#! /bin/bash

# Deleting all locale files and localized man pages installed 
# on system which are *not* listed in /etc/locale.nopurge

set -e
NOPURGECONF=/etc/locale.nopurge

if [ "$1" = "-debug" ] || [ "$1" = "-d" ] \
    || [ "$2" = "-debug" ] || [ "$2" = "-d" ]; then
    set -x
fi

if [ "$1" = "--help" ] || [ "$1" = "-h" ]; then
   echo ""
   echo "Verbose output is triggered with option '-v' or '-verbose'."
   echo "Debugging output is triggered with option '-d' or '-debug'."
   echo "To reconfigure it, run 'dpkg-reconfigure localepurge'."
   echo "Documentation is either available via 'man localepurge'"
   echo "or by reading the docs in /usr/share/doc/localepurge."
   echo ""
   if [ -f $NOPURGECONF ] && fgrep --quiet --line-regexp USE_DPKG $NOPURGECONF ; then
       echo "NB: localepurge has been configured to use dpkg.  Therefore,"
       echo "this script will not do anything."
   fi
   exit 0
fi


# Do nothing and report why if no valid configuration file exists:

if [ ! -f $NOPURGECONF ]
    then
	echo " No $NOPURGECONF file present, exiting ..."
	exit 0
    else
	if fgrep --quiet --line-regexp USE_DPKG $NOPURGECONF
            then
            # Do nothing, dpkg does all the work for us.
            exit 0
	elif fgrep --quiet --line-regexp NEEDSCONFIGFIRST $NOPURGECONF
	    then
		echo
		echo "	  You have to configure \"localepurge\" with the command"
		echo
		echo "	      dpkg-reconfigure localepurge"
		echo
		echo "	  to make $0 actually start to function."
		echo
		echo "	  Nothing to be done, exiting ..."
		echo
		exit 0
	fi
fi


################################################################
## Initialise variables

# Make sure to exclude running under any locale other than C:
export LC_ALL=C

# Initialise local variables
VERBOSE=0
DONTBOTHERNEWLOCALE=0
SHOWFREEDSPACE=0
MANDELETE=0
globaltot=0

if fgrep --quiet --line-regexp DONTBOTHERNEWLOCALE $NOPURGECONF; then
    DONTBOTHERNEWLOCALE=1
fi

if fgrep --quiet --line-regexp SHOWFREEDSPACE $NOPURGECONF; then
    SHOWFREEDSPACE=1
fi

if fgrep --quiet --line-regexp MANDELETE $NOPURGECONF; then
    MANDELETE=1
fi

if fgrep --quiet --line-regexp VERBOSE $NOPURGECONF \
    || [ "$1" = "-verbose" ] || [ "$1" = "-v" ] \
    || [ "$2" = "-verbose" ] || [ "$2" = "-v" ]; then
    VERBOSE=1
fi


################################################################
## Manage the list of locales

# First update $LOCALELIST with newly introduced locales if wanted

LOCALECACHEDIR=/var/cache/localepurge
LOCALELIST="$LOCALECACHEDIR"/localelist
NEWLOCALELIST="$LOCALELIST"-new

((VERBOSE)) && echo "localepurge: checking for existence of $LOCALECACHEDIR..."
if [ ! -d $LOCALECACHEDIR ]; then
	mkdir -m 644 -p $LOCALECACHEDIR
fi

((VERBOSE)) && echo "localepurge: checking for existence of $LOCALELIST..."
if [ ! -f $LOCALELIST ]; then
	touch $LOCALELIST && chmod 664 $LOCALELIST
fi

((VERBOSE)) && echo "localepurge: checking system for new locale ..."

for NEWLOCALE in $(cd /usr/share/locale; ls .)
do 
 if [ -d /usr/share/locale/$NEWLOCALE/LC_MESSAGES ]; then
    if [ ! "$(grep -cx $NEWLOCALE $LOCALELIST)" = "1" ]; then
	echo "$NEWLOCALE" >> "$NEWLOCALELIST"
    fi
 fi
done

for NEWLOCALE in $(ls --ignore="man[1-9]*" /usr/share/man)
do 
 if [ -d /usr/share/man/$NEWLOCALE/man1 ] || [ -d /usr/share/man/$NEWLOCALE/man8 ]; then
    if [ ! "$(grep -cx $NEWLOCALE $LOCALELIST)" = "1" ]; then
	echo "$NEWLOCALE" >> "$NEWLOCALELIST"
    fi
 fi
done

if [ -f $NEWLOCALELIST ]; then
  if ((DONTBOTHERNEWLOCALE)); then
    mv "$NEWLOCALELIST" "$NEWLOCALELIST".temp
    sort -u "$NEWLOCALELIST".temp "$LOCALELIST"> "$NEWLOCALELIST"
    mv "$NEWLOCALELIST" "$LOCALELIST"
    rm "$NEWLOCALELIST".temp
   else
    mv "$NEWLOCALELIST" "$NEWLOCALELIST".temp
    sort -u "$NEWLOCALELIST".temp > "$NEWLOCALELIST"
    rm "$NEWLOCALELIST".temp
  fi
fi

if [ -f "$NEWLOCALELIST" ] && [ $DONTBOTHERNEWLOCALE != yes ]; then
    echo "Some new locales have appeared on your system:"
    echo
    tr '\n' ' ' < "$NEWLOCALELIST" 
    echo
    echo
    echo "They will not be touched until you reconfigure localepurge"
    echo "with the following command:"
    echo
    echo "    dpkg-reconfigure localepurge"
    echo
fi

## Create a Bash extended globbing pattern used to identify
## superfluous locales: start by creating a pattern to match locales
## not to be purged, use it to remove good locales from the list of
## all locales and create a pattern matching superfluous locales.
nopurge=$(
    set -o noglob;		# Disable path expansion and use 'echo'
				# below to change newlines into spaces
    echo $(grep --invert-match --extended-regexp '^[ \t]?(#|$)' $NOPURGECONF)
)
nopurgepat='@(C|'"${nopurge// /|}"')'
shopt -s extglob		# enable extended globbing to use $nopurgepat
localelist=$(grep --invert-match --extended-regexp '^[ \t]?(#|$)' $LOCALELIST)
superfluouslocalepat=$(
    echo -n '@(nonexistent_locale_placeholder'
    for l in $localelist; do
	if [[ $l != $nopurgepat ]]; then echo -n "|$l"; fi
    done
    echo -n ')'
)

################################################################
## Define utility functions 

# Function for disk space calculation
# Usage: get_used_space <dirname>
if ! ((SHOWFREEDSPACE)); then
    function get_used_space () { echo 0; }
else
    if fgrep --quiet --line-regexp QUICKNDIRTYCALC $NOPURGECONF; then
	function get_used_space ()
	{
	    [ -d "$1" ] || return 1 # bail out if there's no such dir
	    set - $(df -P $1); shift $(($# - 6)); echo $3
	}
    else
	function get_used_space ()
	{
	    [ -d "$1" ] || return 1 # bail out if there's no such dir
	    set - $(du -ks $1); echo $1
	}
    fi
fi

# If the first argument is a superfluous locale, removes the regular
# files and the symbolic links given as subsequent arguments
function remove_superfluous_files ()
{
    if [[ "$1" == $superfluouslocalepat ]]; then shift
	local flag
	((VERBOSE)) && flag=-v
	for file; do
	    if [ -f "$file" ] || [ -h "$file" ]; then 
		echo "$file"
	    fi
	done | xargs rm $flag
    fi
}

# If the first argument is a superfluous locale, removes regular files
# and symbolic links under the dirs given as subsequent arguments
function remove_superfluous_files_under ()
{
    if [[ "$1" == $superfluouslocalepat ]]; then shift
	local flag
	((VERBOSE)) && flag=-print
        # ensure directory is not empty to avoid find to exit with error
        if [ -n "$(ls -A "$@" 2>/dev/null)" ]; then
 	    find "$@" -mindepth 1 \( -type f -o -type l \) $flag -delete
        fi
    fi
}

# Compute space before removing files
function spacebefore ()
{
    if ((SHOWFREEDSPACE)); then
	local dir="$1"
	before=$(get_used_space "$dir")
    fi
}

# Compute space freed after removing files and updates global total
function spaceafter ()
{
    if ((SHOWFREEDSPACE)); then
	local dir="$1"
	after=$(get_used_space "$dir")
	tot=$((before < after ? 0 : before - after))
	((tot > 0)) && ((globaltot += tot))
    printf "localepurge: Disk space freed: %6d KiB in %s\n" ${tot} $dir
    fi
}


################################################################
## Now, get the job done

for LDIR in /usr/share/{locale,man,gnome/help,omf,doc/kde/HTML,tcltk,cups/{templates,locale,doc-root},calendar,aptitude,cups/{templates,locale,doc-root},help,vim/vim*/lang}; do
    if [ ! -d "$LDIR" ]; then continue; fi
    spacebefore "$LDIR"
    case "$LDIR" in

    /usr/share/locale)
	    ((VERBOSE)) && echo "localepurge: processing locale files ..."
	    for locale in $(cd "$LDIR"; echo *); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"
	    done ;;

    /usr/share/man)
	    if ! ((MANDELETE)); then continue; fi
	    ((VERBOSE)) && echo "localepurge: processing man pages ..."
	    for locale in $(ls --ignore="man[1-9]*" $LDIR); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"/man[1-9]
	    done ;;

    /usr/share/gnome/help)
	    ((VERBOSE)) && echo "localepurge: processing GNOME files ..."
	    for localedir in "$LDIR"/*/*; do
		locale=${localedir##*/}
		if [ -d "$localedir/../C" ]; then
		    remove_superfluous_files_under "$locale" "$localedir"
		fi
	    done ;;

    /usr/share/omf)
	    ((verbose)) && echo "localepurge: processing OMF files ..."
	    for file in "$LDIR"/*/*; do
		locale=${file##*-}; locale=${locale%.omf}
		if [ -f "${file/%-$locale.omf/-C.omf}" ]; then
		    remove_superfluous_files "$locale" "$file"
		fi
	    done ;;

    /usr/share/doc/kde/HTML)
	    ((VERBOSE)) && echo "localepurge: processing KDE files ..."
	    for locale in $(cd "$LDIR"; echo *); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"
	    done ;;
    
    /usr/share/tcltk)
	    ((VERBOSE)) && echo "localepurge: processing Tcl/Tk files ..."
	    for file in $(cd "$LDIR"; echo t*/msgs/*.msg); do
		locale=$(basename $file .msg)
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done ;;

    /usr/share/aptitude)
	    ((VERBOSE)) && echo "localepurge: processing aptitude files ..."
	    for file in $(cd "$LDIR"; echo aptitude-defaults.??*); do
		locale=${file##aptitude-defaults.}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done

	    for file in $(cd "$LDIR"; echo README.*); do
		locale=${file##README.}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done

	    for file in $(cd "$LDIR"; echo help-*); do
		locale=${file##help-}
		locale=${locale%%.txt}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done

	    for file in $(cd "$LDIR"; echo mine-help-*); do
		locale=${file##mine-help-}
		locale=${locale%%.txt}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done ;;
    
    /usr/share/calendar)
	    ((VERBOSE)) && echo "localepurge: processing calendar files ..."
	    for locale in $(cd "$LDIR"; echo ??_*); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"
	    done ;;

  	/usr/share/aptitude)
	    ((VERBOSE)) && echo "localepurge: processing aptitude files ..."
	    for file in $(cd "$LDIR"; echo aptitude-defaults.??*); do
		locale=${file##aptitude-defaults.}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done

	    for file in $(cd "$LDIR"; echo README.*); do
		locale=${file##README.}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done

	    for file in $(cd "$LDIR"; echo help-*); do
		locale=${file##help-}
		locale=${locale%%.txt}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done

	    for file in $(cd "$LDIR"; echo mine-help-*); do
		locale=${file##mine-help-}
		locale=${locale%%.txt}
		remove_superfluous_files "$locale" "$LDIR/$file"
	    done ;; 
	
    /usr/share/cups/templates)
	    ((VERBOSE)) && echo "localepurge: processing cups templates ..."
	    for locale in $(cd "$LDIR"; echo *); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"
	    done ;;

	/usr/share/cups/locale)
	    ((VERBOSE)) && echo "localepurge: processing cups locales ..."
	    for locale in $(cd "$LDIR"; echo *); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"
	    done ;;

	/usr/share/cups/doc-root)
	    ((VERBOSE)) && echo "localepurge: processing cups locales ..."
	    for locale in $(cd "$LDIR"; echo *); do
		remove_superfluous_files_under "$locale" "$LDIR/$locale"
	    done ;;

    /usr/share/help)
        ((VERBOSE)) && echo "localepurge: processing help files ..."
        # <locale>/<domain>/HELP_CONTENT(files & dirs)
        for locale in $(cd "$LDIR"; echo *); do
            if [[ $locale != "C" ]]; then
                remove_superfluous_files_under "$locale" "$LDIR/$locale"
            fi
        done ;;

    /usr/share/vim/vim*/lang)
        ((VERBOSE)) && echo "localepurge: processing vim files ..."
        for locale in $(cd "$LDIR"; echo *); do
        remove_superfluous_files_under "$locale" "$LDIR/$locale"
        done ;;

	*)
	    echo "localepurge: internal error, exiting"
	    exit 1
    esac
    spaceafter "$LDIR"
done

# Report total disk space freed
if ((SHOWFREEDSPACE)); then
    echo
    echo "Total disk space freed by localepurge: ${globaltot} KiB"
    echo
fi