package cli_test

import (
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"syscall"
	"testing"
	"time"

	"github.com/stretchr/testify/require"
	"sneak.berlin/go/keyfunc/internal/agekey"
	"sneak.berlin/go/keyfunc/internal/mnemonic"
)

func TestTheAgeCommandsPrintTheKey(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	recipient := strings.TrimSpace(run(t, "age", "pub"))
	require.True(t, strings.HasPrefix(recipient, "age1"))

	identity := strings.TrimSpace(run(t, "age", "priv"))
	require.True(t, strings.HasPrefix(identity, "AGE-SECRET-KEY-1"))
}

func TestAFileEncryptedByTheToolIsReadBackByIt(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	plain := written(t, "notes.txt", "the secret\n")
	sealed := filepath.Join(t.TempDir(), "notes.age")

	run(t, "age", "encrypt", "-o", sealed, plain)
	require.Equal(t, "the secret\n", run(t, "age", "decrypt", sealed))
}

func TestTheArmoredFormIsTextThatDecrypts(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	plain := written(t, "notes.txt", "the secret\n")

	armored := run(t, "age", "encrypt", "--armor", plain)
	require.True(t, strings.HasPrefix(
		armored, "-----BEGIN AGE ENCRYPTED FILE-----",
	))

	sealed := written(t, "notes.age", armored)
	require.Equal(t, "the secret\n", run(t, "age", "decrypt", sealed))
}

func TestAnotherRecipientIsAddedAndTheDerivedOneStays(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	theirs := strings.TrimSpace(run(t, "age", "pub", "-n", "7"))
	plain := written(t, "notes.txt", "the secret\n")
	sealed := filepath.Join(t.TempDir(), "notes.age")

	run(t, "age", "encrypt", "--to", theirs, "-o", sealed, plain)

	require.Equal(t, "the secret\n", run(t, "age", "decrypt", sealed))
	require.Equal(t,
		"the secret\n", run(t, "age", "decrypt", "-n", "7", sealed),
	)
}

func TestAFileForAnotherKeyIsRefused(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	plain := written(t, "notes.txt", "the secret\n")
	sealed := filepath.Join(t.TempDir(), "notes.age")

	run(t, "age", "encrypt", "-n", "7", "-o", sealed, plain)

	_, err := execute(t, "age", "decrypt", sealed)
	require.ErrorIs(t, err, agekey.ErrNotRecipient)
}

func TestARefusedDecryptionLeavesTheOutputFileAlone(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	plain := written(t, "notes.txt", "the secret\n")
	sealed := filepath.Join(t.TempDir(), "notes.age")
	existing := written(t, "notes.out", "what was already there\n")

	run(t, "age", "encrypt", "-n", "7", "-o", sealed, plain)

	_, err := execute(t, "age", "decrypt", "-o", existing, sealed)
	require.ErrorIs(t, err, agekey.ErrNotRecipient)

	//nolint:gosec // the test made this path itself
	kept, err := os.ReadFile(existing)
	require.NoError(t, err)
	require.Equal(t, "what was already there\n", string(kept))
}

func TestASignalStopsAnEncryptionAndLeavesNoFile(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	for _, ending := range []os.Signal{
		syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP,
	} {
		interrupted(t, ending, "encrypt", "the start of the secret\n", false)
	}
}

func TestASignalStopsADecryptionAndLeavesNoFile(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	// All of an encryption but its last byte, so the tool reads the
	// header and then waits for the rest.
	sealed := run(t, "age", "encrypt", written(t, "notes.txt", "the secret\n"))
	cut := sealed[:len(sealed)-1]

	for _, ending := range []os.Signal{
		syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP,
	} {
		interrupted(t, ending, "decrypt", cut, false)
	}
}

func TestASignalAsTheInputEndsLeavesNoFile(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	sealed := run(t, "age", "encrypt", written(t, "notes.txt", "the secret\n"))

	// Ctrl-C on "producer | keyfunc age encrypt -o file" ends the
	// producer too, so the input ends just as the signal comes, with
	// enough of it in hand for a whole encryption or decryption. Which
	// of the two reaches the tool first varies, so it is tried often.
	for range 25 {
		interrupted(t, syscall.SIGINT, "encrypt", "the start of the secret\n", true)
		interrupted(t, syscall.SIGINT, "decrypt", sealed, true)
	}
}

func TestAnEncryptionStartedUnderNohupSurvivesAHangup(t *testing.T) {
	t.Setenv(mnemonic.Variable, example())

	directory := t.TempDir()
	named := filepath.Join(directory, "notes")

	// nohup starts the tool with SIGHUP ignored. A tool that caught it
	// anyway would turn it back on and be ended by it.
	command, producer := writing(
		t, directory, "the secret\n",
		"nohup", os.Args[0], "age", "encrypt", "-o", named,
	)

	require.NoError(t, command.Process.Signal(syscall.SIGHUP))
	require.NoError(t, producer.Close())
	waitForTool(t, "SIGHUP under nohup", command)

	require.Equal(t, 0, command.ProcessState.ExitCode())

	left, err := os.ReadDir(directory)
	require.NoError(t, err)
	require.Len(t, left, 1)
	require.Equal(t, "the secret\n", run(t, "age", "decrypt", named))
}

// interrupted runs "age encrypt -o" or "age decrypt -o", as the
// operation says, writing into a directory of its own, and once it has
// begun writing sends it the signal, then ends the input if endInput
// says so and otherwise leaves it open. The tool has to end with status
// 1 and leave the directory empty. A tool that went on reading would
// not end until the input did; one that did not remove the file it was
// writing would leave it there, with what it had written so far; one
// that put that file in place because the input ended would leave the
// named file.
func interrupted(
	t *testing.T, signal os.Signal, operation, input string, endInput bool,
) {
	t.Helper()

	name := operation + " " + signal.String()
	directory := t.TempDir()

	command, producer := writing(
		t, directory, input,
		os.Args[0], "age", operation, "-o", filepath.Join(directory, "notes"),
	)

	require.NoError(t, command.Process.Signal(signal))

	if endInput {
		require.NoError(t, producer.Close())
	}

	waitForTool(t, name, command)

	require.Equal(t, 1, command.ProcessState.ExitCode(), name)

	left, err := os.ReadDir(directory)
	require.NoError(t, err)
	require.Empty(t, left, name)
}

// writing starts argv, the tool told to write into directory, as a
// subprocess reading the input from a pipe, and returns once the tool
// has begun writing the file beside the one it was named. The pipe is
// left open for the caller to end.
func writing(
	t *testing.T, directory, input string, argv ...string,
) (*exec.Cmd, io.WriteCloser) {
	t.Helper()

	//nolint:gosec // this test's own binary as the tool, or nohup running it
	command := exec.CommandContext(t.Context(), argv[0], argv[1:]...)

	command.Env = append(os.Environ(), runAsTool+"=1")

	producer, err := command.StdinPipe()
	require.NoError(t, err)
	require.NoError(t, command.Start())

	_, err = io.WriteString(producer, input)
	require.NoError(t, err)

	// The file beside the named one is made once the mnemonic has been
	// read, before any input is.
	require.Eventually(t, func() bool {
		entries, err := os.ReadDir(directory)

		return err == nil && len(entries) > 0
	}, 5*time.Second, 5*time.Millisecond)

	return command, producer
}

// written puts the contents in a file of that name in a directory of
// this test's own and returns the path to it.
func written(t *testing.T, name, contents string) string {
	t.Helper()

	path := filepath.Join(t.TempDir(), name)
	require.NoError(t, os.WriteFile(path, []byte(contents), 0o600))

	return path
}