# frozen_string_literal: false

# SVG building helpers.
#
# These methods should never need to be called directly, except when designing new flags.
# @private
class USPSFlags
  class Helpers
    class Builders
      class << self
        # Displays an overlay grid with regularly spaced locator markers.
        #
        # This is useful for adjusting or creating new SVG data generators, but should not otherwise need to be called.
        # @private
        def grid(width: USPSFlags::Config::BASE_FLY, height: USPSFlags::Config::BASE_HOIST)
          @width = width
          @height = height
          @stroke_width = @width / 600
          "#{circles}#{horizontal_lines}#{vertical_lines}#{diagonal_lines}"
        end

        # Displays an overlay indicator of concentric circles and radiating lines.
        #
        # This is useful for adjusting or creating new SVG data generators, but should not otherwise need to be called.
        # @private
        def locator
          <<~SVG
            <circle cx="0" cy="0" r="#{USPSFlags::Config::BASE_FLY * 2}" fill="#000000" fill-opacity="0.4" />
            <circle cx="0" cy="0" r="#{USPSFlags::Config::BASE_FLY}" fill="#333333" fill-opacity="0.4" />
            <circle cx="0" cy="0" r="#{USPSFlags::Config::BASE_FLY / 2}" fill="#666666" fill-opacity="0.4" />
            <circle cx="0" cy="0" r="#{USPSFlags::Config::BASE_FLY / 4}" fill="#999999" fill-opacity="0.4" />
            <circle cx="0" cy="0" r="#{USPSFlags::Config::BASE_FLY / 8}" fill="#CCCCCC" fill-opacity="0.4" />
            <circle cx="0" cy="0" r="#{USPSFlags::Config::BASE_FLY / 16}" fill="#FFFFFF" fill-opacity="0.4" />

            <line x1="-#{USPSFlags::Config::BASE_FLY}" y1="-#{USPSFlags::Config::BASE_HOIST}" x2="#{USPSFlags::Config::BASE_FLY}" y2="#{USPSFlags::Config::BASE_HOIST}"  stroke="#FFFFFF" stroke-width="#{USPSFlags::Config::BASE_FLY / 600}" />
            <line x1="-#{USPSFlags::Config::BASE_FLY}" y1="#{USPSFlags::Config::BASE_HOIST}" x2="#{USPSFlags::Config::BASE_FLY}" y2="-#{USPSFlags::Config::BASE_HOIST}" stroke="#FFFFFF" stroke-width="#{USPSFlags::Config::BASE_FLY / 600}" />
            <line x1="0" y1="#{USPSFlags::Config::BASE_HOIST}" x2="0" y2="-#{USPSFlags::Config::BASE_HOIST}" stroke="#FFFFFF" stroke-width="#{USPSFlags::Config::BASE_FLY / 600}" />
            <line x1="-#{USPSFlags::Config::BASE_FLY}" y1="0" x2="#{USPSFlags::Config::BASE_FLY}" y2="0" stroke="#FFFFFF" stroke-width="#{USPSFlags::Config::BASE_FLY / 600}" />

            <rect x="0" y="0" width="#{USPSFlags::Config::BASE_FLY / 30}" height="#{USPSFlags::Config::BASE_FLY / 30}" fill="#333333" fill-opacity="0.6" />
          SVG
        end

      private

        def circles
          <<~SVG
            #{pos_circle(0, 0)}
            #{pos_circle(@width, 0)}
            #{pos_circle(@width, @height)}
            #{pos_circle(0, @height)}
            <circle cx="#{@width * 1 / 4}" cy="#{@height / 2}" r="#{@width / 60}" fill="#999999" fill-opacity="0.4" />
            <circle cx="#{@width * 3 / 4}" cy="#{@height / 2}" r="#{@width / 60}" fill="#999999" fill-opacity="0.4" />
            #{radial_circles}
          SVG
        end

        def radial_circles
          <<~SVG
            #{radial_circle(1, @width / 60)}
            #{radial_circle(2, @width / 60)}
            #{radial_circle(2, @width / 75)}
            #{radial_circle(2, @width / 100)}
            #{radial_circle(3, @width / 60)}
          SVG
        end

        def pos_circle(cx, cy)
          <<~SVG
            <circle cx="#{cx}" cy="#{cy}" r="#{@width / 60}" fill="#000000" fill-opacity="0.4" />
          SVG
        end

        def radial_circle(index, radius)
          <<~SVG
            <circle cx="#{@width / 2}" cy="#{@height * index / 4}" r="#{radius}"  fill="#999999" fill-opacity="0.4" />
          SVG
        end

        def horizontal_lines
          (0..4).map { |index| horizontal_line(index) }.join
        end

        def horizontal_line(index)
          <<~SVG
            <line x1="0" y1="#{@height * index / 4}" x2="#{@width}" y2="#{@height * index / 4}" stroke="#333333" stroke-width="#{@stroke_width}" stroke-opacity="0.5" />
          SVG
        end

        def vertical_lines
          (0..6).map { |index| vertical_line(index) }.join
        end

        def vertical_line(index)
          <<~SVG
            <line y1="0" x1="#{@width * index / 6}" y2="#{@height}" x2="#{@width * index / 6}" stroke="#333333" stroke-width="#{@stroke_width}" stroke-opacity="0.5" />
          SVG
        end

        def diagonal_lines
          diagonal_line(2, 1, 3, 2) +
            diagonal_line(3, 2, 2, 3) +
            diagonal_line(2, 3, 1, 2) +
            diagonal_line(1, 2, 2, 1)
        end

        def diagonal_line(a, b, c, d)
          <<~SVG
            <line x1="#{@width * a / 4}" y1="#{@height * b / 4}" x2="#{@width * c / 4}" y2="#{@height * d / 4}" stroke="#999999" stroke-width="#{@stroke_width}" stroke-opacity="0.5" />
          SVG
        end
      end
    end
  end
end