module CiteProc

	module Asset

		def self.included(base)
			base.extend(ClassMethods)
		end

		attr_reader :asset, :location
		
		def open?
			!asset.nil?
		end
		
		def open(input)
			case
			when input.respond_to?(:read)
				@location = nil
				@asset = input.read
			when input.to_s =~ /^\s*</
				@location = nil
				@asset = input.to_s.dup
			else
				case
				when File.exists?(input)
					@location = input
				when File.exists?(self.class.extend_name(input))
					@location = self.class.extend_name(input)
				when File.exists?(self.class.extend_path(input))
					@location = self.class.extend_path(input)
				else
					@location = input
				end

				Kernel.open(@location, 'r:UTF-8') do |io|
					@asset = io.read
				end
			end
			
			self
		rescue => e
			raise ArgumentError, "failed to open asset #@location (#{input.inspect}): #{e.message}"
		end

		def name
			File.basename(location, self.class.extension).sub(Regexp.new("^#{self.class.prefix}"), '')
		end
		
		alias to_s asset

		def inspect
			"#<CiteProc::#{self.class.name} #{name}>"
		end
		
		module ClassMethods

			attr_accessor :root, :extension, :prefix

			def open(path_or_name)
				new.open(path_or_name)
			end

			def extend_path(input)
				File.join(root.to_s, extend_name(input))
			end
			
			def extend_name(input)
				if File.extname(input) != extension
				  name = [input, extension].compact.join
				else
				  name = input.to_s.dup
				end
				
				unless name.start_with?(prefix.to_s)
				  name = [prefix, name].join
				end
				
				name
			end

		end

	end

	class Style
		
		include Asset
		
		@root = '/usr/local/share/citation-style-language/styles'.freeze
		@extension = '.csl'.freeze
		
	end

	class Locale
		
		include Asset
		
		@root = '/usr/local/share/citation-style-language/locales'.freeze
		@extension = '.xml'.freeze
		@prefix = 'locales-'.freeze
		
		
		def language
			name.split('-')[0]
		end
		
		def region
			name.split('-')[1]
		end
		
	end

end