// Package blobstore stores the bytes of uploaded pictures. Keeping it behind an
// interface means the local filesystem can later be replaced by object storage
// without changing the upload handler.
package blobstore

import (
	"context"
	"errors"
	"io"
)

var (
	// ErrNotFound is returned when a key has no stored object.
	ErrNotFound = errors.New("blob not found")
	// ErrTooLarge is returned when the payload exceeds the configured limit.
	ErrTooLarge = errors.New("blob exceeds maximum size")
)

// BlobStore saves and serves opaque byte payloads addressed by key.
type BlobStore interface {
	// Put stores the contents of r under key and returns the number of bytes
	// written. It must not read more than maxBytes from r.
	Put(ctx context.Context, key string, r io.Reader, maxBytes int64) (int64, error)
	// Get opens the object stored under key. The caller closes the reader.
	Get(ctx context.Context, key string) (io.ReadCloser, error)
	// Delete removes the object stored under key. Deleting a missing key is not
	// an error.
	Delete(ctx context.Context, key string) error
}