#!/bin/bash

# NAME: clipboard-diff
# PATH: $HOME/.local/share/nautilus/scripts
# DESC: Find differences bewteen selected file on disk and clipboard.
# CALL: Called from Nautilus file manager.
# DATE: March 18, 2017. Modified: March 31, 2017.

# NOTE: The clipboard would contain text highlighted on website and copied
#       with <ctrl>+<C>. Requires command `xclip` to be installed.

# Must have the xclip package. On Ubuntu 16.04, not installed by default
command -v xclip >/dev/null 2>&1 || { zenity --error --text "Install xclip using: 'sudo apt install xclip' to use this script.  Aborting."; exit 99; }

# strip new line char passed by Nautilus
FILENAME=$(echo $NAUTILUS_SCRIPT_SELECTED_FILE_PATHS | sed -e 's/\r//g')

# Multiple files can't be selected.
LINE_COUNT=$(wc -l <<< "$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS")
LINE_COUNT=$((LINE_COUNT-1))

if [[ $LINE_COUNT > 1 ]] ; then
    zenity --error --text "Ony one file can be selected at a time! "
    exit 1
fi

# Object type must be "file..." (ie no directories, etc.)
if [ -d "${FILENAME}" ] ; then
    zenity --error --text "$FILENAME is a directory!";
    exit 1
else
    if [ -f "${FILENAME}" ]; then
        : # Bash noop
    else
        zenity --error --text "${FILENAME} is not a file!";
        exit 2
    fi
fi

# Get clipboard contents into working file
workfile="/tmp/clipboard-work-"$(date +%s)
xclip -o > $workfile

# Create temporary file name so two or more open instances won't clash
differences="/tmp/clipboard-diff-"$(date +%s)

# Compare file differences
# -q brief -B ignore blank lines, -u only differences
diff --unified=2 -w -b -B -I --suppress-blank-empty \
        --suppress-common-lines --ignore-all-space \
        ${FILENAME} $workfile > $differences

# If file doesn't exist, errors in diff parameters
# If file size =0 there were no differences
if [[ -f $differences ]] ; then
    if [[ -s $differences ]] ; then
        # File not empty.
        gedit $differences
    else    
        zenity --info --text "$workfile matches $differences"
    fi
else
    zenity --error --text "cliboard-diff - error in diff parameters."
fi

# clean up /tmp directory
rm $workfile
rm $differences

exit 0