 ]; then
        libsuffix="$1"
        shift
      else
        echo "make-shared-from-static: expecting argument for --libsuffix option" 1>&2
        exit 1
      fi
    ;;
    -l*)
      LIBS="$LIBS $1"
      shift
    ;;
    *.a)
      if [ -z "$infile" ]; then
        case "$1" in
          /*)
            infile="$1"
          ;;
          *)
            infile=$(pwd)/$1
          ;;
        esac
        shift
      else
        echo "make-shared-from-static: only one input file allowed" 1>&2
        exit 1
      fi
    ;;
  esac
done

if [ -n "$infile" ]; then
  base_infile=$(basename $infile)
  if $windowsdll; then
    if $msvc; then
      base_name=`echo $base_infile | sed -n -e 's/^lib\(.*\)\.a$/\1/p'`
      outfile="${libprefix}${base_name}${libsuffix}.dll"
      implibfile="$base_name.lib"
      # Modern libtool won't create .a files, but will create directly .lib files.
      # If the .a file does not exist, check for an existing .lib file.
      if [ ! -f "$infile" ]; then
        msvc_infiles="`echo $infile | sed -e 's/\.a$/.lib/'` \
`dirname \"$infile\"`/`echo $base_infile | sed -e 's/\.a$/.lib/' -e 's/^lib//'`"
        for msvc_infile in $msvc_infiles; do
          if [ -f "$msvc_infile" ]; then
            infile="$msvc_infile"
            msvclibmode=true
            break
          fi
        done
      fi
    else
      outfile=$(echo $base_infile | sed 's/\.a$/.dll/')
      implibfile="$outfile.a"
    fi
  else
    outfile=$(echo $base_infile | sed 's/\.a$/.so/')
  fi
else
  echo "make-shared-from-static: no input file specified" 1>&2
  exit 1
fi

NM=nm
SED=sed
global_symbol_pipe="sed -n -e 's/^.*[	 ]\\([ABCDGIRSTW][ABCDGIRSTW]*\\)[	 ][	 ]*_\\([_A-Za-z][_A-iZa-z0-9]*\\)\\{0,1\\}\$/\\1 _\\2 \\2/p' | sed '/ __gnu_lto/d'"
# Ignore DATA symbols for now. They should be be properly exported from
# the source code using dllexport. They can't be re-exported manually like
# this using MSVC.
#export_symbols_cmds="\$NM \$libobjs \$convenience | \$global_symbol_pipe | \$SED -e '/^[BCDGRS][ ]/s/.*[ ]\\\\([^ ]*\\\\)/\\\\1,DATA/' | \$SED -e '/^[AITW][ ]/s/.*[ ]//' | sort | uniq >> \$export_symbols"
export_symbols_cmds="\$NM \$libobjs \$convenience | \$global_symbol_pipe | \$SED -e '/^[BCDGRS][ ]/d' | \$SED -e '/^[AITW][ ]/s/.*[ ]//' | sort | uniq >> \$export_symbols"

mkdir $tmpdir

(
  cd $tmpdir

  $msvclibmode || $AR x $infile

  LIBDIR_ARGS=
  if [ -n "$libdir" ]; then
    LIBDIR_ARGS="-L$libdir"
  fi

  if $windowsdll; then
    if $msvc; then
      export_symbols="$base_name.def"
      echo EXPORTS > $export_symbols
      if $msvclibmode; then
        libobjs="$infile"
      else
        libobjs="*.o"
      fi
      convenience=
      eval cmd=\"$export_symbols_cmds\"
      eval "$cmd"
      link_args="-Wl,-def:$export_symbols $libobjs"
    else
      link_args="-Wl,--export-all-symbols -Wl,--enable-auto-import -Wl,--enable-auto-image-base *.o"
    fi
    $LD -shared $link_args -Wl,--out-implib="$implibfile" -o "$outfile" $LIBDIR_ARGS $LIBS
  else
    $LD -shared -o $outfile *.o $LIBDIR_ARGS $LIBS
  fi

  if $install; then
    if $windowsdll; then
      $INSTALL -d "$libdir"
      $INSTALL -d "$bindir"
      $INSTALL -m755 "$implibfile" "$libdir/$implibfile"
      $INSTALL -m755 "$outfile" "$bindir/$outfile"
    else
      $INSTALL -d "$libdir"
      $INSTALL -m755 "$outfile" "$libdir/$outfile"
    fi
  fi
)

rm -rf $tmpdir