#!/usr/bin/env bash
export LC_ALL=C
set -e -o pipefail

# Check that environment variables assumed to be set by the environment are set
echo "Building for platform triple ${HOST:?not set} with reference timestamp ${SOURCE_DATE_EPOCH:?not set}..."
echo "At most ${MAX_JOBS:?not set} jobs will run at once..."

#####################
# Environment Setup #
#####################

# The depends folder also serves as a base-prefix for depends packages for
# $HOSTs after successfully building.
BASEPREFIX="${PWD}/depends"

# Setup an output directory for our build
OUTDIR="${OUTDIR:-${PWD}/output}"
[ -e "$OUTDIR" ] || mkdir -p "$OUTDIR"

# Setup the directory where our Bitcoin Core build for HOST will occur
DISTSRC="${DISTSRC:-${PWD}/distsrc-${HOST}}"
if [ -e "$DISTSRC" ]; then
    echo "DISTSRC directory '${DISTSRC}' exists, probably because of previous builds... Aborting..."
    exit 1
else
    mkdir -p "$DISTSRC"
fi

# Given a package name and an output name, return the path of that output in our
# current guix environment
store_path() {
    grep --extended-regexp "/[^-]{32}-${1}-[^-]+${2:+-${2}}" "${GUIX_ENVIRONMENT}/manifest" \
        | head --lines=1 \
        | sed --expression='s|^[[:space:]]*"||' \
              --expression='s|"[[:space:]]*$||'
}

# Determine output paths to use in CROSS_* environment variables
CROSS_GLIBC="$(store_path glibc-cross-${HOST})"
CROSS_GLIBC_STATIC="$(store_path glibc-cross-${HOST} static)"
CROSS_KERNEL="$(store_path linux-libre-headers-cross-${HOST})"
CROSS_GCC="$(store_path gcc-cross-${HOST})"
CROSS_GCC_LIBS=( "${CROSS_GCC}/lib/gcc/${HOST}"/* ) # This expands to an array of directories...
CROSS_GCC_LIB="${CROSS_GCC_LIBS[0]}" # ...we just want the first one (there should only be one)

# Set environment variables to point Guix's cross-toolchain to the right
# includes/libs for $HOST
#
# NOTE: CROSS_C_INCLUDE_PATH is missing ${CROSS_GCC_LIB}/include-fixed, because
# the limits.h in it is missing a '#include_next <limits.h>'
#
export CROSS_C_INCLUDE_PATH="${CROSS_GCC_LIB}/include:${CROSS_GLIBC}/include:${CROSS_KERNEL}/include"
export CROSS_CPLUS_INCLUDE_PATH="${CROSS_GCC}/include/c++:${CROSS_GCC}/include/c++/${HOST}:${CROSS_GCC}/include/c++/backward:${CROSS_C_INCLUDE_PATH}"
export CROSS_LIBRARY_PATH="${CROSS_GCC}/lib:${CROSS_GCC}/${HOST}/lib:${CROSS_GCC_LIB}:${CROSS_GLIBC}/lib:${CROSS_GLIBC_STATIC}/lib"

# Sanity check CROSS_*_PATH directories
IFS=':' read -ra PATHS <<< "${CROSS_C_INCLUDE_PATH}:${CROSS_CPLUS_INCLUDE_PATH}:${CROSS_LIBRARY_PATH}"
for p in "${PATHS[@]}"; do
    if [ ! -d "$p" ]; then
        echo "'$p' doesn't exist or isn't a directory... Aborting..."
        exit 1
    fi
done

# Disable Guix ld auto-rpath behavior
export GUIX_LD_WRAPPER_DISABLE_RPATH=yes

# Make /usr/bin if it doesn't exist
[ -e /usr/bin ] || mkdir -p /usr/bin

# Symlink file and env to a conventional path
[ -e /usr/bin/file ] || ln -s --no-dereference "$(command -v file)" /usr/bin/file
[ -e /usr/bin/env ]  || ln -s --no-dereference "$(command -v env)"  /usr/bin/env

# Determine the correct value for -Wl,--dynamic-linker for the current $HOST
glibc_dynamic_linker=$(
    case "$HOST" in
        i686-linux-gnu)      echo /lib/ld-linux.so.2 ;;
        x86_64-linux-gnu)    echo /lib64/ld-linux-x86-64.so.2 ;;
        arm-linux-gnueabihf) echo /lib/ld-linux-armhf.so.3 ;;
        aarch64-linux-gnu)   echo /lib/ld-linux-aarch64.so.1 ;;
        riscv64-linux-gnu)   echo /lib/ld-linux-riscv64-lp64d.so.1 ;;
        *)                   exit 1 ;;
    esac
)

# Environment variables for determinism
export QT_RCC_TEST=1
export QT_RCC_SOURCE_DATE_OVERRIDE=1
export TAR_OPTIONS="--owner=0 --group=0 --numeric-owner --mtime='@${SOURCE_DATE_EPOCH}' --sort=name"
export TZ="UTC"

####################
# Depends Building #
####################

# Build the depends tree, overriding variables that assume multilib gcc
make -C depends --jobs="$MAX_JOBS" HOST="$HOST" \
                                   ${V:+V=1} \
                                   ${SOURCES_PATH+SOURCES_PATH="$SOURCES_PATH"} \
                                   i686_linux_CC=i686-linux-gnu-gcc \
                                   i686_linux_CXX=i686-linux-gnu-g++ \
                                   i686_linux_AR=i686-linux-gnu-ar \
                                   i686_linux_RANLIB=i686-linux-gnu-ranlib \
                                   i686_linux_NM=i686-linux-gnu-nm \
                                   i686_linux_STRIP=i686-linux-gnu-strip \
                                   x86_64_linux_CC=x86_64-linux-gnu-gcc \
                                   x86_64_linux_CXX=x86_64-linux-gnu-g++ \
                                   x86_64_linux_AR=x86_64-linux-gnu-ar \
                                   x86_64_linux_RANLIB=x86_64-linux-gnu-ranlib \
                                   x86_64_linux_NM=x86_64-linux-gnu-nm \
                                   x86_64_linux_STRIP=x86_64-linux-gnu-strip \
                                   qt_config_opts_i686_linux='-platform linux-g++ -xplatform bitcoin-linux-g++'


###########################
# Source Tarball Building #
###########################

# Create the source tarball and move it to "${OUTDIR}/src" if not already there
if [ -z "$(find "${OUTDIR}/src" -name 'bitcoin-*.tar.gz')" ]; then
    ./autogen.sh
    env CONFIG_SITE="${BASEPREFIX}/${HOST}/share/config.site" ./configure --prefix=/
    make dist GZIP_ENV='-9n' ${V:+V=1}
    mkdir -p "${OUTDIR}/src"
    mv "$(find "${PWD}" -name 'bitcoin-*.tar.gz')" "${OUTDIR}/src/"
fi

# Determine the full path to our source tarball
SOURCEDIST="$(find "${OUTDIR}/src" -name 'bitcoin-*.tar.gz')"
# Determine our distribution name (e.g. bitcoin-0.18.0)
DISTNAME="$(basename "$SOURCEDIST" '.tar.gz')"

###########################
# Binary Tarball Building #
###########################

# Create a spec file to normalize ssp linking behaviour
spec_file="$(mktemp)"
cat << EOF > "$spec_file"
*link_ssp:
%{fstack-protector|fstack-protector-all|fstack-protector-strong|fstack-protector-explicit:}
EOF

# Similar flags to Gitian
CONFIGFLAGS="--enable-glibc-back-compat --enable-reduce-exports --disable-bench --disable-gui-tests"
HOST_CFLAGS="-O2 -g -specs=${spec_file} -ffile-prefix-map=${PWD}=."
HOST_CXXFLAGS="-O2 -g -specs=${spec_file} -ffile-prefix-map=${PWD}=."
HOST_LDFLAGS="-Wl,--as-needed -Wl,--dynamic-linker=$glibc_dynamic_linker -static-libstdc++"

# Make $HOST-specific native binaries from depends available in $PATH
export PATH="${BASEPREFIX}/${HOST}/native/bin:${PATH}"
(
    cd "$DISTSRC"

    # Extract the source tarball
    tar --strip-components=1 -xf "${SOURCEDIST}"

    # Configure this DISTSRC for $HOST
    # shellcheck disable=SC2086
    env CONFIG_SITE="${BASEPREFIX}/${HOST}/share/config.site" \
        ./configure --prefix=/ \
                    --disable-ccache \
                    --disable-maintainer-mode \
                    --disable-dependency-tracking \
                    ${CONFIGFLAGS} \
                    CFLAGS="${HOST_CFLAGS}" \
                    CXXFLAGS="${HOST_CXXFLAGS}" \
                    LDFLAGS="${HOST_LDFLAGS}"

    sed -i.old 's/-lstdc++ //g' config.status libtool src/univalue/config.status src/univalue/libtool

    # Build Bitcoin Core
    make --jobs="$MAX_JOBS" ${V:+V=1}

    # Perform basic ELF security checks on a series of executables.
    make -C src --jobs=1 check-security ${V:+V=1}
    # Check that executables only contain allowed gcc, glibc and libstdc++
    # version symbols for Linux distro back-compatibility.
    make -C src --jobs=1 check-symbols  ${V:+V=1}

    # Setup the directory where our Bitcoin Core build for HOST will be
    # installed. This directory will also later serve as the input for our
    # binary tarballs.
    INSTALLPATH="${PWD}/installed/${DISTNAME}"
    mkdir -p "${INSTALLPATH}"
    # Install built Bitcoin Core to $INSTALLPATH
    make install DESTDIR="${INSTALLPATH}" ${V:+V=1}
    (
        cd installed

        # Prune libtool and object archives
        find . -name "lib*.la" -delete
        find . -name "lib*.a" -delete

        # Prune pkg-config files
        rm -r "${DISTNAME}/lib/pkgconfig"

        # Split binaries and libraries from their debug symbols
        {
            find "${DISTNAME}/bin" -type f -executable -print0
            find "${DISTNAME}/lib" -type f -print0
        } | xargs -0 -n1 -P"$MAX_JOBS" -I{} "${DISTSRC}/contrib/devtools/split-debug.sh" {} {} {}.dbg

        cp "${DISTSRC}/doc/README.md" "${DISTNAME}/"

        # Finally, deterministically produce {non-,}debug binary tarballs ready
        # for release
        find "${DISTNAME}" -not -name "*.dbg" -print0 \
            | sort --zero-terminated \
            | tar --create --no-recursion --mode='u+rw,go+r-w,a+X' --null --files-from=- \
            | gzip -9n > "${OUTDIR}/${DISTNAME}-${HOST}.tar.gz" \
            || ( rm -f "${OUTDIR}/${DISTNAME}-${HOST}.tar.gz" && exit 1 )
        find "${DISTNAME}" -name "*.dbg" -print0 \
            | sort --zero-terminated \
            | tar --create --no-recursion --mode='u+rw,go+r-w,a+X' --null --files-from=- \
            | gzip -9n > "${OUTDIR}/${DISTNAME}-${HOST}-debug.tar.gz" \
            || ( rm -f "${OUTDIR}/${DISTNAME}-${HOST}-debug.tar.gz" && exit 1 )
    )
)