package cli_test

import (
	"bytes"
	"io"
	"maps"
	"os"
	"slices"
	"strings"
	"testing"

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

// TestCreateExistingVaultChangesNothing is a regression test for
// https://git.eeqj.de/sneak/secret/issues/74, where running `secret init`
// a second time, or `secret vault create` with the name of an existing
// vault, replaced that vault's keys, so that none of its secrets could be
// decrypted any more. Each must refuse, change nothing, and leave every
// vault's secret readable through its passphrase unlocker.
//
//nolint:paralleltest // the cases share cmd
func TestCreateExistingVaultChangesNothing(t *testing.T) {
	mnemonic := testMnemonicBuffer(t)
	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
	t.Cleanup(passphrase.Destroy)

	// newCLI returns an instance on fs given the mnemonic and the unlock
	// passphrase, as from the environment
	newCLI := func(fs afero.Fs) *cli.Instance {
		c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
		c.Mnemonic = mnemonic
		c.UnlockPassphrase = passphrase

		return c
	}

	// `secret init`, `secret vault create work`, `secret vault select
	// default`, and the secret "x" in each vault. "work" is then not the
	// current vault, which creating it again must not change.
	fs := afero.NewMemMapFs()
	c := newCLI(fs)
	cmd := &cobra.Command{}

	require.NoError(t, c.Init(cmd))
	require.NoError(t, c.CreateVault(cmd, "work"))
	require.NoError(t, c.SelectVault(cmd, "default"))

	vaults, err := vault.ListVaults(fs, testStateDir)
	require.NoError(t, err)
	require.Len(t, vaults, 2)

	for _, name := range vaults {
		value := memguard.NewBufferFromBytes([]byte("value"))
		err := vault.NewVault(fs, testStateDir, name).AddSecret("x", value, false)
		require.NoError(t, err)
	}

	before := snapshotStateDir(t, fs)

	tests := []struct {
		command string
		want    string
		run     func(c *cli.Instance) error
	}{
		{
			"init",
			"failed to create default vault: vault default already exists",
			func(c *cli.Instance) error { return c.Init(cmd) },
		},
		{
			"vault create default",
			"vault default already exists",
			func(c *cli.Instance) error { return c.CreateVault(cmd, "default") },
		},
		{
			"vault create work",
			"vault work already exists",
			func(c *cli.Instance) error { return c.CreateVault(cmd, "work") },
		},
	}

	for _, tt := range tests {
		t.Run(tt.command, func(t *testing.T) {
			fs := newFsFromSnapshot(t, before)

			err := tt.run(newCLI(fs))

			require.EqualError(t, err, tt.want)
			require.Equal(t, before, snapshotStateDir(t, fs))
		})
	}

	// Every case left the state directory exactly as recorded in before, so
	// reading each vault's secret once from it shows that it still decrypts
	// after each case. Without the mnemonic, reading a secret goes through
	// the vault's passphrase unlocker, which is slow.
	for _, name := range vaults {
		vlt := vault.NewVault(fs, testStateDir, name)
		vlt.UnlockPassphrase = passphrase

		value, err := vlt.GetSecret("x")
		require.NoError(t, err)

		unchanged := bytes.Equal([]byte("value"), value.Bytes())
		value.Destroy()

		require.True(t, unchanged, "vault %q kept its secret", name)
	}
}

// TestVaultCreationLeavesNoSecretInEnvironment is a regression test for
// https://git.eeqj.de/sneak/secret/issues/60, where `secret init` and
// `secret vault create` put the mnemonic into the process environment,
// which every program they ran inherited, and SB_SECRET_MNEMONIC and
// SB_UNLOCK_PASSPHRASE were never unset. Each command, given both, must
// leave neither in the environment.
func TestVaultCreationLeavesNoSecretInEnvironment(t *testing.T) {
	t.Setenv(secret.EnvStateDir, t.TempDir())

	run := func(args ...string) {
		t.Setenv(secret.EnvMnemonic, testMnemonic)
		t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)

		// With no terminal to prompt on, this succeeds only if the command
		// read both variables
		_, err := cli.ExecuteCommandInProcess(args, "", nil)
		require.NoError(t, err)

		for _, name := range []string{secret.EnvMnemonic, secret.EnvUnlockPassphrase} {
			_, set := os.LookupEnv(name)
			require.False(t, set, "%s is set after %v", name, args)
		}
	}

	run("init")
	run("vault", "create", "work")
}

// TestStopAtPassphrasePromptLeavesNothing is a regression test for the
// review of https://git.eeqj.de/sneak/secret/pulls/82: `secret init` or
// `secret vault create` stopped at the passphrase prompt left a vault with
// no unlocker, which neither command would then create again. Each must ask
// for the passphrase before writing anything.
//
//nolint:paralleltest // the cases share cmd
func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
	mnemonic := testMnemonicBuffer(t)

	// An empty state directory for `secret init`, and one holding the vault
	// "default" for `secret vault create work`.
	empty := afero.NewMemMapFs()
	require.NoError(t, empty.MkdirAll(testStateDir, secret.DirPerms))

	withDefault := afero.NewMemMapFs()
	_, err := vault.CreateVault(withDefault, testStateDir, "default", mnemonic, nil)
	require.NoError(t, err)

	cmd := &cobra.Command{}

	tests := []struct {
		command string
		fs      afero.Fs
		run     func(c *cli.Instance) error
	}{
		{
			"init",
			empty,
			func(c *cli.Instance) error { return c.Init(cmd) },
		},
		{
			"vault create work",
			withDefault,
			func(c *cli.Instance) error { return c.CreateVault(cmd, "work") },
		},
	}

	for _, tt := range tests {
		t.Run(tt.command, func(t *testing.T) {
			before := snapshotStateDir(t, tt.fs)

			// Given no unlock passphrase, both commands prompt for it, which
			// fails because the tests do not run in a terminal.
			c := cli.NewCLIInstanceWithStateDir(tt.fs, testStateDir)
			c.Mnemonic = mnemonic

			err := tt.run(c)

			require.ErrorContains(t, err, "failed to read passphrase")
			require.Equal(t, before, snapshotStateDir(t, tt.fs))
		})
	}
}

// TestStopDuringCreateLeavesWholeVaultOrNone is a regression test for
// https://git.eeqj.de/sneak/secret/issues/105: `secret init` or `secret vault
// create` killed after the passphrase prompt but before the unlocker was
// written left a vault with no unlocker, which neither command would then
// create again. After the prompt, each command changes the state directory
// only through vault.CreateVault. The test makes that call as the command
// does and records the state directory before each change it makes, and once
// after it returns: what a stop at that point leaves. Each must hold either
// no vault, and not name it current, or exactly the finished vault, which
// opens with the passphrase through its current unlocker. The command run
// again after a stop first takes the lock, which must delete what the stop
// left under a temporary name. Running the command is slow, so it runs once
// on each different state the lock leaves, and must create the vault there,
// or refuse the one there.
//
//nolint:paralleltest // commands on the in-memory filesystem share one lock
func TestStopDuringCreateLeavesWholeVaultOrNone(t *testing.T) {
	mnemonic := testMnemonicBuffer(t)
	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
	t.Cleanup(passphrase.Destroy)

	cmd := &cobra.Command{}
	cmd.SetOut(io.Discard)

	t.Run("init", func(t *testing.T) {
		// From an empty state directory
		fs := afero.NewMemMapFs()
		require.NoError(t, fs.MkdirAll(testStateDir, secret.DirPerms))

		requireStopsLeaveWholeVaultOrNone(t, fs, "default",
			"failed to create default vault: vault default already exists",
			mnemonic, passphrase,
			func(c *cli.Instance) error { return c.Init(cmd) })
	})

	t.Run("vault create work", func(t *testing.T) {
		// From a state directory holding the vault "default"
		fs := afero.NewMemMapFs()
		_, err := vault.CreateVault(fs, testStateDir, "default", mnemonic, nil)
		require.NoError(t, err)

		requireStopsLeaveWholeVaultOrNone(t, fs, "work", "vault work already exists",
			mnemonic, passphrase,
			func(c *cli.Instance) error { return c.CreateVault(cmd, "work") })
	})
}

// requireStopsLeaveWholeVaultOrNone checks, as
// TestStopDuringCreateLeavesWholeVaultOrNone describes, the stops of the
// command run, creating the vault name on fs with mnemonic and passphrase.
// Run again where the vault is there, the command must fail with exists.
func requireStopsLeaveWholeVaultOrNone(
	t *testing.T, fs afero.Fs, name, exists string,
	mnemonic, passphrase *memguard.LockedBuffer,
	run func(c *cli.Instance) error,
) {
	t.Helper()

	var stops []map[string]string

	record := func() { stops = append(stops, snapshotStateDir(t, fs)) }

	_, err := vault.CreateVault(hookFs{Fs: fs, before: record},
		testStateDir, name, mnemonic, passphrase)
	require.NoError(t, err)
	record()

	vaultDir := testStateDir + "/vaults.d/" + name
	require.NotContains(t, stops[0], vaultDir+"/", "no stop before the vault")

	finished := entriesUnder(stops[len(stops)-1], vaultDir)

	opener := vault.NewVault(fs, testStateDir, name)
	opener.UnlockPassphrase = passphrase

	key, err := opener.UnlockVault()
	require.NoError(t, err)
	require.Equal(t, finished[vaultDir+"/pub.age"], key.Recipient().String())

	// Each different state the command run again finds once it holds the lock
	var locked []map[string]string

	for i, stop := range stops {
		if _, there := stop[vaultDir+"/"]; there {
			require.Equal(t, finished, entriesUnder(stop, vaultDir),
				"stop %d left a partial vault", i)
		} else {
			require.NotEqual(t, name, stop[testStateDir+"/currentvault"],
				"stop %d made a missing vault current", i)
		}

		stopped := newFsFromSnapshot(t, stop)
		release, err := vault.LockStateDir(stopped, testStateDir)
		require.NoError(t, err)
		release()

		state := snapshotStateDir(t, stopped)
		for path := range state {
			require.NotContains(t, path, ".tmp-", "stop %d", i)
		}

		if !slices.ContainsFunc(locked, func(s map[string]string) bool {
			return maps.Equal(s, state)
		}) {
			locked = append(locked, state)
		}
	}

	for _, state := range locked {
		c := cli.NewCLIInstanceWithStateDir(newFsFromSnapshot(t, state), testStateDir)
		c.Mnemonic = mnemonic
		c.UnlockPassphrase = passphrase

		if _, there := state[vaultDir+"/"]; there {
			require.EqualError(t, run(c), exists)
		} else {
			require.NoError(t, run(c))
		}
	}
}

// entriesUnder returns the entries of a tree recorded by snapshotStateDir
// that are under dir.
func entriesUnder(tree map[string]string, dir string) map[string]string {
	entries := map[string]string{}

	for path, content := range tree {
		if strings.HasPrefix(path, dir+"/") {
			entries[path] = content
		}
	}

	return entries
}

// hookFs passes every call through to Fs, but first calls before for each
// call that can change the filesystem.
type hookFs struct {
	afero.Fs

	before func()
}

//nolint:ireturn // implements afero.Fs
func (h hookFs) Create(name string) (afero.File, error) {
	h.before()

	return h.Fs.Create(name)
}

//nolint:ireturn // implements afero.Fs
func (h hookFs) OpenFile(
	name string, flag int, perm os.FileMode,
) (afero.File, error) {
	h.before()

	return h.Fs.OpenFile(name, flag, perm)
}

func (h hookFs) Mkdir(name string, perm os.FileMode) error {
	h.before()

	return h.Fs.Mkdir(name, perm)
}

func (h hookFs) MkdirAll(path string, perm os.FileMode) error {
	h.before()

	return h.Fs.MkdirAll(path, perm)
}

func (h hookFs) Remove(name string) error {
	h.before()

	return h.Fs.Remove(name)
}

func (h hookFs) RemoveAll(path string) error {
	h.before()

	return h.Fs.RemoveAll(path)
}

func (h hookFs) Rename(oldname, newname string) error {
	h.before()

	return h.Fs.Rename(oldname, newname)
}