package hostbox

import (
	"context"
	"io"
	"sync"

	"github.com/carlosframework/platform/internal/lease"
)

// RequestStore bounds complete SDK operations, including retries. Check must
// inspect current captured authority and aggregate lease health. The supplied
// context must also be cancelled by the operation owner on lease loss.
type RequestStore struct {
	Store lease.VersionedStore
	Check func(context.Context) error
}

func (s RequestStore) request(ctx context.Context) (context.Context, context.CancelFunc, error) {
	if ctx == nil || s.Store == nil || s.Check == nil {
		return nil, nil, ErrUnsupported
	}
	bounded, cancel := context.WithTimeout(ctx, RequestLimit)
	if err := s.Check(bounded); err != nil {
		cancel()
		return nil, nil, err
	}
	if err := bounded.Err(); err != nil {
		cancel()
		return nil, nil, err
	}
	return bounded, cancel, nil
}
func (s RequestStore) ListVersions(ctx context.Context, bucket, prefix string) ([]lease.ObjectVersion, error) {
	ctx, cancel, err := s.request(ctx)
	if err != nil {
		return nil, err
	}
	defer cancel()
	return s.Store.ListVersions(ctx, bucket, prefix)
}
func (s RequestStore) GetVersion(ctx context.Context, bucket, key, version string) ([]byte, error) {
	ctx, cancel, err := s.request(ctx)
	if err != nil {
		return nil, err
	}
	defer cancel()
	return s.Store.GetVersion(ctx, bucket, key, version)
}
func (s RequestStore) OpenVersion(ctx context.Context, bucket, key, version string) (io.ReadCloser, error) {
	ctx, cancel, err := s.request(ctx)
	if err != nil {
		return nil, err
	}
	r, err := s.Store.OpenVersion(ctx, bucket, key, version)
	if err != nil {
		cancel()
		return nil, err
	}
	if r == nil {
		cancel()
		return nil, ErrUnsupported
	}
	return &requestReader{ReadCloser: r, cancel: cancel}, nil
}
func (s RequestStore) CopyVersion(ctx context.Context, sb, sk, sv, db, dk string, createOnly bool) (string, string, error) {
	ctx, cancel, err := s.request(ctx)
	if err != nil {
		return "", "", err
	}
	defer cancel()
	return s.Store.CopyVersion(ctx, sb, sk, sv, db, dk, createOnly)
}
func (s RequestStore) DeleteVersion(ctx context.Context, bucket, key, version string) error {
	ctx, cancel, err := s.request(ctx)
	if err != nil {
		return err
	}
	defer cancel()
	return s.Store.DeleteVersion(ctx, bucket, key, version)
}
func (s RequestStore) PutIfAbsent(ctx context.Context, bucket, key string, body []byte) (string, error) {
	ctx, cancel, err := s.request(ctx)
	if err != nil {
		return "", err
	}
	defer cancel()
	return s.Store.PutIfAbsent(ctx, bucket, key, body)
}

type requestReader struct {
	io.ReadCloser
	cancel context.CancelFunc
	once   sync.Once
}

func (r *requestReader) Close() error { err := r.ReadCloser.Close(); r.once.Do(r.cancel); return err }

var _ lease.VersionedStore = RequestStore{}