// Package http2 提供 HTTP/2 TLS 连接集成测试。
//
// 该文件测试 HTTP/2 服务器的 TLS 相关功能：
//   - TLS 握手成功/失败
//   - ALPN 协商 h2/http1.1
//   - HTTP/1.1 回退路径
//
// 作者：xfy
package http2

import (
	"context"
	"crypto/rand"
	"crypto/rsa"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"math/big"
	"net"
	"net/http"
	"slices"
	"sync"
	"testing"
	"time"

	"github.com/valyala/fasthttp"
	"rua.plus/lolly/internal/config"
)

// generateTestCert 生成测试用自签名证书。
func generateTestCert(t *testing.T) (tls.Certificate, *x509.CertPool) {
	t.Helper()

	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		t.Fatalf("Failed to generate private key: %v", err)
	}

	template := &x509.Certificate{
		SerialNumber: big.NewInt(1),
		Subject: pkix.Name{
			Organization: []string{"Test Org"},
		},
		NotBefore:             time.Now(),
		NotAfter:              time.Now().Add(time.Hour),
		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
		DNSNames:              []string{"localhost"},
		IPAddresses:           []net.IP{net.ParseIP("127.0.0.1")},
	}

	certDER, err := x509.CreateCertificate(rand.Reader, template, template, &privateKey.PublicKey, privateKey)
	if err != nil {
		t.Fatalf("Failed to create certificate: %v", err)
	}

	cert := tls.Certificate{
		Certificate: [][]byte{certDER},
		PrivateKey:  privateKey,
	}

	certPool := x509.NewCertPool()
	certPool.AppendCertsFromPEM(certDER)

	return cert, certPool
}

// TestTLSHandshakeSuccess 测试 TLS 握手成功。
func TestTLSHandshakeSuccess(t *testing.T) {
	cert, _ := generateTestCert(t)

	handler := func(ctx *fasthttp.RequestCtx) {
		ctx.WriteString("Hello HTTP/2")
		ctx.SetStatusCode(fasthttp.StatusOK)
	}

	cfg := &config.HTTP2Config{
		Enabled:              true,
		MaxConcurrentStreams: 100,
	}

	tlsConfig := &tls.Config{
		Certificates: []tls.Certificate{cert},
		NextProtos:   []string{"h2", "http/1.1"},
	}

	server, err := NewServer(cfg, handler, tlsConfig)
	if err != nil {
		t.Fatalf("Failed to create server: %v", err)
	}

	// 创建管道连接
	serverConn, clientConn := net.Pipe()
	defer func() {
		_ = serverConn.Close()
		_ = clientConn.Close()
	}()

	// 包装服务器端连接为 TLS
	tlsServerConn := tls.Server(serverConn, tlsConfig)

	// 需要先 Add(1) 因为 handleConnection 会调用 Done()
	server.connWg.Add(1)

	// 在后台处理连接
	go func() {
		server.handleConnection(tlsServerConn)
	}()

	// 客户端 TLS 握手
	tlsClientConfig := &tls.Config{
		InsecureSkipVerify: true,
		NextProtos:         []string{"h2"},
	}
	tlsClientConn := tls.Client(clientConn, tlsClientConfig)

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := tlsClientConn.HandshakeContext(ctx); err != nil {
		t.Fatalf("TLS handshake failed: %v", err)
	}

	// 验证协商的协议
	state := tlsClientConn.ConnectionState()
	if state.NegotiatedProtocol != "h2" {
		t.Errorf("Expected negotiated protocol 'h2', got '%s'", state.NegotiatedProtocol)
	}

	// 关闭连接
	_ = tlsClientConn.Close()
	_ = tlsServerConn.Close()

	// 等待处理完成
	done := make(chan struct{})
	go func() {
		server.connWg.Wait()
		close(done)
	}()
	select {
	case <-done:
		t.Log("Connection handling completed")
	case <-time.After(2 * time.Second):
		t.Log("Timeout waiting for connection handling")
	}
}

// TestTLSHandshakeFailure 测试 TLS 握手失败。
func TestTLSHandshakeFailure(t *testing.T) {
	cert, _ := generateTestCert(t)

	handler := func(ctx *fasthttp.RequestCtx) {
		ctx.WriteString("Hello")
	}

	cfg := &config.HTTP2Config{
		Enabled: true,
	}

	tlsConfig := &tls.Config{
		Certificates: []tls.Certificate{cert},
		NextProtos:   []string{"h2"},
	}

	server, err := NewServer(cfg, handler, tlsConfig)
	if err != nil {
		t.Fatalf("Failed to create server: %v", err)
	}

	serverConn, clientConn := net.Pipe()

	// 包装服务器端连接为 TLS
	tlsServerConn := tls.Server(serverConn, tlsConfig)

	// 需要先 Add(1) 因为 handleConnection 会调用 Done()
	server.connWg.Add(1)

	// 在后台处理连接
	go func() {
		server.handleConnection(tlsServerConn)
	}()

	// 客户端不进行 TLS 握手，直接发送无效数据
	_, _ = clientConn.Write([]byte("INVALID DATA NOT TLS"))

	// 等待处理完成
	time.Sleep(200 * time.Millisecond)

	// 关闭连接
	_ = clientConn.Close()
	_ = tlsServerConn.Close()

	// 等待处理完成
	done := make(chan struct{})
	go func() {
		server.connWg.Wait()
		close(done)
	}()
	select {
	case <-done:
		t.Log("Connection handling completed after handshake failure")
	case <-time.After(2 * time.Second):
		t.Log("Timeout waiting for connection handling")
	}
}

// TestALPNNegotiationH2 测试 ALPN 协商选择 h2。
func TestALPNNegotiationH2(t *testing.T) {
	cert, _ := generateTestCert(t)

	handler := func(ctx *fasthttp.RequestCtx) {
		ctx.WriteString("OK")
	}

	cfg := &config.HTTP2Config{
		Enabled: true,
	}

	tlsConfig := &tls.Config{
		Certificates: []tls.Certificate{cert},
		NextProtos:   []string{"h2", "http/1.1"},
	}

	server, err := NewServer(cfg, handler, tlsConfig)
	if err != nil {
		t.Fatalf("Failed to create server: %v", err)
	}

	// 验证 ALPN 配置
	alpnConfig := server.ALPNConfig()
	if alpnConfig == nil {
		t.Fatal("ALPN config should not be nil")
	}

	foundH2 := slices.Contains(alpnConfig.NextProtos, "h2")
	if !foundH2 {
		t.Error("ALPN config should include h2 protocol")
	}
}

// TestALPNHTTP11Fallback 测试 ALPN 协商回退到 HTTP/1.1。
func TestALPNHTTP11Fallback(t *testing.T) {
	cert, _ := generateTestCert(t)

	handler := func(ctx *fasthttp.RequestCtx) {
		ctx.WriteString("HTTP/1.1 response")
		ctx.SetStatusCode(fasthttp.StatusOK)
	}

	cfg := &config.HTTP2Config{
		Enabled: true,
	}

	tlsConfig := &tls.Config{
		Certificates: []tls.Certificate{cert},
		NextProtos:   []string{"h2", "http/1.1"},
	}

	server, err := NewServer(cfg, handler, tlsConfig)
	if err != nil {
		t.Fatalf("Failed to create server: %v", err)
	}

	serverConn, clientConn := net.Pipe()
	defer func() {
		_ = serverConn.Close()
		_ = clientConn.Close()
	}()

	tlsServerConn := tls.Server(serverConn, tlsConfig)

	// 需要先 Add(1) 因为 handleConnection 会调用 Done()
	server.connWg.Add(1)

	go func() {
		server.handleConnection(tlsServerConn)
	}()

	// 客户端只支持 HTTP/1.1
	tlsClientConfig := &tls.Config{
		InsecureSkipVerify: true,
		NextProtos:         []string{"http/1.1"},
	}
	tlsClientConn := tls.Client(clientConn, tlsClientConfig)

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := tlsClientConn.HandshakeContext(ctx); err != nil {
		t.Fatalf("TLS handshake failed: %v", err)
	}

	// 验证协商的协议是 http/1.1
	state := tlsClientConn.ConnectionState()
	if state.NegotiatedProtocol != "http/1.1" {
		t.Errorf("Expected negotiated protocol 'http/1.1', got '%s'", state.NegotiatedProtocol)
	}

	_ = tlsClientConn.Close()
	_ = tlsServerConn.Close()
}

// TestTLSListenerWrapper 测试 TLS 监听器包装。
func TestTLSListenerWrapper(t *testing.T) {
	cert, _ := generateTestCert(t)

	// 创建底层监听器
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("Failed to create listener: %v", err)
	}
	defer func() { _ = ln.Close() }()

	tlsConfig := &tls.Config{
		Certificates: []tls.Certificate{cert},
	}

	// 包装监听器
	wrappedLn := WrapTLSListener(ln, tlsConfig)
	if wrappedLn == nil {
		t.Fatal("WrapTLSListener returned nil")
	}

	// 验证 NextProtos 已设置
	if len(tlsConfig.NextProtos) == 0 {
		t.Error("NextProtos should be set after wrapping")
	}

	foundH2 := false
	foundHTTP11 := false
	for _, proto := range tlsConfig.NextProtos {
		if proto == "h2" {
			foundH2 = true
		}
		if proto == "http/1.1" {
			foundHTTP11 = true
		}
	}
	if !foundH2 || !foundHTTP11 {
		t.Error("NextProtos should include both h2 and http/1.1")
	}
}

// TestTLSListenerExistingProtos 测试已有 NextProtos 的情况。
func TestTLSListenerExistingProtos(t *testing.T) {
	cert, _ := generateTestCert(t)

	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("Failed to create listener: %v", err)
	}
	defer func() { _ = ln.Close() }()

	tlsConfig := &tls.Config{
		Certificates: []tls.Certificate{cert},
		NextProtos:   []string{"custom-proto"},
	}

	wrappedLn := WrapTLSListener(ln, tlsConfig)
	if wrappedLn == nil {
		t.Fatal("WrapTLSListener returned nil")
	}

	// 已有 NextProtos 不应被覆盖
	if len(tlsConfig.NextProtos) != 1 || tlsConfig.NextProtos[0] != "custom-proto" {
		t.Errorf("Existing NextProtos should not be overwritten, got %v", tlsConfig.NextProtos)
	}
}

// TestServeHTTP1Fallback 测试 HTTP/1.1 回退。
func TestServeHTTP1Fallback(t *testing.T) {
	handler := func(ctx *fasthttp.RequestCtx) {
		ctx.WriteString("HTTP/1.1 response")
		ctx.SetStatusCode(fasthttp.StatusOK)
		ctx.Response.Header.Set("X-Test", "value")
	}

	cfg := &config.HTTP2Config{
		Enabled: true,
	}

	server, err := NewServer(cfg, handler, nil)
	if err != nil {
		t.Fatalf("Failed to create server: %v", err)
	}

	serverConn, clientConn := net.Pipe()
	defer func() {
		_ = serverConn.Close()
		_ = clientConn.Close()
	}()

	var wg sync.WaitGroup
	wg.Go(func() {
		server.serveHTTP1(serverConn)
	})

	// 发送 HTTP/1.1 请求
	request := "GET /test HTTP/1.1\r\nHost: localhost\r\n\r\n"
	_, _ = clientConn.Write([]byte(request))

	// 读取响应
	buf := make([]byte, 1024)
	_ = clientConn.SetReadDeadline(time.Now().Add(2 * time.Second))
	n, err := clientConn.Read(buf)
	if err != nil {
		t.Fatalf("Failed to read response: %v", err)
	}

	response := string(buf[:n])
	if response == "" {
		t.Error("Expected non-empty response")
	}

	// 关闭连接
	_ = clientConn.Close()
	wg.Wait()
}

// TestConnectionPoolOperations 测试连接池操作。
func TestConnectionPoolOperations(t *testing.T) {
	pool := newConnectionPool()

	// 创建模拟连接
	conn1 := &mockTestConn{remoteAddr: &net.TCPAddr{IP: net.ParseIP("127.0.0.1"), Port: 12345}}
	conn2 := &mockTestConn{remoteAddr: &net.TCPAddr{IP: net.ParseIP("127.0.0.1"), Port: 12346}}

	// 添加连接
	pool.add("client1", conn1)
	pool.add("client1", conn2)

	// 验证连接数
	if count := pool.count("client1"); count != 2 {
		t.Errorf("Expected 2 connections, got %d", count)
	}

	// 获取连接
	conns := pool.get("client1")
	if len(conns) != 2 {
		t.Errorf("Expected 2 connections, got %d", len(conns))
	}

	// 移除连接
	pool.remove("client1", conn1)
	if count := pool.count("client1"); count != 1 {
		t.Errorf("Expected 1 connection after removal, got %d", count)
	}

	// 关闭所有连接
	pool.closeAll()
	if count := pool.count("client1"); count != 0 {
		t.Errorf("Expected 0 connections after closeAll, got %d", count)
	}
}

// mockTestConn 是用于测试的模拟连接。
type mockTestConn struct {
	remoteAddr net.Addr
}

func (m *mockTestConn) Read(_ []byte) (n int, err error)  { return 0, nil }
func (m *mockTestConn) Write(_ []byte) (n int, err error) { return 0, nil }
func (m *mockTestConn) Close() error                      { return nil }
func (m *mockTestConn) LocalAddr() net.Addr               { return m.remoteAddr }
func (m *mockTestConn) RemoteAddr() net.Addr              { return m.remoteAddr }
func (m *mockTestConn) SetDeadline(_ time.Time) error     { return nil }
func (m *mockTestConn) SetReadDeadline(_ time.Time) error { return nil }
func (m *mockTestConn) SetWriteDeadline(_ time.Time) error {
	return nil
}

// TestIsHTTP2RequestMethod 测试 HTTP/2 请求检测。
func TestIsHTTP2RequestMethod(t *testing.T) {
	tests := []struct {
		name            string
		method          string
		proto           int
		want            bool
		hasPseudoHeader bool
	}{
		{"PRI method", "PRI", 1, true, false},
		{"HTTP/2 version", "GET", 2, true, false},
		{"HTTP/1.1", "GET", 1, false, false},
		{"With pseudo header", "GET", 1, true, true},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req, err := http.NewRequest(tt.method, "http://example.com/", nil)
			if err != nil {
				t.Fatalf("Failed to create request: %v", err)
			}
			if tt.proto == 2 {
				req.ProtoMajor = 2
			}
			if tt.hasPseudoHeader {
				req.Header.Set(":method", "GET")
			}

			if got := IsHTTP2Request(req); got != tt.want {
				t.Errorf("IsHTTP2Request() = %v, want %v", got, tt.want)
			}
		})
	}
}

// TestGetALPNProtocolNonTLS 测试获取 ALPN 协议（非 TLS）。
func TestGetALPNProtocolNonTLS(t *testing.T) {
	// 非 TLS 连接
	plainConn := &mockTestConn{}
	if proto := GetALPNProtocol(plainConn); proto != "" {
		t.Errorf("Expected empty protocol for non-TLS connection, got '%s'", proto)
	}
}

// TestValidateSettingsFunc 测试设置验证。
func TestValidateSettingsFunc(t *testing.T) {
	tests := []struct {
		name     string
		settings Settings
		wantErr  bool
	}{
		{
			name:     "valid settings",
			settings: DefaultSettings(),
			wantErr:  false,
		},
		{
			name: "zero max concurrent streams",
			settings: Settings{
				MaxConcurrentStreams: 0,
				MaxFrameSize:         16384,
				MaxHeaderListSize:    4096,
			},
			wantErr: true,
		},
		{
			name: "invalid max frame size - too small",
			settings: Settings{
				MaxConcurrentStreams: 100,
				MaxFrameSize:         1000,
				MaxHeaderListSize:    4096,
			},
			wantErr: true,
		},
		{
			name: "invalid max frame size - too large",
			settings: Settings{
				MaxConcurrentStreams: 100,
				MaxFrameSize:         20000000,
				MaxHeaderListSize:    4096,
			},
			wantErr: true,
		},
		{
			name: "invalid initial window size",
			settings: Settings{
				MaxConcurrentStreams: 100,
				MaxFrameSize:         16384,
				InitialWindowSize:    3000000000,
				MaxHeaderListSize:    4096,
			},
			wantErr: true,
		},
		{
			name: "zero max header list size",
			settings: Settings{
				MaxConcurrentStreams: 100,
				MaxFrameSize:         16384,
				MaxHeaderListSize:    0,
			},
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := ValidateSettings(tt.settings)
			if (err != nil) != tt.wantErr {
				t.Errorf("ValidateSettings() error = %v, wantErr %v", err, tt.wantErr)
			}
		})
	}
}

// TestParseSettingsFunc 测试设置解析。
func TestParseSettingsFunc(t *testing.T) {
	cfg := &config.HTTP2Config{
		MaxConcurrentStreams: 200,
		MaxHeaderListSize:    2048576,
		PushEnabled:          false,
	}

	settings := ParseSettings(cfg)

	if settings.MaxConcurrentStreams != 200 {
		t.Errorf("Expected MaxConcurrentStreams 200, got %d", settings.MaxConcurrentStreams)
	}
	if settings.MaxHeaderListSize != 2048576 {
		t.Errorf("Expected MaxHeaderListSize 2048576, got %d", settings.MaxHeaderListSize)
	}
	if settings.EnablePush {
		t.Error("Expected EnablePush to be false")
	}
}

// TestDefaultSettingsFunc 测试默认设置。
func TestDefaultSettingsFunc(t *testing.T) {
	settings := DefaultSettings()

	if settings.HeaderTableSize != 4096 {
		t.Errorf("Expected HeaderTableSize 4096, got %d", settings.HeaderTableSize)
	}
	if !settings.EnablePush {
		t.Error("Expected EnablePush to be true")
	}
	if settings.MaxConcurrentStreams != 250 {
		t.Errorf("Expected MaxConcurrentStreams 250, got %d", settings.MaxConcurrentStreams)
	}
	if settings.InitialWindowSize != 65535 {
		t.Errorf("Expected InitialWindowSize 65535, got %d", settings.InitialWindowSize)
	}
	if settings.MaxFrameSize != 16384 {
		t.Errorf("Expected MaxFrameSize 16384, got %d", settings.MaxFrameSize)
	}
	if settings.MaxHeaderListSize != 1048576 {
		t.Errorf("Expected MaxHeaderListSize 1048576, got %d", settings.MaxHeaderListSize)
	}
}

// TestSupportsHTTP2Func 测试 HTTP/2 支持检测。
func TestSupportsHTTP2Func(t *testing.T) {
	tests := []struct {
		name       string
		setupReq   func(*http.Request)
		wantResult bool
	}{
		{
			name: "HTTP/2 request",
			setupReq: func(r *http.Request) {
				r.ProtoMajor = 2
			},
			wantResult: true,
		},
		{
			name: "h2c upgrade",
			setupReq: func(r *http.Request) {
				r.Header.Set("Upgrade", "h2c")
			},
			wantResult: true,
		},
		{
			name: "HTTP2-Settings header",
			setupReq: func(r *http.Request) {
				r.Header.Set("HTTP2-Settings", "some-settings")
			},
			wantResult: true,
		},
		{
			name:       "HTTP/1.1 without upgrade",
			setupReq:   func(r *http.Request) {},
			wantResult: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req, err := http.NewRequest("GET", "http://example.com/", nil)
			if err != nil {
				t.Fatalf("Failed to create request: %v", err)
			}
			tt.setupReq(req)

			if got := SupportsHTTP2(req); got != tt.wantResult {
				t.Errorf("SupportsHTTP2() = %v, want %v", got, tt.wantResult)
			}
		})
	}
}