#!/bin/bash
#
# build static bash because we need exercises in minimalism
# Copyright © 2015 Robert Xu <robxu9@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# For Linux, also builds musl for truly static linking if
# musl is not installed.

set -e
set -o pipefail
shopt -s nullglob

# load version info
# shellcheck source=./version.sh
. version.sh

target="$1"
arch="$2"

if [[ "$target" == "" ]]; then
  echo "! no target specified" >&2
  exit 1
fi

if [[ "$arch" == "" ]]; then
  echo "! no arch specified" >&2
  exit 1
fi

if [ -d build ]; then
  echo "= removing previous build directory"
  rm -rf build
fi

mkdir build # make build directory
pushd build

# pre-prepare gpg for verificaiton
echo "= preparing gpg"
GNUPGHOME="$(mktemp -d)"
export GNUPGHOME
# public key for bash
gpg --batch --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys 7C0135FB088AAF6C66C650B9BB5869F064EA74AB
# public key for musl
gpg --batch --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys 836489290BB6B70F99FFDA0556BCDB593020450F

# download tarballs
echo "= downloading bash"
curl -LO http://ftp.gnu.org/gnu/bash/bash-${bash_version}.tar.gz
curl -LO http://ftp.gnu.org/gnu/bash/bash-${bash_version}.tar.gz.sig
gpg --batch --verify bash-${bash_version}.tar.gz.sig bash-${bash_version}.tar.gz

echo "= extracting bash"
tar -xf bash-${bash_version}.tar.gz

echo "= patching bash"
bash_patch_prefix=$(echo "bash${bash_version}" | sed -e 's/\.//g')
for lvl in $(seq 1 $bash_patch_level); do
    curl -LO http://ftp.gnu.org/gnu/bash/bash-${bash_version}-patches/"${bash_patch_prefix}"-"$(printf '%03d' "$lvl")"
    curl -LO http://ftp.gnu.org/gnu/bash/bash-${bash_version}-patches/"${bash_patch_prefix}"-"$(printf '%03d' "$lvl")".sig
    gpg --batch --verify "${bash_patch_prefix}"-"$(printf '%03d' "$lvl")".sig "${bash_patch_prefix}"-"$(printf '%03d' "$lvl")"

    pushd bash-${bash_version}
    patch -p0 < ../"${bash_patch_prefix}"-"$(printf '%03d' "$lvl")"
    popd
done

echo "= patching with any custom patches we have"
for i in ../custom/*.patch; do
    echo $i
    pushd bash-${bash_version}
    patch -p1 < ../"$i"
    popd
done

configure_args=()

if [ "$target" = "linux" ]; then
  if [ "$(grep ID= < /etc/os-release | head -n1)" = "ID=alpine" ]; then
    echo "= skipping installation of musl because this is alpine linux (and it is already installed)"
  else
    echo "= downloading musl"
    curl -LO https://musl.libc.org/releases/musl-${musl_version}.tar.gz
    curl -LO https://musl.libc.org/releases/musl-${musl_version}.tar.gz.asc
    gpg --batch --verify musl-${musl_version}.tar.gz.asc musl-${musl_version}.tar.gz

    echo "= extracting musl"
    tar -xf musl-${musl_version}.tar.gz

    echo "= building musl"
    working_dir=$(pwd)

    install_dir=${working_dir}/musl-install

    pushd musl-${musl_version}
    ./configure --prefix="${install_dir}"
    make install
    popd # musl-${musl-version}

    echo "= setting CC to musl-gcc"
    export CC=${working_dir}/musl-install/bin/musl-gcc
  fi
  export CFLAGS="-static"
else
  echo "= WARNING: your platform does not support static binaries."
  echo "= (This is mainly due to non-static libc availability.)"
  if [[ $target == "macos" ]]; then
    # set minimum version of macOS to 10.13
    export MACOSX_DEPLOYMENT_TARGET="10.13"
    # https://www.gnu.org/software/bash/manual/html_node/Compilers-and-Options.html
    export CC="clang -std=c89 -Wno-implicit-function-declaration -Wno-return-type"

    # use included gettext to avoid reading from other places, like homebrew
    configure_args=("${configure_args[@]}" "--with-included-gettext")

    # if $arch is aarch64 for mac, target arm64e
    if [[ $arch == "aarch64" ]]; then
      export CFLAGS="-target arm64-apple-macos"
      configure_args=("${configure_args[@]}" "--host=aarch64-apple-darwin")
    else
      export CFLAGS="-target x86_64-apple-macos10.12"
      configure_args=("${configure_args[@]}" "--host=x86_64-apple-macos10.12")
    fi
  fi
fi

echo "= building bash"

pushd bash-${bash_version}
autoconf -f
CFLAGS="$CFLAGS -Os" ./configure --without-bash-malloc "${configure_args[@]}"
make
make tests
popd # bash-${bash_version}

popd # build

if [ ! -d releases ]; then
  mkdir releases
fi

echo "= extracting bash binary"
cp build/bash-${bash_version}/bash releases

echo "= done"