#!/bin/sh

VERSION=$(cat .version)
DATE=$(date +%Y%m%d)

# All absolutely required tools, one per line to ease diff.
# See function 'has_or_abort, below, for syntax
#  - Hopefully, if gcc is present, then all associated tools will be
#  - awk must be GNU awk
#  - makeinfo for building docs, even if discarded later on
#  - others obvious... :-/
TOOLS_TO_CHECK='
make/^GNU
gcc
awk/^GNU
sed
bison
flex
makeinfo
automake
libtool
patch
tar
gzip
bzip2
'

PREFIX_DEFAULT=/usr/local

BINDIR_set=
LIBDIR_set=
DOCDIR_set=
MANDIR_set=
LOCAL_set=

FORCE=0

do_quit=
CONTRIB_list=

# Simply print the error message, and exit. Obvious, he?
do_error() {
    echo "${@}"
    exit 1
}

# A small function to test for existence of various tools
# Usage: has_or_abort foobar
#          -> foobar must exist in PATH
# Usage: has_or_abort foobar/string
#          -> foobar must exist in PATH, and $(foobar --version) must contain 'string'
has_or_abort() {
    tool=$(echo "${1}/" |cut -d / -f 1)
    regexp=$(echo "${1}/" |cut -d / -f 2)
    printf "Checking for '${tool}'... "
    where=$(which "${tool}" 2>/dev/null || true)
    if [ -z "${where}" ]; then
        printf "not found!"
        [ ${FORCE} -eq 0 ] && do_error " bailing out..."
        echo
    else
        printf "${where}"
        if [ -n "${regexp}" ]; then
            str=$(${tool} --version 2>&1 |egrep "${regexp}" |head -n 1)
            if [ -z "${str}" ]; then
                printf " failed: '${tool} --version' does not match regexp '${regexp}'"
                [ ${FORCE} -eq 0 ] && do_error " bailing out..."
            fi
        fi
        echo
    fi
    return 0
}

# Given an option string and the following argument,
# echoes the value of the option.
# If --var=val => echoes val and returns 0, meaning second arg was not consumed
# If --var val => echoes val and returns non null, meaning second arg was used
get_optval(){
    local ret
    case "$1" in
        --*=?*)
            echo "${1}" |cut -d '=' -f 2-
            ret=0
            ;;
        *)
            echo "${2}"
            ret=1
            ;;
    esac
    return ${ret}
}

# The set_xxx functions will set the corresponding configuration variable
# They return 0 if second arg was not consumed, and non-zero if it was consumed.
set_prefix() {
    PREFIX=$(get_optval "$1" "$2")
    return $?
}
set_bindir() {
    BINDIR_set=1
    BINDIR=$(get_optval "$1" "$2")
    return $?
}
set_libdir() {
    LIBDIR_set=1
    LIBDIR=$(get_optval "$1" "$2")
    return $?
}
set_docdir() {
    DOCDIR_set=1
    DOCDIR=$(get_optval "$1" "$2")
    return $?
}
set_mandir() {
    MANDIR_set=1
    MANDIR=$(get_optval "$1" "$2")
    return $?
}

# The set_contrib function is different in that it will work like the others,
# except in two cases:
# If all => replaces all with the list of all available contribs
# If list => just echoes the list of all available contribs, and instructs
# caller to quit immediately by setting do_quit to non null.
# (can't use the return code, see above).
set_contrib() {
    opt_val=$(get_optval "$1" "$2")
    local ret=$?
    case "${opt_val}" in
        all)
            CONTRIB_list=$(LC_ALL=C ls -1 contrib/*.patch.lzma  \
                           |xargs -I {} basename {} .patch.lzma \
                           |sed -r -e ':a; /$/N; s/\n/,/; ta;'
                          )
            ;;
        list)
            do_quit=1
            echo "Available contributions:"
            LC_ALL=C ls -1 contrib/*.patch.lzma     \
            |xargs -I {} basename {} .patch.lzma    \
            |sed -r -e 's/^/  /;'
            ;;
        *)  CONTRIB_list="${CONTRIB_list},${opt_val}";;
    esac
    return $ret
}

do_help() {
    cat <<__EOF__
\`configure' configures crosstool-NG ${VERSION} to adapt to many kind of systems.

USAGE: ./configure [OPTION]...

Defaults for the options are specified in brackets.

Configuration:
  -h, --help              display this help and exit                                                                                                                  
      --force             force ./configure to complete, even if one or more
                          tools were not found. Use at your own risk, only if
                          you know what you are doing!

Installation directories:
  --prefix=PREFIX         install files in PREFIX [${PREFIX_DEFAULT}]
  --local                 don't install, and use current directory

By default, \`make install' will install all the files in
\`${PREFIX_DEFAULT}/bin', \`${PREFIX_DEFAULT}/lib' etc.  You can specify
an installation prefix other than \`${PREFIX_DEFAULT}' using \`--prefix',
for instance \`--prefix=\${HOME}'.

For better control, use the options below.

Fine tuning of the installation directories:
  --bindir=DIR            user executables [PREFIX/bin]
  --libdir=DIR            object code libraries [PREFIX/lib]
  --docdir=DIR            info documentation [PREFIX/share/doc]
  --mandir=DIR            man documentation [PREFIX/share/man]

Optional Features:
  --with-contrib=XXX      Include externally contributed features found in the
                          contrib/ sub-directory. Set to a comma-separated list
                          of features. Use 'all' to use all contributions, and
                          'list' to see which are available.
__EOF__
}

#---------------------------------------------------------------------
# Set user's options

while [ $# -ne 0 ]; do
    case "$1" in
        --prefix*)  set_prefix "$1" "$2" && shift || shift 2;;
        --bindir*)  set_bindir "$1" "$2" && shift || shift 2;;
        --libdir*)  set_libdir "$1" "$2" && shift || shift 2;;
        --docdir*)  set_docdir "$1" "$2" && shift || shift 2;;
        --mandir*)  set_mandir "$1" "$2" && shift || shift 2;;
        --local)    LOCAL_set=1; shift;;
        --force)    FORCE=1; shift;;
        --with-contrib*)
                    set_contrib "$1" "$2" && shift || shift 2
                    [ "${do_quit}" = "1" ] && exit 0
                    ;;
        --help|-h)  do_help; exit 0;;
        *)          do_help; exit 1;;
    esac
done

# Use defaults
[ -z "${PREFIX}" ] && set_prefix "" "${PREFIX_DEFAULT}"

# Special case when installing locally
if [ "${LOCAL_set}" = "1" ]; then
    set_prefix "" $(pwd)
    set_bindir "" $(pwd)
    set_libdir "" $(pwd)
    set_docdir "" $(pwd)/docs
    set_mandir "" $(pwd)/docs
fi

#---------------------------------------------------------------------
# Some sanity checks, now

# If this version is a svn snapshot, try to get the revision number
# If we can't get the revision number, use date
printf "Computing version string... "
case "${VERSION}" in
  *+svn)
    REVISION=$(LC_ALL=C svnversion)
    case "${REVISION}" in
      exported)
        VERSION="${VERSION}unknown@$(date +%Y%m%d.%H%M%S)";;
      *)
        URL=$(LC_ALL=C svn info 2>/dev/null |egrep 'URL: ' |cut -d ' ' -f 2-)
        ROOT=$(LC_ALL=C svn info 2>/dev/null |egrep 'Repository Root: ' |cut -d ' ' -f 3-)
        VERSION="${VERSION}${URL#${ROOT}}@${REVISION}"
        ;;
    esac
    # Arrange to have no / in the directory name, no need to create an
    # arbitrarily deep directory structure
    VERSION=$(echo "${VERSION}" |sed -r -e 's|/+|_|g;')
    ;;
esac
echo "${VERSION}"

# Now we have the version string, we can build up the paths
[ -z "${BINDIR_set}" ] && BINDIR="${PREFIX}/bin"
[ -z "${LIBDIR_set}" ] && LIBDIR="${PREFIX}/lib/ct-ng-${VERSION}"
[ -z "${DOCDIR_set}" ] && DOCDIR="${PREFIX}/share/doc/ct-ng-${VERSION}"
[ -z "${MANDIR_set}" ] && MANDIR="${PREFIX}/share/man/man1"

# Check bash is present, and at least version 3.0
printf "Checking '/bin/bash' is at least bash-3.0... "
[ -x /bin/bash ] || do_error "bash 3.0 or above was not found in '/bin/bash'"
bash_version=$(/bin/bash -c 'echo ${BASH_VERSION}')
bash_major=$(/bin/bash -c 'echo ${BASH_VERSINFO[0]}')
[ ${bash_major} -ge 3 ] || do_error "bash 3.0 or above is needed ('/bin/bash' is '${bash_version}')"
echo "${bash_version}"

# Check the existence of absolutely required tools
for tool in ${TOOLS_TO_CHECK}; do
    has_or_abort "${tool}"
done

# It's safer to change all ',' to spaces rather than setting IFS
CONTRIB_list=$(echo "${CONTRIB_list}" |sed -r -e 's/,+/ /g;')
if [ -n "${CONTRIB_list}" ]; then
    has_or_abort lzcat
    printf "Applying contributed code: "
    for c in ${CONTRIB_list}; do
        printf "${c}, "
        if [ ! -f "contrib/${c}.patch.lzma" ]; then
            do_error "Contribution '${c}' does not exist"
        fi
        lzcat "contrib/${c}.patch.lzma" |patch -p1 >/dev/null 2>&1
    done
    echo "done"
fi

printf "Building up Makefile... "
sed -r -e "s,@@BINDIR@@,${BINDIR},g;"   \
       -e "s,@@LIBDIR@@,${LIBDIR},g;"   \
       -e "s,@@DOCDIR@@,${DOCDIR},g;"   \
       -e "s,@@MANDIR@@,${MANDIR},g;"   \
       -e "s,@@VERSION@@,${VERSION},g;" \
       -e "s,@@DATE@@,${DATE},g;"       \
       -e "s,@@LOCAL@@,${LOCAL_set},g;" \
       Makefile.in >Makefile
echo "done"

cat <<__EOF__

crosstool-NG configured as follows:
  PREFIX='${PREFIX}'
  BINDIR='${BINDIR}'
  LIBDIR='${LIBDIR}'
  DOCDIR='${DOCDIR}'
  MANDIR='${MANDIR}'
  CONTRIB='${CONTRIB_list}'
__EOF__