#!/bin/sh

##  author:  parv, parv UNDERSCORE AT yahoo DOT com
##  date:  may 14 2002
##
##  license:  free to use as you please w/ proper credit given
##
##  name:  search-ports-descr
##
##  purpose:  to search thru each port's description file; currently
##  this file name is 'pkg-descr' on freebsd.
##
##  usage:
##    search-ports-descr <regex pattern as handled by egrep>
##
##    to list lines mentioning 'mozilla' or 'jdk', (or, both)...
##      search-ports-descr 'mozilla|jdk'
##
##    to list lines mentioning perl...
##      search-ports-descr perl
##
#  4 lines around the line w/ pattern are printed via "grep -4"; see grep(1)
#  for details.
#
#  possible modification would be to add option handling to specify alternate
#  ports tree root, name of package description file, cache directory & file.
#  until then, set those 4 variables below as required.
#
#  another possible modification could be is to first search INDEX in
#  $ports_tree to look for the given pattern in the one-line-description.
#  from there get the corresponding detailed port description file name to get
#  more context.
#
#  there are only about 8-9 lines of actual code; everything else is dedicated
#  for error handling.  oh well...


# set to the root of ports tree; freebsd default is /usr/ports
ports_root='/misc/ports'

# file containing port description in each port directory
descr_file='pkg-descr'

# save the $descr_file listing to avoid wait & hardship on the disk
cache_dir="${HOME}/log/ports"
cache_file="${cache_dir}/port-descr.list"

# since "echo ... && exit 1" was often used, created a function to handle it
Err_Exit()
{
  echo "
holy cow!  ${@}
" 1>&2

  exit 1
}

# exit if $ports_root is not a directory
[ ! -d "${ports_root}" ] \
  && Err_Exit "$ports_root is not a directory; please change $ports_root in $0."

# exit if no search pattern given
case $# in
  0)
    Err_Exit 'please provide a search pattern'
  ;;

  *)
  ;;
esac


Chmod()
{ # try to change permissions ($1) of file(s) ${2 ..}
  case $# in
    0|1)
      Err_Exit 'only one or none argument was given for chmod'
    ;;

    *)
      local perm
      perm="${1}"
      shift

      chmod "${perm}" "${@}"
      [ ! $? ] && Err_Exit "'chmod $perm ${@}' failed"
    ;;
  esac
}

List_Cache_Dir()
{
  # create $cache_dir if it doesn't exist
  #
  if [ ! -e "${cache_dir}" ]
  then
    mkdir -m 700 -p "${cache_dir}"
    [ ! $? ] \
      && Err_Exit "'mkdir -m 700 -p $cache_dir' failed;
$cache_dir directory could not be created."

  # exit if $cache_dir is not a directory
  #
  elif  [ ! -d "${cache_dir}" ]
  then
      Err_Exit "
$cache_dir is not a directory; please move it or,
change \$cache_dir in $0.
"
  fi

  # try to change listing permissions; else exit
  #
  [ ! -x "${cache_dir}" ] \
    && echo " $cache_dir could not be listed; trying to change permissions..." \
    && Chmod 'u+x' "${cache_dir}"
}

Create_Cache_File()
{
  # before trying to create $cache_file, first create/check $cache_dir
  #
  List_Cache_Dir

  # create $cache_file if it doesn't exist
  #
  if [ ! -e "${cache_file}" ]
  then
    echo " trying to create $cache_file cache..."

    [ ! -w "${cache_dir}" ] \
      && echo "   $cache_dir is not writable; trying to change permissions..." \
      && Chmod 'u+w' "${cache_dir}"

    echo "   searching for all the $descr_file named files in $ports_root"

    find "${ports_root}" -type f -maxdepth 3 -mindepth 3 \
      -name "${descr_file}" -print \
    | sort >> "${cache_file}"

    [ $? ] && echo '   ...done'
    [ ! $? ] && Err_Exit '...failed'
  fi

  # exit if $cache_file is unreadable
  [ ! -r "${cache_file}" ] && Chmod 'u+r' "${cache_file}"
}

# create $cache_file if unreadable/doesn't exist
#
[ ! -e "${cache_file}" -o ! -r "${cache_file}" ] && Create_Cache_File


# finally search thru the $cache_file listing
#
echo " searching for pattern '${@}' ..."

while read descr
do
#set -x -v
  egrep -i  "${@}" "${descr}" >/dev/null 2>&1  || continue

  echo ">>--<<  ${descr%${descr_file}}"
  echo ' '

  grep -4 -E -i "${@}" "${descr}"

  echo ' '
  echo ' '
done < "${cache_file}"

set +x +v