package generic

import (
	"maps"
	"slices"
	"testing"
)

type X struct{}

func TestZero(t *testing.T) {
	if Zero[int]() != 0 {
		t.Errorf("Zero[int]() != 0")
	}
	if Zero[string]() != "" {
		t.Errorf(`Zero[string]() != ""`)
	}
	if Zero[bool]() != false {
		t.Errorf("Zero[bool]() != false")
	}
	if Zero[*X]() != nil {
		t.Errorf("Zero[*X]() != nil")
	}
}

func TestIsZero(t *testing.T) {
	tests := []struct {
		name string
		val  any
		want bool
	}{
		{
			name: "int zero",
			val:  0,
			want: true,
		},
		{
			"int non-zero",
			1,
			false,
		},
		{
			"string zero",
			"",
			true,
		},
		{
			"string non-zero",
			"x",
			false,
		},
		{
			"nil pointer",
			(*X)(nil),
			true,
		},
		{
			"non-nil pointer",
			Ptr(X{}),
			false,
		},
	}

	for _, tt := range tests {
		switch v := tt.val.(type) {
		case int:
			got := IsZero(v)
			if got != tt.want {
				t.Errorf("%s: got %v, want %v", tt.name, got, tt.want)
			}
		case string:
			got := IsZero(v)
			if got != tt.want {
				t.Errorf("%s: got %v, want %v", tt.name, got, tt.want)
			}
		case *X:
			got := IsZero(v)
			if got != tt.want {
				t.Errorf("%s: got %v, want %v", tt.name, got, tt.want)
			}
		}
	}
}

func TestPtr(t *testing.T) {
	v := 42
	p := Ptr(v)
	if p == nil || *p != v {
		t.Errorf("Ptr(42) = %v, want pointer to 42", p)
	}
}

func TestKeys(t *testing.T) {
	m := map[string]int{"a": 1, "b": 2, "c": 3}
	seq := Keys(maps.All(m))
	keys := slices.Collect(seq)
	want := slices.Collect(maps.Keys(m))

	slices.Sort(keys)
	slices.Sort(want)
	if !slices.Equal(keys, want) {
		t.Errorf("Keys() = %v, want %v", keys, want)
	}
}

func TestValue(t *testing.T) {
	m := map[string]int{"a": 1, "b": 2, "c": 3}
	seq := Value(maps.All(m))
	values := slices.Collect(seq)
	want := slices.Collect(maps.Values(m))

	// unordered compare
	slices.Sort(values)
	slices.Sort(want)
	if !slices.Equal(values, want) {
		t.Errorf("Values() = %v, want %v", values, want)
	}
}

func TestSet_Add_Has_Del(t *testing.T) {
	s := NewSet[int]()
	if s.Has(10) {
		t.Errorf("Set should not contain 10 initially")
	}
	s.Add(10)
	if !s.Has(10) {
		t.Errorf("Set should contain 10 after Add")
	}
	s.Del(10)
	if s.Has(10) {
		t.Errorf("Set should not contain 10 after Del")
	}
}

func TestSet_All(t *testing.T) {
	s := NewSet[string]()
	s.Add("x")
	s.Add("y")
	s.Add("z")

	got := slices.Collect(s.All())
	want := []string{"x", "y", "z"}

	slices.Sort(got)
	slices.Sort(want)
	if !slices.Equal(got, want) {
		t.Errorf("Set.All() = %v, want %v", got, want)
	}
}