package vaultik_test

import (
	"bytes"
	"context"
	"database/sql"
	"io"
	"os"
	"path/filepath"
	"sync"
	"testing"
	"time"

	"github.com/spf13/afero"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"sneak.berlin/go/vaultik/internal/config"
	"sneak.berlin/go/vaultik/internal/database"
	"sneak.berlin/go/vaultik/internal/log"
	"sneak.berlin/go/vaultik/internal/snapshot"
	"sneak.berlin/go/vaultik/internal/storage"
	"sneak.berlin/go/vaultik/internal/types"
	"sneak.berlin/go/vaultik/internal/ui"
	"sneak.berlin/go/vaultik/internal/vaultik"
)

// Shared fixture values used across the vaultik integration tests.
const (
	testLabel        = "test"
	testHostname     = "test-host"
	testAgePublicKey = "age1ezrjmfpwsc95svdg0y54mums3zevgzu0x0ecq2f7tp8a05g" +
		"l0sjq9q9wjg"
	testAgeSecretKey = "AGE-SECRET-KEY-19CR5YSFW59HM4TLD6GXVEDMZFTVVF7PPHKU" +
		"T68TXSFPK7APHXA2QS2NJA5"
)

// MockStorer implements storage.Storer for testing
type MockStorer struct {
	mu    sync.Mutex
	data  map[string][]byte
	calls []string
}

func NewMockStorer() *MockStorer {
	return &MockStorer{
		data:  make(map[string][]byte),
		calls: make([]string, 0),
	}
}

func (m *MockStorer) Put(_ context.Context, key string, reader io.Reader) error {
	m.mu.Lock()
	defer m.mu.Unlock()

	m.calls = append(m.calls, "Put:"+key)

	data, err := io.ReadAll(reader)
	if err != nil {
		return err
	}

	m.data[key] = data

	return nil
}

func (m *MockStorer) PutWithProgress(
	ctx context.Context, key string, reader io.Reader,
	_ int64, _ storage.ProgressCallback,
) error {
	return m.Put(ctx, key, reader)
}

func (m *MockStorer) Get(_ context.Context, key string) (io.ReadCloser, error) {
	m.mu.Lock()
	defer m.mu.Unlock()

	m.calls = append(m.calls, "Get:"+key)

	data, exists := m.data[key]
	if !exists {
		return nil, storage.ErrNotFound
	}

	return io.NopCloser(bytes.NewReader(data)), nil
}

func (m *MockStorer) Stat(_ context.Context, key string) (*storage.ObjectInfo, error) {
	m.mu.Lock()
	defer m.mu.Unlock()

	m.calls = append(m.calls, "Stat:"+key)

	data, exists := m.data[key]
	if !exists {
		return nil, storage.ErrNotFound
	}

	return &storage.ObjectInfo{
		Key:  key,
		Size: int64(len(data)),
	}, nil
}

func (m *MockStorer) Delete(_ context.Context, key string) error {
	m.mu.Lock()
	defer m.mu.Unlock()

	m.calls = append(m.calls, "Delete:"+key)
	delete(m.data, key)

	return nil
}

func (m *MockStorer) List(_ context.Context, prefix string) ([]string, error) {
	m.mu.Lock()
	defer m.mu.Unlock()

	m.calls = append(m.calls, "List:"+prefix)

	var keys []string

	for key := range m.data {
		if len(prefix) == 0 ||
			(len(key) >= len(prefix) && key[:len(prefix)] == prefix) {
			keys = append(keys, key)
		}
	}

	return keys, nil
}

func (m *MockStorer) ListStream(
	_ context.Context, prefix string,
) <-chan storage.ObjectInfo {
	ch := make(chan storage.ObjectInfo)

	go func() {
		defer close(ch)

		m.mu.Lock()
		defer m.mu.Unlock()

		for key, data := range m.data {
			if len(prefix) == 0 ||
				(len(key) >= len(prefix) && key[:len(prefix)] == prefix) {
				ch <- storage.ObjectInfo{
					Key:  key,
					Size: int64(len(data)),
				}
			}
		}
	}()

	return ch
}

func (m *MockStorer) Info() storage.Info {
	return storage.Info{
		Type:     "mock",
		Location: "memory",
	}
}

// GetCalls returns the list of operations that were called
func (m *MockStorer) GetCalls() []string {
	m.mu.Lock()
	defer m.mu.Unlock()

	calls := make([]string, len(m.calls))
	copy(calls, m.calls)

	return calls
}

// GetStorageSize returns the number of objects in storage
func (m *MockStorer) GetStorageSize() int {
	m.mu.Lock()
	defer m.mu.Unlock()

	return len(m.data)
}

// writeTestFileTree creates each file (and its parent directory) in fs.
func writeTestFileTree(t *testing.T, fs afero.Fs, files map[string]string) {
	t.Helper()

	for path, content := range files {
		dir := filepath.Dir(path)

		err := fs.MkdirAll(dir, 0755)
		if err != nil {
			t.Fatalf("failed to create directory %s: %v", dir, err)
		}

		err = afero.WriteFile(fs, path, []byte(content), 0644)
		if err != nil {
			t.Fatalf("failed to create test file %s: %v", path, err)
		}
	}
}

// createTestSnapshotRecord inserts a snapshot row so scans have a
// snapshot to attach to.
func createTestSnapshotRecord(
	t *testing.T, repos *database.Repositories, snapshotID string,
) {
	t.Helper()

	ctx := context.Background()

	err := repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
		snap := &database.Snapshot{
			ID:             types.SnapshotID(snapshotID),
			Hostname:       testHostname,
			VaultikVersion: "test-version",
			StartedAt:      time.Now(),
		}

		return repos.Snapshots.Create(ctx, tx, snap)
	})
	require.NoError(t, err)
}

// TestEndToEndBackup tests the full backup workflow with mocked dependencies
// verifyEndToEndBackupState checks storage upload calls, database file
// rows, and chunk mappings after the end-to-end backup scan.
func verifyEndToEndBackupState(
	ctx context.Context, t *testing.T,
	repos *database.Repositories, mockStorage *MockStorer,
) {
	t.Helper()

	// Verify storage operations
	calls := mockStorage.GetCalls()
	t.Logf("Storage operations performed: %v", calls)

	// Should have uploaded at least one blob
	blobUploads := 0

	for _, call := range calls {
		if len(call) > 4 && call[:4] == "Put:" {
			if len(call) > 10 && call[4:10] == "blobs/" {
				blobUploads++
			}
		}
	}

	assert.Positive(t, blobUploads, "Should upload at least one blob")

	// Verify files in database
	files, err := repos.Files.ListByPrefix(ctx, "/home/user")
	require.NoError(t, err)
	// Count only regular files (not directories)
	regularFiles := 0

	for _, f := range files {
		if f.Mode&0x80000000 == 0 { // Check if regular file (not directory)
			regularFiles++
		}
	}

	assert.Equal(t, 4, regularFiles, "Should have 4 regular files in database")

	// Verify chunks were created by checking a specific file
	fileChunks, err := repos.FileChunks.GetByPath(ctx,
		"/home/user/documents/file1.txt")
	require.NoError(t, err)
	assert.NotEmpty(t, fileChunks, "Should have chunks for file1.txt")
}

// newEndToEndTestConfig builds the standard config used by the
// end-to-end backup test.
func newEndToEndTestConfig() *config.Config {
	return &config.Config{
		Snapshots: map[string]config.SnapshotConfig{
			testLabel: {
				Paths: []string{"/home/user"},
			},
		},
		Exclude:          []string{"*.tmp", "*.log"},
		ChunkSize:        config.Size(16 * 1024),  // 16KB chunks
		BlobSizeLimit:    config.Size(100 * 1024), // 100KB blobs
		CompressionLevel: 3,
		AgeRecipients:    []string{testAgePublicKey},
		AgeSecretKey:     testAgeSecretKey,
		S3: config.S3Config{
			Endpoint:        "http://localhost:9000", // MinIO endpoint for testing
			Region:          "us-east-1",
			Bucket:          "test-bucket",
			AccessKeyID:     "test-access",
			SecretAccessKey: "test-secret",
		},
		IndexPath: ":memory:", // In-memory SQLite database
	}
}

func TestEndToEndBackup(t *testing.T) {
	// Initialize logger
	log.Initialize(log.Config{})
	t.Parallel()

	// Create in-memory filesystem
	fs := afero.NewMemMapFs()

	// Create test directory structure and files
	testFiles := map[string]string{
		"/home/user/documents/file1.txt": "This is file 1 content",
		"/home/user/documents/file2.txt": "This is file 2 content with more data",
		"/home/user/pictures/photo1.jpg": "Binary photo data here...",
		"/home/user/code/main.go": "package main\n\nfunc main() {\n" +
			"\tprintln(\"Hello, World!\")\n}",
	}

	writeTestFileTree(t, fs, testFiles)

	// Create mock storage
	mockStorage := NewMockStorer()

	cfg := newEndToEndTestConfig()

	// For a true end-to-end test, we'll create a simpler test that focuses on
	// the core backup logic using the scanner directly with our mock storage
	ctx := context.Background()

	// Create in-memory database
	db, err := database.New(ctx, ":memory:")

	require.NoError(t, err)

	defer func() {
		err := db.Close()
		if err != nil {
			t.Errorf("failed to close database: %v", err)
		}
	}()

	repos := database.NewRepositories(db)

	// Create scanner with mock storage
	scanner := snapshot.NewScanner(snapshot.ScannerConfig{
		FS:               fs,
		ChunkSize:        cfg.ChunkSize.Int64(),
		Repositories:     repos,
		Storage:          mockStorage,
		MaxBlobSize:      cfg.BlobSizeLimit.Int64(),
		CompressionLevel: cfg.CompressionLevel,
		AgeRecipients:    cfg.AgeRecipients,
		EnableProgress:   false,
	})

	// Create a snapshot record
	snapshotID := "test-snapshot-001"
	createTestSnapshotRecord(t, repos, snapshotID)

	// Run the backup scan
	result, err := scanner.Scan(ctx, "/home/user", snapshotID)
	require.NoError(t, err)

	// Verify scan results. The scanner counts both files and
	// directories: 4 files + directories (/home, /home/user,
	// /home/user/documents, /home/user/pictures, /home/user/code).
	assert.GreaterOrEqual(t, result.FilesScanned, 4, "Should scan at least 4 files")
	assert.Positive(t, result.BytesScanned, "Should scan some bytes")
	assert.Positive(t, result.ChunksCreated, "Should create chunks")
	assert.Positive(t, result.BlobsCreated, "Should create blobs")

	verifyEndToEndBackupState(ctx, t, repos, mockStorage)

	// Verify blobs were uploaded to storage
	assert.Positive(t, mockStorage.GetStorageSize(), "Should have blobs in storage")

	// Complete the snapshot - just verify we got results
	// In a real integration test, we'd update the snapshot record

	// Create snapshot manager to test metadata export
	snapshotManager := &snapshot.SnapshotManager{}
	snapshotManager.SetFilesystem(fs)

	// Note: We can't fully test snapshot metadata export without a proper S3 client mock
	// that implements all required methods. This would require refactoring the S3 client
	// interface to be more testable.

	t.Logf("Backup completed successfully:")
	t.Logf("  Files scanned: %d", result.FilesScanned)
	t.Logf("  Bytes scanned: %d", result.BytesScanned)
	t.Logf("  Chunks created: %d", result.ChunksCreated)
	t.Logf("  Blobs created: %d", result.BlobsCreated)
	t.Logf("  Storage size: %d objects", mockStorage.GetStorageSize())
}

// TestBackupAndVerify tests backing up files and verifying the blobs
func TestBackupAndVerify(t *testing.T) {
	// Initialize logger
	log.Initialize(log.Config{})
	t.Parallel()

	// Create in-memory filesystem
	fs := afero.NewMemMapFs()

	// Create test files
	testContent := "This is a test file with some content that should be backed up"
	err := fs.MkdirAll("/data", 0755)
	require.NoError(t, err)
	err = afero.WriteFile(fs, "/data/test.txt", []byte(testContent), 0644)
	require.NoError(t, err)

	// Create mock storage
	mockStorage := NewMockStorer()

	// Create test database
	ctx := context.Background()
	db, err := database.New(ctx, ":memory:")

	require.NoError(t, err)

	defer func() {
		err := db.Close()
		if err != nil {
			t.Errorf("failed to close database: %v", err)
		}
	}()

	repos := database.NewRepositories(db)

	// Create scanner
	scanner := snapshot.NewScanner(snapshot.ScannerConfig{
		FS:               fs,
		ChunkSize:        int64(1024 * 16), // 16KB chunks
		Repositories:     repos,
		Storage:          mockStorage,
		MaxBlobSize:      int64(1024 * 1024), // 1MB blobs
		CompressionLevel: 3,
		AgeRecipients:    []string{testAgePublicKey},
	})

	// Create a snapshot
	snapshotID := "test-snapshot-001"
	createTestSnapshotRecord(t, repos, snapshotID)

	// Run the backup
	result, err := scanner.Scan(ctx, "/data", snapshotID)
	require.NoError(t, err)

	// Verify backup created blobs
	assert.Positive(t, result.BlobsCreated, "Should create at least one blob")
	assert.Equal(t, mockStorage.GetStorageSize(), result.BlobsCreated,
		"Storage should have the blobs")

	// Verify we can retrieve the blob from storage
	objects, err := mockStorage.List(ctx, "blobs/")
	require.NoError(t, err)
	assert.Len(t, objects, result.BlobsCreated,
		"Should have correct number of blobs in storage")

	// Get the first blob and verify it exists
	if len(objects) > 0 {
		blobKey := objects[0]
		t.Logf("Verifying blob: %s", blobKey)

		// Get blob info
		blobInfo, err := mockStorage.Stat(ctx, blobKey)
		require.NoError(t, err)
		assert.Positive(t, blobInfo.Size, "Blob should have content")

		// Get blob content
		reader, err := mockStorage.Get(ctx, blobKey)
		require.NoError(t, err)

		defer func() { _ = reader.Close() }()

		// Verify blob data is encrypted (should not contain plaintext)
		blobData, err := io.ReadAll(reader)
		require.NoError(t, err)
		assert.NotContains(t, string(blobData), testContent, "Blob should be encrypted")
		assert.NotEmpty(t, blobData, "Blob should have data")
	}

	t.Logf("Backup and verify test completed successfully")
}

// TestBackupAndRestore tests the full backup and restore workflow
// This test verifies that the restore code correctly handles the binary SQLite
// database format that is exported by the snapshot manager.
// runBackupPhase performs the backup half of the round-trip test:
// create the snapshot, scan the data directory, complete the snapshot,
// and export its metadata, verifying the metadata upload.
func runBackupPhase(
	ctx context.Context, t *testing.T, fs afero.Fs,
	repos *database.Repositories, mockStorage *MockStorer,
	cfg *config.Config, dataDir, dbPath, agePublicKey string,
) string {
	t.Helper()

	// Create snapshot manager
	sm := snapshot.NewSnapshotManager(snapshot.SnapshotManagerParams{
		Repos:   repos,
		Storage: mockStorage,
		Config:  cfg,
	})
	sm.SetFilesystem(fs)

	// Create scanner
	scanner := snapshot.NewScanner(snapshot.ScannerConfig{
		FS:               fs,
		Storage:          mockStorage,
		ChunkSize:        int64(16 * 1024),
		MaxBlobSize:      int64(100 * 1024),
		CompressionLevel: 3,
		AgeRecipients:    []string{agePublicKey},
		Repositories:     repos,
	})

	// Create a snapshot
	snapshotID, err := sm.CreateSnapshotWithName(
		ctx, testHostname, "", "test-version", "test-git")
	require.NoError(t, err)
	t.Logf("Created snapshot: %s", snapshotID)

	// Run the backup (scan)
	result, err := scanner.Scan(ctx, dataDir, snapshotID)
	require.NoError(t, err)
	t.Logf("Scan complete: %d files, %d blobs",
		result.FilesScanned, result.BlobsCreated)

	// Complete the snapshot
	err = sm.CompleteSnapshot(ctx, snapshotID)
	require.NoError(t, err)

	// Export snapshot metadata (this uploads db.zst.age and manifest.json.zst)
	err = sm.ExportSnapshotMetadata(ctx, dbPath, snapshotID)
	require.NoError(t, err)
	t.Logf("Exported snapshot metadata")

	// Verify metadata was uploaded
	keys, err := mockStorage.List(ctx, "metadata/")
	require.NoError(t, err)
	t.Logf("Metadata keys: %v", keys)
	assert.GreaterOrEqual(t, len(keys), 2,
		"Should have at least db.zst.age and manifest.json.zst")

	return snapshotID
}

func TestBackupAndRestore(t *testing.T) {
	// Initialize logger
	log.Initialize(log.Config{})
	t.Parallel()

	// Create real temp directory for the database (SQLite needs real filesystem)
	realTempDir := t.TempDir()

	// Use real OS filesystem for this test
	fs := afero.NewOsFs()

	// Create test directory structure and files
	dataDir := filepath.Join(realTempDir, "data")
	testFiles := map[string]string{
		filepath.Join(dataDir, "file1.txt"): "This is file 1 content",
		filepath.Join(dataDir, "file2.txt"): "This is file 2 content " +
			"with more data",
		filepath.Join(dataDir, "subdir", "file3.txt"): "This is file 3 " +
			"in a subdirectory",
	}

	// Create directories and files
	writeTestFileTree(t, fs, testFiles)

	ctx := context.Background()

	// Create mock storage
	mockStorage := NewMockStorer()

	// Test keypair
	agePublicKey := testAgePublicKey
	ageSecretKey := testAgeSecretKey

	// Create database file
	dbPath := filepath.Join(realTempDir, "test.db")
	db, err := database.New(ctx, dbPath)
	require.NoError(t, err)

	defer func() { _ = db.Close() }()

	repos := database.NewRepositories(db)

	// Create config for snapshot manager
	cfg := &config.Config{
		AgeSecretKey:     ageSecretKey,
		AgeRecipients:    []string{agePublicKey},
		CompressionLevel: 3,
	}

	snapshotID := runBackupPhase(
		ctx, t, fs, repos, mockStorage, cfg, dataDir, dbPath, agePublicKey)

	// Close the source database
	err = db.Close()
	require.NoError(t, err)

	// Create Vaultik instance for restore
	vaultikApp := &vaultik.Vaultik{
		Config:  cfg,
		Storage: mockStorage,
		Fs:      fs,
		Stdout:  io.Discard,
		Stderr:  io.Discard,
		UI:      ui.NewWithColor(io.Discard, false),
	}
	vaultikApp.SetContext(ctx)

	// Try to restore - this should work with binary SQLite format
	restoreDir := filepath.Join(realTempDir, "restored")
	err = vaultikApp.Restore(&vaultik.RestoreOptions{
		SnapshotID: snapshotID,
		TargetDir:  restoreDir,
	})
	require.NoError(t, err, "Restore should succeed with binary SQLite database format")

	// Verify restored files match originals
	for origPath, expectedContent := range testFiles {
		restoredPath := filepath.Join(restoreDir, origPath)
		restoredContent, err := afero.ReadFile(fs, restoredPath)
		require.NoError(t, err,
			"Should be able to read restored file: %s", restoredPath)
		assert.Equal(t, expectedContent, string(restoredContent),
			"Restored content should match original for: %s", origPath)
	}

	t.Log("Backup and restore test completed successfully")
}

// setupE2ESourceTree writes a representative mix of file sizes (empty
// file, tiny text file, file under the chunk boundary, multi-chunk
// file, nested subdirectories), a permission-restricted file, an empty
// directory, and a symlink. It returns the content map keyed by path
// plus the restricted-file, empty-dir, and symlink paths.
func setupE2ESourceTree(
	t *testing.T, fs afero.Fs, dataDir string, chunkSize int64,
) (map[string][]byte, string, string, string) {
	t.Helper()

	testFiles := map[string][]byte{
		filepath.Join(dataDir, "empty.txt"): {},
		filepath.Join(dataDir, "small.txt"): []byte("hello vaultik"),
		filepath.Join(dataDir, "subdir", "medium.bin"): bytesPattern(
			"medium-", int(chunkSize/2)),
		filepath.Join(dataDir, "subdir", "large.bin"): bytesPattern(
			"large-", int(chunkSize*4)),
		filepath.Join(dataDir, "deep", "nest", "leaf.txt"): []byte("leaf"),
	}

	for path, content := range testFiles {
		require.NoError(t, fs.MkdirAll(filepath.Dir(path), 0o755))
		require.NoError(t, afero.WriteFile(fs, path, content, 0o644))
	}

	// Create a file with non-default permissions.
	restrictedPath := filepath.Join(dataDir, "restricted.txt")
	require.NoError(t, afero.WriteFile(fs, restrictedPath, []byte("secret"), 0o600))

	testFiles[restrictedPath] = []byte("secret")

	// Create an empty directory (should survive round-trip).
	emptyDir := filepath.Join(dataDir, "emptydir")
	require.NoError(t, fs.MkdirAll(emptyDir, 0o755))

	// Create a symlink.
	symlinkPath := filepath.Join(dataDir, "link-to-small")
	require.NoError(t, os.Symlink("small.txt", symlinkPath))

	return testFiles, restrictedPath, emptyDir, symlinkPath
}

// TestEndToEndFileStorage exercises the full backup → restore loop against the
// real `file://` storage backend (FileStorer) on a real OS filesystem. This is
// the closest local approximation of a production backup: encrypted blobs get
// written to disk, the metadata SQLite database is exported through the same
// blobgen pipeline as a real backup, and restoration reads them back through
// the public Vaultik.Restore entrypoint. It is the canonical end-to-end smoke
// test for 1.0.
// runFileStorageBackup performs the backup half of the file-storage
// end-to-end test against a real on-disk FileStorer, verifies the
// on-disk layout, and closes the index database so the restore half
// runs from remote bytes only.
func runFileStorageBackup(
	ctx context.Context, t *testing.T, fs afero.Fs,
	dataDir, storeDir, dbPath string,
	chunkSize, maxBlobSize int64,
) (*config.Config, *storage.FileStorer, string) {
	t.Helper()

	// FileStorer is the real-world local-disk backend.
	storer, err := storage.NewFileStorer(storeDir)
	require.NoError(t, err)

	cfg := &config.Config{
		AgeRecipients:    []string{testAgePublicKey},
		AgeSecretKey:     testAgeSecretKey,
		CompressionLevel: 3,
		Hostname:         testHostname,
	}

	db, err := database.New(ctx, dbPath)
	require.NoError(t, err)

	defer func() { _ = db.Close() }()

	repos := database.NewRepositories(db)

	sm := snapshot.NewSnapshotManager(snapshot.SnapshotManagerParams{
		Repos:   repos,
		Storage: storer,
		Config:  cfg,
	})
	sm.SetFilesystem(fs)

	scanner := snapshot.NewScanner(snapshot.ScannerConfig{
		FS:               fs,
		Storage:          storer,
		ChunkSize:        chunkSize,
		MaxBlobSize:      maxBlobSize,
		CompressionLevel: cfg.CompressionLevel,
		AgeRecipients:    cfg.AgeRecipients,
		Repositories:     repos,
	})

	snapshotID, err := sm.CreateSnapshotWithName(
		ctx, cfg.Hostname, "e2e", "test-version", "test-git")
	require.NoError(t, err)

	scanResult, err := scanner.Scan(ctx, dataDir, snapshotID)
	require.NoError(t, err)
	require.Positive(t, scanResult.FilesScanned)
	require.Positive(t, scanResult.BlobsCreated)

	require.NoError(t, sm.CompleteSnapshot(ctx, snapshotID))
	require.NoError(t, sm.ExportSnapshotMetadata(ctx, dbPath, snapshotID))

	// Verify the backup actually landed on disk under blobs/ and metadata/.
	// The metadata subdirectory uses the hashed remote key, not the human
	// snapshot ID, so the on-disk structure doesn't leak hostname/name/time.
	blobInfo, err := os.Stat(filepath.Join(storeDir, "blobs"))
	require.NoError(t, err)
	require.True(t, blobInfo.IsDir())

	metaInfo, err := os.Stat(filepath.Join(
		storeDir, "metadata", snapshot.RemoteSnapshotKey(snapshotID)))
	require.NoError(t, err)
	require.True(t, metaInfo.IsDir())

	// Tear down the source DB before restore — restore must work using only
	// the remote bytes plus the secret key, with no help from the local index.
	require.NoError(t, db.Close())

	return cfg, storer, snapshotID
}

func TestEndToEndFileStorage(t *testing.T) {
	log.Initialize(log.Config{})
	t.Parallel()

	// Real OS filesystem (SQLite + FileStorer both need it).
	fs := afero.NewOsFs()
	tempDir := t.TempDir()

	dataDir := filepath.Join(tempDir, "source")
	storeDir := filepath.Join(tempDir, "remote")
	restoreDir := filepath.Join(tempDir, "restored")
	dbPath := filepath.Join(tempDir, "index.sqlite")

	// Write a representative mix of file sizes:
	//   - empty file
	//   - tiny text file
	//   - file just under chunk boundary
	//   - file forcing multiple chunks
	//   - nested subdirectories
	chunkSize := int64(64 * 1024)
	maxBlobSize := int64(512 * 1024)

	testFiles, restrictedPath, emptyDir, symlinkPath :=
		setupE2ESourceTree(t, fs, dataDir, chunkSize)

	ctx := context.Background()

	cfg, storer, snapshotID := runFileStorageBackup(
		ctx, t, fs, dataDir, storeDir, dbPath, chunkSize, maxBlobSize)

	restoreVaultik := &vaultik.Vaultik{
		Config:  cfg,
		Storage: storer,
		Fs:      fs,
		Stdout:  io.Discard,
		Stderr:  io.Discard,
		UI:      ui.NewWithColor(io.Discard, false),
	}
	restoreVaultik.SetContext(ctx)

	require.NoError(t, restoreVaultik.Restore(&vaultik.RestoreOptions{
		SnapshotID: snapshotID,
		TargetDir:  restoreDir,
		Verify:     true,
	}))

	verifyE2ERestoredTree(t, fs, restoreDir, testFiles,
		restrictedPath, emptyDir, symlinkPath)
}

// verifyE2ERestoredTree byte-compares every restored file and checks the
// restricted-permission file, empty directory, and symlink special cases.
func verifyE2ERestoredTree(
	t *testing.T, fs afero.Fs, restoreDir string,
	testFiles map[string][]byte,
	restrictedPath, emptyDir, symlinkPath string,
) {
	t.Helper()

	// Byte-equality compare every original against its restored copy.
	for origPath, expected := range testFiles {
		restoredPath := filepath.Join(restoreDir, origPath)
		got, err := afero.ReadFile(fs, restoredPath)
		require.NoError(t, err, "restored file missing: %s", restoredPath)
		require.Equalf(t, expected, got, "byte-equality failed for %s", origPath)
	}

	// Verify the restricted file kept its permissions.
	restoredRestricted := filepath.Join(restoreDir, restrictedPath)
	rInfo, err := os.Stat(restoredRestricted)
	require.NoError(t, err)
	assert.Equal(t, os.FileMode(0o600), rInfo.Mode().Perm(),
		"restricted file should preserve 0600 permissions")

	// Verify the empty directory was restored.
	restoredEmptyDir := filepath.Join(restoreDir, emptyDir)
	dInfo, err := os.Stat(restoredEmptyDir)
	require.NoError(t, err, "empty directory should be restored")
	assert.True(t, dInfo.IsDir(), "emptydir should be a directory")

	// Verify the symlink was restored with the correct target.
	restoredSymlink := filepath.Join(restoreDir, symlinkPath)
	target, err := os.Readlink(restoredSymlink)
	require.NoError(t, err, "symlink should be restored")
	assert.Equal(t, "small.txt", target, "symlink target should be preserved")
}

// TestDedupOnlySnapshotRestores backs up the same directory twice without
// touching it between runs, then restores the SECOND (fully-deduplicated)
// snapshot. The second snapshot uploads no new blobs — every chunk is
// already in storage from the first run. This test guards against the
// regression where snapshot_blobs was populated only for blobs uploaded
// during the snapshot, leaving fully-deduplicated snapshots unrestorable
// with "chunk X not found in any blob" errors.
// dedupBackupEnv bundles the moving parts of the dedup round-trip test.
type dedupBackupEnv struct {
	cfg         *config.Config
	storer      *storage.FileStorer
	db          *database.DB
	repos       *database.Repositories
	sm          *snapshot.SnapshotManager
	makeScanner func() *snapshot.Scanner
}

// writeDedupSourceFiles writes the two deterministic source files used
// by the dedup test and returns their expected contents by path.
func writeDedupSourceFiles(
	t *testing.T, fs afero.Fs, dataDir string, chunkSize int64,
) map[string][]byte {
	t.Helper()

	testFiles := map[string][]byte{
		filepath.Join(dataDir, "a.bin"): bytesPattern("a-", int(chunkSize*3)),
		filepath.Join(dataDir, "b.bin"): bytesPattern("b-", int(chunkSize*2)),
	}
	for path, content := range testFiles {
		require.NoError(t, fs.MkdirAll(filepath.Dir(path), 0o755))
		require.NoError(t, afero.WriteFile(fs, path, content, 0o644))
	}

	return testFiles
}

// setupDedupBackupEnv creates the storer, config, database, snapshot
// manager, and scanner factory for the dedup round-trip test.
func setupDedupBackupEnv(
	ctx context.Context, t *testing.T, fs afero.Fs,
	storeDir, dbPath string, chunkSize, maxBlobSize int64,
) *dedupBackupEnv {
	t.Helper()

	storer, err := storage.NewFileStorer(storeDir)
	require.NoError(t, err)

	cfg := &config.Config{
		AgeRecipients:    []string{testAgePublicKey},
		AgeSecretKey:     testAgeSecretKey,
		CompressionLevel: 3,
		Hostname:         testHostname,
	}

	db, err := database.New(ctx, dbPath)
	require.NoError(t, err)

	repos := database.NewRepositories(db)

	makeScanner := func() *snapshot.Scanner {
		return snapshot.NewScanner(snapshot.ScannerConfig{
			FS:               fs,
			Storage:          storer,
			ChunkSize:        chunkSize,
			MaxBlobSize:      maxBlobSize,
			CompressionLevel: cfg.CompressionLevel,
			AgeRecipients:    cfg.AgeRecipients,
			Repositories:     repos,
		})
	}
	sm := snapshot.NewSnapshotManager(snapshot.SnapshotManagerParams{
		Repos: repos, Storage: storer, Config: cfg,
	})
	sm.SetFilesystem(fs)

	return &dedupBackupEnv{
		cfg:         cfg,
		storer:      storer,
		db:          db,
		repos:       repos,
		sm:          sm,
		makeScanner: makeScanner,
	}
}

// runDedupSnapshot creates a "dedup" snapshot, scans dataDir into it,
// completes it, and exports its metadata, returning the snapshot ID and
// scan result.
func runDedupSnapshot(
	ctx context.Context, t *testing.T,
	sm *snapshot.SnapshotManager, scanner *snapshot.Scanner,
	hostname, dataDir, dbPath string,
) (string, *snapshot.ScanResult) {
	t.Helper()

	id, err := sm.CreateSnapshotWithName(ctx, hostname, "dedup", "v", "g")
	require.NoError(t, err)

	result, err := scanner.Scan(ctx, dataDir, id)
	require.NoError(t, err)

	require.NoError(t, sm.CompleteSnapshot(ctx, id))
	require.NoError(t, sm.ExportSnapshotMetadata(ctx, dbPath, id))

	return id, result
}

func TestDedupOnlySnapshotRestores(t *testing.T) {
	log.Initialize(log.Config{})
	t.Parallel()

	fs := afero.NewOsFs()
	tempDir := t.TempDir()

	dataDir := filepath.Join(tempDir, "source")
	storeDir := filepath.Join(tempDir, "remote")
	restoreDir := filepath.Join(tempDir, "restored")
	dbPath := filepath.Join(tempDir, "index.sqlite")

	chunkSize := int64(64 * 1024)
	maxBlobSize := int64(512 * 1024)

	ctx := context.Background()

	testFiles := writeDedupSourceFiles(t, fs, dataDir, chunkSize)

	env := setupDedupBackupEnv(
		ctx, t, fs, storeDir, dbPath, chunkSize, maxBlobSize)

	defer func() { _ = env.db.Close() }()

	cfg, storer, repos, sm := env.cfg, env.storer, env.repos, env.sm
	makeScanner := env.makeScanner
	db := env.db

	// First snapshot — uploads all blobs.
	_, r1 := runDedupSnapshot(ctx, t, sm, makeScanner(),
		cfg.Hostname, dataDir, dbPath)
	require.Positive(t, r1.BlobsCreated,
		"first snapshot should upload at least one blob")

	// Second snapshot — same data, every chunk dedups. Sleep past the
	// second-precision timestamp so the snapshot IDs differ.
	time.Sleep(1100 * time.Millisecond)

	id2, r2 := runDedupSnapshot(ctx, t, sm, makeScanner(),
		cfg.Hostname, dataDir, dbPath)
	require.Equal(t, 0, r2.BlobsCreated,
		"second snapshot should upload zero new blobs (fully dedup'd)")

	// snapshot_blobs for id2 must be populated despite no uploads.
	blobHashes, err := repos.Snapshots.GetBlobHashes(ctx, id2)
	require.NoError(t, err)
	require.NotEmpty(t, blobHashes, "snapshot_blobs for fully-dedup'd snapshot "+
		"must reference blobs uploaded by prior snapshot")

	require.NoError(t, db.Close())

	restoreVaultik := &vaultik.Vaultik{
		Config:  cfg,
		Storage: storer,
		Fs:      fs,
		Stdout:  io.Discard,
		Stderr:  io.Discard,
		UI:      ui.NewWithColor(io.Discard, false),
	}
	restoreVaultik.SetContext(ctx)

	require.NoError(t, restoreVaultik.Restore(&vaultik.RestoreOptions{
		SnapshotID: id2,
		TargetDir:  restoreDir,
		Verify:     true,
	}))

	for origPath, expected := range testFiles {
		restoredPath := filepath.Join(restoreDir, origPath)
		got, err := afero.ReadFile(fs, restoredPath)
		require.NoError(t, err, "restored file missing: %s", restoredPath)
		require.Equalf(t, expected, got, "byte-equality failed for %s", origPath)
	}
}

// bytesPattern returns a deterministic byte slice of length n with a tag prefix,
// useful for forcing chunker behavior with reproducible content.
func bytesPattern(tag string, n int) []byte {
	out := make([]byte, n)
	for i := range out {
		out[i] = tag[i%len(tag)] ^ byte(i&0xff)
	}

	return out
}