#!/usr/bin/env bash

# PDF2ARCHIVE 0.3.2
# (C) 2018 Matteo Seclì <secli.matteo@gmail.com>
#
# 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/>.


#=====# INITIALIZE VARIABLES #=====#
VERSION="0.3.2"
INPUT=""
OUTPUT=""
QUALITYOPTS=""
DEBUG=false
VALIDATE=false
MSGOPTS="-dQUIET -sstdout=/dev/null"
VERAMSGOPTS=""
#ERROPTS="2>/dev/null"


#=====# HELP FUNCTION #=====#
help()
{
    TOTLEN="38"   # Adjust this
    TITLESTRING="PDF2ARCHIVE, version $VERSION"
    SPACEL=$(echo "($TOTLEN-${#TITLESTRING})/2 + (36-${#TITLESTRING})%2 - 1" | bc)
    SPACER=$(echo "($TOTLEN-${#TITLESTRING})/2 - 1" | bc)
    TITLESTRING=$(printf "|%-${SPACEL}s%s%-${SPACER}s|" "" "$TITLESTRING" "")
    DASHSTRING=$(eval printf "%.0s-" {1..$TOTLEN})
    echo \
"$DASHSTRING
$TITLESTRING
$DASHSTRING

OVERVIEW:
  A simple Ghostscript-based PDF to PDF/A-1B converter.

USAGE:
  $0 [options] input.pdf [output.pdf]

EXAMPLES:
  Convert 'input.pdf' in PDF/A-1B format; the output is 'input-PDFA.pdf':
      $0 input.pdf
  Convert 'input.pdf' in PDF/A-1B format; the output is 'output.pdf':
      $0 input.pdf output.pdf
  Convert 'input.pdf' in PDF/A-1B format and perform a high-quality compression:
      $0 --quality=high input.pdf
  Convert 'input.pdf' in PDF/A-1B format and specify the document title:
      $0 --title=\"Title of your nice document\" input.pdf
  Convert 'input.pdf' in PDF/A-1B format and validate the result:
      $0 --validate input.pdf

OPTIONS:
  -h, --help          Show the help
  --quality=<value>   Set  the  quality of  the  output  when  downsampling. The
                      possible values  are  'high',  'medium'  and  'low', where
                      'high' gives the highest output  quality. By specifying no
                      option, no additional downsampling is done.
  --title=<value>     Title of the resulting PDF/A file
  --author=<value>    Author of the resulting PDF/A file
  --subject=<value>   Subject of the resulting PDF/A file
  --keywords=<value>  Comma-separated keywords of the resulting PDF/A file
  --cleanmetadata     Clean  all the standard  metadata  fields, except the ones
                      specified via the command line options.
  --validate          Validate  the resulting file. The  validation is done with
                      VeraPDF, you need a working Java installation.
  --validate-only     Perform only the validation on the input file, again using
                      VeraPDF
  --debug             Write additional debug information on screen
  -v, --version       Show the program version

LICENSE:
  GPLv3

AUTHORS:
  (C) 2017-2018 Matteo Seclì"
}


#=====# RUN HELPER FUNCTION #=====#
run() {
    if $DEBUG; then
        #v=$(exec 2>&1 && set -x && set -- "$@")
        #echo "#${v#*--}"
        "$@"
    else
        "$@" 2>/dev/null #>/dev/null 2>&1
    fi
}


#=====# CHECKS #=====#
if [ "$(which gs)" == "" ]; then
    echo "  ERROR: Ghostscript is not installed or it's not in the path"
    exit
fi


#=====# VALIDATION #=====#

javaCheck() {
    if [ "$(which java)" == "" ]; then
        echo "  ERROR: Java is not installed or it's not in the path"
        echo "  Cannot perform validation"
        exit 1
    fi
}

validate() {
    echo "  Validating..."
    echo "  $(./verapdf/verapdf "$1" --extract --flavour 1b --format text "$2")"
}


#=====# INPUT PARSER #=====#
if [ "$1" == "" ]; then
    help
    exit
fi
while [ "$1" != "" ]; do
    PARAM=`echo $1 | awk -F= '{print $1}'`
    VALUE=`echo $1 | awk -F= '{print $2}'`
    case $PARAM in
        -h | --help)
            help
            exit
            ;;
        -v | --version)
            echo $VERSION
            exit
            ;;
        --debug)
            DEBUG=true
            MSGOPTS=""
            VERAMSGOPTS="--verbose"
            #ERROPTS=""
            ;;
        --quality)
            if [ "$VALUE" == "high" ]; then
                QUALITYOPTS="-dPDFSETTINGS=/printer"
            elif [ "$VALUE" == "medium" ]; then
                QUALITYOPTS="-dPDFSETTINGS=/ebook"
            elif [ "$VALUE" == "low" ]; then
                QUALITYOPTS="-dPDFSETTINGS=/screen"
            else
                echo "  ERROR: unknown quality option '$VALUE'"
                help
                exit 1
            fi
            ;;
        --cleanmetadata)
            [ -z ${PDFTITLE+x} ] && PDFTITLE=""
            [ -z ${PDFAUTHOR+x} ] && PDFAUTHOR=""
            [ -z ${PDFSUBJECT+x} ] && PDFSUBJECT=""
            [ -z ${PDFKEYWORDS+x} ] && PDFKEYWORDS=""
            [ -z ${PDFCREATOR+x} ] && PDFCREATOR=""
            [ -z ${PDFPRODUCER+x} ] && PDFPRODUCER=""
            [ -z ${PDFCREATIONDATE+x} ] && PDFCREATIONDATE=""
            [ -z ${PDFMODDATE+x} ] && PDFMODDATE=""
            [ -z ${PDFTRAPPED+x} ] && PDFTRAPPED=""
            ;;
        --title)
            PDFTITLE=$VALUE
            ;;
        --author)
            PDFAUTHOR=$VALUE
            ;;
        --subject)
            PDFSUBJECT=$VALUE
            ;;
        --keywords)
            PDFKEYWORDS=$VALUE
            ;;
        --validate)
            javaCheck
            VALIDATE=true
            ;;
        --validate-only)
            javaCheck
            validate $VERAMSGOPTS $2
            exit
            ;;
        *.pdf)
            if [ "$INPUT" == "" ]; then
                INPUT=$PARAM
            elif [ "$OUTPUT" == "" ]; then
                OUTPUT=$PARAM
            else
                echo "  ERROR: too many PDF files as input!"
                help
                exit 1
            fi
            ;;
        *)
            echo "  ERROR: unknown parameter \"$PARAM\""
            help
            exit 1
            ;;
    esac
    shift
done

#=====# SET UP ALL THE STUFF #=====#
echo "=== Welcome to PDF2ARCHIVE ==="
if [ "$OUTPUT" == "" ]; then
    OUTPUT="${INPUT%.pdf}-PDFA.pdf"
fi
TMPFILE=$(mktemp)
TMPDIR=$(mktemp -d)
PSTMPFILE=$TMPDIR/PDFA_def.ps
ICCTMPFILE=$TMPDIR/AdobeRGB1998.icc
INFOTMPFILE=$TMPDIR/pdf_minimal_info.ps
echo \
"%!PS
% Extract PDF info in a minimal way.
% Inspired by 'toolbin/pdf_info.ps'.

/QUIET true def
File dup (r) file runpdfbegin
Trailer /Info knownoget {
dup /Title knownoget { (__knowninfoTitle: ) print = flush } if
dup /Author knownoget { (__knowninfoAuthor: ) print = flush } if
dup /Subject knownoget { (__knowninfoSubject: ) print = flush } if
dup /Keywords knownoget { (__knowninfoKeywords: ) print = flush } if
dup /Creator knownoget { (__knowninfoCreator: ) print = flush } if
dup /Producer knownoget { (__knowninfoProducer: ) print = flush } if
dup /CreationDate knownoget { (__knowninfoCreationDate: ) print = flush } if
dup /ModDate knownoget { (__knowninfoModDate: ) print = flush } if
dup /Trapped knownoget { (__knowninfoTrapped: ) print = flush } if
} if
quit
" > $INFOTMPFILE


#=====# PRESERVE UNSPECIFIED KNOWN STANDARD METADATA #=====#
# Notes:
#     'iconv' is necessary to filter out all the invalid bytes.
#     If it's not used, sed (unless it's GNU sed) will fail with
#     'RE error: illegal byte sequence'. A solution to this is to
#     use 'LC_CTYPE=C && LANG=C && echo "$METADUMP" ...' in the
#     variable assignments; however, this produces bad PDF files.
#
METADUMP=$(gs -dNOSAFER -dNODISPLAY -q -sFile="$INPUT" $INFOTMPFILE | iconv -f utf-8 -t utf-8 -c)
[ -z ${PDFTITLE+x} ] && PDFTITLE=$(echo "$METADUMP" | grep "__knowninfoTitle: " | sed "s/^__knowninfoTitle: //g")
[ -z ${PDFAUTHOR+x} ] && PDFAUTHOR=$(echo "$METADUMP" | grep "__knowninfoAuthor: " | sed "s/^__knowninfoAuthor: //g")
[ -z ${PDFSUBJECT+x} ] && PDFSUBJECT=$(echo "$METADUMP" | grep "__knowninfoSubject: " | sed "s/^__knowninfoSubject: //g")
[ -z ${PDFKEYWORDS+x} ] && PDFKEYWORDS=$(echo "$METADUMP" | grep "__knowninfoKeywords: " | sed "s/^__knowninfoKeywords: //g")
[ -z ${PDFCREATOR+x} ] && PDFCREATOR=$(echo "$METADUMP" | grep "__knowninfoCreator: " | sed "s/^__knowninfoCreator: //g")
[ -z ${PDFPRODUCER+x} ] && PDFPRODUCER=$(echo "$METADUMP" | grep "__knowninfoProducer: " | sed "s/^__knowninfoProducer: //g")
[ -z ${PDFCREATIONDATE+x} ] && PDFCREATIONDATE=$(echo "$METADUMP" | grep "__knowninfoCreationDate: " | sed "s/^__knowninfoCreationDate: //g")
[ -z ${PDFMODDATE+x} ] && PDFMODDATE=$(echo "$METADUMP" | grep "__knowninfoModDate: " | sed "s/^__knowninfoModDate: //g")
[ -z ${PDFTRAPPED+x} ] && PDFTRAPPED=$(echo "$METADUMP" | grep "__knowninfoTrapped: " | sed "s/^__knowninfoTrapped: //g")
# Replace "Trapped" string, if not empty, with an operator. Fixes 3Heights.
if [ "$PDFTRAPPED" != "" ]; then
  PDFTRAPPED="/$(tr '[:lower:]' '[:upper:]' <<< ${PDFTRAPPED:0:1})$(tr '[:upper:]' '[:lower:]' <<< ${PDFTRAPPED:1})"
fi
# Check if the operator is allowed, otherwise empty variable.
if [ "$PDFTRAPPED" != "/True" ] && [ "$PDFTRAPPED" != "/False" ]; then
  PDFTRAPPED=""
fi


#=====# PRINT DEBUG INFO #=====#
if $DEBUG; then
    echo "  DEBUG: running PDF2ARCHIVE, version $VERSION"
    echo "  DEBUG: using Ghostscript binary at $(which gs), version $(gs --version)"
    echo "  DEBUG: the input file is '$INPUT'"
    echo "  DEBUG: the output file is '$OUTPUT'"
    echo "  DEBUG: the intermediate processing file is $TMPFILE"
    echo "  DEBUG: the temporary directory is $TMPDIR"
    echo "  DEBUG: the current quality options are '$QUALITYOPTS'"
    echo "  DEBUG: PDF title '$PDFTITLE'"
    echo "  DEBUG: PDF author '$PDFAUTHOR'"
    echo "  DEBUG: PDF subject '$PDFSUBJECT'"
    echo "  DEBUG: PDF keywords '$PDFKEYWORDS'"
    echo "  DEBUG: PDF creator '$PDFCREATOR'"
    echo "  DEBUG: PDF producer '$PDFPRODUCER'"
    echo "  DEBUG: PDF creation date '$PDFCREATIONDATE'"
    echo "  DEBUG: PDF modification date '$PDFMODDATE'"
    echo "  DEBUG: PDF trapping '$PDFTRAPPED'"
fi


#=====# CREATE THE PS DEFINITION FILE #=====#
echo "  Creating the definition file..."
echo \
"%!
% This prefix file for creating a PDF/A document is derived from
% the sample included with Ghostscript 9.07, released under the
% GNU Affero General Public License.
% Modified 4/15/2013 by MCB Systems.

% Feel free to modify entries marked with \"Customize\".

% This assumes an ICC profile to reside in the file (AdobeRGB1998.icc),
% unless the user modifies the corresponding line below.

% The color space described by the ICC profile must correspond to the
% ProcessColorModel specified when using this prefix file (GRAY with
% DeviceGray, RGB with DeviceRGB, and CMYK with DeviceCMYK).

% Define entries in the document Info dictionary :

/ICCProfile ($ICCTMPFILE)   % Customize.
def

[ /Title ($PDFTITLE)                  % Customize." > $PSTMPFILE
if [ "$PDFAUTHOR" != "" ]; then
  echo "  /Author ($PDFAUTHOR)" >> $PSTMPFILE
fi
if [ "$PDFSUBJECT" != "" ]; then
  echo "  /Subject ($PDFSUBJECT)" >> $PSTMPFILE
fi
if [ "$PDFKEYWORDS" != "" ]; then
  echo "  /Keywords ($PDFKEYWORDS)" >> $PSTMPFILE
fi
if [ "$PDFCREATOR" != "" ]; then
  echo "  /Creator ($PDFCREATOR)" >> $PSTMPFILE
fi
echo \
"%  /Producer                          % Reserved to GS
%  /CreationDate                      % Reserved to GS
%  /ModDate                           % Reserved to GS" >> $PSTMPFILE
if [ "$PDFTRAPPED" != "" ]; then
  echo "  /Trapped $PDFTRAPPED" >> $PSTMPFILE
fi
echo \
"  /DOCINFO pdfmark

% Define an ICC profile :

[/_objdef {icc_PDFA} /type /stream /OBJ pdfmark
[{icc_PDFA} <</N systemdict /ProcessColorModel get /DeviceGray eq {1} {systemdict /ProcessColorModel get /DeviceRGB eq {3} {4} ifelse} ifelse >> /PUT pdfmark
[{icc_PDFA} ICCProfile (r) file /PUT pdfmark

% Define the output intent dictionary :

[/_objdef {OutputIntent_PDFA} /type /dict /OBJ pdfmark
[{OutputIntent_PDFA} <<
  /Type /OutputIntent             % Must be so (the standard requires).
  /S /GTS_PDFA1                   % Must be so (the standard requires).
  /DestOutputProfile {icc_PDFA}            % Must be so (see above).
  /OutputConditionIdentifier (AdobeRGB1998)      % Customize
>> /PUT pdfmark
[{Catalog} <</OutputIntents [ {OutputIntent_PDFA} ]>> /PUT pdfmark
" >> $PSTMPFILE


#=====# CREATE THE COLOR PROFILE FILE #=====#
echo -n -e "\\x00\\x00\\x02\\x30\\x41\\x44\\x42\\x45\\x02\\x10\\x00\\x00\\x6d\\x6e\\x74\\x72\\x52\\x47\\x42\\x20\\x58\\x59\\x5a\\x20\\x07\\xd0\\x00\\x08\\x00\\x0b\\x00\\x13\\x00\\x33\\x00\\x3b\\x61\\x63\\x73\\x70\\x41\\x50\\x50\\x4c\\x00\\x00\\x00\\x00\\x6e\\x6f\\x6e\\x65\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\xf6\\xd6\\x00\\x01\\x00\\x00\\x00\\x00\\xd3\\x2d\\x41\\x44\\x42\\x45\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x0a\\x63\\x70\\x72\\x74\\x00\\x00\\x00\\xfc\\x00\\x00\\x00\\x32\\x64\\x65\\x73\\x63\\x00\\x00\\x01\\x30\\x00\\x00\\x00\\x6b\\x77\\x74\\x70\\x74\\x00\\x00\\x01\\x9c\\x00\\x00\\x00\\x14\\x62\\x6b\\x70\\x74\\x00\\x00\\x01\\xb0\\x00\\x00\\x00\\x14\\x72\\x54\\x52\\x43\\x00\\x00\\x01\\xc4\\x00\\x00\\x00\\x0e\\x67\\x54\\x52\\x43\\x00\\x00\\x01\\xd4\\x00\\x00\\x00\\x0e\\x62\\x54\\x52\\x43\\x00\\x00\\x01\\xe4\\x00\\x00\\x00\\x0e\\x72\\x58\\x59\\x5a\\x00\\x00\\x01\\xf4\\x00\\x00\\x00\\x14\\x67\\x58\\x59\\x5a\\x00\\x00\\x02\\x08\\x00\\x00\\x00\\x14\\x62\\x58\\x59\\x5a\\x00\\x00\\x02\\x1c\\x00\\x00\\x00\\x14\\x74\\x65\\x78\\x74\\x00\\x00\\x00\\x00\\x43\\x6f\\x70\\x79\\x72\\x69\\x67\\x68\\x74\\x20\\x32\\x30\\x30\\x30\\x20\\x41\\x64\\x6f\\x62\\x65\\x20\\x53\\x79\\x73\\x74\\x65\\x6d\\x73\\x20\\x49\\x6e\\x63\\x6f\\x72\\x70\\x6f\\x72\\x61\\x74\\x65\\x64\\x00\\x00\\x00\\x64\\x65\\x73\\x63\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x11\\x41\\x64\\x6f\\x62\\x65\\x20\\x52\\x47\\x42\\x20\\x28\\x31\\x39\\x39\\x38\\x29\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x58\\x59\\x5a\\x20\\x00\\x00\\x00\\x00\\x00\\x00\\xf3\\x51\\x00\\x01\\x00\\x00\\x00\\x01\\x16\\xcc\\x58\\x59\\x5a\\x20\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x63\\x75\\x72\\x76\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x01\\x02\\x33\\x00\\x00\\x63\\x75\\x72\\x76\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x01\\x02\\x33\\x00\\x00\\x63\\x75\\x72\\x76\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x01\\x02\\x33\\x00\\x00\\x58\\x59\\x5a\\x20\\x00\\x00\\x00\\x00\\x00\\x00\\x9c\\x18\\x00\\x00\\x4f\\xa5\\x00\\x00\\x04\\xfc\\x58\\x59\\x5a\\x20\\x00\\x00\\x00\\x00\\x00\\x00\\x34\\x8d\\x00\\x00\\xa0\\x2c\\x00\\x00\\x0f\\x95\\x58\\x59\\x5a\\x20\\x00\\x00\\x00\\x00\\x00\\x00\\x26\\x31\\x00\\x00\\x10\\x2f\\x00\\x00\\xbe\\x9c" > $ICCTMPFILE


#=====# DO THE ACTUAL CONVERSION #=====#
echo "  Compressing PDF & embedding fonts..."
run gs $MSGOPTS \
    -dBATCH -dNOPAUSE -dNOOUTERSAVE \
    -dCompatibilityLevel=1.4 \
    -dEmbedAllFonts=true -dSubsetFonts=true \
    -dCompressFonts=true -dCompressPages=true \
    -sColorConversionStrategy=RGB \
    -dDownsampleMonoImages=false -dDownsampleGrayImages=false -dDownsampleColorImages=false \
    -dAutoFilterColorImages=false -dAutoFilterGrayImages=false \
    -sDEVICE=pdfwrite \
    -sOutputFile="$TMPFILE" "$INPUT"
echo "  Converting to PDF/A-1B..."
run gs $MSGOPTS \
    -dPDFA=1 -dBATCH -dNOPAUSE -dNOOUTERSAVE \
    $QUALITYOPTS \
    -dCompatibilityLevel=1.4 -dPDFACompatibilityPolicy=1 \
    -sProcessColorModel=DeviceRGB -sColorConversionStrategy=RGB \
    -sOutputICCProfile=$ICCTMPFILE \
    -sDEVICE=pdfwrite \
    -sOutputFile="$OUTPUT" "$TMPFILE" $PSTMPFILE
echo "  Removing temporary files..."
rm $TMPFILE
echo "  Done, now ESSE3 is happy! ;)"


#=====# VALIDATE THE RESULT #=====#
if $VALIDATE; then
    validate $VERAMSGOPTS "$OUTPUT"
else
    echo "  Suggestion: validate the resulting PDF to be sure it's PDF/A-1B compliant."
fi