#!/bin/bash
# -------
# File:        skel-install
# Description: Simple (but useful) tool to install files in the skel
#              directory from cpkg scripts
# Author:      Luis Garcia Gisbert <garcia_luigis@gva.es>
#              (written for LliureX in June 2007)
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along 
# with this program; if not, write to the Free Software Foundation, Inc., 
# 51 Franklin St, Fifth Floor, Boston MA 02110-1301 USA
# --------

set -e

PATH="/usr/sbin:/usr/bin:/sbin:/bin"

usage() {
  CMD_NAME="$(basename "$0")"
  exit_message \
"Usage: $CMD_NAME [options] [SOURCE_FILE|-] (SKEL_RELATIVE)TARGET_FILE\n\
       where options are: [-n] [-t|--template] [-p|--preserve] [-m |--mode=MODE] [-o |--owner=OWNER] [-g |--group=GROUP]\n\
       Installs \"SOURCE_FILE\" in  \"$SKEL_DIR/TARGET_FILE\" (or in \"$TEMPLATES_DIR/TARGET_FILE\" if -t option is used)\n\
       If \"SOURCE_FILE\" is omitted, or equals to "-", standard input is used, otherwise, it must exist.\n\
       All the directory components of \"$SKEL_DIR/TARGET_FILE\" are created if required.\n\
       If 'real target' exists \"(/TARGET_FILE)\", its MODE,OWNER and GROUP are used as default\n\
       instead of $DEFMODE, $DEFOWNER:$DEFGROUP. Use parameters to override this values and/or behaviour."
}

exit_message() {
   [ "$VERBOSE" ] && echo -e "$1"  >&2
   exit 1
}

skel_md(){
   TDIR="$(dirname "$1")"
   # check if there is nothing to do
   [ ! -d "$TDIR" ] || return 0
   mkdir -p "$TDIR" &>/dev/null || return 1
   # remove first "./", add a "/" at end and remove superfluous "/"
   TDIR="$(echo "${TDIR}/"|sed -e "s%/\+%/%g;s%^\./%%")"
   # separate first dir component of TDIR
   FDIR="${TDIR%%/*}"
   TDIR="${TDIR#*/}"
   PDIR="/"
   while [ "$TDIR" ] ; do
      SUBDIR="${TDIR%%/*}"
      TDIR="${TDIR#*/}"
      PDIR="${PDIR}/${SUBDIR}"
      [ -d "${PDIR}" ] || return 0
      DMODE="$(find "${PDIR}" -maxdepth 0 -printf "%m")"
      DOW_GR="$(find "${PDIR}" -maxdepth 0 -printf "%u:%g")"
      chmod "$DMODE" "${FDIR}/${PDIR}" || return 1
      chown "${DOW_GR}" "${FDIR}/${PDIR}" || return 1
   done
   return 0
}

# variables
# ---------
SKEL_DIR="./skel"
TEMPLATES_DIR="./templates"
DEFMODE="644"
DEFOWNER="root"
DEFGROUP="root"

MODE=""
OWNER=""
GROUP=""
SOURCE_FILE=""
TARGET_FILE=""
VERBOSE="Y"
# to store non-opt arguments
declare -a ARGV
# Bash arrays are 0-based, but we like ARGC to be equal to the number of non-option arguments.
# To solve this issue, we use a "C-like" ARGV vector by setting ARGV[0] with the name of script
# ('basename' of script for arbitrary cosmetic reasons), so real arguments begin with index 1
# the array will be ARGC+1 elements
ARGC=0
ARGV[0]="$(basename "$0")"

# main
# ----

TARGET_DIR="$SKEL_DIR"

while [ $# -ge 1 ] ; do
   case "$1" in
      --group=*)
         GROUP="${1#--group=}"
         shift
         ;;
      -g)
         # -g GROUP as equivalent to --group=GROUP
         [ -z "$2" ] && usage
         GROUP="$2"
         shift 2
         ;;
      --owner=*)
         OWNER="${1#--owner=}"
         shift
         ;;
      -o)
         # -o OWNER as equivalent to --owner=MODE
         [ -z "$2" ] && usage
         OWNER="$2"
         shift 2
         ;;
      --mode=*)
         MODE="${1#--mode=}"
         shift
         ;;
      -m)
         # -m MODE as equivalent to --mode=MODE
         [ -z "$2" ] && usage
         MODE="$2"
         shift 2
         ;;
      -n)
        # short option (no-verbose)
        VERBOSE=""
        shift
        ;;
      -t|--template)
        # short option (use templates dir instead of skel)
        TARGET_DIR="$TEMPLATES_DIR"
        shift
        ;;
      -p|--preserve)
        # short option (use permisisons/owner/group from SOURCE)
        PRESERVE="YES"
        shift
        ;;
      -?*)
         # an invalid option -* or --* but not a single -
         usage
         ;;
      *)
         ARGC=$(( $ARGC +1 ))
         ARGV[$ARGC]="$1"
         shift
         ;;
     esac
done

case $ARGC in
   0)
      # no files 
      usage
      ;;
   1)
      # just one file ... asume stdin
      TARGET_FILE="${ARGV[1]}"
      SOURCE_FILE="-"
      ;;
   2)
     # 2 files, first is source and last is target
      SOURCE_FILE="${ARGV[1]}"
      TARGET_FILE="${ARGV[2]}"
      ;;
   *)
    # this (simple) script only install one file, so exit
      usage
      ;;
esac

PROTO_FILE="/${TARGET_FILE}"

# check for source
if [ "$SOURCE_FILE" != "-" ] ; then
   [ -r "$SOURCE_FILE" ] || exit_message "Unable read source file \"$SOURCE_FILE\""
   if [ "$PRESERVE" ] ; then
      PROTO_FILE="$SOURCE_FILE"
   fi
fi

# check for target in "real world"
if [ -f "${PROTO_FILE}" ] ; then
   DEFMODE="$(find "${PROTO_FILE}" -printf "%m")"
   DEFOWNER="$(find "${PROTO_FILE}" -printf "%u")"
   DEFGROUP="$(find "${PROTO_FILE}" -printf "%g")"
fi

REAL_TARGET="${TARGET_DIR}/${TARGET_FILE}"
skel_md "$REAL_TARGET" &>/dev/null || exit_message "Unable to create directory for \"$REAL_TARGET\""
[ -f "$REAL_TARGET" ] || touch "$REAL_TARGET" &>/dev/null || exit_message "Unable to create file \"$REAL_TARGET\""

# use default values for unset variables
chmod "${MODE:="$DEFMODE"}" "$REAL_TARGET" &>/dev/null || exit_message "Error setting file permissions to \"${MODE:="$DEFMODE"}\""
chown "${OWNER:="$DEFOWNER"}:${GROUP:="$DEFGROUP"}" "$REAL_TARGET" &>/dev/null || exit_message "Error setting owner and group to \"${OWNER:="$DEFOWNER"}:${GROUP:="$DEFGROUP"}\""

# OK, 'cat' over the target
cat "$SOURCE_FILE" > "$REAL_TARGET" 2>/dev/null || exit_message "Error writing file \"$REAL_TARGET\""

exit 0