package conversion

import (
	"encoding/json"
	"testing"

	"nex/backend/internal/conversion/canonical"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.uber.org/zap"
)

// mockProtocolAdapter 模拟协议适配器
type mockProtocolAdapter struct {
	protocolName    string
	passthrough     bool
	ifaceType       InterfaceType
	supportsIface   map[InterfaceType]bool
	decodeReqFn     func([]byte) (*canonical.CanonicalRequest, error)
	encodeReqFn     func(*canonical.CanonicalRequest, *TargetProvider) ([]byte, error)
	decodeRespFn    func([]byte) (*canonical.CanonicalResponse, error)
	encodeRespFn    func(*canonical.CanonicalResponse) ([]byte, error)
	streamDecoderFn func() StreamDecoder
	streamEncoderFn func() StreamEncoder
}

func newMockAdapter(name string, passthrough bool) *mockProtocolAdapter {
	return &mockProtocolAdapter{
		protocolName:  name,
		passthrough:   passthrough,
		ifaceType:     InterfaceTypeChat,
		supportsIface: map[InterfaceType]bool{},
	}
}

func (m *mockProtocolAdapter) ProtocolName() string  { return m.protocolName }
func (m *mockProtocolAdapter) ProtocolVersion() string { return "1.0" }
func (m *mockProtocolAdapter) SupportsPassthrough() bool { return m.passthrough }

func (m *mockProtocolAdapter) DetectInterfaceType(nativePath string) InterfaceType {
	return m.ifaceType
}

func (m *mockProtocolAdapter) BuildUrl(nativePath string, interfaceType InterfaceType) string {
	return nativePath
}

func (m *mockProtocolAdapter) BuildHeaders(provider *TargetProvider) map[string]string {
	return map[string]string{"Authorization": "Bearer " + provider.APIKey}
}

func (m *mockProtocolAdapter) SupportsInterface(interfaceType InterfaceType) bool {
	if v, ok := m.supportsIface[interfaceType]; ok {
		return v
	}
	return interfaceType == InterfaceTypeChat
}

func (m *mockProtocolAdapter) DecodeRequest(raw []byte) (*canonical.CanonicalRequest, error) {
	if m.decodeReqFn != nil {
		return m.decodeReqFn(raw)
	}
	req := &canonical.CanonicalRequest{}
	_ = json.Unmarshal(raw, req)
	return req, nil
}

func (m *mockProtocolAdapter) EncodeRequest(req *canonical.CanonicalRequest, provider *TargetProvider) ([]byte, error) {
	if m.encodeReqFn != nil {
		return m.encodeReqFn(req, provider)
	}
	return json.Marshal(req)
}

func (m *mockProtocolAdapter) DecodeResponse(raw []byte) (*canonical.CanonicalResponse, error) {
	if m.decodeRespFn != nil {
		return m.decodeRespFn(raw)
	}
	resp := &canonical.CanonicalResponse{}
	_ = json.Unmarshal(raw, resp)
	return resp, nil
}

func (m *mockProtocolAdapter) EncodeResponse(resp *canonical.CanonicalResponse) ([]byte, error) {
	if m.encodeRespFn != nil {
		return m.encodeRespFn(resp)
	}
	return json.Marshal(resp)
}

func (m *mockProtocolAdapter) CreateStreamDecoder() StreamDecoder {
	if m.streamDecoderFn != nil {
		return m.streamDecoderFn()
	}
	return &noopStreamDecoder{}
}

func (m *mockProtocolAdapter) CreateStreamEncoder() StreamEncoder {
	if m.streamEncoderFn != nil {
		return m.streamEncoderFn()
	}
	return &noopStreamEncoder{}
}

func (m *mockProtocolAdapter) EncodeError(err *ConversionError) ([]byte, int) {
	return []byte(`{"error":"mock"}`), 400
}

func (m *mockProtocolAdapter) DecodeModelsResponse(raw []byte) (*canonical.CanonicalModelList, error) {
	return &canonical.CanonicalModelList{}, nil
}

func (m *mockProtocolAdapter) EncodeModelsResponse(list *canonical.CanonicalModelList) ([]byte, error) {
	return json.Marshal(list)
}

func (m *mockProtocolAdapter) DecodeModelInfoResponse(raw []byte) (*canonical.CanonicalModelInfo, error) {
	return &canonical.CanonicalModelInfo{}, nil
}

func (m *mockProtocolAdapter) EncodeModelInfoResponse(info *canonical.CanonicalModelInfo) ([]byte, error) {
	return json.Marshal(info)
}

func (m *mockProtocolAdapter) DecodeEmbeddingRequest(raw []byte) (*canonical.CanonicalEmbeddingRequest, error) {
	return &canonical.CanonicalEmbeddingRequest{}, nil
}

func (m *mockProtocolAdapter) EncodeEmbeddingRequest(req *canonical.CanonicalEmbeddingRequest, provider *TargetProvider) ([]byte, error) {
	return json.Marshal(req)
}

func (m *mockProtocolAdapter) DecodeEmbeddingResponse(raw []byte) (*canonical.CanonicalEmbeddingResponse, error) {
	return &canonical.CanonicalEmbeddingResponse{}, nil
}

func (m *mockProtocolAdapter) EncodeEmbeddingResponse(resp *canonical.CanonicalEmbeddingResponse) ([]byte, error) {
	return json.Marshal(resp)
}

func (m *mockProtocolAdapter) DecodeRerankRequest(raw []byte) (*canonical.CanonicalRerankRequest, error) {
	return &canonical.CanonicalRerankRequest{}, nil
}

func (m *mockProtocolAdapter) EncodeRerankRequest(req *canonical.CanonicalRerankRequest, provider *TargetProvider) ([]byte, error) {
	return json.Marshal(req)
}

func (m *mockProtocolAdapter) DecodeRerankResponse(raw []byte) (*canonical.CanonicalRerankResponse, error) {
	return &canonical.CanonicalRerankResponse{}, nil
}

func (m *mockProtocolAdapter) EncodeRerankResponse(resp *canonical.CanonicalRerankResponse) ([]byte, error) {
	return json.Marshal(resp)
}

// noopStreamDecoder 空流式解码器
type noopStreamDecoder struct{}

func (d *noopStreamDecoder) ProcessChunk(rawChunk []byte) []canonical.CanonicalStreamEvent { return nil }
func (d *noopStreamDecoder) Flush() []canonical.CanonicalStreamEvent                       { return nil }

// noopStreamEncoder 空流式编码器
type noopStreamEncoder struct{}

func (e *noopStreamEncoder) EncodeEvent(event canonical.CanonicalStreamEvent) [][]byte { return nil }
func (e *noopStreamEncoder) Flush() [][]byte                                          { return nil }

// ============ 测试用例 ============

func TestNewConversionEngine(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	assert.NotNil(t, engine)
	assert.Equal(t, registry, engine.GetRegistry())
}

func TestNewConversionEngine_LoggerInjection(t *testing.T) {
	t.Run("nil_logger_uses_global", func(t *testing.T) {
		registry := NewMemoryRegistry()
		engine := NewConversionEngine(registry, nil)
		assert.NotNil(t, engine.logger)
	})

	t.Run("custom_logger", func(t *testing.T) {
		registry := NewMemoryRegistry()
		customLogger := zap.NewNop()
		engine := NewConversionEngine(registry, customLogger)
		assert.Equal(t, customLogger, engine.logger)
	})
}

func TestRegisterAdapter(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)

	adapter := newMockAdapter("test-proto", true)
	err := engine.RegisterAdapter(adapter)
	require.NoError(t, err)

	protocols := registry.ListProtocols()
	assert.Contains(t, protocols, "test-proto")
}

func TestIsPassthrough_SameProtocol(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	adapter := newMockAdapter("openai", true)
	_ = engine.RegisterAdapter(adapter)

	assert.True(t, engine.IsPassthrough("openai", "openai"))
}

func TestIsPassthrough_DifferentProtocol(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("openai", true))
	_ = engine.RegisterAdapter(newMockAdapter("anthropic", true))

	assert.False(t, engine.IsPassthrough("openai", "anthropic"))
}

func TestIsPassthrough_NoPassthrough(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("custom", false))

	assert.False(t, engine.IsPassthrough("custom", "custom"))
}

func TestDetectInterfaceType(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	adapter := newMockAdapter("test", true)
	adapter.ifaceType = InterfaceTypeChat
	_ = engine.RegisterAdapter(adapter)

	ifaceType, err := engine.DetectInterfaceType("/v1/chat/completions", "test")
	require.NoError(t, err)
	assert.Equal(t, InterfaceTypeChat, ifaceType)
}

func TestDetectInterfaceType_NonExistentProtocol(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)

	_, err := engine.DetectInterfaceType("/v1/chat", "nonexistent")
	assert.Error(t, err)
}

func TestConvertHttpRequest_Passthrough(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("openai", true))

	provider := NewTargetProvider("https://api.openai.com", "sk-test", "gpt-4")
	spec := HTTPRequestSpec{
		URL:    "/v1/chat/completions",
		Method: "POST",
		Body:   []byte(`{"model":"gpt-4","messages":[{"role":"user","content":"hi"}]}`),
	}

	result, err := engine.ConvertHttpRequest(spec, "openai", "openai", provider)
	require.NoError(t, err)
	assert.Equal(t, "https://api.openai.com/v1/chat/completions", result.URL)
	assert.Equal(t, spec.Body, result.Body)
}

func TestConvertHttpRequest_CrossProtocol(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)

	clientAdapter := newMockAdapter("client-proto", false)
	clientAdapter.decodeReqFn = func(raw []byte) (*canonical.CanonicalRequest, error) {
		return &canonical.CanonicalRequest{
			Model:    "test-model",
			Messages: []canonical.CanonicalMessage{{Role: canonical.RoleUser, Content: []canonical.ContentBlock{canonical.NewTextBlock("hi")}}},
		}, nil
	}
	_ = engine.RegisterAdapter(clientAdapter)

	providerAdapter := newMockAdapter("provider-proto", false)
	providerAdapter.encodeReqFn = func(req *canonical.CanonicalRequest, p *TargetProvider) ([]byte, error) {
		return json.Marshal(map[string]any{"model": p.ModelName})
	}
	_ = engine.RegisterAdapter(providerAdapter)

	provider := NewTargetProvider("https://example.com", "key", "my-model")
	spec := HTTPRequestSpec{
		URL:    "/v1/chat",
		Method: "POST",
		Body:   []byte(`{"model":"test"}`),
	}

	result, err := engine.ConvertHttpRequest(spec, "client-proto", "provider-proto", provider)
	require.NoError(t, err)
	assert.Contains(t, result.URL, "https://example.com")
	assert.NotNil(t, result.Body)
}

func TestConvertHttpResponse_Passthrough(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("openai", true))

	spec := HTTPResponseSpec{
		StatusCode: 200,
		Body:       []byte(`{"id":"123"}`),
	}

	result, err := engine.ConvertHttpResponse(spec, "openai", "openai", InterfaceTypeChat)
	require.NoError(t, err)
	assert.Equal(t, 200, result.StatusCode)
	assert.Equal(t, spec.Body, result.Body)
}

func TestCreateStreamConverter_Passthrough(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("openai", true))

	converter, err := engine.CreateStreamConverter("openai", "openai")
	require.NoError(t, err)
	_, ok := converter.(*PassthroughStreamConverter)
	assert.True(t, ok)
}

func TestCreateStreamConverter_Canonical(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("client", false))
	_ = engine.RegisterAdapter(newMockAdapter("provider", false))

	converter, err := engine.CreateStreamConverter("client", "provider")
	require.NoError(t, err)
	_, ok := converter.(*CanonicalStreamConverter)
	assert.True(t, ok)
}

func TestEncodeError(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)
	_ = engine.RegisterAdapter(newMockAdapter("openai", true))

	convErr := NewConversionError(ErrorCodeInvalidInput, "测试错误")
	body, statusCode, err := engine.EncodeError(convErr, "openai")
	require.NoError(t, err)
	assert.Equal(t, 400, statusCode)
	assert.NotNil(t, body)
}

func TestEncodeError_NonExistentProtocol(t *testing.T) {
	registry := NewMemoryRegistry()
	engine := NewConversionEngine(registry, nil)

	convErr := NewConversionError(ErrorCodeInvalidInput, "测试错误")
	body, statusCode, err := engine.EncodeError(convErr, "nonexistent")
	require.NoError(t, err)
	assert.Equal(t, 500, statusCode)
	assert.Contains(t, string(body), "测试错误")
}

func TestRegistry_DuplicateRegistration(t *testing.T) {
	registry := NewMemoryRegistry()
	adapter := newMockAdapter("openai", true)

	err := registry.Register(adapter)
	require.NoError(t, err)

	err = registry.Register(adapter)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "适配器已注册")
}

func TestRegistry_GetNonExistent(t *testing.T) {
	registry := NewMemoryRegistry()

	_, err := registry.Get("nonexistent")
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "未找到适配器")
}