package set

import "testing"

func TestIntersection(t *testing.T) {
	s1 := New[int](1, 2, 3, 4)
	s2 := New[int](3, 4, 5, 6)
	want := New[int](3, 4)
	got := s1.Intersection(s2)
	if !got.Equal(want) {
		t.Errorf("Intersection() = %v; want %v", got, want)
	}
}

func TestIntersection_Empty(t *testing.T) {
	s1 := New[int](1, 2)
	s2 := New[int](3, 4)
	want := New[int]()
	got := s1.Intersection(s2)
	if !got.Equal(want) {
		t.Errorf("Intersection() = %v; want %v", got, want)
	}
}

func TestIntersection_Identical(t *testing.T) {
	s1 := New[int](1, 2, 3)
	s2 := New[int](1, 2, 3)
	want := New[int](1, 2, 3)
	got := s1.Intersection(s2)
	if !got.Equal(want) {
		t.Errorf("Intersection() = %v; want %v", got, want)
	}
}

func TestIntersection_Subset(t *testing.T) {
	s1 := New[int](1, 2, 3, 4, 5)
	s2 := New[int](2, 3)
	want := New[int](2, 3)
	got := s1.Intersection(s2)
	if !got.Equal(want) {
		t.Errorf("Intersection() = %v; want %v", got, want)
	}
}

func TestIntersection_EmptySet(t *testing.T) {
	s1 := New[int](1, 2, 3)
	s2 := New[int]()
	want := New[int]()
	got := s1.Intersection(s2)
	if !got.Equal(want) {
		t.Errorf("Intersection() = %v; want %v", got, want)
	}
}

func TestIntersection_BothEmpty(t *testing.T) {
	s1 := New[int]()
	s2 := New[int]()
	want := New[int]()
	got := s1.Intersection(s2)
	if !got.Equal(want) {
		t.Errorf("Intersection() = %v; want %v", got, want)
	}
}

func TestDifference(t *testing.T) {
	s1 := New[int](1, 2, 3, 4)
	s2 := New[int](3, 4, 5, 6)
	want := New[int](1, 2)
	got := s1.Difference(s2)
	if !got.Equal(want) {
		t.Errorf("Difference() = %v; want %v", got, want)
	}
}

func TestDifference_Empty(t *testing.T) {
	s1 := New[int](1, 2)
	s2 := New[int](1, 2)
	want := New[int]()
	got := s1.Difference(s2)
	if !got.Equal(want) {
		t.Errorf("Difference() = %v; want %v", got, want)
	}
}

func TestDifference_Subset(t *testing.T) {
	s1 := New[int](1, 2, 3, 4, 5)
	s2 := New[int](2, 3)
	want := New[int](1, 4, 5)
	got := s1.Difference(s2)
	if !got.Equal(want) {
		t.Errorf("Difference() = %v; want %v", got, want)
	}
}

func TestDifference_EmptySet(t *testing.T) {
	s1 := New[int](1, 2, 3)
	s2 := New[int]()
	want := New[int](1, 2, 3)
	got := s1.Difference(s2)
	if !got.Equal(want) {
		t.Errorf("Difference() = %v; want %v", got, want)
	}
}

func TestDifference_BothEmpty(t *testing.T) {
	s1 := New[int]()
	s2 := New[int]()
	want := New[int]()
	got := s1.Difference(s2)
	if !got.Equal(want) {
		t.Errorf("Difference() = %v; want %v", got, want)
	}
}

func TestUnion(t *testing.T) {
	s1 := New[int](1, 2, 3)
	s2 := New[int](3, 4, 5)
	want := New[int](1, 2, 3, 4, 5)
	got := s1.Union(s2)
	if !got.Equal(want) {
		t.Errorf("Union() = %v; want %v", got, want)
	}
}

func TestUnion_EmptySet(t *testing.T) {
	s1 := New[int](1, 2, 3)
	s2 := New[int]()
	want := New[int](1, 2, 3)
	got := s1.Union(s2)
	if !got.Equal(want) {
		t.Errorf("Union() = %v; want %v", got, want)
	}
}

func TestUnion_BothEmpty(t *testing.T) {
	s1 := New[int]()
	s2 := New[int]()
	want := New[int]()
	got := s1.Union(s2)
	if !got.Equal(want) {
		t.Errorf("Union() = %v; want %v", got, want)
	}
}

func TestAdd(t *testing.T) {
	want := New[int](1, 2, 3)
	got := New[int]()
	got.Add(1)
	got.Add(2)
	got.Add(3)
	if !got.Equal(want) {
		t.Errorf("Add() = %v; want %v", got, want)
	}
}

func TestRemov(t *testing.T) {
	want := New[int](1, 3)
	got := New[int](1, 2, 3)
	got.Remove(2)
	if !got.Equal(want) {
		t.Errorf("Remove() = %v; want %v", got, want)
	}
}
func TestContains(t *testing.T) {
	s := New[int](1, 2, 3)
	if !s.Contains(2) {
		t.Errorf("Contains(2) = false; want true")
	}
	if s.Contains(4) {
		t.Errorf("Contains(4) = true; want false")
	}
}

func TestSize(t *testing.T) {
	s := New[int](1, 2, 3, 4)
	want := 4
	got := s.Size()
	if got != want {
		t.Errorf("Size() = %d; want %d", got, want)
	}
}

func TestToSlice(t *testing.T) {
	s := New[int](1, 2, 3)
	want := []int{1, 2, 3}
	got := s.ToSlice()
	mapping := make(map[int]bool)
	for _, v := range got {
		mapping[v] = true
	}
	for _, v := range want {
		if !mapping[v] {
			t.Errorf("ToSlice() missing element %d; got %v", v, got)
		}
	}
}