#!/bin/sh
#
# /usr/local/bin/localpdf2ps2pdf
# Copyright 2008-2023  Jonas Smedegaard <dr@jones.dk>
#
# Refry PDF file.
#

set -e

PRG="$(basename "$0")"

# Default options
PDF2PSOPTS=""
PS2PDFOPTS="-dDownsampleColorImages=true -dColorImageResolution=150"

showhelp() {
	cat <<EOF
Usage:   $PRG INFILE [ OUTFILE ] [ pdf2ps opts ] [ -- ps2pdf opts ]

Defaults:
    OUTFILE:  INFILE with trailing ".pdf" replaced with "_lowres.pdf".
    pdf2ps:  $pdf2psOPTS
    ps2pdf:   $PS2PDFOPTS

Examples:
    $PRG file.pdf dFirstPage=7 -dLastPage=9
    $PRG file.pdf -- -dPDFA -dPDFACompatibilityPolicy=1
    $PRG file.pdf -- -dPDFSETTINGS=/screen
    $PRG file.pdf -dLanguageLevel=3 -- -dPDFSETTINGS=/prepress

First example above picks pages 7-9.
Second example above reduces PDF complexity.
Third example reduces image size for screen-only use.
Fourth example preserves complexity and image size for professional use.

Defaults reduce file size for 300 DPI color print use.

EOF
}

exit1() {
	echo >&2 "ERROR: $1"
	exit 1
}

[ $# -gt 0 ] || exit1 "Input file missing"

infile=
outfile=
pdf2psopts=
pstopdfopts=
while [ $# -gt 0 ]; do
	case $1 in
		-h|--help)
			showhelp
			exit 0
			;;
		--)
			shift
			break
			;;
		-*)
			pdf2psopts="$pdf2psopts $1"
			shift
			;;
		*)
			if [ -z "$infile" ]; then
				infile="$1"
			elif [ -z "$outfile" ]; then
				outfile="$1"
			else
				exit1 "Too many parameters"
			fi
			shift
			;;
	esac
done
ps2pdfopts="$@"

# Use defaults if not overridden
outfile="${outfile:-$(basename "$infile" .pdf)_lowres.pdf}"
pdf2psopts="${pdf2psopts:-$PDF2PSOPTS}"
ps2pdfopts="${ps2pdfopts:-$PS2PDFOPTS}"

[ ! -e "$outfile" ] || exit1 "Output file already exists"

tmpfile=$(mktemp -t "$PRG.XXXXXXXXXX") || exit 1

pdf2ps $pdf2psopts "$infile" "$tmpfile" || rm "$tmpfile"
ps2pdf $ps2pdfopts "$tmpfile" "$outfile"

rm "$tmpfile"

exit 0