//nolint:testpackage // sets the unexported fields of Instance
package cli

import (
	"io"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"git.eeqj.de/sneak/secret/internal/secret"
	"git.eeqj.de/sneak/secret/internal/vault"
	"github.com/spf13/afero"
	"github.com/spf13/cobra"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// addAtOnce runs one add of the secret name per value, all at once, and
// returns their errors.
func addAtOnce(
	fs afero.Fs, stateDir, name string, force bool, values []string,
) []error {
	errs := make(chan error, len(values))

	for _, value := range values {
		go func() {
			cli := NewCLIInstanceWithStateDir(fs, stateDir)
			cli.cmd = &cobra.Command{}
			cli.cmd.SetIn(strings.NewReader(value))

			errs <- cli.AddSecret(name, force)
		}()
	}

	results := make([]error, 0, len(values))
	for range values {
		results = append(results, <-errs)
	}

	return results
}

// numbered returns count distinct values starting with prefix.
func numbered(prefix string, count int) []string {
	values := make([]string, 0, count)
	for i := range count {
		values = append(values, prefix+"-"+strconv.Itoa(i))
	}

	return values
}

// TestConcurrentAddsKeepEveryVersion runs adds of one secret at once, on
// the in-memory and on the real filesystem. Without the state directory
// lock, adds of a new secret all find it absent and replace each other, and
// forced adds read the same highest version number and overwrite each
// other's version. With it they behave as if run one after another.
//
//nolint:paralleltest // t.Setenv forbids parallel subtests
func TestConcurrentAddsKeepEveryVersion(t *testing.T) {
	t.Setenv(secret.EnvMnemonic, testMnemonic)

	const adds = 8

	for _, tc := range []struct {
		name     string
		fs       afero.Fs
		stateDir string
	}{
		{"memory", afero.NewMemMapFs(), testStateDir},
		{"real", afero.NewOsFs(), t.TempDir()},
	} {
		t.Run(tc.name, func(t *testing.T) {
			_, err := vault.CreateVault(tc.fs, tc.stateDir, "default")
			require.NoError(t, err)

			// One add creates the secret; the others find that it exists
			created := 0

			for _, err := range addAtOnce(tc.fs, tc.stateDir, "shared", false,
				numbered("create", adds)) {
				if err == nil {
					created++
				} else {
					require.ErrorIs(t, err, vault.ErrSecretExists)
				}
			}

			require.Equal(t, 1, created, "exactly one add creates the secret")

			// Every forced add stores a version of its own
			for _, err := range addAtOnce(tc.fs, tc.stateDir, "shared", true,
				numbered("force", adds)) {
				require.NoError(t, err)
			}

			vlt, err := vault.GetCurrentVault(tc.fs, tc.stateDir)
			require.NoError(t, err)

			vaultDir, err := vlt.GetDirectory()
			require.NoError(t, err)

			versions, err := secret.ListVersions(tc.fs,
				filepath.Join(vaultDir, "secrets.d", "shared"))
			require.NoError(t, err)
			require.Len(t, versions, adds+1, "one version per successful add")

			values := make(map[string]bool, len(versions))

			for _, version := range versions {
				value, err := vlt.GetSecretVersion("shared", version)
				require.NoError(t, err)

				values[string(value)] = true
			}

			assert.Len(t, values, adds+1, "every add stored its own value")
		})
	}
}

// readNotifier passes reads through to Reader and closes reading at the
// first one.
type readNotifier struct {
	io.Reader

	reading chan struct{}
	once    sync.Once
}

func (r *readNotifier) Read(p []byte) (int, error) {
	r.once.Do(func() { close(r.reading) })

	return r.Reader.Read(p)
}

// TestEncryptPipedIntoAdd runs `secret encrypt key | secret add name` in
// one process, starting encrypt once add is reading its input. Had add
// taken the state directory lock before reading, it would hold the lock
// while waiting for encrypt's output, and encrypt would wait for the lock
// to store its key: neither would finish.
func TestEncryptPipedIntoAdd(t *testing.T) {
	t.Setenv(secret.EnvMnemonic, testMnemonic)

	fs := afero.NewMemMapFs()
	_, err := vault.CreateVault(fs, testStateDir, "default")
	require.NoError(t, err)
	require.NoError(t, afero.WriteFile(fs, "/plaintext", []byte("piped"), 0o600))

	pipeReader, pipeWriter := io.Pipe()
	// If the test gives up, this makes add's read fail, so that both
	// commands return and release the lock the other tests use
	t.Cleanup(func() { _ = pipeReader.Close() })

	const commands = 2

	input := &readNotifier{Reader: pipeReader, reading: make(chan struct{})}
	results := make(chan error, commands)

	go func() {
		add := NewCLIInstanceWithStateDir(fs, testStateDir)
		add.cmd = &cobra.Command{}
		add.cmd.SetIn(input)

		results <- add.AddSecret("encrypted", false)
	}()

	go func() {
		<-input.reading

		encrypt := NewCLIInstanceWithStateDir(fs, testStateDir)
		encrypt.cmd = &cobra.Command{}
		encrypt.cmd.SetOut(pipeWriter)

		err := encrypt.Encrypt("key", "/plaintext", "")
		// Ends add's input, as the end of the pipe does
		_ = pipeWriter.CloseWithError(err)

		results <- err
	}()

	timeout := time.After(10 * time.Second)

	for range commands {
		select {
		case err := <-results:
			require.NoError(t, err)
		case <-timeout:
			t.Fatal("secret encrypt piped into secret add never finished")
		}
	}
}

// TestFailedCommandReleasesLock checks that a command failing after it
// took the state directory lock leaves the lock free for the next command.
func TestFailedCommandReleasesLock(t *testing.T) {
	t.Parallel()

	fs := afero.NewMemMapFs()
	cli := NewCLIInstanceWithStateDir(fs, testStateDir)

	// Fails once it holds the lock: there is no current vault
	err := cli.RemoveSecret(&cobra.Command{}, "missing", false)
	require.Error(t, err)

	taken := make(chan func(), 1)

	go func() {
		release, err := vault.LockStateDir(fs, testStateDir)
		if assert.NoError(t, err) {
			taken <- release
		}
	}()

	select {
	case release := <-taken:
		release()
	case <-time.After(10 * time.Second):
		t.Fatal("the failed command left the state directory locked")
	}
}