$: << '../lib'

require 'geo_graf/intersection_calculator'

describe GeoGraf::IntersectionCalculator do
  describe "#intersections" do
    subject(:intersections) { described_class.new(input).intersections }

    context "given no shape" do
      let(:input) { [] }

      it "returns no intersections" do
        expect(intersections).to be_empty
      end
    end

    context "given only one shape" do
      let(:input) {
        [{
          id: 1,
          polygon_coords: [[-2, -2], [2, -2], [-2, 1], [-2, -2]]
        }]
      }

      it "returns no intersections" do
        expect(intersections).to be_empty
      end
    end

    context "given two nonintersecting shapes" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, -2], [2, -2], [-2, 1], [-2, -2]]
          },
          {
            id: 2,
            polygon_coords: [[100, 100], [102, 100], [100, 101], [100, 100]]
          }
        ]
      }

      it "returns no intersections" do
        expect(intersections).to be_empty
      end
    end

    context "given two identical shapes" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, -2], [2, -2], [-2, 1], [-2, -2]]
          },
          {
            id: 2,
            polygon_coords: [[-2, -2], [2, -2], [-2, 1], [-2, -2]]
          }
        ]
      }

      it "returns an intersection of the second one containing the first one 100%" do
        expect(intersections).to match_array([{id: 1, contained_area_percentage: 100, container_id: 2}])
      end
    end

    context "given one square inside the other" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, -2], [2, -2], [2, 2], [-2, 2], [-2, -2]]
          },
          {
            id: 2,
            polygon_coords: [[-2, -2], [0, -2], [0, 0], [-2, 0], [-2, -2]]
          }
        ]
      }

      it "returns an intersection of the first one containing the second one 100%" do
        expect(intersections).to match_array([{id: 2, contained_area_percentage: 100, container_id: 1}])
      end
    end

    context "given one square intersecting the other 25%" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, -2], [2, -2], [2, 2], [-2, 2], [-2, -2]]
          },
          {
            id: 2,
            polygon_coords: [[-3, -3], [-1, -3], [-1, -1], [-3, -1], [-3, -3]]
          }
        ]
      }

      it "returns an intersection of the first one containing the second one 25%" do
        expect(intersections).to match_array([{id: 2, contained_area_percentage: 25, container_id: 1}])
      end
    end

    context "given one square intersecting the other square of the same size 50%" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, -2], [2, -2], [2, 2], [-2, 2], [-2, -2]]
          },
          {
            id: 2,
            polygon_coords: [[-4, -2], [0, -2], [0, 2], [-4, 2], [-4, -2]]
          }
        ]
      }

      it "returns an intersection of the second one containing the first one 50%" do
        expect(intersections).to match_array([{id: 1, contained_area_percentage: 50, container_id: 2}])
      end
    end

    context "given multiple shapes of which some intersect" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, -2], [2, -2], [2, 2], [-2, 2], [-2, -2]]
          },
          {
            id: 2,
            polygon_coords: [[-1, 1], [-4, 1], [-4, -2], [-1, -2], [-1, 1]]
          },
          {
            id: 3,
            polygon_coords: [[-3, -3], [-1, -3], [-1, -1], [-3, -1], [-3, -3]]
          },
          {
            id: 4,
            polygon_coords: [[-1, 8], [-3, 8], [-3, 6], [-1, 6], [-1, 8]]
          },
          {
            id: 5,
            polygon_coords: [[11, 6], [11, 0], [2, 6], [11, 6]]
          },
          {
            id: 6,
            polygon_coords: [[5, 4], [8, 4], [8, 2], [5, 2], [5, 4]]
          },
          {
            id: 7,
            polygon_coords: [[3, -3], [1, -3], [1, -1], [3, -1], [3, -3]]
          }
        ]
      }

      it "returns 4 intersections" do
        expect(intersections).to match_array([
          {id: 2, contained_area_percentage: 33, container_id: 1},
          {id: 3, contained_area_percentage: 50, container_id: 2},
          {id: 3, contained_area_percentage: 25, container_id: 1},
          {id: 6, contained_area_percentage: 49, container_id: 5}, # 49% because of it's not a plane but a sphere
          {id: 7, contained_area_percentage: 25, container_id: 1}
        ])
      end
    end

    context "given multiple shapes on the both sides of 180 degrees line of which some intersect" do
      let(:input) {
        [
          {
            id: 1,
            polygon_coords: [[-2, 178], [2, 178], [2, -178], [-2, -178], [-2, 178]]
          },
          {
            id: 2,
            polygon_coords: [[-1, -179], [-4, -179], [-4, 178], [-1, 178], [-1, -179]]
          },
          {
            id: 3,
            polygon_coords: [[-3, 177], [-1, 177], [-1, 179], [-3, 179], [-3, 177]]
          },
          {
            id: 4,
            polygon_coords: [[-1, -172], [-3, -172], [-3, -174], [-1, -174], [-1, -172]]
          },
          {
            id: 5,
            polygon_coords: [[11, -174], [11, 180], [2, -174], [11, -174]]
          },
          {
            id: 6,
            polygon_coords: [[5, -176], [8, -176], [8, -178], [5, -178], [5, -176]]
          },
          {
            id: 7,
            polygon_coords: [[3, 177], [1, 177], [1, 179], [3, 179], [3, 177]]
          }
        ]
      }

      it "returns 4 intersections" do
        expect(intersections).to match_array([
          {id: 2, contained_area_percentage: 33, container_id: 1},
          {id: 3, contained_area_percentage: 50, container_id: 2},
          {id: 3, contained_area_percentage: 25, container_id: 1},
          {id: 6, contained_area_percentage: 49, container_id: 5}, # 49% because of it's not a plane but a sphere
          {id: 7, contained_area_percentage: 25, container_id: 1}
        ])
      end
    end
  end
end