#!/bin/sh

# (C) Copyright Collin Doering 2011
#
# 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 3 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, see <http://www.gnu.org/licenses/>.

# File: link-conf.sh
# Author: Collin J. Doering <rekahsoft@gmail.com>
# Date: Jun  4, 2011

# TODO: * add support for a 'interactive' option [ -i | --interactive ]
#       * add support for a link-to option so you can link the given config-dir files to
#         somewhere other then $HOME

# lnfrec takes:
# $1: the config dir in question
# $2: the current directory in the recursive call (used internally to recurse the config dir)
# $3: boolean specifying option relink
# $4: boolean specifying option clean
# $5: boolean specifying option verbose
# $6: boolean specifying option force
# $7: boolean specifying option dry
function lnfrec () {
    # for each file in $1 directory do link (default),  relink ($3) or clean ($4) along with options
    # verbose ($5) and force ($6)
    for f in `ls -aA $1/$2`; do
	case "$f" in
	    .)
		;;
	    ..)
		;;
	    */.)
		;;
	    */..)
		;;
            *~)
                ;;
	    .git)
		;;
            .gitignore)
                ;;
	    *)
		# If the current file being recursed on from the given config dir ($1) is a directory
		if [[ -d "$1$2/$f" ]]; then
		    # If the file currently being recursed on from the config dir ($1) in $HOME  is not a directory
		    # (that is $HOME$2/$f); then create the directory $HOME$2/$f
		    if [[ ! -d "$HOME$2/$f" ]]; then
		        $5 && echo "Creating dir $HOME$2/$f"
			! $7 && mkdir "$HOME$2/$f"
		    fi
		    # recurse further into config dir to $1$2/$f
		    lnfrec "$1" "$2/$f" $3 $4 $5 $6 $7
		# If the current file being recursed on from the given config dir ($1) in $HOME is not a directory
		# and is not a file or a link, then create a hardlink from $1$2/$f to $HOME$2/$f
		elif [[ ! -e "$HOME$2/$f"  && ! -L "$HOME$2/$f" ]]; then
		    $5 && echo "Linked $1$2/$f -> $HOME$2/$f"
		    ! $7 && ln "$1$2/$f" "$HOME$2/$f"
		# Otherwise: the file exists ($HOME$2/$f)
		else
		    NUM_LINKS=$(ls -al "$HOME$2/$f" | cut -d' ' -f2)
		    
		    # If the relink option is set
		    if $3; then
			# check if the config file $HOME$2/$f has more then one hardlink; if so then relink
			if [[ $NUM_LINKS -gt 1 ]]; then
			    $5 && echo "Re-linking $1$2/$f -> $HOME$2/$f"
			    ! $7 && rm "$HOME$2/$f"
			    ! $7 && ln "$1$2/$f" "$HOME$2/$f"
			# if the force option is set (along with the relink option)
			elif $6; then
			    echo "Warning! Removing regular file $HOME$2/$f"
			    ! $7 && rm "$HOME$2/$f"
			    $5 && echo "Re-linking $1$2/$f -> $HOME$2/$f"
			    ! $7 && ln "$1$2/$f" "$HOME$2/$f"
			else
			    $5 && echo "$HOME$2/$f only has one file reference! Skipping.."
			fi
		    # If the clean option is set
		    elif $4; then
			# Check if the config file $HOME$2/$f has more then one hardlink; if so then clean the file from home
			if [[ $NUM_LINKS -gt 1 ]]; then
			    $5 && echo "Cleaning $HOME$2/$f"
			    ! $7 && rm "$HOME$2/$f"
			# If the force option is set (along with clean)
			elif $6; then
			    echo "Warning! Forcing removal of $HOME$2/$f"
			    $5 && echo "Cleaning $HOME$2/$f"
			    ! $7 && rm "$HOME$2/$f"
			else
			    $5 && echo "$HOME$2/$f only has one file reference! Skipping.."
			fi
		    else
			$5 && echo "$HOME$2/$f already linked! Skipping.."
		    fi # will fault if not given proper arguments! Internal usage only!
		fi
		;;
	esac
    done
}

function displayHelp () {
    echo "Usage: link-conf [-r|--relink] [-f|--force] [-c|--clean] [-v|--verbose] [-d|--dry] [-h|--help] config-dir"
}

# Option variables set when parsing cli parameters
RELINK=false
CLEAN=false
VERBOSE=false
FORCE=false
DRY=false
CONFIG_DIR=""

# Use getopt to parse given cli arguments
args=`getopt -n link-conf -o rcfvdh -l relink,clean,force,verbose,dry,help -- $*`
if [ ! $? ]; then
    echo "Failed to parse arguments!"
    displayHelp
    exit 1
fi

# Set arguments to the new ones done by using getopt
set -- $args

while true; do
    case "$1" in
	-r | --relink)
	    if $CLEAN; then
		echo "Error! Cannot specify relink and clean at once!"
		exit 1
	    elif [ !$RELINK ]; then
		RELINK=true
	    else
		echo "Error! -r | --relink used more then once!"
		exit 1
	    fi
	    ;;
	-c | --clean)
	    if $RELINK; then
		echo "Error! Cannot specify relink and clean at once!"
		exit 1
	    elif [ !$CLEAN ]; then
		CLEAN=true
	    else
		echo "Error! -c | --clean used more then once!"
		exit 1
	    fi
	    ;;
	-v | --verbose)
	    if [ !$VERBOSE ]; then
		VERBOSE=true
	    else
		echo "Error! -v | --verbose used more then once!"
		exit 1
	    fi
	    ;;
	-f | --force)
	    if [ !$FORCE ]; then
		FORCE=true
	    else
		echo "Error! -f | --force used more then once!"
		exit 1
	    fi
	    ;;
	-d | --dry)
	    if [ !$DRY ]; then
		DRY=true
	    else
		echo "Error! -d | --dry used more then once!"
		exit 1
	    fi
	    ;;
	-h | --help)
	    displayHelp
	    exit 0
	    ;;
	--)
	    shift
	    for arg; do
		maybe_dir=$(echo $arg | sed "s/^\([\']\)\(.*\)\1\$/\2/g")
		if [ "$CONFIG_DIR" == "" ]; then
		    if [[ -d "$maybe_dir" ]]; then
			CONFIG_DIR="$maybe_dir"
		    else
			echo "Error! The path given \"$maybe_dir\" is not a valid directory!"
			exit 1
		    fi
		else
		    echo "Error! More then one config dir was given!"
		    displayHelp
		    exit 1
		fi
	    done
	    break
	    ;;
	*)
	    echo "Internal error!"
	    exit 1
	    ;;
    esac
    shift
done

# Notify the user if it is a dry run
if $DRY; then
    echo "Dry run.."
fi

# Run the recursive hard linking algorithm
lnfrec "$CONFIG_DIR" "" $RELINK $CLEAN $VERBOSE $FORCE $DRY

# exit gracefully
exit 0