package inventory

import "testing"

func TestLevelFor(t *testing.T) {
	const low = int64(5)
	cases := []struct {
		qty  int64
		want Level
	}{
		{-3, LevelNone},
		{0, LevelNone},
		{1, LevelLow},
		{5, LevelLow}, // at the watermark is still low
		{6, LevelHigh},
		{1000, LevelHigh},
	}
	for _, c := range cases {
		if got := LevelFor(c.qty, low); got != c.want {
			t.Errorf("LevelFor(%d, %d) = %q, want %q", c.qty, low, got, c.want)
		}
	}
}

func TestLevelInStock(t *testing.T) {
	if LevelNone.InStock() {
		t.Error("none should not be in stock")
	}
	if !LevelLow.InStock() || !LevelHigh.InStock() {
		t.Error("low and high should be in stock")
	}
}

func TestLevelChangedRoundTrip(t *testing.T) {
	in := LevelChanged{SKU: "ABC-1", Location: "se", Level: LevelLow}
	raw, err := in.Encode()
	if err != nil {
		t.Fatalf("encode: %v", err)
	}
	out, err := Decode(raw)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	if out != in {
		t.Errorf("round-trip mismatch: got %+v, want %+v", out, in)
	}
}