#!/bin/sh
#
# This code is licensed under the GPL version 2 or later.  See
# the COPYING file in the top-level directory.

substat=".git-submodule-status"

command=$1
shift
maybe_modules="$@"

test -z "$maybe_modules" && exit 0
test -z "$GIT" && GIT=$(command -v git)

cd "$(dirname "$0")/.."

no_git_error=
if ! test -e ".git"; then
    no_git_error='no git checkout exists'
elif test -z "$GIT"; then
    no_git_error='git binary not found'
fi

is_git() {
    test -z "$no_git_error"
}

update_error() {
    echo "$0: $*"
    echo
    echo "Unable to automatically checkout GIT submodules '$modules'."
    echo "If you require use of an alternative GIT binary (for example to"
    echo "enable use of a transparent proxy), please disable automatic"
    echo "GIT submodule checkout with:"
    echo
    echo " $ ./configure --disable-download"
    echo
    echo "and then manually update submodules prior to running make, with:"
    echo
    echo " $ GIT='tsocks git' scripts/git-submodule.sh update $modules"
    echo
    exit 1
}

validate_error() {
    if is_git && test "$1" = "validate"; then
        echo "GIT submodules checkout is out of date, and submodules"
        echo "configured for validate only. Please run"
        echo "  scripts/git-submodule.sh update $maybe_modules"
        echo "from the source directory or call configure with"
        echo "  --enable-download"
    fi
    exit 1
}

check_updated() {
    local CURSTATUS OLDSTATUS
    CURSTATUS=$($GIT submodule status $module)
    OLDSTATUS=$(grep $module $substat)
    test "$CURSTATUS" = "$OLDSTATUS"
}

if is_git; then
    test -e $substat || touch $substat
    modules=""
    for m in $maybe_modules
    do
        $GIT submodule status $m 1> /dev/null 2>&1
        if test $? = 0
        then
            modules="$modules $m"
            grep $m $substat > /dev/null 2>&1 || $GIT submodule status $module >> $substat
        else
            echo "warn: ignoring non-existent submodule $m"
        fi
    done
else
    modules=$maybe_modules
fi

case "$command" in
status|validate)
    for module in $modules; do
        if is_git; then
            check_updated $module || validate_error "$command"
        elif ! (set xyz "$module"/* && test -e "$2"); then
            # The directory does not exist or it contains no files
            echo "$0: sources not available for $module and $no_git_error"
            validate_error "$command"
        fi
    done
    ;;

update)
    is_git || {
        echo "$0: unexpectedly called with submodules but $no_git_error"
        exit 1
    }

    $GIT submodule update --init $modules 1>/dev/null
    test $? -ne 0 && update_error "failed to update modules"
    for module in $modules; do
        check_updated $module || echo Updated "$module"
    done

    (while read -r REPLY; do
        for module in $modules; do
            case $REPLY in
                *" $module "*) continue 2 ;;
            esac
        done
        printf '%s\n' "$REPLY"
    done
    $GIT submodule status $modules
    test $? -ne 0 && update_error "failed to save git submodule status" >&2) < $substat > $substat.new
    mv -f $substat.new $substat
    ;;
esac

exit 0