#! /bin/bash

# AUTHOR:	(c) Ricardo Ferreira
# NAME:		Compress PDF 1.4
# DESCRIPTION:	A nice Nautilus script with a GUI to compress and optimize PDF files
# REQUIRES:	ghostscript, poppler-utils, zenity
# LICENSE:	GNU GPL v3 (http://www.gnu.org/licenses/gpl.html)
# WEBSITE:	https://launchpad.net/compress-pdf

# Messages
		# English (en-US)
		error_nofiles="No file selected."
		error_noquality="No optimization level selected."
		error_ghostscript="PDF Compress requires the ghostscript package, which is not installed. Please install it and try again."
		error_nopdf="The selected file is not a valid PDF archive."
		label_filename="Save PDF as..."
		label_level="Please choose an optimization level below."
		optimization_level="Optimization Level"
		level_default="Default"
		level_screen="Screen-view only"
		level_low="Low Quality"
		level_high="High Quality"
		level_color="High Quality (Color Preserving)"
		job_done="has been successfully compressed"

VERSION="1.4"
ZENITY=$(which zenity)

pdf_file=$(basename "$1")

# Check if Ghostscript is installed
GS="/usr/bin/ghostscript"
if [ ! -x $GS ]; then
        $ZENITY --error --title="Compress PDF "$VERSION"" --text="$error_ghostscript"
        exit 0;
fi

# Check if the user has selected any files
if [ -z "$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS" ]; then
        $ZENITY --error --title="Compress PDF "$VERSION"" --text="$error_nofiles"
        exit 0;
fi

# Check if the selected file is a PDF
mimetype=$(file -b -i "$1")
if [ -z "`echo $mimetype | grep -i 'pdf' `" ]; then
	$ZENITY --error --title="Compress PDF "$VERSION"" --text="$error_nopdf"
        exit 0;
fi

# Choose output file name
temp_filename=.temp-"$pdf_file"
suggested_filename=compressed-"$pdf_file"
output_filename=$($ZENITY --file-selection --save --confirm-overwrite --filename="$suggested_filename" --title="$label_filename")

if [ "$?" = 1 ] ; then
        exit 0;
fi

# Extract metadata from the original PDF
pdfinfo "$1" | sed -e 's/^ *//;s/ *$//;s/ \{1,\}/ /g' -e 's/^/  \//' -e '/CreationDate/,$d' -e 's/$/)/' -e 's/: / (/' > .pdfmarks
sed -i '1s/^ /[/' .pdfmarks
sed -i '/:)$/d' .pdfmarks
echo "  /DOCINFO pdfmark" >> .pdfmarks

function gsoptimise {
local DPI=150
local OUTPUT="$1"
shift
gs      -q -dNOPAUSE -dBATCH -dSAFER \
        -sDEVICE=pdfwrite \
        -dCompatibilityLevel=1.4 \
        -dEmbedAllFonts=true \
        -dSubsetFonts=true \
        -dUseFlateCompression=true \
        -dOptimize=true \
        -dProcessColorModel=/DeviceRGB \
        -dUseCIEColor=true \
        -dDownsampleGrayImages=true \
        -dGrayImageDownsampleType=/Bicubic \
        -dGrayImageResolution=$DPI \
        -dAutoFilterGrayImages=false \
        -dDownsampleMonoImages=true \
        -dMonoImageDownsampleType=/Bicubic \
        -dMonoImageResolution=$DPI \
        -dDownsampleColorImages=true \
        -dColorImageDownsampleType=/Bicubic \
        -dColorImageResolution=$DPI \
        -dAutoFilterColorImages=false \
        -dPDFSETTINGS=/default \
        -sOutputFile="$OUTPUT" \
         "$@"
}

# Execute ghostscript while showing a progress bar
(echo "0" ;
 gsoptimise "$temp_filename" "$1" .pdfmarks ;
 rm .pdfmarks
 echo "100") | (if `$ZENITY --progress --pulsate --auto-close --title="Compress PDF "$VERSION""`;
                 then
                     mv -f "$temp_filename" "$output_filename" &
                     notify-send "Compress PDF" "$pdf_file $job_done"
                 else
                     killall gs 
                     rm "$temp_filename"
                     exit
                 fi)