package transcode

import "testing"

// TestFormatOfNormalizes 断言「字符串 → Format」只有一处转换，且归一化口径稳定：
// 去空白、转小写、去前导点（design/25 §6.2：与 mediafetch.AudioFormatOf 同源）。
func TestFormatOfNormalizes(t *testing.T) {
	cases := map[string]Format{
		"amr":    FormatAMR,
		".amr":   FormatAMR,
		"AMR":    FormatAMR,
		"  .AmR": FormatAMR,
		"wav":    FormatWAV,
		".WAV":   FormatWAV,
		"":       Format(""),
	}
	for in, want := range cases {
		if got := FormatOf(in); got != want {
			t.Errorf("FormatOf(%q) = %q, want %q", in, got, want)
		}
	}
}

// TestFormatName 断言 FormatName 是 FormatOf 的逆（对已归一的格式名）。
func TestFormatName(t *testing.T) {
	for _, f := range []Format{FormatAMR, FormatAMRWB, FormatWAV} {
		if got := FormatOf(FormatName(f)); got != f {
			t.Errorf("FormatOf(FormatName(%q)) = %q, want %q", f, got, f)
		}
	}
}

// TestSniff 断言魔数嗅探：认得出（AMR-NB / AMR-WB / WAV）、嗅不出即 false
// （deny-by-default）。
func TestSniff(t *testing.T) {
	riffWAV := append([]byte("RIFF\x24\x00\x00\x00WAVE"), make([]byte, 8)...)
	cases := []struct {
		name string
		data []byte
		want Format
		ok   bool
	}{
		{"amr-nb magic", []byte(amrNBMagic), FormatAMR, true},
		{"amr-nb stream", amrStubBytes(0x3c, 1, 2, 3), FormatAMR, true},
		{"amr-wb magic", []byte(amrWBMagic), FormatAMRWB, true},
		{"wav", riffWAV, FormatWAV, true},
		{"empty", nil, "", false},
		{"short", []byte("#!AM"), "", false},
		{"text", []byte("hello world"), "", false},
		{"riff without wave", []byte("RIFF\x24\x00\x00\x00AVI "), "", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got, ok := Sniff(tc.data)
			if ok != tc.ok || got != tc.want {
				t.Fatalf("Sniff = (%q, %v), want (%q, %v)", got, ok, tc.want, tc.ok)
			}
		})
	}
}

// TestAMRWBMagicIsRecognizedButUnsupported 断言「认得出但没这条路」：
// AMR-WB 的魔数能被嗅出（报错因此能说清问题），但注册表里没有它 →
// ErrUnsupportedFormat（design/25 §3.3 后置）。
func TestAMRWBMagicIsRecognizedButUnsupported(t *testing.T) {
	eng := NewEngine(DefaultLimits(), WithCodecs(DefaultCodecs()...))
	if got, ok := Sniff([]byte(amrWBMagic)); !ok || got != FormatAMRWB {
		t.Fatalf("Sniff(amr-wb) = (%q, %v)", got, ok)
	}
	if eng.Supports(FormatAMRWB, FormatWAV) {
		t.Fatalf("amr-wb -> wav must stay unsupported this round")
	}
}