#!/bin/bash
#
# Copyright (C) 2020 Kyle Schwarz
#
# 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 3 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/>.
#

v_script="4git"
v_mingww64="8git"
v_binutils="2.35git"
v_gcc="10git"
v_gmp="6.2.1"
v_mpfr="4.1.0"
v_mpc="1.2.1"
v_isl="0.23"

show_help()
{
  cat <<HELP
usage: mingw-w64-build [OPTION]... ARCH...
Build the MinGW-w64 toolchain for ARCH(s) (i686 or x86_64).

  -h, --help         display this help and exit
  --version          output version information and exit
  --enable-pthreads  enable pthreads via winpthreads

Creates directories 'src' and 'bld' in the current directory and
  removes them when complete.

examples:
  mingw-w64-build i686
  mingw-w64-build x86_64
  mingw-w64-build i686 x86_64
HELP
}

show_version()
{
  cat <<VERSION
mingw-w64-build $v_script
Copyright (C) 2020 Kyle Schwarz
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
VERSION
}

error_exit()
{
  local error_text="$1"
  shift

  if [[ -z "$error_text" ]]; then
    error_text="See 'build.log' for further details."
  fi

  echo "mingw-w64-build: error: $error_text" >&3

  exit 1
}

clean_build()
{
  local build_dir="$1"

  rm -fr "$build_dir"
  mkdir -p "$build_dir"
  cd "$build_dir" || error_exit
}

download_sources()
{
  cd "$src" || error_exit

  echo "downloading mingw-w64" >&3
  git clone --depth 1 -b v8.x https://git.code.sf.net/p/mingw-w64/mingw-w64 mingw-w64-$v_mingww64 || error_exit

  echo "downloading binutils" >&3
  git clone --depth 1 -b binutils-2_35-branch git://sourceware.org/git/binutils-gdb.git binutils-$v_binutils || error_exit

  echo "downloading gcc" >&3
  git clone --depth 1 -b releases/gcc-10 git://gcc.gnu.org/git/gcc.git gcc-$v_gcc || error_exit

  local urls=(
    "https://ftp.gnu.org/gnu/gmp/gmp-$v_gmp.tar.xz"
    "https://ftp.gnu.org/gnu/mpfr/mpfr-$v_mpfr.tar.xz"
    "https://ftp.gnu.org/gnu/mpc/mpc-$v_mpc.tar.gz"
    "http://isl.gforge.inria.fr/isl-$v_isl.tar.xz"
  )

  for url in "${urls[@]}"; do
    local archive="${url##*/}"
    echo "downloading $archive" >&3
    curl -O "$url" || error_exit
    echo "extracting $archive" >&3
    tar -xf "$archive" || error_exit
  done

  cd "$src/gcc-$v_gcc" || error_exit

  ln -s "../gmp-$v_gmp" "gmp"
  ln -s "../mpfr-$v_mpfr" "mpfr"
  ln -s "../mpc-$v_mpc" "mpc"
  ln -s "../isl-$v_isl" "isl"
}

build_toolchain()
{
  local host="$1-w64-mingw32"
  local prefix="$wd/$host"
  export PATH="$prefix/bin:$PATH"

  if [[ "$1" = "i686" ]]; then
    i686_dwarf2="--disable-sjlj-exceptions --with-dwarf2"
  fi

  if [[ "$pthreads" = true ]]; then
    enable_threads="--enable-threads=posix"
  fi

  rm -fr "$prefix"

  clean_build "$bld/binutils"
  echo "configuring binutils" >&3
  "../../src/binutils-$v_binutils/configure" --prefix="$prefix" --disable-shared \
    --enable-static --with-sysroot="$prefix" --target="$host" \
    --disable-multilib --disable-nls --enable-lto --disable-werror || error_exit
  echo "building binutils" >&3
  make -j $cpus || error_exit
  echo "installing binutils" >&3
  make install || error_exit

  clean_build "$bld/mingw-w64"
  echo "configuring mingw-w64-headers" >&3
  "../../src/mingw-w64-$v_mingww64/mingw-w64-headers/configure" --build="$build" \
    --host="$host" --prefix="$prefix/$host" || error_exit
  echo "installing mingw-w64-headers" >&3
  make install || error_exit
  cd "$prefix" || error_exit
  ln -s "./$host" "./mingw" || error_exit

  clean_build "$bld/gcc"
  echo "configuring gcc" >&3
  "../../src/gcc-$v_gcc/configure" --target="$host" --disable-shared \
    --enable-static --disable-multilib --prefix="$prefix" $i686_dwarf2 \
    --enable-languages=c,c++ --disable-nls $enable_threads || error_exit
  echo "running 'make-gcc' for gcc" >&3
  make -j $cpus all-gcc || error_exit
  echo "running 'install-gcc' for gcc" >&3
  make install-gcc || error_exit

  clean_build "$bld/mingw-w64"
  echo "configuring mingw-w64-crt" >&3
  "../../src/mingw-w64-$v_mingww64/mingw-w64-crt/configure" --build="$build" --host="$host" \
    --prefix="$prefix/$host" --with-sysroot="$prefix/$host" || error_exit
  echo "building mingw-w64-crt" >&3
  make -j $cpus || error_exit
  echo "installing mingw-w64-crt" >&3
  make install || error_exit

  if [[ "$pthreads" = true ]]; then
    clean_build "$bld/winpthreads"
    echo "configuring winpthreads" >&3
    "../../src/mingw-w64-$v_mingww64/mingw-w64-libraries/winpthreads/configure" --build="$build" \
      --host="$host" --disable-shared --enable-static --prefix="$prefix/$host" || error_exit
    echo "building winpthreads" >&3
    make -j $cpus || error_exit
    echo "installing winpthreads" >&3
    make install || error_exit
  fi

  cd "$bld/gcc" || error_exit
  echo "building gcc" >&3
  make -j $cpus || error_exit
  echo "installing gcc" >&3
  make install || error_exit

  return 0
}

while :; do
  case $1 in
    -h|--help)
      show_help
      exit
      ;;
    --version)
      show_version
      exit
      ;;
    --enable-pthreads)
      pthreads=true
      ;;
    -?*)
      echo "mingw-w64-build: error: unknown option: '$1'" >&2
      exit
      ;;
    *)
      break
  esac

  shift
done

if [[ "$PWD" = *" "* ]]; then
  echo "mingw-w64-build: error: working path contains spaces" >&2
  exit 1
fi

if [[ -z "$@" ]]; then
  echo "mingw-w64-build: error: missing ARCH option" >&2
  echo "See 'mingw-w64-build --help' for build options." >&2
  exit 1
fi

for arch in $@; do
  if [[ "$arch" != "i686" ]] && [[ "$arch" != "x86_64" ]]; then
    echo "mingw-w64-build: error: invalid ARCH: '$arch'" >&2
    exit 1
  fi
done

progs=(
  "curl"
  "gzip"
  "bzip2"
  "git"
  "make"
  "g++"
  "tr"
  "tar"
  "svn"
  "flex"
  "bison"
  "makeinfo"
)
missing_progs=""
for prog in "${progs[@]}"; do
  if ! command -v $prog >/dev/null; then
    missing_progs="$prog $missing_progs"
  fi
done
if [[ -n "$missing_progs" ]]; then
  echo "mingw-w64-build: missing required program(s): $missing_progs" >&2
  exit 1
fi

cpus=$(grep -c processor /proc/cpuinfo 2>/dev/null || sysctl -n hw.ncpu | tr -d "\n" 2>/dev/null)
(( cpus += 2 ))
build=$(curl -s "http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD" | sh)
wd="$PWD"
src="$wd/src"
bld="$wd/bld"
log="$wd/bld/build.log"

rm -fr "$log" "$src" "$bld"
mkdir "$bld" "$src"
download_sources 3>&1 1>>"$log" 2>&1

for arch in $@; do
  build_toolchain "$arch" 3>&1 1>>"$log" 2>&1
done
rm -fr "$bld" "$src"

exit 0