package smtp2shoutrrr

import (
	"context"
	"fmt"
	"net"
	"testing"
	"time"

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

func dialSMTP(t *testing.T, port int) (net.Conn, error) {
	t.Helper()

	return net.DialTimeout("tcp", fmt.Sprintf("localhost:%d", port), 200*time.Millisecond)
}

func TestServerShutsDownOnContextCancel(t *testing.T) {
	config := &Config{Port: 2530, Username: "testuser", Password: "testpass"}
	server := NewSMTPServer(config)

	ctx, cancel := context.WithCancel(context.Background())
	t.Cleanup(cancel)

	stopped := make(chan error, 1)
	go func() {
		stopped <- server.Start(ctx)
	}()

	require.Eventually(t, func() bool {
		conn, err := dialSMTP(t, config.Port)
		if err != nil {
			return false
		}
		require.NoError(t, conn.Close())
		return true
	}, 5*time.Second, 20*time.Millisecond, "server never started listening")

	cancel()

	select {
	case err := <-stopped:
		require.NoError(t, err)
	case <-time.After(shutdownTimeout + time.Second):
		t.Fatal("server did not shut down after context cancellation")
	}

	_, err := dialSMTP(t, config.Port)
	require.Error(t, err, "listener should be released once Start returns")
}

func TestServerStartReturnsListenError(t *testing.T) {
	config := &Config{Port: 2531, Username: "testuser", Password: "testpass"}

	blocker, err := net.Listen("tcp", fmt.Sprintf(":%d", config.Port))
	require.NoError(t, err)
	t.Cleanup(func() { _ = blocker.Close() })

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

	require.Error(t, NewSMTPServer(config).Start(ctx))
}