# frozen_string_literal: false

# Core SVG data for the file headers.
#
# This class should never need to be called directly.
# @private
class USPSFlags
  class Core
    class Headers
      def initialize(width: nil, height: nil, pennant: false, scale: nil, title: 'USPS Flag')
        @width = width
        @height = height
        @title = title
        scale ||= 3
        @generated_at = Time.now.strftime('%Y%m%d.%H%S%z')

        if @width.nil? || @height.nil?
          no_sizes(scale, pennant)
        else
          set_view_size(width, height, scale)
        end
      end

      def svg
        svg = +''
        svg << header_top
        svg << trademark unless @title == 'US Ensign'
        svg << '</metadata>'

        svg
      end

    private

      def no_sizes(scale, pennant)
        @width = USPSFlags::Config::BASE_FLY / scale
        @height = (@width * Rational(2, 3)).to_i
        @view_width = USPSFlags::Config::BASE_FLY
        @view_height = USPSFlags::Config::BASE_HOIST
        set_pennant_height(@height) if pennant
      end

      def set_pennant_height(height)
        @height = height / 4
        @view_height = USPSFlags::Config::BASE_HOIST / 4
      end

      def set_view_size(width, height, scale)
        @view_width = width * scale
        @view_height = height * scale
      end

      def header_top
        <<~SVG
          <?xml version="1.0" standalone="no"?>
          <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20010904//EN" "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
          <svg version="1.0" xmlns="http://www.w3.org/2000/svg" width="#{@width}" height="#{@height}" viewBox="-#{@view_width * 0.001} -#{@view_height * 0.002} #{@view_width * 1.004} #{@view_height * 1.005}" preserveAspectRatio="xMidYMid meet">
          <title>#{@title}</title>
          <metadata>
          <desc id="created-by">Julian Fiander</desc>
          <desc id="generated-at">#{@generated_at}</desc>
        SVG
      end

      def trademark
        <<~SVG
          <desc id="trademark-desc">This image is a registered trademark of United States Power Squadrons.</desc>
          <desc id="trademark-link">https://www.usps.org/images/secretary/itcom/trademark.pdf</desc>
        SVG
      end
    end
  end
end