#!/bin/bash

trap "exit" INT

dirname=`dirname "$0"`

# Parse options
output_dir=
font_file=
face_index=0
hb_view=hb-view
hb_info=hb-info
hb_svg_compare=$dirname/hb-svg-compare
tolerance=0
font_size=upem
features=
variations=
face_loader=ot
shaper=ot
font_funcs1=ot
font_funcs2=fontations
clear1=false
clear2=false
unicodes=
glyphs=
quiet=false
help=false
while test $# -gt 0; do
	case "$1" in
		-o|--output-dir)
			shift
			output_dir=$1
			shift
			;;
		--font-file)
			shift
			font_file=$1
			shift
			;;
		--face-index)
			shift
			face_index=$1
			shift
			;;
		--hb-view)
			shift
			hb_view=$1
			shift
			;;
		--hb-info)
			shift
			hb_info=$1
			shift
			;;
		--hb-svg-compare)
			shift
			hb_svg_compare=$1
			shift
			;;
		--tolerance)
			shift
			tolerance=$1
			shift
			;;
		--font-size)
			shift
			font_size=$1
			shift
			;;
		--features)
			shift
			features=$1
			shift
			;;
		--variations)
			shift
			variations=$1
			shift
			;;
		--unicodes)
			shift
			unicodes=$1
			shift
			;;
		--face-loader)
			shift
			face_loader=$1
			shift
			;;
		--shaper)
			shift
			shaper=$1
			shift
			;;
		--font-funcs1)
			shift
			font_funcs1=$1
			shift
			;;
		--font-funcs2)
			shift
			font_funcs2=$1
			shift
			;;
		--clear1)
			shift
			clear1=true
			;;
		--clear2)
			shift
			clear2=true
			;;
		--quiet)
			quiet=true
			shift
			;;
		--help)
			help=true
			shift
			;;
		*)
			if test "x$font_file" == x; then
				font_file=$1
				shift
			else
				glyphs="$glyphs $1"
				shift
			fi
			;;
	esac
done

if $help; then
	cmd=`basename "$0"`
	echo "Usage: $cmd [OPTIONS] FONTFILE [GLYPH...]"
	echo "Render a font with two font backends and compare the results."
	echo
	echo "Options:"
	echo "  -o, --output-dir DIR: Output in DIR"
	echo "  --font-file FONTFILE: Font file to render"
	echo "  --hb-view HB_VIEW: Path to hb-view; default $hb_view"
	echo "  --hb-info HB_INFO: Path to hb-info; default $hb_info"
	echo "  --hb-svg-compare HB_SVG_COMPARE: Path to hb-svg-compare; default $hb_svg_compare"
	echo "  --tolerance TOLERANCE: Tolerance for SVG comparison; default $tolerance"
	echo "  --font-size SIZE: Font size; default $font_size"
	echo "  --features FEATURES: Font features; default none"
	echo "  --variations VARIATIONS: Font variations; default none"
	echo "  --face-loader: Face loader; default $face_loader"
	echo "  --shaper: Shaper; default $shaper"
	echo "  --font-funcs0 font_funcs: First font-funcs; default $font_funcs1"
	echo "  --font-funcs1 font_funcs: Second font-funcs; default $font_funcs2"
	echo "  --clear1: Clear first font backend output if exists"
	echo "  --clear2: Clear second font backend output if exists"
	echo "  --unicodes CODES: Unicodes to render"
	echo "  --quiet: Quiet mode"
	echo "  --help: Print help"
	exit 0
fi

if test "x$font_file" == x; then
	echo "No font file specified." >&2
	exit 2
fi
if ! which "$hb_view" 2>/dev/null >/dev/null; then
	echo "'$hb_view' not found" >&2
	exit 2
fi
if ! which "$hb_info" 2>/dev/null >/dev/null; then
	echo "'$hb_info' not found" >&2
	exit 2
fi
if ! test -f "$font_file"; then
	echo "Font file '$font_file' not found" >&2
	exit 2
fi

# Sanity check Unicode values
if test "x$unicodes" != x; then
	echo "$unicodes" |
	tr ' ' '\n' |
	grep -v '^U[+][0-9a-fA-F]\+$' &&
	{
		echo "Invalid Unicode values" >&2
		exit 2
	}
fi

$quiet || echo "Comparing '$font_file' with '$font_funcs1' and '$font_funcs2' font backends. " >&2

if test "x$output_dir" == x; then
	output_dir=`mktemp -d`
	echo "Output in '$output_dir'" >&2
fi
mkdir -p "$output_dir" || exit 1

# Populate glyphs file
glyphs_file="$output_dir/glyphs"
> "$glyphs_file"
echo "$unicodes" |
sed 's/^U+//' |
grep . |
while read unicode; do
	echo "uni$unicode"
done >> "$glyphs_file"
echo "$glyphs" |
tr ' ' '\n' |
grep . >> "$glyphs_file"
if test "x$unicodes" == x -a "x$glyphs" == x; then
	$quiet || echo "No unicodes or glyphs specified. Comparing all glyphs in the font." >&2
	num_glyphs=`$hb_info --quiet --show-glyph-count "$font_file"`
	$quiet || echo "Font has $num_glyphs glyphs." >&2
	seq 0 $((num_glyphs - 1)) |
	sed 's/^/gid/' >> "$glyphs_file"
fi
num_glyphs=`cat "$glyphs_file" | wc -l`

flavor=
if test "$features" != ""; then
	flavor="$flavor.features=$features"
fi
if test "$variations" != ""; then
	flavor="$flavor.variations=$variations"
fi

# Render with both font backends
if $clear1; then
	funcs_prefix="$output_dir/$font_funcs1$flavor"
	$quiet || echo "Clearing '$funcs_prefix'... " >&2
	rm -rf "$funcs_prefix"
fi
if $clear2; then
	funcs_prefix="$output_dir/$font_funcs2$flavor"
	$quiet || echo "Clearing '$funcs_prefix'... " >&2
	rm -rf "$funcs_prefix"
fi
for font_funcs in "$font_funcs1" "$font_funcs2"; do
	test "x$font_funcs" == x && continue
	$quiet || echo "Rendering with font backend '$font_funcs'..." >&2

	funcs_prefix="$output_dir/$font_funcs$flavor"
	mkdir -p "$funcs_prefix"
	count=0
	cat "$glyphs_file" |
	while read glyph; do
		dir="$funcs_prefix"
		svg="$dir/$glyph.svg"
		if test -f "$svg"; then
			continue
		fi
		count=$((count + 1))
		if test $((count % 100)) == 0; then
			$quiet || echo -n . >&2
		fi
		echo \
			--font-file="$font_file" \
			--face-index=$face_index \
			--glyphs \
			--face-loader=$face_loader \
			--shaper=$this_shaper \
			--font-funcs=$font_funcs \
			--features="$features" \
			--variations="$variations" \
			--output-format=svg \
			--font-size=$font_size \
			--output-file="$svg" \
			"$glyph"
	done |
	sed 's/ /;/g' |
	"$hb_view" --batch >/dev/null
	$quiet || echo "" >&2
done

test "x$font_funcs1" == x || test "x$font_funcs2" == x && exit 0

diff="$output_dir/diff$flavor"
rm -f "$diff"
> "$diff"
test "x$flavor" == x || ln -f -s "diff$flavor" "$output_dir/diff"
$quiet || echo "Comparing SVGs into '$diff'..." >&2
funcs1_prefix="$output_dir/$font_funcs1$flavor"
funcs2_prefix="$output_dir/$font_funcs2$flavor"
count=0
cat "$glyphs_file" |
while read glyph; do
	count=$((count + 1))
	if test $((count % 100)) == 0; then
		$quiet || echo -n . >&2
	fi

	svg1="$funcs1_prefix/$glyph.svg"
	svg2="$funcs2_prefix/$glyph.svg"

	if ! test -f "$svg1" || ! test -f "$svg2"; then
		echo -e "\n$glyph not rendered." >&2
		exit 1
	fi

	echo -e "$svg1\t$svg2"
done |
"$hb_svg_compare" "$tolerance" |
while read line; do
	$quiet || echo -e "\n$line"
	echo "$line" >> "$diff"
done
# Sort diff by error
sort -n -o "$diff.tmp" "$diff" && mv "$diff.tmp" "$diff" || exit 1
# Count number of differences
num_diffs=`cat "$diff" | wc -l`
$quiet || echo -e "\nFound $num_diffs differences in $num_glyphs glyphs." >&2