#!/bin/bash

set -e
set -o pipefail

SMISTRIP=/usr/bin/smistrip
CONFDIR=/etc/snmp-mibs-downloader

. $CONFDIR/snmp-mibs-downloader.conf

download_mibs()
{
  TMP="$(mktemp -d)"
  if [ ! -z "$ARCHIVE" ]; then
    ARCHTMP="$(mktemp -d)"
    if [ "$ARCHTYPE" == "dirgz" ]; then
      if [ ! -z "$HOST" ]; then
        echo "Downloading a whole directory with compressed content"
        echo "is not supported."
        exit 1
      else
        cp "$DIR/$ARCHIVE"/* "$ARCHTMP/"
        gzip -d "$ARCHTMP"/* || /bin/true
      fi
    else
      if [ ! -z "$HOST" ]; then
        wget -O "$ARCHTMP/$ARCHIVE" -q -nv "$HOST/$DIR/$ARCHIVE"
      else
        cp "$DIR/$ARCHIVE" "$ARCHTMP/$ARCHIVE"
      fi

      case "$ARCHTYPE" in
      tar)
        tar -C "$ARCHTMP" -xf "$ARCHTMP/$ARCHIVE"
        ;;
      tgz)
        tar -C "$ARCHTMP" -xzf "$ARCHTMP/$ARCHIVE"
        ;;
      zip)
        unzip -d "$ARCHTMP" "$ARCHTMP/$ARCHIVE"
        ;;
      esac
    fi
  fi

  while read -r file mibs; do
    if [ "$file" != "#" ]; then
      if [ ! -z "$PREFIX" ]; then
        file="$PREFIX$file"
      fi
      if [ ! -z "$SUFFIX" ]; then
        file="$file$SUFFIX"
      fi
      if [ -z "$ARCHIVE" ]; then
        archive_fetcher=(wget -O - -q -nv "$HOST/$DIR/$file")
      else
        archive_fetcher=(cat "$ARCHTMP/$ARCHDIR/$file")
      fi
      "${archive_fetcher[@]}" \
          | tr -d \\r \
          | $SMISTRIP -v -a -d "$TMP" -m "$mibs" -
    fi
  done <"$CONFDIR/$CONF"

  if [ ! -z "$DIFF" ]; then
    patch -d "$TMP" <"$CONFDIR/$DIFF"
  fi

  if [ ! -d "$BASEDIR/$DEST" ]; then
    mkdir -p "$BASEDIR/$DEST"
  fi
  cp "$TMP"/* "$BASEDIR/$DEST"

  rm -f "$BASEDIR/$DEST/.index"
  rm -fr "$TMP"
  if [ ! -z "$ARCHTMP" ]; then
    rm -rf "$ARCHTMP"
  fi
}

list_mibs()
{
  while read -r file mibs; do
    if [ "$file" = "#" ]; then
      continue
    fi

    echo "$mibs" | tr ':' '\n'
  done <"$CONFDIR/$CONF"
}

MODE='get'

while [ $# -gt 0 ]; do
  case $1 in
  --get)
    MODE='get'
    ;;
  --list)
    MODE='list'
    ;;
  *)
    break
  esac

  shift
done

if [ $MODE = get ]; then
  echo ""
  echo "Downloading documents and extracting MIB files."
  echo "This will take some minutes."
  echo ""
  echo "In case this process fails, it can always be repeated later by executing"
  echo "$0 again."
  echo ""
fi

sources=$1
if [ -z "$sources" ]; then
  sources="$AUTOLOAD"
fi

for i in $sources; do
  TMP=
  ARCHTMP=
  HOST=
  DIR=
  CONF=
  DEST=
  DIFF=
  PREFIX=
  SUFFIX=
  ARCHIVE=
  ARCHTYPE=
  ARCHDIR=

  . "$CONFDIR/$i.conf"

  if [ $MODE = list ]; then
    list_mibs
  else
    download_mibs
  fi
done