backend

type Backend interface {
	// Object operations
	GetObject(ctx context.Context, req *GetObjectRequest) (*GetObjectResponse, error)
	HeadObject(ctx context.Context, bucket, key string) (*HeadObjectResponse, error)
	PutObject(ctx context.Context, req *PutObjectRequest) (*PutObjectResponse, error)
	DeleteObject(ctx context.Context, req *DeleteObjectRequest) error

	// Bucket operations
	CreateBucket(ctx context.Context, req *CreateBucketRequest) (*CreateBucketResponse, error)
	DeleteBucket(ctx context.Context, req *DeleteBucketRequest) error
	HeadBucket(ctx context.Context, req *HeadBucketRequest) (*HeadBucketResponse, error)
	ListBuckets(ctx context.Context, ownerID string) (*ListBucketsResponse, error)
	ListObjects(ctx context.Context, req *ListObjectsRequest) (*ListObjectsResponse, error)

	// Multipart upload operations
	CreateMultipartUpload(ctx context.Context, req *CreateMultipartUploadRequest) (*CreateMultipartUploadResponse, error)
	UploadPart(ctx context.Context, req *UploadPartRequest) (*UploadPartResponse, error)
	CompleteMultipartUpload(ctx context.Context, req *CompleteMultipartUploadRequest) (*CompleteMultipartUploadResponse, error)
	AbortMultipartUpload(ctx context.Context, bucket, key, uploadID string) error

	// Backend info
	Type() string
	Close() error
}

type BucketInfo struct {
	Name         string
	CreationDate time.Time
	Region       string
}

type BucketMetadata struct {
	Name         string    `json:"name"`
	Region       string    `json:"region"`
	OwnerID      string    `json:"owner_id"`      // Access key ID of owner
	OwnerDisplay string    `json:"owner_display"` // Display name
	CreationDate time.Time `json:"creation_date"`
	Public       bool      `json:"public"`      // Allow anonymous access
	ObjectLock   bool      `json:"object_lock"` // Object lock enabled
	Versioning   string    `json:"versioning"`  // Enabled, Suspended, or empty
}

type CompleteMultipartUploadRequest struct {
	Bucket   string
	Key      string
	UploadID string
	Parts    []CompletedPart
}

type CompleteMultipartUploadResponse struct {
	Location string
	Bucket   string
	Key      string
	ETag     string
}

type CompletedPart struct {
	PartNumber int
	ETag       string
}

type CreateBucketRequest struct {
	Bucket            string
	Region            string // From LocationConstraint in request body
	OwnerID           string // Access key ID of the authenticated user
	OwnerDisplayName  string // Display name (optional)
	ObjectLockEnabled bool   // For object lock (future)
	ObjectOwnership   string // BucketOwnerEnforced, BucketOwnerPreferred, ObjectWriter
}

type CreateBucketResponse struct {
	Location string // The bucket's location (e.g., /bucket-name)
}

type CreateMultipartUploadRequest struct {
	Bucket      string
	Key         string
	ContentType string
}

type CreateMultipartUploadResponse struct {
	Bucket   string
	Key      string
	UploadID string
}

type DeleteBucketRequest struct {
	Bucket  string
	OwnerID string // For ownership verification
}

type DeleteObjectRequest struct {
	Bucket string
	Key    string
}

type GetObjectRequest struct {
	Bucket     string
	Key        string
	RangeStart int64 // -1 means not specified
	RangeEnd   int64 // -1 means not specified
}

type GetObjectResponse struct {
	Body         io.ReadCloser
	ContentType  string
	ContentRange string
	Size         int64
	ETag         string
	LastModified time.Time
	StatusCode   int // 200 for full content, 206 for partial
}

type HeadBucketRequest struct {
	Bucket string
}

type HeadBucketResponse struct {
	Region string
	Name   string
}

type HeadObjectResponse struct {
	ContentType   string
	ContentLength int64
	ETag          string
	LastModified  time.Time
}

type ListBucketsResponse struct {
	Buckets []BucketInfo
	Owner   OwnerInfo
}

type ListObjectsRequest struct {
	Bucket       string
	Prefix       string
	Delimiter    string
	MaxKeys      int
	StartAfter   string
	EncodingType string
}

type ListObjectsResponse struct {
	Name           string
	Prefix         string
	Delimiter      string
	MaxKeys        int
	KeyCount       int
	IsTruncated    bool
	Contents       []ObjectInfo
	CommonPrefixes []string
}

type ObjectInfo struct {
	Key          string
	Size         int64
	LastModified time.Time
	ETag         string
	ContentType  string
	StorageClass string
	IsDir        bool
}

type OwnerInfo struct {
	ID          string
	DisplayName string
}

type PutObjectRequest struct {
	Bucket          string
	Key             string
	Body            io.Reader
	ContentLength   int64
	ContentType     string
	ContentEncoding string
	IsChunked       bool
	DecodedLength   int64 // For aws-chunked encoding
}

type PutObjectResponse struct {
	ETag string
}

type S3Error struct {
	Code       S3ErrorCode
	Message    string
	StatusCode int
	Resource   string
}

type S3ErrorCode string

type UploadPartRequest struct {
	Bucket          string
	Key             string
	UploadID        string
	PartNumber      int
	Body            io.Reader
	ContentLength   int64
	ContentEncoding string
	IsChunked       bool
	DecodedLength   int64
}

type UploadPartResponse struct {
	ETag       string
	PartNumber int
}