package dec

import "testing"

func TestParseString(t *testing.T) {
	cases := map[string]string{
		"8.105000000000000000":     "8.105",
		"0":                        "0",
		"-0.5":                     "-0.5",
		".25":                      "0.25",
		"75924.000000000000000000": "75924",
		"0.000000000000000001":     "0.000000000000000001",
		"+3":                       "3",
	}
	for in, want := range cases {
		d, err := Parse(in)
		if err != nil {
			t.Fatalf("Parse(%q): %v", in, err)
		}
		if got := d.String(); got != want {
			t.Errorf("Parse(%q).String() = %q, want %q", in, got, want)
		}
	}
	for _, bad := range []string{"", "-", "1e5", "1.2.3", "abc", "0.0000000000000000001", "."} {
		if _, err := Parse(bad); err == nil {
			t.Errorf("Parse(%q) accepted, want error", bad)
		}
	}
}

func TestArithmetic(t *testing.T) {
	a, b := MustParse("8.105"), MustParse("53.846")
	if got := a.Mul(b).String(); got != "436.42183" {
		t.Errorf("Mul = %s", got)
	}
	if got := MustParse("1").Quo(MustParse("3")).String(); got != "0.333333333333333333" {
		t.Errorf("Quo 1/3 = %s", got)
	}
	if got := MustParse("2").Quo(MustParse("3")).String(); got != "0.666666666666666667" {
		t.Errorf("Quo 2/3 = %s (want half-up)", got)
	}
	if got := MustParse("-2").Quo(MustParse("3")).String(); got != "-0.666666666666666667" {
		t.Errorf("Quo -2/3 = %s", got)
	}
}

func TestTicks(t *testing.T) {
	tick := MustParse("0.001")
	if !MustParse("8.105").IsMultipleOf(tick) || MustParse("8.1055").IsMultipleOf(tick) {
		t.Fatal("IsMultipleOf wrong")
	}
	if got := MustParse("8.1059").FloorTo(tick).String(); got != "8.105" {
		t.Errorf("FloorTo = %s", got)
	}
	if got := MustParse("8.1051").CeilTo(tick).String(); got != "8.106" {
		t.Errorf("CeilTo = %s", got)
	}
	if got := MustParse("-1.5").FloorTo(MustParse("1")).String(); got != "-2" {
		t.Errorf("FloorTo negative = %s", got)
	}
}

func FuzzParseRoundTrip(f *testing.F) {
	for _, s := range []string{"0", "1.5", "-0.000000000000000001", "123456789.987654321"} {
		f.Add(s)
	}
	f.Fuzz(func(t *testing.T, s string) {
		d, err := Parse(s)
		if err != nil {
			return
		}
		d2, err := Parse(d.String())
		if err != nil || !d2.Equal(d) {
			t.Fatalf("round trip %q -> %q failed", s, d.String())
		}
	})
}