require 'json'
require 'active_support/all'
require 'fileutils'
require 'shellwords'

class ::Metadata2FontsCss < ::Middleman::Extension
	def initialize app, **options_hash, &block
		super
		@additional_extentions = %w[woff]
	end
	def included() true end
	alias registered included
	class <<self
		def included() true end
		alias registered included
	end

	FontFace = <<EOF.gsub( /^\s*(.*?)\s*$/, '\1').gsub /\n/m, ''
    @font-face {
      font-family: "%<name>s";
      font-weight: %<weight>i;
      font-style: %<style>s;
      src:
        local("%<fullName>s"),
        local("%<postScriptName>s"),
        url("%<woff>s") format("woff"),
        url("%<ttf>s") format("truetype");
    }
EOF

	def manipulate_resource_list resources
		fonts_css = StringIO.new
		resources.lazy.
			select {|res| Pathname.new( res.path).basename.to_s == 'METADATA.json' }.
			map do |res|
				JSON.parse( File.read( f))['fonts'].each do |font|
					font = font.symbolize_keys
					font[:ttf]  = "/assets/fonts/#{font[:filename]}"
					font[:woff] = "/assets/fonts/#{font[:filename].gsub /\.[ot]tf\Z/, '.woff'}"
					fonts_css.printf FontFace, font
				end
			end

		resources.delete_if do |res|
			path = Pathname.new res.path
			if 'assets' == path.descend.first.to_s
				case path.basename.to_s
				when 'METADATA.pb' then true
				when 'METADATA.json' then true
				when 'DESCRIPTION.en_us.html' then true
				when 'OFL.txt' then true
				else false
				end
			else false
			end
		end

		resources << ::Middleman::Sitemap::StringResource.new(
			self.app.sitemap,
			'assets/styles/fonts.css',
			fonts_css.string)

		resources
	end
end

::Middleman::Extensions.register :fonts_css, ::Metadata2FontsCss

class ::Fonts4Web < ::Middleman::Extension
	def initialize app, **options_hash, &block
		super
		@converter = 'sfnt2woff-zopfli'
		@cachepath = Pathname.new '.fonts_cache'
	end
	def included() true end
	alias registered included
	class <<self
		def included() true end
		alias registered included
	end

	def spawn *a, **options
		a = a.map &:to_s
		if options[:verbose]
			pre = ''
			pre = "cd #{Shellwords.escape options[:chdir]}; "  if options.has_key? :chdir
			STDERR.puts "$ #{pre}#{a.shelljoin}"
		end
		options.delete :verbose
		options[:chdir] &&= options[:chdir].to_s
		pid = Process.spawn *a, **options
		_, status = Process.wait2 pid
		status
	end

	def convert builder, src, dest = nil
		# files:
		f = src.basename
		d = Pathname.new "#{src.basename src.extname}.woff"

		# files in cache:
		symlink = @cachepath + f
		cache_dest = @cachepath + d
		relsrc = src.expand_path.relative_path_from @cachepath.expand_path
		dest = dest ? Pathname.new( dest) : cache_dest

		@cachepath.mkpath

		# dest is not older than src, we can use the cache
		if dest.exist? and dest.lstat >= src.lstat
			builder.trigger :identical, "#{dest}"
			return dest
		end

		# cache_dest is older than source
		unless cache_dest.exist? and cache_dest.lstat >= src.lstat
			# prepare cache-files:
			symlink.unlink  if begin symlink.lstat; rescue Errno::ENOENT; false; end
			symlink.make_symlink relsrc

			# convert:
			status = spawn @converter, symlink.basename, chdir: symlink.dirname
			raise "Convertion #{src} failed!"  unless 0 == status.exitstatus
			raise "Convertion #{src} failed!"  unless cache_dest.exist?
		end

		# deliver dest:
		unless cache_dest == dest
			FileUtils.copy cache_dest, dest, verbose: false
		end

		builder.trigger :created, "#{dest}"
		dest
	end

	def after_build builder
		paths = ::Middleman::Util.all_files_under( app.config[:build_dir])
		paths.each do |path|
			path = Pathname.new path
			if 'assets' == path.relative_path_from( Pathname.new(@app.config[:build_dir])).descend.first.to_s
				case path.extname
				when '.otf', '.ttf'
					new = path.dirname + "#{path.basename path.extname}.woff"
					woff = convert builder, path, path.dirname + "#{path.basename path.extname}.woff"
				end
			end
		end
	end
end

::Middleman::Extensions.register :fonts4web, ::Fonts4Web