package transcode

import (
	"errors"
	"testing"
)

// TestRegistryRegisterAndLookup 断言注册 / 查找 / 发现三件事。
func TestRegistryRegisterAndLookup(t *testing.T) {
	reg := NewRegistry()
	codec := newStubCodec()
	if err := reg.Register(codec); err != nil {
		t.Fatalf("register: %v", err)
	}
	got, ok := reg.Lookup(FormatAMR, FormatWAV)
	if !ok || got != Codec(codec) {
		t.Fatalf("lookup = (%v, %v), want the registered codec", got, ok)
	}
	if _, ok := reg.Lookup(FormatWAV, FormatAMR); ok {
		t.Fatalf("reverse route must not exist")
	}
	if n := reg.Len(); n != 1 {
		t.Fatalf("Len = %d, want 1", n)
	}
	if formats := reg.Formats(); len(formats) != 2 || formats[0] != FormatAMR || formats[1] != FormatWAV {
		t.Fatalf("Formats = %v, want [amr wav]（去重且有序）", formats)
	}
}

// TestRegistryRejectsBadCodecs 断言不合法注册项被拒（nil / 空格式 / 自我转换），
// 且 repeated 注册返回 ErrDuplicate。
func TestRegistryRejectsBadCodecs(t *testing.T) {
	reg := NewRegistry()
	cases := []struct {
		name  string
		codec Codec
	}{
		{"nil", nil},
		{"empty from", &stubCodec{from: "", to: FormatWAV}},
		{"empty to", &stubCodec{from: FormatAMR, to: ""}},
		{"identity", &stubCodec{from: FormatWAV, to: FormatWAV}},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if err := reg.Register(tc.codec); !errors.Is(err, ErrInvalidCodec) {
				t.Fatalf("err = %v, want ErrInvalidCodec", err)
			}
		})
	}
	if err := reg.Register(newStubCodec()); err != nil {
		t.Fatalf("register: %v", err)
	}
	if err := reg.Register(newStubCodec()); !errors.Is(err, ErrDuplicate) {
		t.Fatalf("duplicate err = %v, want ErrDuplicate", err)
	}
	if n := reg.Len(); n != 1 {
		t.Fatalf("Len = %d after a rejected duplicate, want 1", n)
	}
}

// TestRegistryFormatsDedupe 断言多路共享格式时 Formats 去重。
func TestRegistryFormatsDedupe(t *testing.T) {
	reg := NewRegistry()
	if err := reg.Register(&stubCodec{from: FormatAMR, to: FormatWAV}); err != nil {
		t.Fatalf("register: %v", err)
	}
	if err := reg.Register(&stubCodec{from: FormatWAV, to: FormatAMRWB}); err != nil {
		t.Fatalf("register: %v", err)
	}
	want := []Format{FormatAMR, FormatAMRWB, FormatWAV}
	got := reg.Formats()
	if len(got) != len(want) {
		t.Fatalf("Formats = %v, want %v", got, want)
	}
	for i := range want {
		if got[i] != want[i] {
			t.Fatalf("Formats = %v, want %v（有序）", got, want)
		}
	}
}