-module(ttf_parser).
-export([read/1]).

-import(font_directory, [parse_font_directory/1]).
-import(table, [parse_table/4]).

parse_at_table_directory(File, TableDirectory, TableTag, Info) ->
	TableDirectoryEntry = proplists:get_value(TableTag, TableDirectory),
	Offset = proplists:get_value(offset, TableDirectoryEntry),
	Length = proplists:get_value(length, TableDirectoryEntry),
	<<_:Offset/binary, Table:Length/binary, _/binary>> = File,
	parse_table(TableTag, Table, Length, Info).
parse_at_table_directory(File, TableDirectory, TableTag) -> parse_at_table_directory(File, TableDirectory, TableTag, {}).

read(Filename) ->
	{ok, File} = file:read_file(Filename),
	FontDirectory = parse_font_directory(File),
	TableDirectory = proplists:get_value(table_directory, FontDirectory),
	
	FontHeader = parse_at_table_directory(File, TableDirectory, head),
	HorizontalHeader = parse_at_table_directory(File, TableDirectory, hhea),
	MaximumProfile = parse_at_table_directory(File, TableDirectory, maxp),
	HorizontalMetrics = parse_at_table_directory(File, TableDirectory, hmtx, [
		{number_of_h_metrics, proplists:get_value(number_of_h_metrics, HorizontalHeader)}, 
		{num_glyphs, proplists:get_value(num_glyphs, MaximumProfile)}
	]),
	[
		{font_header, FontHeader},
		{horizontal_header, HorizontalHeader},
		{maximum_profile, MaximumProfile},
		{horizontal_metrics, HorizontalMetrics}
	].