#!/bin/bash


# I acknowledge that this is weird.  Autoconf/automake are just too heavy for this task.

echo "Configuring.  Please answer the following questions:"

# Read through config.mk.in.  Every time a variable pops up, emit the comment
# before it and prompt the user for a value, using the setting in config.mk.in as a default

TEMPFILE=.config.temp
declare -A CONFIG

COMMENT=""

echo -n > $TEMPFILE

get_default() {
    V=$1
    if ! [[ -e config.mk ]]; then
        return ""
    fi
    grep "$V = " config.mk | sed -e 's/.* = \+//'
}

while read LINE <&4; do
    if echo "$LINE" | grep -q '^#'; then
        COMMENT=$(echo "$LINE" | sed -e 's/^#\+ *//')
    elif echo "$LINE" | grep -q '^[0-9A-Z_]\+ *= *'; then

        VARNAME=$(echo "$LINE" | sed -e 's/ *=.*//')
        DEFAULT="$(get_default $VARNAME)"
        if [[ -z "$DEFAULT" ]]; then
            DEFAULT=$(echo "$LINE" | sed -e 's/^[0-9A-Z_]\+ *= *//')
        fi

        # if there are prefix vars that are false, we need to skip
        SKIP=0
        for K in "${!CONFIG[@]}"; do
            if echo "$VARNAME" | grep -q "^${K}"; then
                if [[ ${CONFIG[$K]} -eq 0 ]]; then
                    SKIP=1
                    break
                fi
            fi
        done

        if [[ SKIP -eq 0 ]]; then
            echo
            echo "$COMMENT"
            #echo "$LINE"
            echo "(default: ${DEFAULT})"
            echo -n "> "
            read VALUE

            if [[ -z $VALUE ]]; then
                VALUE="${DEFAULT}"
            fi

            CONFIG[${VARNAME}]="${VALUE}"

            echo "# ${COMMENT}" >> $TEMPFILE
            echo "${VARNAME} = ${VALUE}" >> $TEMPFILE
            echo >> $TEMPFILE
        fi
    fi
done 4< <(cat config.mk.in)

echo

if [[ -e config.mk ]]; then
    echo "Backing up your old config to config.mk.bak"
    cp config.mk config.mk.bak
fi

echo "All done!  Putting your configuration into config.mk."
mv $TEMPFILE config.mk