#!/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... :-/
#
# Format of a pattern to check for, one per line:
#   pattern := var_name : tool_pattern  OR  tool_pattern
#   tool_pattern := tool_test  OR  tool_pattern || tool_test
#   tool_test := tool=regexp OR tool
#   tool := basename of the tool  OR  absolute pathname to the tool
#   regexp := valid grep(1) extended regular expression, $( tool --version)
#             will be matched against this regexp.
#
# In case a pattern list is given (eg foo || bar || buz), then tests are performed
# from left to right, stopping at the first matching test (like the shell
# would parse 'foo || bar || buz' ).
#
# Examples:
#    bash:bash=^GNU bash, version 3\.
#     - if ${bash} is set and non-null, does nothing
#     - else ensures that bash exists in the PATH, and that $( bash --version )
#       matches the regexp '^GNU bash, version 3\.'
#       - if so, then sets bash="$( which bash )"
#    autoconf=(GNU Autoconf) || autoconf2.50
#     - does not look at an existing variable
#     - ensures that:
#         - 'autoconf' is to be found in the PATH, and that $( autoconf --version )
#           matches the regexp '(GNU Autoconf)' (which btw is the signature of
#           autoconf >= 2.50),
#       OR that:
#         - 'autoconf2.50' is to be found in the PATH
#
TOOLS_TO_CHECK='
bash:bash=^GNU bash, version [34]\.
cut
xargs
install:install=GNU coreutils
make:make=^GNU Make
gcc
awk:awk=^GNU Awk || gawk=^GNU Awk
bison
flex
makeinfo
automake=\(GNU automake\) (1\.[[:digit:]]{2,}\.|[2-9][[:digit:]]*\.)
libtool=\(GNU libtool.*\) (2[[:digit:]]*\.|1\.6[[:digit:]]*\.|1\.5\.[2-9][[:digit:]]+)
curl || wget
patch
tar
gzip
bzip2
'

PREFIX_DEFAULT=/usr/local

BINDIR_set=
LIBDIR_set=
DOCDIR_set=
MANDIR_set=
LOCAL_set=

do_quit=

# 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 test_pattern (see top of file, TOOLS_TO_CHECK, for
#                                   complete pattern format)
has_or_abort() {
    local save_IFS
    local var_name
    local var_value
    local tool_pattern
    local field

    var_name="$( echo "${1}" |"${sed}" -r -e 's/^(([^=:]+):.+|[^:=]+=.+|[^:=]+)$/\2/;' )"
    field="${var_name:+2}"
    field="${field:-1}"
    tool_pattern="$( echo "${1}" |cut -d : -f ${field}- |"${sed}" -r -e 's/ *\|\| */\n/g;' )"

    save_IFS="${IFS}"
    # Set IFS to \n only
    IFS='
'
    for item in ${tool_pattern}; do
        case "${item}" in
            *=*)
                tool="${item%%=*}"
                regexp="${item#*=}"
                ;;
            *)  tool="${item}"
                regexp=
                ;;
        esac

        printf "Checking for '${tool}'... "
        if [ -n "${var_name}" ]; then
            eval var_value='"${'"${var_name}"'}"'
            if [ -n "${var_value}" ]; then
                echo "${var_value} (cached)"
                return 0
            fi
        fi
        where=$( which "${tool}" 2>/dev/null )
        if [ -z "${where}" ]; then
            echo "not found"
            where=
            continue
        elif [ -n "${regexp}" ]; then
            tool_version=$( ${tool} --version 2>&1 )
            str=$( echo "${tool_version}" |"${grep}" -E "${regexp}" |head -n 1 )
            if [ -z "${str}" ]; then
                echo "not found"
                where=""
                continue
            fi
        fi
        break
    done
    if [ -z "${where}" ]; then
        for item in ${tool_pattern}; do
            case "${item}" in
                *=*)
                    tool="${item%%=*}"
                    regexp="${item#*=}"
                    ;;
                *)  tool="${item}"
                    regexp=
                    ;;
            esac
            printf "  could not find '${tool}'"
            [ -n "${regexp}" ] && printf " matching regexp '${regexp}'"
            echo
        done
        echo "Either you are missing entirely the needed tool,"
        echo "or the version you have is tool old."
        if [ -n "${var_name}" ]; then
            echo "You can give the path to this tool using: --with-${var_name}=PATH"
        fi
        # FORCE can be set in the environment
        [ -z "${FORCE}" ] && do_error "Bailing out..."
    else
        echo "${where}"
        if [ -n "${var_name}" ]; then
            eval ${var_name}='"'"${where}"'"'
        fi
    fi
    IFS="${save_IFS}"
    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(){
    case "$1" in
        --*=?*)
            echo "${1#*=}"
            return 0
            ;;
        *)
            echo "${2}"
            return 1
            ;;
    esac
}

# 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" "$2" )"
}
set_bindir() {
    BINDIR_set=1
    BINDIR="$( get_optval "$1" "$2" )"
}
set_libdir() {
    LIBDIR_set=1
    LIBDIR="$( get_optval "$1" "$2" )"
}
set_docdir() {
    DOCDIR_set=1
    DOCDIR="$( get_optval "$1" "$2" )"
}
set_mandir() {
    MANDIR_set=1
    MANDIR="$( get_optval "$1" "$2" )"
}
set_tool() {
    local var_name="${1%%=*}"
    var_name="${var_name#--with-}"
    eval ${var_name}="\$( get_optval "$1" "$2" )"
}

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

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-install=PATH     Specify the full PATH to GNU install
  --with-make=PATH        Specify the full PATH to GNU make
  --with-grep=PATH        Specify the full PATH to GNU grep
  --with-sed=PATH         Specify the full PATH to GNU sed
  --with-awk=PATH         Specify the full PATH to GNU awk
  --with-bash=PATH        Specify the full PATH to bash >= 3.0
__EOF__
}

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

while [ $# -ne 0 ]; do
    case "$1" in
        --local)    LOCAL_set=1; shift;;
        --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;;
        --with-*)   set_tool   "$1" "$2" && shift || shift 2;;
        --help|-h)  do_help; exit 0;;
        *)          echo "Unrecognised option: '${1}'"; 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

# We check for grep and sed manually, because they are used in has_or_abort
printf "Checking for 'grep'... "
if [ -n "${grep}" ]; then
    echo "${grep} (cached)"
else
    grep="$( which grep 2>/dev/null )"
    if [ -z "${grep}" ]; then
        echo "not found"
    else
        echo "${grep}"
        printf "Checking whether '${grep}' supports -E... "
        if echo 'foo' |"${grep}" -E 'foo' >/dev/null 2>&1; then
            echo "yes"
        else
            echo "no"
            grep=
        fi
    fi
fi
if [ -z "${grep}" ]; then
    echo "Either you are missing entirely the needed tool,"
    echo "or the version you have is tool old."
    echo "You can give the path to this tool using: --with-grep=PATH"
    do_error "Bailing out..."
fi

printf "Checking for 'sed'... "
if [ -n "${sed}" ]; then
    echo "${sed} (cached)"
else
    sed="$( which sed 2>/dev/null )"
    if [ -z "${sed}" ]; then
        echo "not found"
    else
        echo "${sed}"
        printf "Checking wether '${sed}' supports -i and -e... "
        touch .ct-ng.sed.test
        if "${sed}" -r -i -e 's/foo/bar/' .ct-ng.sed.test >/dev/null 2>&1; then
            echo "yes"
        else
            echo "no"
            sed=
        fi
        rm -f .ct-ng.sed.test
    fi
fi
if [ -z "${sed}" ]; then
    echo "Either you are missing entirely the needed tool,"
    echo "or the version you have is tool old."
    echo "You can give the path to this tool using: --with-sed=PATH"
    do_error "Bailing out..."
fi

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

#---------------------------------------------------------------------
# Compute the version string

# 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 "${VERSION}" in
    *+svn|svn)
        REVISION="$( 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="$( LC_ALL=C svn info 2>/dev/null      \
                         |"${grep}" '^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}"

#---------------------------------------------------------------------
# Compute and check install paths

# 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 that install PATHs are absolute
for p in BIN LIB DOC MAN; do
    var="${p}DIR"
    eval v='"${'"${var}"'}"'
    case "${v}" in
        /*) ;;
        *)  do_error "'${var}' is not an absolute path: '${v}'"
    esac
done

#---------------------------------------------------------------------
# That's all, folks!

printf "Building up Makefile... "
var_list="grep
          sed
          $( printf "${TOOLS_TO_CHECK}"                                 \
             |"${sed}" -r -e 's/^(([^=:]+):.+|[^:=]+=.+|[^:=]+)$/\2/;'
           )"
var_sed="$( for var_name in ${var_list}; do
                eval echo 's,@@${var_name}@@,${'"${var_name}"'},g'
            done 
          )"
"${sed}" -r -e "s,@@BINDIR@@,${BINDIR},g
                s,@@LIBDIR@@,${LIBDIR},g
                s,@@DOCDIR@@,${DOCDIR},g
                s,@@MANDIR@@,${MANDIR},g
                s,@@VERSION@@,${VERSION},g
                s,@@DATE@@,${DATE},g
                ${var_sed}
                s,@@LOCAL@@,${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}'

Now run:
  make
  make install
__EOF__