# frozen_string_literal: true

require "test_helper"

class GeometryTest < Minitest::Test
  def setup
    @data = MoonModel::DataSet.new
  end

  def test_solid_one_piece_is_a_closed_outer_volume_without_inner_surface
    solid = structure("solid")
    hollow = structure("hollow")

    assert solid.valid?
    assert_manifold solid
    assert_equal hollow.triangles.length / 2, solid.triangles.length
    assert_equal hollow.vertices.length / 2, solid.vertices.length
  end

  def test_solid_single_color_grid_remains_manifold
    config = config_for("solid", "grid" => { "enabled" => true, "depth_mm" => 0.4 })
    mesh = MoonModel::Geometry.build(config, @data).parts.first[:meshes].first

    assert mesh.valid?
    assert_manifold mesh
  end

  def test_segmented_output_is_hollow_even_when_solid_is_requested
    config = config_for("solid", "purpose" => "box", "assembly" => "eight_piece")
    result = MoonModel::Geometry.build(config, @data)

    assert result.segmented?
    assert_equal "hollow", result.statistics["interior"]
  end

  private

  def structure(interior)
    MoonModel::Geometry.build(config_for(interior), @data).parts.first[:meshes].first
  end

  def config_for(interior, extra = {})
    MoonModel::Config.new({
      "size" => { "value" => 40 },
      "shell" => { "interior" => interior },
      "resolution" => { "longitude_segments" => 24 }
    }.merge(extra))
  end

  def assert_manifold(mesh)
    edge_uses = Hash.new(0)
    mesh.triangles.each do |triangle|
      triangle.each_index do |index|
        edge_uses[[triangle[index], triangle[(index + 1) % 3]].sort] += 1
      end
    end
    assert edge_uses.values.all? { |count| count == 2 }, "every edge must belong to exactly two faces"
  end
end