#!/bin/bash
# Copyright © 2017 Hartmut Goebel <address@hidden>
# License: GNU Public License v3.0 or (at your choice) later

ARGS=$(getopt -o "C" -l "pure,container" -- "$@")
if [ $? -ne 0 ] ; then exit 1 ; fi # Bad arguments
eval set -- "$ARGS"

USE_CONTAINER=
PURE_ENV=

CONTAINER_PACKAGES="strace"  # gdb

while true ; do
    case "$1" in
	-C|--container)
	    shift;
	    USE_CONTAINER="yes" ;;
	--pure)
	    shift;
	    PURE_ENV="--pure" ;;
	--) shift ; break ;;
    esac
done


function package_from_path () {
    local pkg name version
    pkg=$(basename "$1")
    pkg=${pkg#guix-build-}
    pkg=${pkg%.drv-*}
    version=${pkg##*-}
    name=${pkg%-*}
    echo $name"@"$version
}


function oldest_dir () {
    find "$1/" -maxdepth 1 -mindepth 1 -type d 2>/dev/null | \
	xargs ls -tdr | head -1
}

function get_build_dir () {
    BUILD_DIR="${1}"
    if [ -d "${BUILD_DIR}" ] ; then
	echo $BUILD_DIR
    elif [ -z "${BUILD_DIR}" ] ; then
	ls -td {,/var}/tmp/guix-build-*.drv-* 2>/dev/null | head -1
	echo >&2 "No package name given, using $BUILD_DIR"
    elif [ "${BUILD_DIR#{,/var}/tmp/}" = "$BUILD_DIR" ] ; then
	ls -td {,/var}/tmp/guix-build-"$BUILD_DIR"-* 2>/dev/null | head -1
    else
	ls -td {,/var}/tmp/"$BUILD_DIR" 2>/dev/null | head -1
    fi
}

BUILD_DIR=$(get_build_dir "$1")
if [ ! -d "$BUILD_DIR" ] ; then
    echo >&2 "Not found: $1"
    exit 10
fi

# hG special: create a symlink from /var/tmp to /tmp
if [ "${BUILD_DIR#/var/tmp/}" != "$BUILD_DIR" ] ; then
    ln -s "$BUILD_DIR" /tmp 2>/dev/null
    CONTAINER_OPTIONS="CONTAINER_OPTIONS --share=$BUILD_DIR=${BUILD_DIR#/var}"
    BUILD_DIR=${BUILD_DIR#/var}
    #BUILD_DIR=/tmp/$(basename $BUILD_DIR)   
fi
echo "Using $BUILD_DIR"

pkg=$(package_from_path "$BUILD_DIR")


inifile=$BUILD_DIR/.guix-env-inifile
cat > $inifile <<EOF
echo "----------------- Starting init-file --------------"
cd $BUILD_DIR
source $BUILD_DIR/environment-variables
#set -x
PS1="[$pkg \W]\$ "
export PS1
cd $(oldest_dir $BUILD_DIR)
echo \$PWD
EOF

if [ -n "$USE_CONTAINER" ] ; then
    cat >> $inifile <<EOF
if [ "${BUILD_DIR#/var/tmp/}" != "$BUILD_DIR" ] ; then
    ln -s "$BUILD_DIR" /tmp
fi
#rm /bin/sh
echo "You may no want to run e.g.:"
echo "strace -f -o log make check"
PATH=\$GUIX_ENVIRONMENT/bin:\$PATH
exec /bin/sh
EOF
fi
#echo '------------' ; cat $inifile ; echo '------------'

if [ -n "$USE_CONTAINER" ] ; then
    if [ -x "$PWD/pre-inst-env" ] ; then
	d="$PWD"
    else
	d=$(dirname "$0")
    fi
    cd $BUILD_DIR
    $d/pre-inst-env guix environment --fallback -C $pkg \
	--no-grafts $CONTAINER_OPTIONS \
	--ad-hoc $CONTAINER_PACKAGES # -- /bin/sh $inifile
else
    env -i HOME=/tmp bash --noprofile --init-file $inifile
fi
rm -f $inifile