#!/bin/bash


set -x 
TMPDIR="$(mktemp -d)"

mkdir -p "$TMPDIR/a" "$TMPDIR/b" "$TMPDIR/c"
PDF_FILE="$(realpath "$1")"
ANNOT_FILE="$(realpath "${1}.annot")"
cp -l "$PDF_FILE" "$TMPDIR/a/file.pdf";
if [ -e "$ANNOT_FILE" ]; then
    cp "$PDF_FILE" "$TMPDIR/b/file.pdf";
    chmod u+w "$TMPDIR/b/file.pdf"
    qprint --binary --decode "$ANNOT_FILE" | patch -d "$TMPDIR/b" --binary;
    cp "$TMPDIR/b/file.pdf" "$TMPDIR/c/file.pdf";
else
    cp "$PDF_FILE" "$TMPDIR/b/file.pdf";
    cp "$PDF_FILE" "$TMPDIR/c/file.pdf";
    chmod u+w "$TMPDIR/b/file.pdf"
fi;


(cd "$TMPDIR/b"
 chmod u+w "file.pdf"
 if which okular > /dev/null 2>&1; then
     okular "file.pdf"
 else 
     ## evince really should just use the same document-directory
     gsettings set org.gnome.Evince document-directory "'file://$TMPDIR/b'";
     evince "file.pdf"
 fi;
);

if ! cmp "$TMPDIR/b/file.pdf" "$TMPDIR/c/file.pdf"; then
    (cd "$TMPDIR";
     diff -Nura a b ) | qprint --encode --binary > "$ANNOT_FILE"
fi;
if ! [ -s "$ANNOT_FILE" ]; then
    rm -f "$ANNOT_FILE";
fi;
rm -f "$TMPDIR/a/file.pdf"
rm -f "$TMPDIR/b/file.pdf"
rm -f "$TMPDIR/c/file.pdf"
rmdir "$TMPDIR/a" "$TMPDIR/b" "$TMPDIR/c" "$TMPDIR"