refactor(files): single file client facade + CLI/TUI migration (#38)

- FileClient composes FileStore/Searcher backends; Read()/Write()/Search()
  select REST/DAV/PG/ES with transient read fallback. Client.Files() returns
  it and *FileClient implements FileStore, so existing callers keep working.
- Entry gains backend-native Updated + folder FilesCount/FoldersCount so
  dav ls output round-trips.
- cmd/oo dav/projects files and cmd/office/fetch download/preview/delete go
  through FileStore; oo search goes through the facade.
- Mark transport methods that FileStore now abstracts as deprecated.

file_facade_test.go

@@ -0,0 +1,230 @@
+package onlyoffice
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+	"testing"
+)
+
+// fakeStore is a FileStore test double; it records which backend served a call
+// and returns a canned result or error.
+type fakeStore struct {
+	name    string
+	entries []Entry
+	err     error
+	calls   *[]string
+}
+
+func (f *fakeStore) record(op string) {
+	if f.calls != nil {
+		*f.calls = append(*f.calls, op+":"+f.name)
+	}
+}
+
+func (f *fakeStore) Name() string { return f.name }
+
+func (f *fakeStore) List(_ context.Context, _ string) ([]Entry, error) {
+	f.record("list")
+	if f.err != nil {
+		return nil, f.err
+	}
+	return f.entries, nil
+}
+
+func (f *fakeStore) Stat(_ context.Context, id string) (Entry, error) {
+	f.record("stat")
+	if f.err != nil {
+		return Entry{}, f.err
+	}
+	return Entry{ID: id, Title: "t-" + f.name, Provider: f.name}, nil
+}
+
+func (f *fakeStore) CreateFolder(_ context.Context, _, title string) (Entry, error) {
+	f.record("mkdir")
+	if f.err != nil {
+		return Entry{}, f.err
+	}
+	return Entry{ID: "new", Title: title, Provider: f.name}, nil
+}
+
+func (f *fakeStore) Upload(_ context.Context, _, title string, _ io.Reader) (Entry, error) {
+	f.record("upload")
+	return Entry{ID: "up", Title: title, Provider: f.name}, f.err
+}
+
+func (f *fakeStore) Download(_ context.Context, _ string, _ io.Writer) (int64, error) {
+	f.record("download")
+	return 0, f.err
+}
+
+func (f *fakeStore) Move(_ context.Context, _ []string, _ string) error {
+	f.record("move")
+	return f.err
+}
+
+func (f *fakeStore) Copy(_ context.Context, _ []string, _ string) error {
+	f.record("copy")
+	return f.err
+}
+
+func (f *fakeStore) Rename(_ context.Context, _, _ string) error {
+	f.record("rename")
+	return f.err
+}
+
+func (f *fakeStore) Delete(_ context.Context, _ []string) error {
+	f.record("delete")
+	return f.err
+}
+
+type fakeSearcher struct{ name string }
+
+func (s *fakeSearcher) Name() string { return s.name }
+
+func (s *fakeSearcher) Search(_ context.Context, _ SearchQuery) ([]SearchHit, error) {
+	return []SearchHit{{Entry: Entry{Title: s.name}}}, nil
+}
+
+func newFacadeTestClient(stores map[string]FileStore, read, write []string) *FileClient {
+	return &FileClient{
+		stores:     stores,
+		searchers:  map[string]Searcher{},
+		readOrder:  read,
+		writeOrder: write,
+	}
+}
+
+// TestFileClientIsFileStore guarantees the facade can stand in for the
+// interface anywhere a plain FileStore is expected.
+func TestFileClientIsFileStore(t *testing.T) {
+	var _ FileStore = (*FileClient)(nil)
+}
+
+func TestClientFilesPrefersRESTForReadsAndWrites(t *testing.T) {
+	c := NewClient(Credentials{})
+	f := c.Files()
+	if got := f.Read().Name(); got != ProviderREST {
+		t.Errorf("Read().Name() = %q, want %q", got, ProviderREST)
+	}
+	if got := f.Write().Name(); got != ProviderREST {
+		t.Errorf("Write().Name() = %q, want %q", got, ProviderREST)
+	}
+	if got := f.Name(); got != ProviderREST {
+		t.Errorf("Name() = %q, want %q", got, ProviderREST)
+	}
+}
+
+func TestFileClientPostgresTakesReadPriority(t *testing.T) {
+	pg := &fakeStore{name: ProviderPG}
+	f := newFacadeTestClient(
+		map[string]FileStore{ProviderREST: &fakeStore{name: ProviderREST}, ProviderPG: pg},
+		[]string{ProviderPG, ProviderREST},
+		[]string{ProviderREST},
+	)
+	if got := f.Read().Name(); got != ProviderPG {
+		t.Errorf("Read().Name() = %q, want %q", got, ProviderPG)
+	}
+	if got := f.Write().Name(); got != ProviderREST {
+		t.Errorf("Write().Name() = %q, want %q (PG is read-only)", got, ProviderREST)
+	}
+}
+
+func TestFileClientRegisterStoreNormalizesName(t *testing.T) {
+	pg := &fakeStore{name: "pg"}
+	f := newFacadeTestClient(map[string]FileStore{}, []string{ProviderPG}, nil)
+	f.RegisterStore("  POSTGRES  ", pg)
+	if got := f.Read(); got != pg {
+		t.Fatalf("Read() = %v, want registered postgres store", got)
+	}
+	f.RegisterStore("", pg)
+	f.RegisterStore("pg", nil)
+}
+
+func TestFileClientReadFallsBackOnlyOnTransient(t *testing.T) {
+	var calls []string
+	primary := &fakeStore{name: "primary", err: fmt.Errorf("onlyoffice: list: 503 unavailable"), calls: &calls}
+	secondary := &fakeStore{name: "secondary", entries: []Entry{{ID: "1"}}, calls: &calls}
+	f := newFacadeTestClient(
+		map[string]FileStore{"primary": primary, "secondary": secondary},
+		[]string{"primary", "secondary"},
+		nil,
+	)
+	got, err := f.List(context.Background(), "root")
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+	if len(got) != 1 || got[0].ID != "1" {
+		t.Fatalf("List() = %+v, want secondary entry", got)
+	}
+	want := []string{"list:primary", "list:secondary"}
+	if fmt.Sprint(calls) != fmt.Sprint(want) {
+		t.Fatalf("call order = %v, want %v", calls, want)
+	}
+}
+
+func TestFileClientReadStopsOnPermanentError(t *testing.T) {
+	var calls []string
+	primary := &fakeStore{name: "primary", err: errors.New("onlyoffice: not found"), calls: &calls}
+	secondary := &fakeStore{name: "secondary", entries: []Entry{{ID: "1"}}, calls: &calls}
+	f := newFacadeTestClient(
+		map[string]FileStore{"primary": primary, "secondary": secondary},
+		[]string{"primary", "secondary"},
+		nil,
+	)
+	if _, err := f.List(context.Background(), "root"); err == nil {
+		t.Fatal("expected permanent error to be returned")
+	}
+	if len(calls) != 1 || calls[0] != "list:primary" {
+		t.Fatalf("secondary backend must not run on a permanent error: %v", calls)
+	}
+}
+
+func TestFileClientWriteUsesWriteBackend(t *testing.T) {
+	var calls []string
+	rest := &fakeStore{name: ProviderREST, calls: &calls}
+	dav := &fakeStore{name: ProviderDAV, calls: &calls}
+	f := newFacadeTestClient(
+		map[string]FileStore{ProviderREST: rest, ProviderDAV: dav},
+		[]string{ProviderREST},
+		[]string{ProviderREST, ProviderDAV},
+	)
+	if _, err := f.CreateFolder(context.Background(), "p", "t"); err != nil {
+		t.Fatalf("CreateFolder: %v", err)
+	}
+	if _, err := f.Upload(context.Background(), "p", "t", nil); err != nil {
+		t.Fatalf("Upload: %v", err)
+	}
+	if len(calls) != 2 || calls[0] != "mkdir:rest" || calls[1] != "upload:rest" {
+		t.Fatalf("write calls = %v, want REST", calls)
+	}
+}
+
+func TestFileClientWriteWithoutBackend(t *testing.T) {
+	f := newFacadeTestClient(map[string]FileStore{}, nil, nil)
+	if err := f.Delete(context.Background(), []string{"1"}); !errors.Is(err, errNoWriteBackend) {
+		t.Fatalf("Delete err = %v, want errNoWriteBackend", err)
+	}
+	if _, err := f.List(context.Background(), "root"); !errors.Is(err, errNoReadBackend) {
+		t.Fatalf("List err = %v, want errNoReadBackend", err)
+	}
+}
+
+func TestFileClientSearchSelection(t *testing.T) {
+	f := &FileClient{searchers: map[string]Searcher{}, searchOrder: []string{ProviderES}}
+	_, err := f.Search()
+	if err == nil || !strings.Contains(err.Error(), "ONLYOFFICE_ES_URL") {
+		t.Fatalf("Search without backend = %v, want ONLYOFFICE_ES_URL hint", err)
+	}
+	es := &fakeSearcher{name: "fake-es"}
+	f.RegisterSearcher(ProviderES, es)
+	got, err := f.Search()
+	if err != nil {
+		t.Fatalf("Search: %v", err)
+	}
+	if got.Name() != "fake-es" {
+		t.Fatalf("searcher = %q, want fake-es", got.Name())
+	}
+}