package datasets

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

func TestLocalStoreBeginWriteResume(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStore(dir, "gfs-test")
	if err != nil {
		t.Fatalf("NewLocalStore: %v", err)
	}

	epoch := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
	h, err := store.BeginWrite(epoch)
	if err != nil {
		t.Fatalf("BeginWrite: %v", err)
	}
	if err := os.WriteFile(h.Path(), []byte("partial"), 0o644); err != nil {
		t.Fatalf("write partial: %v", err)
	}
	if err := h.Manifest().Mark("step000-A"); err != nil {
		t.Fatalf("mark: %v", err)
	}

	// Re-open should see the previous manifest entry.
	h2, err := store.BeginWrite(epoch)
	if err != nil {
		t.Fatalf("BeginWrite resume: %v", err)
	}
	if !h2.Manifest().Has("step000-A") {
		t.Errorf("resumed manifest missing step000-A; units = %v", h2.Manifest().Units())
	}

	// Commit promotes the temp file and removes the manifest.
	if err := h2.Commit(); err != nil {
		t.Fatalf("Commit: %v", err)
	}
	if !store.Exists(epoch) {
		t.Errorf("Exists after commit returned false")
	}
	if _, err := os.Stat(filepath.Join(dir, store.manifestPath(epoch))); !os.IsNotExist(err) {
		t.Errorf("manifest should be removed, got err=%v", err)
	}

	// Listing finds the committed epoch.
	epochs, err := store.List()
	if err != nil {
		t.Fatalf("List: %v", err)
	}
	if len(epochs) != 1 || !epochs[0].Equal(epoch) {
		t.Errorf("List = %v, want [%v]", epochs, epoch)
	}

	// Remove cleans up.
	if err := store.Remove(epoch); err != nil {
		t.Fatalf("Remove: %v", err)
	}
	if store.Exists(epoch) {
		t.Errorf("Exists after remove returned true")
	}
}

func TestLocalStoreAbort(t *testing.T) {
	dir := t.TempDir()
	store, _ := NewLocalStore(dir, "gfs-test")
	epoch := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)

	h, _ := store.BeginWrite(epoch)
	os.WriteFile(h.Path(), []byte("x"), 0o644)
	h.Manifest().Mark("step000-A")

	if err := h.Abort(); err != nil {
		t.Fatalf("Abort: %v", err)
	}
	if _, err := os.Stat(h.Path()); !os.IsNotExist(err) {
		t.Errorf("temp file should be removed after abort, got %v", err)
	}
}