package codec

import (
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestRegistry(t *testing.T) {
	registry := NewRegistry()

	// 测试获取默认编解码器
	defaultCodec := registry.Default()
	require.NotNil(t, defaultCodec, "Expected default codec to be non-nil")
	assert.Equal(t, "binary", defaultCodec.Name(), "Expected default codec to be binary")
}

func TestRegistryGet(t *testing.T) {
	registry := NewRegistry()
	_ = registry.Register("json", NewJSONCodec())
	_ = registry.Register("plain", NewPlainCodec())

	// 测试获取JSON编解码器
	codec, err := registry.Get("json")
	require.NoError(t, err, "Expected no error when getting json codec")
	assert.NotNil(t, codec, "Expected codec to be non-nil")
	assert.Equal(t, "json", codec.Name(), "Expected codec name to be 'json'")

	// 测试获取二进制编解码器
	codec, err = registry.Get("binary")
	require.NoError(t, err, "Expected no error when getting binary codec")
	assert.NotNil(t, codec, "Expected codec to be non-nil")
	assert.Equal(t, "binary", codec.Name(), "Expected codec name to be 'binary'")

	// 测试获取Plain编解码器
	codec, err = registry.Get("plain")
	require.NoError(t, err, "Expected no error when getting plain codec")
	assert.NotNil(t, codec, "Expected codec to be non-nil")
	assert.Equal(t, "plain", codec.Name(), "Expected codec name to be 'plain'")

	// 测试获取不存在的编解码器
	_, err = registry.Get("nonexistent")
	assert.Error(t, err, "Expected error for nonexistent codec")
}

func TestRegistryGetEmptyName(t *testing.T) {
	registry := NewRegistry()

	// 测试空名称（应该返回默认编解码器）
	codec, err := registry.Get("")
	require.NoError(t, err, "Expected no error when getting codec with empty name")
	assert.NotNil(t, codec, "Expected codec to be non-nil")
	assert.Equal(t, "binary", codec.Name(), "Expected default codec to be binary")
}

func TestRegistryRegister(t *testing.T) {
	registry := NewRegistry()

	// 创建自定义编解码器
	customCodec := &testCodec{name: "custom"}

	// 注册自定义编解码器
	err := registry.Register("custom", customCodec)
	require.NoError(t, err, "Expected no error when registering codec")

	// 获取自定义编解码器
	retrieved, err := registry.Get("custom")
	require.NoError(t, err, "Expected no error when getting custom codec")
	assert.Equal(t, "custom", retrieved.Name(), "Expected codec name to be 'custom'")
}

func TestRegistryRegisterEmptyName(t *testing.T) {
	registry := NewRegistry()

	// 测试注册空名称编解码器
	customCodec := &testCodec{name: "custom"}
	err := registry.Register("", customCodec)
	assert.Error(t, err, "Expected error for empty codec name")
}

func TestRegistryRegisterNilCodec(t *testing.T) {
	registry := NewRegistry()

	// 测试注册nil编解码器
	err := registry.Register("nil", nil)
	assert.Error(t, err, "Expected error for nil codec")
}

func TestRegistryConcurrent(t *testing.T) {
	registry := NewRegistry()

	// 并发注册和获取编解码器
	done := make(chan bool, 100)
	for i := 0; i < 100; i++ {
		go func(id int) {
			codec := &testCodec{name: string(rune(id))}
			registry.Register(string(rune(id)), codec)
			_, _ = registry.Get(string(rune(id)))
			done <- true
		}(i)
	}

	// 等待所有goroutine完成
	for i := 0; i < 100; i++ {
		<-done
	}
}

// SetDefault is an internal method, tested through behavior
// Default codec is JSON by default, which is tested in TestRegistry

// testCodec 测试用的编解码器
type testCodec struct {
	name string
}

func (c *testCodec) Name() string {
	return c.name
}

func (c *testCodec) Encode(v interface{}) ([]byte, error) {
	return []byte("test"), nil
}

func (c *testCodec) Decode(data []byte, v interface{}) error {
	return nil
}