#!/usr/bin/env bash

# This is my Linux server configuration utility (sconfig.sh)
# Read more about it here: https://git.socialnerds.org/david/sconfig

# ***** CONFIG *****

# general information
NAME="sconfig"
TITLE="Server Configuration"
DESCRIPTION="The Linux server configuration utility"
VERSION="0.2"
AUTHOR="david@socialnerds.org"
WEBSITE="https://git.socialnerds.org/david/sconfig"
REPO="$WEBSITE.git"
LICENSE="https://git.socialnerds.org/david/sconfig/raw/branch/main/LICENSE"

# default settings
CONFIGFILE="/etc/sconfig/sconfig.conf"
DEBUG=0
LOGFILE=""

declare -A CONFIG
CONFIG=([debug_enabled]=$DEBUG
        [logfile]="$LOGFILE"
        [btrfs_enabled]=
        [btrfs_subvols]="/"
        [btrfs_versions]=30
        [miab_enabled]=
        [miab_host]="box.example.com"
        [miab_user]="admin@example.com"
        [miab_password]="verysecret!=+%password"
        [healthchecks_enabled]=
        [healthchecks_baseurl]=""
        [healthchecks_id]="")

declare -A PACKAGES
PACKAGES=([ubuntu]="curl less vim"
          [arch]="curl less vim"
          [debian]="curl less vim")

# external library files and command prerequsites
# both unused for now
#LIBRARIES=("library.sh" "ui.sh")
#DEPENDENCIES=("curl" "more" "sort")

# ***** FUNCTION DEFINITIONS *****
# execute upon Ctrl-C detection
function bashtrap {
  library_log warn "Ctrl-C detected, exiting"
  exit 2
}

# return 1/false if not executed as root
function amiroot {
  if [ "$(whoami)" != "root" ]; then
    return 1
  fi
}

# check if stdout is a TTY and return 1 if it is not
# for detecting if executed by cron (or user)
function amitty {
  if [ ! -t 1 ]; then
    return 1
  fi
}

# general text output method
# usage: output <loglevel> <message>
function library_log {
  if [ "$1" != "debug" -o $DEBUG -eq 1 ]; then
    echo "[$1] ${@:2}"
    if [ "$LOGFILE" -a -w "$LOGFILE" ]; then
      echo "[$(date +%Y%m%d%H%M%S)][$1] ${@:2}" >> "$LOGFILE"
    fi
  fi
}

# very simple configfile parser
# it fills a global variable with key=value pairs from a configfile
# usage: config_read <path/to/configfile>
function config_read {
  if [ "$1" -a -r "$1" ]; then
    local FILE="$1"
    while read -r LINE || [ -n "$LINE" ]; do
      local FILTER='^[0-9a-zA-Z]+[_-]?[0-9a-zA-Z]+=.*$'
      if [[ "$LINE" =~ $FILTER ]]; then
        CONFIG[${LINE%%=*}]=${LINE#*=}
      fi
    done < $FILE
  else
    return 1
  fi
}

# very simple configfile writer
# it (over)writes a configfile with key=value pairs from a global variable
# usage: config_write <path/to/configfile>
function config_write {
  if [ "$1" ]; then
    local FILE="$1"
    for KEY in ${!CONFIG[@]}; do
      echo "$KEY=${CONFIG[$KEY]}"
    done | sort > $FILE
  else
    return 1
  fi
}

# get the linux distribution id from /etc/os-release
# only systems with this file present are supported
function library_get_distro {
  local RELEASE_FILE="/etc/os-release"
  if [ -r $RELEASE_FILE ]; then
    while read -r LINE || [ -n "$LINE" ]; do
      local FILTER='^ID='
      if [[ "$LINE" =~ $FILTER ]]; then
        echo "${LINE#*=}"; break
      fi
    done < $RELEASE_FILE
  fi
}

# retrieve path to this script
#function get_scriptpath {
#  local DIRNAME="$(dirname $0)"
#  if [ -L $0 ]; then
#    local DIRLINK="$(dirname $(readlink $0))"
#    if [ $DIRLINK == "."  ]; then
#      local SCRIPTPATH="$DIRNAME"
#    else
#      local SCRIPTPATH="$DIRNAME/$DIRLINK"
#    fi
#  else
#    local SCRIPTPATH="$DIRNAME"
#  fi
#  if [[ $SCRIPTPATH =~ ^/.* ]]; then
#    echo "$SCRIPTPATH"
#  else
#    #TODO: redirect stdout and stderr for cd to /dev/null
#    cd $SCRIPTPATH; echo "$PWD"
#  fi
#}

#function main {
#  for MODULE in ${MODULES[@]}; do
#    library_log debug "Module found ($MODULE)"
#  done
#  library_log info "This is an informational message"; sleep 2
#}

# print the usage message
function usage {
  echo; echo "Usage: $(basename $0) <OPTIONS>"
  echo ""; echo "OPTIONS:"
  echo "  -h           Show help message"
  echo "  -i           Show script information (Version, etc.)"
  echo "  -c <file>    Use custom configuration file"
  echo "  -l <file>    Use custom log file"
  echo "  -d|-v        Enable verbose output"; echo
}

# print general information
function info {
  echo; echo "$NAME - $DESCRIPTION"; echo
  echo "Version:     $VERSION"
  echo "Author:      $AUTHOR"
  echo "Website:     $WEBSITE"
  echo "License:     $LICENSE"; echo
}

# ***** START *****
# bashtrap initialization
trap bashtrap INT

# require root
if ! amiroot; then
  library_log error "You need to run this script with elevated privileges"
  exit 1
fi

# option handler
while getopts "c:l:dvih" ARG; do
  case $ARG in
    c)
      CONFIGFILE="$OPTARG"
      library_log debug "Custom config file set by command line option [-$ARG $OPTARG]"
      ;;
    l)
      LOGFILE="$OPTARG"
      library_log debug "Custom log file set by command line option [-$ARG $OPTARG]"
      ;;
    d|v)
      if [ ! $DEBUG -eq 1 ]; then
        DEBUG=1
        library_log debug "Debug mode enabled by command line option [-$ARG]"
      fi
      ;;
    i)
      info; exit 0
      ;;
    h)
      usage; exit 0
      ;;
    *)
      usage; exit 1
      ;;
  esac
done

# loading config values (from $CONFIGFILE)
if ! config_read "$CONFIGFILE"; then
  library_log warning "Could not read config file, skipping [$CONFIGFILE]"
fi

# setting runtime variables
#SCRIPTPATH="$(get_scriptpath)"
#MODULES=($(ls $SCRIPTPATH/modules/*.sh))
if [ ! $DEBUG -eq 1 ]; then
  DEBUG=${CONFIG[debug_enabled]}
fi
if [ -z $LOGFILE ]; then
  LOGFILE=${CONFIG[logfile]}
fi

# create logfile if missing
if [ "$LOGFILE" -a ! -w "$LOGFILE" ]; then
  if [ ! -d $(dirname "$LOGFILE") ]; then
    mkdir -p $(dirname "$LOGFILE")
  fi
  touch "$LOGFILE"
fi

# create configfile if missing
if [ ! -w $CONFIGFILE ]; then
  if [ ! -d $(dirname $CONFIGFILE) ]; then
    mkdir -p $(dirname $CONFIGFILE)
  fi
  # write config values (to $CONFIGFILE)
  library_log info "Creating new config file [$CONFIGFILE]"
  if ! config_write "$CONFIGFILE"; then
    library_log warning "Could not write to config file [$CONFIGFILE]"
  fi
fi

# fix file permissions
library_log debug "Fixing file permissions"
chown $(id -u):$(id -g) "$CONFIGFILE"
chmod 600 "$CONFIGFILE"
if [ "$LOGFILE" ]; then
  chown $(id -u):$(id -g) "$LOGFILE"
  chmod 644 "$LOGFILE"
fi

# loading libraries
#for LIBRARY in ${LIBRARIES[@]}; do
#  if [ -r $SCRIPTPATH/$LIBRARY ]; then
#    source $SCRIPTPATH/$LIBRARY
#    if [ $DEBUG -eq 1 ]; then
#      echo "[debug] Library loaded [$LIBRARY]"
#    fi
#  else
#    echo "[error] Library not found [$LIBRARY]"
#    exit 1
#  fi
#done

# checking for the availibility of ${DEPENDENCIES[@]}
#TODO: loop through all before reporting the missing depenencies
#for DEPENDENCY in ${DEPENDENCIES[@]}; do
#  if ! $(command -v $DEPENDENCY &> /dev/null); then
#    library_log error "Dependency not found [$DEPENDENCY]"
#    #exit 1
#  fi
#done

# update package repositories and install required packages
case "$(library_get_distro)" in
  debian|ubuntu|raspbian)
    library_log info "Updating package repositories"
    apt-get update > /dev/null
    if [ $? -eq 0 ]; then
      library_log debug "Success!"
    else
      library_log error "An error occured while updating package repositories"
      exit 1
    fi
    ;;
  arch)
    library_log info "Updating package repositories"
    pacman -Sy > /dev/null
    if [ $? -eq 0 ]; then
      library_log debug "Success!"
    else
      library_log error "An error occured while updating package repositories"
      exit 1
    fi
    ;;
  *)
    library_log error "Could not determine your operating system"
    exit 1
    ;;
esac

# main program, execute only if called directly
if [ $(basename $0) == "$NAME" -o $(basename $0) == "$NAME.sh" ]; then
  # output useful debugging information
  library_log debug "*****  START  *****"
#  main
fi

# ***** END *****
library_log debug "*****  END  *****"
exit 0