package release

import (
	"context"
	"errors"
	"testing"
	"time"
)

func TestSerialBumpFromMissing(t *testing.T) {
	s := NewDirStore(t.TempDir())
	ctx := context.Background()
	doc, etag, err := ReadSerial(ctx, s)
	if err != nil || doc.Serial != 0 || etag != "" {
		t.Fatalf("missing serial should read as zero: %+v %q %v", doc, etag, err)
	}
	if err := BumpSerial(ctx, s, time.Unix(1754640000, 0).UTC()); err != nil {
		t.Fatal(err)
	}
	doc, etag, err = ReadSerial(ctx, s)
	if err != nil || doc.Serial != 1 || doc.Schema != 1 || etag == "" {
		t.Fatalf("first bump: %+v %q %v", doc, etag, err)
	}
	if doc.BumpedAt == "" {
		t.Fatal("bumped_at not stamped")
	}
}

func TestSerialBumpIncrements(t *testing.T) {
	s := NewDirStore(t.TempDir())
	ctx := context.Background()
	for i := 0; i < 3; i++ {
		if err := BumpSerial(ctx, s, time.Unix(1754640000, 0).UTC()); err != nil {
			t.Fatal(err)
		}
	}
	doc, _, _ := ReadSerial(ctx, s)
	if doc.Serial != 3 {
		t.Fatalf("serial = %d, want 3", doc.Serial)
	}
}

func TestSerialGarbageObjectStillBumps(t *testing.T) {
	// A bucket-writer can corrupt the object; a bump must recover, not wedge.
	s := NewDirStore(t.TempDir())
	ctx := context.Background()
	if _, err := s.Put(ctx, SerialKey, []byte("not json"), ""); err != nil {
		t.Fatal(err)
	}
	if err := BumpSerial(ctx, s, time.Unix(1754640000, 0).UTC()); err != nil {
		t.Fatal(err)
	}
	doc, _, err := ReadSerial(ctx, s)
	if err != nil || doc.Serial != 1 {
		t.Fatalf("recovery bump: %+v %v", doc, err)
	}
}

// serialCancelStore cancels a context at a chosen point and is otherwise the
// DirStore beneath it, whose Put ignores its context.
type serialCancelStore struct {
	Store
	onGet, onPut func()
	puts         int
}

func (s *serialCancelStore) Get(ctx context.Context, key string) ([]byte, string, error) {
	if s.onGet != nil {
		s.onGet()
	}
	return s.Store.Get(ctx, key)
}

func (s *serialCancelStore) Put(ctx context.Context, key string, body []byte, ifMatch string) (string, error) {
	s.puts++
	if s.onPut != nil {
		s.onPut()
		return "", ErrCASConflict // a race lost, so BumpSerial retries
	}
	return s.Store.Put(ctx, key, body, ifMatch)
}

// A caller whose context ended while BumpSerial read the serial gets no
// write, even from a store that ignores its context (db region forward,
// Astra round 1, P2).
func TestSerialBumpDoesNotWriteAfterItsContextEnds(t *testing.T) {
	dir := NewDirStore(t.TempDir())
	ctx, cancel := context.WithCancel(context.Background())
	s := &serialCancelStore{Store: dir, onGet: cancel}
	if err := BumpSerial(ctx, s, time.Now()); !errors.Is(err, context.Canceled) {
		t.Fatalf("err %v, want the context's", err)
	}
	if doc, etag, _ := ReadSerial(context.Background(), dir); doc.Serial != 0 || etag != "" || s.puts != 0 {
		t.Fatalf("the serial was written after its context ended: %+v, %d puts", doc, s.puts)
	}
}

// The same check holds before a retry's write.
func TestSerialBumpRetryDoesNotWriteAfterItsContextEnds(t *testing.T) {
	dir := NewDirStore(t.TempDir())
	ctx, cancel := context.WithCancel(context.Background())
	s := &serialCancelStore{Store: dir}
	s.onPut = func() { cancel(); s.onPut = nil }
	if err := BumpSerial(ctx, s, time.Now()); !errors.Is(err, context.Canceled) {
		t.Fatalf("err %v, want the context's", err)
	}
	if doc, _, _ := ReadSerial(context.Background(), dir); doc.Serial != 0 || s.puts != 1 {
		t.Fatalf("a retry wrote the serial after its context ended: %+v, %d puts", doc, s.puts)
	}
}