#!/bin/sh

myname="${0##*/}"

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

PREFIX_DEFAULT=/usr/local

BINDIR_set=
LIBDIR_set=
DOCDIR_set=
MANDIR_set=
LOCAL_set=
FORCE=

do_quit=

# Simply print the error message, and exit. Obvious, he?
do_error() {
    printf "${myname}: ${@}\n"
    exit 1
}

# 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 "$1" in
        --*=?*)
            printf "${1#*=}"
            return 0
            ;;
        *)
            printf "${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" )"
}

# var_list is a list of variables, each one holding a path to a
# tool, either detected by ./configure, or specified by the user.
var_list=""

# This function adds a variable name to the above list of variable names.
# $1: the name of the variable to add to the list
add_to_var_list() {
    var_list="${var_list} ${1}"
}

# A function to test for required tools/headers/libraries
# Return 0 (true) if found, !0 (false) if not found
#
# $*: [prog|inc|lib]=<name[ name...]>
#     the name(s) of tool(s) to test for
#     mandatory
#       eg: prog=bash   prog="curl wget"
# $*: var=<var_name>
#     the name of the variable to test and set
#     optional
#       eg: var=bash    if ${bash} is set and non-null, use that,
#                       else check for bash and set bash=$(which bash)
# $*: ver=<regexp>
#     for each 'prog', test if $(prog --version) matches 'regexp'
#     optional
#       eg: ver='^GNU bash, version [34]\.'
# $*: err=<error_message>
#     the error message to print if tool is missing
#     optional, defaults to: '${prog}: none found'
#       eg: err="'bash' 3.x or above was not found"
check_for() {
    local prog inc lib
    local var ver err
    local val
    local item
    local where
    local status

    for item in "${@}"; do
        case "${item}" in
            prog=*|inc=*|lib=*|var=*|ver=*|err=*)
                eval ${item%%=*}="'${item#*=}'"
                ;;
            *)  do_error "has_or_abort: incorrect parameters: '$@'";;
        esac
    done

    case "${prog}:${inc}:${lib}" in
        ?*::)
            for item in ${prog}; do
                printf "Checking for '${item}'... "
                if [ -n "${var}" ]; then
                    eval val="\${${var}}"
                    if [ -n "${val}" ]; then
                        printf "${val} (cached)\n"
                        add_to_var_list "${var}"
                        return 0
                    fi
                fi
                where="$( which "${item}" 2>/dev/null )"
                if [ -z "${where}" ]; then
                    printf "no\n"
                    continue
                elif [ -n "${ver}" ]; then
                    str=$( LC_ALL=C "${where}" --version 2>&1   \
                           |grep -E "${ver}"                    \
                           |head -n 1
                         )
                    if [ -z "${str}" ]; then
                        printf "no\n"
                        unset where
                        continue
                    fi
                fi
                status="${where}"
                break
            done
            ;;
        :?*:)
            for item in ${inc}; do
                printf "Checking for '${item}'... "
                if printf "#include \"${item}\"" |gcc -x c -c - -o /dev/null >/dev/null 2>&1; then
                    where="${item}"
                    status=yes
                    break;
                fi
                printf "no\n"
            done
            ;;
        ::?*)
            for item in ${lib}; do
                printf "Checking for '${item}'... "
                where="$( gcc -print-file-name="${item}" )"
                if [ "${where}" != "${item}" ]; then
                    where="$( readlink "${where}" )"
                    status=yes
                    break;
                fi
                printf "no\n"
            done
            ;;
    esac

    if [ -z "${status}" ]; then
        printf "\n${err:-${prog}${inc}${lib}: none found}\n\n"
        printf "Either you are missing entirely the needed tool,\n"
        printf "or the version you have is too old.\n"
        if [ -n "${var}" ]; then
            printf "You can give the path to this tool using: --with-${var}=PATH\n"
        fi
        printf "\n"
        return 1
    fi

    printf "${status}"
    if [ -n "${var}" ]; then
        eval ${var}='"'"${where}"'"'
        add_to_var_list "${var}"
    fi
    printf "\n"
}

# This function checks for a tool, and aborts if not found
# See check_for(), above, for how to call has_or_abort
has_or_abort() {
    if ! check_for "$@"; then
        # FORCE can be set in the environment
        [ -z "${FORCE}" ] && do_error "Bailing out..."
        printf "\n"
        printf "<*                                          *>\n"
        printf "<*            FORCE in action:              *>\n"
        printf "<* Continuing despite missing pre-requisite *>\n"
        printf "<*          Prepare for breakage            *>\n"
        printf "<*                                          *>\n"
        printf "\n"
    fi
}

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 continue, even in case
                          some pre-requisites are missing

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 >= 3.80
  --with-grep=PATH        Specify the full PATH to GNU grep
  --with-sed=PATH         Specify the full PATH to GNU sed
  --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="y"; 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" "$2" && shift || shift 2;;
        --force)    FORCE=1; shift;;
        --help|-h)  do_help; exit 0;;
        # Skip, auto-stuff compatibility
        --build=*|--host=*|--infodir=*|--datadir=*|--sysconfdir=*|--localstatedir=*) shift;;
        --build|--host|--infodir|--datadir|--sysconfdir|--localstatedir)             shift 2;;
        *)          printf "Unrecognised option: '${1}'\n"; do_help; exit 1;;
    esac
done

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

# Special case when installing locally
if [ "${LOCAL_set}" = "y" ]; then
    set_prefix "" "$( 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 check_for()
printf "Checking for 'grep'... "
if [ -n "${grep}" ]; then
    printf "${grep} (cached)\n"
else
    grep="$( which grep 2>/dev/null )"
    if [ -z "${grep}" ]; then
        printf "not found\n"
    else
        printf "${grep}\n"
        printf "Checking whether '${grep}' supports -E... "
        if echo 'foo' |"${grep}" -E 'foo' >/dev/null 2>&1; then
            printf "yes\n"
        else
            printf "no\n"
            grep=
        fi
    fi
fi
if [ -z "${grep}" ]; then
    printf "Either you are missing entirely the needed tool,\n"
    printf "or the version you have is too old.\n"
    printf "You can give the path to this tool using: --with-grep=PATH\n"
    do_error "Bailing out..."
fi
add_to_var_list grep

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

# The regular list of tools we can now easily check for
has_or_abort prog=bash                              \
             var=bash                               \
             ver='^GNU bash, version (3\.[1-9]|4)'  \
             err="'bash' 3.1 or above was not found"
has_or_abort prog=cut
has_or_abort prog=install var=install
has_or_abort prog=make                                  \
             var=make                                   \
             ver='^GNU Make (3.[89][[:digit:]]|[4-9])'  \
             err="GNU 'make' 3.80 or above was not found"
has_or_abort prog=gcc
has_or_abort prog="awk gawk" ver='^GNU Awk' err="GNU 'awk' was not found"
has_or_abort prog=bison
has_or_abort prog=flex
has_or_abort prog=makeinfo
has_or_abort prog=automake                                                      \
             ver='\(GNU automake\) (1\.[[:digit:]]{2,}|[2-9][[:digit:]]*\.)'    \
             err="'automake' 1.10 or above was not found"
has_or_abort prog=libtool                                                                           \
             var=libtool                                                                            \
             ver='\(GNU libtool.*\) (2[[:digit:]]*\.|1\.6[[:digit:]]*\.|1\.5\.[2-9][[:digit:]]+)'   \
             err="'libtool' 1.5.26 or above was not found"
has_or_abort prog=stat
has_or_abort prog="aria2c curl wget"
has_or_abort prog=cvs
has_or_abort prog=patch
has_or_abort prog=tar
has_or_abort prog=gzip
has_or_abort prog=bzip2
has_or_abort prog=lzma
has_or_abort prog=readlink
has_or_abort prog=objcopy var=objcopy
has_or_abort prog=objdump var=objdump
has_or_abort prog=readelf var=readelf
has_or_abort prog=patch var=patch

has_or_abort inc="ncurses/ncurses.h ncurses/curses.h ncurses.h curses.h"    \
             err="'ncurses' headers files were not found"

ncurses_libs="$( for l in ncursesw ncurses curses; do   \
                     for x in so a dylib; do            \
                         printf "lib$l.$x ";            \
                     done;                              \
                 done                                   \
               )"
has_or_abort lib="${ncurses_libs}"                  \
             err="'ncurses' library was not found"

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

# If this version is n hg clone, try to get the revision number
# If we can't get the revision number, use date
printf "Computing version string... "
case "${VERSION}" in
    *+hg|hg)
        REVISION="$( hg id -n 2>/dev/null || true )"
        case "${REVISION}" in
            "")
                VERSION="${VERSION}_unknown@$( date +%Y%m%d.%H%M%S )";;
            *)
                VERSION="${VERSION}_$( hg id -b )@${REVISION%%+}_$( hg id -i )"
                ;;
        esac
        # Arrange to have no / in the directory name, no need to create an
        # arbitrarily deep directory structure
        VERSION="$( printf "${VERSION}\n" |"${sed}" -r -e 's|/+|_|g;' )"
        ;;
esac
printf "${VERSION}\n"

#---------------------------------------------------------------------
# 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"
[ -z "${DOCDIR_set}" ] && DOCDIR="${PREFIX}/share/doc"
[ -z "${MANDIR_set}" ] && MANDIR="${PREFIX}/share/man"

# Install support files in our own sub-dir, so as not to mangle (system)
# files and dirs, but only if not --local
if [ -z "${LOCAL_set}" ]; then
    LIBDIR="${LIBDIR}/ct-ng-${VERSION}"
    DOCDIR="${DOCDIR}/ct-ng-${VERSION}"
fi

# 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_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
__EOF__
if [ "${LOCAL_set}" != "y" ]; then
    printf "  make install\n"
fi