#!/bin/bash

dir=`mktemp --directory`

hb_shape=$1

shift

fontfile=$1

if test "x${fontfile:0:1}" == 'x-'; then

	echo "Specify font file before other options." >&2

	exit 1

fi

shift

if ! echo "$hb_shape" | grep -q 'hb-shape'; then

	echo "Specify hb-shape (not hb-view, etc)." >&2

	exit 1

fi

options=

have_text=false

for arg in "$@"; do

	if test "x${arg:0:1}" == 'x-'; then

		if echo "$arg" | grep -q ' '; then

			echo "Space in argument is not supported: '$arg'." >&2

			exit 1

		fi

		options="$options${options:+ }$arg"

		continue

	fi

	if $have_text; then

		echo "Too many arguments found...  Use '=' notation for options: '$arg'" >&2

		exit 1;

	fi

	text="$arg"

	have_text=true

done

if ! $have_text; then

	text=`cat`

fi

unicodes=`echo "$text" | ./hb-unicode-decode`

glyphs=`echo "$text" | $hb_shape $options "$fontfile"`

if test $? != 0; then

	echo "hb-shape failed." >&2

	exit 2

fi

cp "$fontfile" "$dir/font.ttf"

pyftsubset \

	--glyph-names \

	--no-hinting \

	"$dir/font.ttf" \

	--text="$text"

if ! test -s "$dir/font.subset.ttf"; then

	echo "Subsetter didn't produce nonempty subset font in $dir/font.subset.ttf" >&2

	exit 2

fi

# Verify that subset font produces same glyphs!

glyphs_subset=`echo "$text" | $hb_shape $options "$dir/font.subset.ttf"`

if ! test "x$glyphs" = "x$glyphs_subset"; then

	echo "Subset font produced different glyphs!" >&2

	echo "Perhaps font doesn't have glyph names; checking visually..." >&2

	hb_view=${hb_shape/shape/view}

	echo "$text" | $hb_view $options "$dir/font.ttf" --output-format=png --output-file="$dir/orig.png"

	echo "$text" | $hb_view $options "$dir/font.subset.ttf" --output-format=png --output-file="$dir/subset.png"

	if ! cmp "$dir/orig.png" "$dir/subset.png"; then

		echo "Images differ.  Please inspect $dir/*.png." >&2

		echo "$glyphs"

		echo "$glyphs_subset"

		exit 2

	fi

	echo "Yep; all good." >&2

	rm -f "$dir/orig.png"

	rm -f "$dir/subset.png"

	glyphs=$glyphs_subset

fi

sha1sum=`sha1sum "$dir/font.subset.ttf" | cut -d' ' -f1`

subset="fonts/sha1sum/$sha1sum.ttf"

mv "$dir/font.subset.ttf" "$subset"

# There ought to be an easier way to do this, but it escapes me...

unicodes_file=`mktemp`

glyphs_file=`mktemp`

echo "$unicodes" > "$unicodes_file"

echo "$glyphs" > "$glyphs_file"

# Open the "file"s

exec 3<"$unicodes_file"

exec 4<"$glyphs_file"

while read uline <&3 && read gline <&4; do

	echo "$subset:$options:$uline:$gline"

done

rm -f "$dir/font.ttf"

rmdir "$dir"