# Core SVG data for the US Ensign.
#
# This class should never need to be called directly.
# @private
class USPSFlags::Core::US
  def svg
    @base_hoist = 2000.to_f
    @base_fly = @base_hoist*1.91

    @canton_hoist = @base_hoist*7/13
    @canton_fly = @canton_hoist*Math.sqrt(2)

    @star_offset = 20 # Half of scaled star height

    svg = stripes
    svg << stars(:odd)
    svg << stars(:even)

    # star_diameter = base_hoist*4/5/13
    # svg << <<~SVG
    #   <circle cx="#{@canton_fly*6/12}" cy="#{@canton_hoist*4/10-5}" r="#{star_diameter/2}" fill="#999999" fill-opacity="0.4" />
    # SVG

    svg
  end

  private
  def stars(type = :odd)
    rows = {
      odd: (1..9).step(2).to_a,
      even: (2..8).step(2).to_a
    }
    columns = {
      odd: (1..11).step(2).to_a,
      even: (2..10).step(2).to_a
    }

    svg = ""
    rows[type].each do |r|
      columns[type].each do |c|
        svg << <<~SVG
          <g transform="translate(#{@canton_fly*c/12}, #{@star_offset+@canton_hoist*r/10})"><g transform="scale(0.31)">#{USPSFlags::Core.star}</g></g>
        SVG
      end
    end
    svg
  end

  def stripes
    <<~SVG
      <rect x="0" y="0" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="#{@base_hoist*1/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#FFFFFF" />
      <rect x="0" y="#{@base_hoist*2/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="#{@base_hoist*3/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#FFFFFF" />
      <rect x="0" y="#{@base_hoist*4/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="#{@base_hoist*5/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#FFFFFF" />
      <rect x="0" y="#{@base_hoist*6/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="#{@base_hoist*7/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#FFFFFF" />
      <rect x="0" y="#{@base_hoist*8/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="#{@base_hoist*9/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#FFFFFF" />
      <rect x="0" y="#{@base_hoist*10/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="#{@base_hoist*11/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#FFFFFF" />
      <rect x="0" y="#{@base_hoist*12/13}" width="#{@base_fly}" height="#{@base_hoist/13}" fill="#{USPSFlags::Config::RED}" />
      <rect x="0" y="0" width="#{@canton_fly}" height="#{@canton_hoist}" fill="#{USPSFlags::Config::BLUE}" />
    SVG
  end
end