#!/bin/bash
#  $HeadURL$ $LastChangedRevision$

#  Modules
. $(miniade) || { echo "${0##*/}: ERROR: miniade failed (hint: run 'miniade' to see error)" >&2; exit 1; }

#  Configurable stuff

#  Other globals

main()
{
    local MY_ARGS
    local REAL_FUNCTION PRESENT BEFORE AFTER TEXT FILE REPLACE STATE

    #  Defaults for options
    LOGIC=true
    PRESENT=unset
    BEFORE=unset
    AFTER=unset
    REPLACE=unset
    TEXT=unset
    FILE=unset

    #  Process options
    special_opts_handler()
    {
        case $1 in
            --present=*) PRESENT="${1#*=}" ;;
            --before=*)  BEFORE="${1#*=}" ;;
            --after=*)   AFTER="${1#*=}" ;;
            --replace=*) REPLACE="${1#*=}" ;;
            --text=*)    TEXT="${1#*=}" ;;
            --file=*)    FILE=${1#*=} ;;
            *)           return 1 ;;
        esac
    }
    miniade_process_options --help-handler=help --special-opts-handler=special_opts_handler MY_ARGS "$@" && set -- "${MY_ARGS[@]}"

    #  Process arguments
    [ $# = 0 ] || miniade_bad_usage

    #  Sanity checks and derivations
    check_not_unset TEXT FILE
    check_all_but_one_unset AFTER BEFORE REPLACE
    if [[ $PRESENT = unset ]]; then
        PRESENT=$TEXT
        PRESENT="${PRESENT//./\\.}"
        PRESENT="${PRESENT//\*/\\*}"
        PRESENT="${PRESENT//\+/\\+}"
        PRESENT="${PRESENT//\(/\\\(}"
        PRESENT="${PRESENT//\)/\\\)}"
        PRESENT="^$PRESENT\$"
        miniade_debug 4 "main: PRESENT not defined; converted [$TEXT] safe regexp [$PRESENT]"
    fi
    if [ "X$BEFORE" = XSOF ]; then
        miniade_warning "please use 'BOF' instead of 'SOF'"
        BEFORE=BOF
    fi

    #  Get state
    if  [ ! -f $FILE -o ! -r $FILE ]; then
        STATE=unconfigured
    elif perlgrep "$PRESENT" $FILE; then
        STATE=configured
    else 
        STATE=unconfigured
    fi

    #  If already in desired state, do nothing
    if $LOGIC && [ $STATE = configured ]; then
        return 0

    elif ! $LOGIC && [ $STATE = unconfigured ]; then
        return 0

    #  Make changes
    elif ! $LOGIC && [ $STATE = configured ]; then
        miniade_internal "not implemented"
    
    elif $LOGIC && [ $STATE = unconfigured ]; then
	mkdir -p $(dirname $FILE)
        touch $FILE
        if [[ $AFTER =~ ^EOF$ ]]; then
            echo "$TEXT" >> $FILE
        elif [[ $BEFORE =~ ^BOF$ ]]; then
            TMP_FILE=$(mktemp)
            { echo "$TEXT"; cat $FILE; } > $TMP_FILE
            cat $TMP_FILE > $FILE
            rm -f $TMP_FILE
        elif [[ $AFTER != unset ]] && perlgrep "$AFTER" $FILE; then
            perl -0777 -pi -e 'BEGIN { sub r { ($s)=@_; $s =~ s/\\\\/\\/g; $s =~ s/\\n/\n/g; $s =~ s/\\t/\t/g; return $s; } $desired_after = &r(shift); $desired_text = &r(shift); } s/($desired_after)/$1$desired_text/ms;' "$AFTER" "$TEXT" $FILE
        elif [[ $AFTER != unset ]]; then
            miniade_error "$FILE: $AFTER: not found in file (1)"
        elif [[ $BEFORE != unset ]] && perlgrep "$BEFORE" $FILE; then
            perl -0777 -pi -e 'BEGIN { sub r { ($s)=@_; $s =~ s/\\\\/\\/g; $s =~ s/\\n/\n/g; $s =~ s/\\t/\t/g; return $s; } $desired_before = &r(shift); $desired_text = &r(shift); } s/($desired_before)/$desired_text$1/ms;' "$BEFORE" "$TEXT" $FILE
        elif [[ $BEFORE != unset ]]; then
            miniade_error "$FILE: $BEFORE: not found in file (2)"
        elif [[ $BEFORE != unset ]] && perlgrep "$BEFORE" $FILE; then
            perl -0777 -pi -e 'BEGIN { sub r { ($s)=@_; $s =~ s/\\\\/\\/g; $s =~ s/\\n/\n/g; $s =~ s/\\t/\t/g; return $s; } $desired_before = &r(shift); $desired_text = &r(shift); } s/($desired_before)/$desired_text$1/ms;' "$BEFORE" "$TEXT" $FILE
        elif [[ $BEFORE != unset ]]; then
            miniade_error "$FILE: $BEFORE: not found in file (3)"
        elif [[ $REPLACE != unset ]] && perlgrep "$REPLACE" $FILE; then
            perl -0777 -pi -e 'BEGIN { sub r { ($s)=@_; $s =~ s/\\\\/\\/g; $s =~ s/\\n/\n/g; $s =~ s/\\t/\t/g; return $s; } $desired_replace = &r(shift); $desired_text = &r(shift); } s/$desired_replace/$desired_text/ms;' "$REPLACE" "$TEXT" $FILE
        elif [[ $REPLACE != unset ]]; then
            miniade_error "$FILE: $REPLACE: not found in file (4)"
        else
            miniade_internal "this should not happen"
        fi
    fi
}

perlgrep()
{
    local PATTERN FILE RC

    PATTERN="$1"
    FILE="$2"

    RC=0
    perl -0777 -ne 'BEGIN { sub r { ($s)=@_; $s =~ s/\\\\/\\/g; $s =~ s/\\n/\n/g; $s =~ s/\\t/\t/g; return $s; } $rc = 1; $pattern = &r(shift); } END { exit $rc; } if (/$pattern/ms) { $rc=0; last; }' "$PATTERN" "$FILE" || RC=$?

    return $RC
}

check_not_unset()
{
    local VAR VAL
    for VAR in "$@"; do
        eval "VAL=\"\$$VAR\""
        miniade_debug 20 "check_not_unset: VAR=$VAR, VAL=$VAL"
        [ "X$VAL" != Xunset ] || miniade_bad_usage
    done
}

check_all_but_one_unset()
{
    local SET_COUNT UNSET_COUNT

    SET_COUNT=0
    UNSET_COUNT=0

    for VAR in "$@"; do
        eval "VAL=\$$VAR"
        miniade_debug 10 "check_all_but_one_unset: $VAR=$VAL"
        case $VAL in
            unset) ((++UNSET_COUNT)) ;;
            *)     ((++SET_COUNT)) ;;
        esac
    done

    [ $SET_COUNT = 1 ] || miniade_bad_usage
}

help()
{
    local PROGNAME

    miniade_get_progname PROGNAME
    echo "Usage: $PROGNAME [ <standard-options> ] --text=<text> --file=<file> [ --present=<text> ] --{before|after|replace}=<text>"
    exit 0
}

main "$@"