package server_test

import (
	"context"
	"net"
	"testing"

	"git.eeqj.de/sneak/routewatch/internal/config"
	"git.eeqj.de/sneak/routewatch/internal/logger"
	"git.eeqj.de/sneak/routewatch/internal/metrics"
	"git.eeqj.de/sneak/routewatch/internal/server"
	"git.eeqj.de/sneak/routewatch/internal/streamer"
)

// TestStartFailsWhenPortIsHeld holds a port with a listener of its own and
// checks that Start on that port returns an error. Before the fix Start
// listened in a goroutine, only logged the failure and returned nil, so the
// daemon kept running without its web server.
func TestStartFailsWhenPortIsHeld(t *testing.T) {
	t.Parallel()

	var listenConfig net.ListenConfig

	held, err := listenConfig.Listen(t.Context(), "tcp", ":0")
	if err != nil {
		t.Fatalf("failed to open the test listener: %v", err)
	}
	defer func() { _ = held.Close() }()

	addr, ok := held.Addr().(*net.TCPAddr)
	if !ok {
		t.Fatalf("test listener address %v is not a TCP address", held.Addr())
	}

	port := addr.Port
	log := logger.New()
	s := server.New(nil, streamer.New(log, metrics.New()), log,
		&config.Config{Port: port})

	defer func() { _ = s.Stop(context.Background()) }()

	err = s.Start(t.Context())
	if err == nil {
		t.Fatalf("Start returned nil while port %d was held by another listener",
			port)
	}
}