package tests

import (
	"context"
	"log/slog"
	"net"
	"net/http"
	"net/url"
	"testing"
	"time"

	"github.com/gorilla/websocket"
	"github.com/jfraeys/fetch_ml/internal/api/datasets"
	"github.com/jfraeys/fetch_ml/internal/api/jobs"
	jupyterj "github.com/jfraeys/fetch_ml/internal/api/jupyter"
	"github.com/jfraeys/fetch_ml/internal/api/ws"
	"github.com/jfraeys/fetch_ml/internal/auth"
	"github.com/jfraeys/fetch_ml/internal/experiment"
	"github.com/jfraeys/fetch_ml/internal/logging"
)

// setupTestServer creates a test server with WebSocket handler and returns the address
func setupTestServer(t *testing.T) string {
	logger := logging.NewLogger(slog.LevelInfo, false)
	authConfig := &auth.Config{Enabled: false}
	expManager := experiment.NewManager(t.TempDir())

	jobsHandler := jobs.NewHandler(expManager, logger, nil, nil, authConfig, nil)
	jupyterHandler := jupyterj.NewHandler(logger, nil, authConfig)
	datasetsHandler := datasets.NewHandler(logger, nil, "")

	wsHandler := ws.NewHandler(authConfig, logger, expManager, "", nil, nil, nil, nil, nil, jobsHandler, jupyterHandler, datasetsHandler)

	// Create listener to get actual port
	listener, err := (&net.ListenConfig{}).Listen(context.Background(), "tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("Failed to create listener: %v", err)
	}
	addr := listener.Addr().String()

	server := &http.Server{
		Handler:           wsHandler,
		ReadHeaderTimeout: 5 * time.Second,
	}

	// Start server
	serverErr := make(chan error, 1)
	go func() {
		serverErr <- server.Serve(listener)
	}()

	// Wait for server to start
	select {
	case err := <-serverErr:
		t.Fatalf("Failed to start server: %v", err)
	case <-time.After(100 * time.Millisecond):
		// Server should be ready
	}

	t.Cleanup(func() {
		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		_ = server.Shutdown(ctx)
		<-serverErr // Wait for server to stop
	})

	return addr
}

func TestWebSocketRealConnection(t *testing.T) {
	t.Parallel() // Enable parallel execution

	// Setup test server
	addr := setupTestServer(t)

	// Test 1: Basic WebSocket connection
	u := url.URL{Scheme: "ws", Host: addr, Path: "/ws"}
	conn, resp, err := websocket.DefaultDialer.Dial(u.String(), nil)
	if resp != nil && resp.Body != nil {
		defer func() { _ = resp.Body.Close() }()
	}
	if err != nil {
		t.Fatalf("Failed to connect to WebSocket: %v", err)
	}
	defer func() { _ = conn.Close() }()

	t.Log("Successfully established WebSocket connection")

	// Test 2: Send a status request
	_ = conn.SetWriteDeadline(time.Now().Add(5 * time.Second))
	// New protocol: [opcode:1][api_key_hash:16]
	statusMsg := []byte{0x02}                          // opcode
	statusMsg = append(statusMsg, make([]byte, 16)...) // 16-byte API key hash
	err = conn.WriteMessage(websocket.BinaryMessage, statusMsg)
	if err != nil {
		t.Fatalf("Failed to send status request: %v", err)
	}

	// Test 3: Read response with timeout
	_ = conn.SetReadDeadline(time.Now().Add(5 * time.Second))
	messageType, message, err := conn.ReadMessage()
	if err != nil {
		if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
			t.Log("Read timeout - this is expected for status request")
		} else {
			t.Logf("Failed to read message: %v", err)
		}
	} else {
		t.Logf("Received message type %d: %s", messageType, string(message))
	}

	// Test 4: Send invalid message
	_ = conn.SetWriteDeadline(time.Now().Add(5 * time.Second))
	err = conn.WriteMessage(websocket.TextMessage, []byte("invalid"))
	if err != nil {
		t.Fatalf("Failed to send invalid message: %v", err)
	}

	// Try to read response (may get error due to server closing connection)
	_ = conn.SetReadDeadline(time.Now().Add(2 * time.Second))
	_, _, err = conn.ReadMessage()
	if err != nil {
		if websocket.IsCloseError(err, websocket.ClosePolicyViolation) {
			t.Log("Server correctly closed connection due to invalid message")
		} else {
			t.Logf("Server handled invalid message with error: %v", err)
		}
	}
}

func TestWebSocketBinaryProtocol(t *testing.T) {
	t.Parallel() // Enable parallel execution

	// Setup test server
	addr := setupTestServer(t)

	time.Sleep(100 * time.Millisecond)

	// Connect to WebSocket
	u := url.URL{Scheme: "ws", Host: addr, Path: "/ws"}
	conn, resp, err := websocket.DefaultDialer.Dial(u.String(), nil)
	if resp != nil && resp.Body != nil {
		defer func() { _ = resp.Body.Close() }()
	}
	if err != nil {
		t.Fatalf("Failed to connect to WebSocket: %v", err)
	}
	defer func() { _ = conn.Close() }()

	// Test 4: Send binary message with queue job opcode using new protocol
	// Create binary message with new protocol:
	// [opcode:1][api_key_hash:16][commit_id:20][priority:1][job_name_len:1][job_name:var]
	jobName := "test_job"
	commitID := "aaaaaaaaaaaaaaaaaaaa" // 20-byte commit ID

	binaryMessage := []byte{0x01}                              // OpcodeQueueJob
	binaryMessage = append(binaryMessage, make([]byte, 16)...) // 16-byte API key hash
	binaryMessage = append(binaryMessage, []byte(commitID)...) // 20-byte commit ID
	binaryMessage = append(binaryMessage, 5)                   // priority
	binaryMessage = append(binaryMessage, byte(len(jobName)))  // job name length
	binaryMessage = append(binaryMessage, []byte(jobName)...)  // job name

	err = conn.WriteMessage(websocket.BinaryMessage, binaryMessage)
	if err != nil {
		t.Fatalf("Failed to send binary message: %v", err)
	}

	t.Log("Successfully sent binary queue job message")

	// Read response (if any)
	_ = conn.SetReadDeadline(time.Now().Add(2 * time.Second))
	_, message, err := conn.ReadMessage()
	if err != nil {
		if websocket.IsCloseError(err, websocket.CloseNormalClosure) {
			t.Log("Connection closed normally after binary message")
		} else {
			t.Logf("No response received (expected): %v", err)
		}
	} else {
		t.Logf("Received response to binary message: %s", string(message))
	}
}

func TestWebSocketConcurrentConnections(t *testing.T) {
	t.Parallel() // Enable parallel execution

	// Setup test server
	addr := setupTestServer(t)

	// Test 5: Multiple concurrent connections
	numConnections := 5
	connections := make([]*websocket.Conn, numConnections)
	errors := make([]error, numConnections)

	// Create multiple connections
	for i := range numConnections {
		u := url.URL{Scheme: "ws", Host: addr, Path: "/ws"}
		conn, resp, err := websocket.DefaultDialer.Dial(u.String(), nil)
		if resp != nil && resp.Body != nil {
			_ = resp.Body.Close()
		}
		if err != nil {
			errors[i] = err
			continue
		}
		connections[i] = conn
	}

	// Close all connections
	for _, conn := range connections {
		if conn != nil {
			_ = conn.Close()
		}
	}

	// Verify all connections succeeded
	for i, err := range errors {
		if err != nil {
			t.Errorf("Connection %d failed: %v", i, err)
		}
	}

	successCount := 0
	for _, conn := range connections {
		if conn != nil {
			successCount++
		}
	}

	if successCount != numConnections {
		t.Errorf("Expected %d successful connections, got %d", numConnections, successCount)
	}

	t.Logf("Successfully established %d concurrent WebSocket connections", successCount)
}

func TestWebSocketConnectionResilience(t *testing.T) {
	t.Parallel() // Enable parallel execution

	// Setup test server
	addr := setupTestServer(t)

	// Test 6: Connection resilience and reconnection
	u := url.URL{Scheme: "ws", Host: addr, Path: "/ws"}

	// First connection
	conn1, resp1, err := websocket.DefaultDialer.Dial(u.String(), nil)
	if resp1 != nil && resp1.Body != nil {
		defer func() { _ = resp1.Body.Close() }()
	}
	if err != nil {
		t.Fatalf("Failed to establish first connection: %v", err)
	}

	// Send a message
	err = conn1.WriteJSON(map[string]interface{}{
		"opcode": 0x02,
		"data":   "",
	})
	if err != nil {
		t.Fatalf("Failed to send message on first connection: %v", err)
	}

	// Close first connection
	_ = conn1.Close()

	// Wait a moment
	time.Sleep(100 * time.Millisecond)

	// Reconnect
	conn2, resp2, err := websocket.DefaultDialer.Dial(u.String(), nil)
	if resp2 != nil && resp2.Body != nil {
		defer func() { _ = resp2.Body.Close() }()
	}
	if err != nil {
		t.Fatalf("Failed to reconnect: %v", err)
	}
	defer func() { _ = conn2.Close() }()

	// Send message on reconnected connection
	err = conn2.WriteJSON(map[string]interface{}{
		"opcode": 0x02,
		"data":   "",
	})
	if err != nil {
		t.Fatalf("Failed to send message on reconnected connection: %v", err)
	}

	t.Log("Successfully tested connection resilience and reconnection")
}