# frozen_string_literal: true

require 'eac_ruby_utils/templates/file'

module EacRubyUtils
  module Templates
    class Directory
      TEMPLATE_EXTNAME = '.template'

      attr_reader :path

      def initialize(path)
        @path = path.is_a?(::Pathname) ? path : ::Pathname.new(path.to_s)
      end

      def apply(variables_source, directory)
        TemplateNode.new(self, '.', directory, variables_source).apply
      end

      def child(subpath)
        child_path = ::File.join(path, subpath)
        return ::EacRubyUtils::Templates::File.new(child_path) if ::File.file?(child_path)
        return ::EacRubyUtils::Templates::Directory.new(child_path) if ::File.directory?(child_path)

        raise "Child \"#{subpath}\" from \"#{path}\" not found"
      end

      def children
        path.children.map do |path_child|
          child(path_child.basename.to_path)
        end
      end

      private

      def apply_fs_object(source_relative, target)
        if ::File.directory?(source_absolute(source_relative))
          apply_directory(source_relative, target)
        elsif ::File.file?(source_absolute(source_relative))
        end
      end

      def source_absolute(source_relative)
        ::File.expand_path(source_relative, path)
      end

      class TemplateNode
        attr_reader :source_directory, :source_relative, :target_root_directory, :variables_source

        def initialize(source_directory, source_relative, target_root_directory, variables_source)
          @source_directory = source_directory
          @source_relative = source_relative
          @target_root_directory = target_root_directory
          @variables_source = variables_source
        end

        def apply
          if file?
            apply_file
          elsif directory?
            apply_directory
          else
            raise "Unknown filesystem type: #{source_absolute}"
          end
        end

        private

        def apply_directory
          ::FileUtils.mkdir_p(target_absolute)
          Dir.entries(source_absolute).each do |entry|
            child(entry).apply unless %w[. ..].include?(entry)
          end
        end

        def apply_file
          if ::File.extname(source_absolute) == TEMPLATE_EXTNAME
            ::EacRubyUtils::Templates::File.new(source_absolute).apply_to_file(
              variables_source, target_absolute
            )
          else
            ::FileUtils.cp(source_absolute, target_absolute)
          end
        end

        def child(entry)
          TemplateNode.new(source_directory, ::File.join(source_relative, entry),
                           target_root_directory, variables_source)
        end

        def file?
          ::File.file?(source_absolute)
        end

        def directory?
          ::File.directory?(source_absolute)
        end

        def source_absolute
          ::File.expand_path(source_relative, source_directory.path)
        end

        def target_absolute
          ::File.expand_path(source_relative, target_root_directory)
                .gsub(/#{::Regexp.quote(TEMPLATE_EXTNAME)}\z/, '')
        end
      end
    end
  end
end