package cli_test

import (
	"bufio"
	"io"
	"os"
	"os/exec"
	"strings"
	"syscall"
	"testing"
	"time"

	"github.com/creack/pty"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"golang.org/x/term"
	"sneak.berlin/go/keyfunc/internal/mnemonic"
)

// TestEndOfInputAtThePromptEndsTheTool starts "age pub" and, at the
// prompt, types Ctrl-D. The tool has to end with status 1, say that the
// mnemonic is empty, and leave the terminal set as it found it, so with
// echo on again.
//
// pty.Open returns the two ends of a new terminal: tty is the end the
// tool uses as its terminal, and ptmx the end the test reads what the
// terminal shows from and types into.
func TestEndOfInputAtThePromptEndsTheTool(t *testing.T) {
	t.Setenv(mnemonic.Variable, "")
	t.Setenv(mnemonic.CommandVariable, "")

	ptmx, tty, err := pty.Open()
	require.NoError(t, err)

	defer func() { _ = ptmx.Close() }()
	defer func() { _ = tty.Close() }()

	before, err := term.GetState(int(tty.Fd()))
	require.NoError(t, err)

	command, terminal := prompted(t, ptmx, tty)

	_, err = ptmx.WriteString("\x04") // Ctrl-D
	require.NoError(t, err)

	waitForTool(t, "Ctrl-D at the prompt", command)
	require.Equal(t, failedStatus, command.ProcessState.ExitCode())

	after, err := term.GetState(int(tty.Fd()))
	require.NoError(t, err)
	require.Equal(t, before, after, "the terminal settings were not restored")

	// With the tool ended and this end closed too, ptmx gives what is
	// left on the terminal and then an error.
	require.NoError(t, tty.Close())

	said, _ := io.ReadAll(terminal)
	require.Contains(t, string(said), mnemonic.ErrEmpty.Error())
}

// TestASignalAtThePromptPutsTheTerminalBack starts "age pub" and, at
// the prompt, once the tool has turned echo off, sends it SIGINT. The
// tool has to be ended by SIGINT, which a shell reports as status 130,
// and leave the terminal set as it found it, so with echo on again.
func TestASignalAtThePromptPutsTheTerminalBack(t *testing.T) {
	t.Setenv(mnemonic.Variable, "")
	t.Setenv(mnemonic.CommandVariable, "")

	ptmx, tty, err := pty.Open()
	require.NoError(t, err)

	defer func() { _ = ptmx.Close() }()
	defer func() { _ = tty.Close() }()

	before, err := term.GetState(int(tty.Fd()))
	require.NoError(t, err)

	command, _ := prompted(t, ptmx, tty)

	// The prompt is shown just before echo is turned off, and the
	// signal has to come while it is off.
	require.Eventually(t, func() bool {
		now, err := term.GetState(int(tty.Fd()))

		return err == nil && !assert.ObjectsAreEqual(before, now)
	}, 5*time.Second, 5*time.Millisecond, "the tool did not turn echo off")

	require.NoError(t, command.Process.Signal(syscall.SIGINT))
	waitForTool(t, "SIGINT at the prompt", command)

	status, ok := command.ProcessState.Sys().(syscall.WaitStatus)
	require.True(t, ok)
	require.True(t, status.Signaled(), "the tool was not ended by the signal")
	require.Equal(t, syscall.SIGINT, status.Signal())

	after, err := term.GetState(int(tty.Fd()))
	require.NoError(t, err)
	require.Equal(t, before, after, "the terminal settings were not restored")
}

// prompted starts "age pub" as a subprocess, for a test that has set no
// mnemonic, with the terminal's tty end on all three streams, and
// returns once the tool has shown the prompt. The reader returned reads
// what the terminal shows from its ptmx end. Reading ptmx stops at a
// deadline, so a prompt that never comes fails the test instead of
// hanging it.
func prompted(t *testing.T, ptmx, tty *os.File) (*exec.Cmd, *bufio.Reader) {
	t.Helper()

	require.NoError(t, ptmx.SetReadDeadline(time.Now().Add(10*time.Second)))

	//nolint:gosec // this test's own binary as the tool
	command := exec.CommandContext(t.Context(), os.Args[0], "age", "pub")

	command.Env = append(os.Environ(), runAsTool+"=1")
	command.Stdin = tty
	command.Stdout = tty
	command.Stderr = tty

	require.NoError(t, command.Start())

	var shown string

	terminal := bufio.NewReader(ptmx)
	for !strings.HasSuffix(shown, "mnemonic: ") {
		char, err := terminal.ReadByte()
		require.NoError(t, err, "the tool did not prompt: %q", shown)

		shown += string(char)
	}

	return command, terminal
}