package secret_test

import (
	"os"
	"path/filepath"
	"testing"
	"time"

	"filippo.io/age"
	"github.com/awnumar/memguard"
	"github.com/spf13/afero"
	"sneak.berlin/go/secret/internal/secret"
	"sneak.berlin/go/secret/pkg/agehd"
)

// testMnemonic is the standard BIP39 test vector mnemonic.
//
//nolint:dupword // BIP39 test mnemonic repeats words by design
const testMnemonic = "abandon abandon abandon abandon abandon abandon " +
	"abandon abandon abandon abandon abandon about"

// testMnemonicBuffer returns testMnemonic in a locked buffer that is
// destroyed when the test ends.
func testMnemonicBuffer(t *testing.T) *memguard.LockedBuffer {
	t.Helper()

	mnemonic := memguard.NewBufferFromBytes([]byte(testMnemonic))
	t.Cleanup(mnemonic.Destroy)

	return mnemonic
}

// writeTestPublicKey writes the unlocker public key and verifies it exists.
func writeTestPublicKey(
	t *testing.T, fs afero.Fs, unlockerDir string, agePublicKey string,
) {
	t.Helper()

	pubKeyPath := filepath.Join(unlockerDir, "pub.age")

	err := afero.WriteFile(fs, pubKeyPath, []byte(agePublicKey), secret.FilePerms)
	if err != nil {
		t.Fatalf("Failed to write public key: %v", err)
	}

	// Verify the file exists
	exists, err := afero.Exists(fs, pubKeyPath)
	if err != nil {
		t.Fatalf("Failed to check if public key exists: %v", err)
	}

	if !exists {
		t.Errorf("Public key file should exist at %s", pubKeyPath)
	}
}

// writeTestPrivateKey encrypts the private key with the passphrase,
// writes it, and verifies it exists.
func writeTestPrivateKey(
	t *testing.T,
	fs afero.Fs,
	unlockerDir string,
	agePrivateKey string,
	testPassphrase string,
) {
	t.Helper()

	privKeyBuffer := memguard.NewBufferFromBytes([]byte(agePrivateKey))
	defer privKeyBuffer.Destroy()

	passphraseBuffer := memguard.NewBufferFromBytes([]byte(testPassphrase))
	defer passphraseBuffer.Destroy()

	encryptedPrivKey, err := secret.EncryptWithPassphrase(
		privKeyBuffer, passphraseBuffer)
	if err != nil {
		t.Fatalf("Failed to encrypt private key: %v", err)
	}

	privKeyPath := filepath.Join(unlockerDir, "priv.age")

	err = afero.WriteFile(fs, privKeyPath, encryptedPrivKey, secret.FilePerms)
	if err != nil {
		t.Fatalf("Failed to write encrypted private key: %v", err)
	}

	// Verify the file exists
	exists, err := afero.Exists(fs, privKeyPath)
	if err != nil {
		t.Fatalf("Failed to check if private key exists: %v", err)
	}

	if !exists {
		t.Errorf("Encrypted private key file should exist at %s", privKeyPath)
	}
}

// writeTestLongTermKey encrypts the derived long-term key to the
// unlocker's recipient, writes it, and verifies it exists.
func writeTestLongTermKey(
	t *testing.T, fs afero.Fs, unlockerDir string, agePublicKey string,
) {
	t.Helper()

	// Derive a long-term identity from the test mnemonic
	ltIdentity, err := agehd.DeriveIdentity(testMnemonic, 0)
	if err != nil {
		t.Fatalf("Failed to derive long-term identity: %v", err)
	}

	// Encrypt long-term private key to the unlocker's recipient
	recipient, err := age.ParseX25519Recipient(agePublicKey)
	if err != nil {
		t.Fatalf("Failed to parse recipient: %v", err)
	}

	ltPrivKeyBuffer := memguard.NewBufferFromBytes([]byte(ltIdentity.String()))
	defer ltPrivKeyBuffer.Destroy()

	encryptedLtPrivKey, err := secret.EncryptToRecipient(ltPrivKeyBuffer, recipient)
	if err != nil {
		t.Fatalf("Failed to encrypt long-term private key: %v", err)
	}

	ltPrivKeyPath := filepath.Join(unlockerDir, "longterm.age")

	err = afero.WriteFile(fs, ltPrivKeyPath, encryptedLtPrivKey, secret.FilePerms)
	if err != nil {
		t.Fatalf("Failed to write encrypted long-term private key: %v", err)
	}

	// Verify the file exists
	exists, err := afero.Exists(fs, ltPrivKeyPath)
	if err != nil {
		t.Fatalf("Failed to check if long-term key exists: %v", err)
	}

	if !exists {
		t.Errorf("Encrypted long-term key file should exist at %s", ltPrivKeyPath)
	}
}

// newTestPassphraseUnlocker creates a temp unlocker directory and a
// passphrase unlocker with a fresh age identity for testing.
func newTestPassphraseUnlocker(
	t *testing.T, fs afero.Fs,
) (*secret.PassphraseUnlocker, *age.X25519Identity, string) {
	t.Helper()

	// Create the directory structure in a temp dir
	unlockerDir := filepath.Join(t.TempDir(), "unlocker")

	err := os.MkdirAll(unlockerDir, secret.DirPerms)
	if err != nil {
		t.Fatalf("Failed to create unlocker directory: %v", err)
	}

	// Set up test metadata
	metadata := secret.UnlockerMetadata{
		Type:      "passphrase",
		CreatedAt: time.Now(),
		Flags:     []string{},
	}

	// Create passphrase unlocker
	unlocker := secret.NewPassphraseUnlocker(fs, unlockerDir, metadata)

	// Generate a test age identity
	ageIdentity, err := age.GenerateX25519Identity()
	if err != nil {
		t.Fatalf("Failed to generate age identity: %v", err)
	}

	return unlocker, ageIdentity, unlockerDir
}

//nolint:paralleltest // subtests share real-FS state, order matters
func TestPassphraseUnlockerWithRealFS(t *testing.T) {
	// This test uses real filesystem
	if os.Getenv("CI") == "true" {
		t.Log("Running in CI environment with real filesystem")
	}

	// Use the real filesystem
	fs := afero.NewOsFs()

	// Test data
	testPassphrase := "test-passphrase-123"

	unlocker, ageIdentity, unlockerDir := newTestPassphraseUnlocker(t, fs)
	agePrivateKey := ageIdentity.String()
	agePublicKey := ageIdentity.Recipient().String()

	// Test writing public key
	t.Run("WritePublicKey", func(t *testing.T) {
		writeTestPublicKey(t, fs, unlockerDir, agePublicKey)
	})

	// Test encrypting private key with passphrase
	t.Run("EncryptPrivateKey", func(t *testing.T) {
		writeTestPrivateKey(t, fs, unlockerDir, agePrivateKey, testPassphrase)
	})

	// Test writing long-term key
	t.Run("WriteLongTermKey", func(t *testing.T) {
		writeTestLongTermKey(t, fs, unlockerDir, agePublicKey)
	})

	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
	defer passphrase.Destroy()

	unlocker.Passphrase = passphrase

	// Test getting identity with the passphrase the unlocker was given,
	// twice: using it must leave it intact for the next use
	t.Run("GetIdentityWithPassphrase", func(t *testing.T) {
		for range 2 {
			identity, err := unlocker.GetIdentity()
			if err != nil {
				t.Fatalf("Failed to get identity with passphrase: %v", err)
			}

			// Verify the identity matches what we expect
			expectedPubKey := ageIdentity.Recipient().String()

			actualPubKey := identity.Recipient().String()
			if actualPubKey != expectedPubKey {
				t.Errorf("Public key mismatch. Expected %s, got %s",
					expectedPubKey, actualPubKey)
			}
		}
	})

	unlocker.Passphrase = nil

	// Test getting identity from prompt (this would require mocking the
	// prompt). For real integration tests, we'd need a way to mock the
	// passphrase input. Here we just verify the error is what we expect
	// when no passphrase is available.
	t.Run("GetIdentityWithoutPassphrase", func(t *testing.T) {
		// This should fail since we're not in an interactive terminal
		_, err := unlocker.GetIdentity()
		if err == nil {
			t.Errorf("Should have failed to get identity without a passphrase")
		}
	})

	// Test removing the unlocker
	t.Run("RemoveUnlocker", func(t *testing.T) {
		err := unlocker.Remove()
		if err != nil {
			t.Fatalf("Failed to remove unlocker: %v", err)
		}

		// Verify the directory is gone
		exists, err := afero.DirExists(fs, unlockerDir)
		if err != nil {
			t.Fatalf("Failed to check if unlocker directory exists: %v", err)
		}

		if exists {
			t.Errorf("Unlocker directory should not exist after removal")
		}
	})
}