pail

type Bucket interface {
	// Check validity of the bucket. This is dependent on the underlying
	// implementation.
	Check(context.Context) error

	// Exists returns whether the given key exists in the bucket or not.
	Exists(context.Context, string) (bool, error)

	// Join concatenates elements with the appropriate path separator of
	// the bucket, ignoring empty elements. This is analogous to
	// `filepath.Join`.
	Join(...string) string

	// Produces a Writer and Reader interface to the file named by
	// the string.
	Writer(context.Context, string) (io.WriteCloser, error)
	Reader(context.Context, string) (io.ReadCloser, error)

	// Put and Get write simple byte streams (in the form of
	// io.Readers) to/from specified keys.
	//
	// TODO: consider if these, particularly Get are not
	// substantively different from Writer/Reader methods, or
	// might just be a wrapper.
	Put(context.Context, string, io.Reader) error
	Get(context.Context, string) (io.ReadCloser, error)

	// Upload and Download write files from the local file
	// system to the specified key.
	Upload(context.Context, string, string) error
	Download(context.Context, string, string) error

	SyncBucket

	// Copy does a special copy operation that does not require downloading
	// a file. Note that CopyOptions.DestinationBucket must have the same
	// type as the calling bucket object.
	Copy(context.Context, CopyOptions) error

	// Remove the specified object(s) from the bucket.
	// RemoveMany continues on error and returns any accumulated errors.
	Remove(context.Context, string) error
	RemoveMany(context.Context, ...string) error

	// Remove all objects with the given prefix, continuing on error and
	// returning any accumulated errors.
	// Note that this operation is not atomic.
	RemovePrefix(context.Context, string) error

	// Remove all objects matching the given regular expression, continuing
	// on error and returning any accumulated errors.
	// Note that this operation is not atomic.
	RemoveMatching(context.Context, string) error

	// List returns an iterator over the contents of a bucket with the
	// the given prefix. Contents are iterated lexicographically by key
	// name.
	List(context.Context, string) (BucketIterator, error)
}

type BucketItem interface {
	Bucket() string
	Name() string
	Hash() string
	Get(context.Context) (io.ReadCloser, error)
}

type BucketIterator interface {
	Next(context.Context) bool
	Err() error
	Item() BucketItem
}

type CopyOptions struct {
	SourceKey         string
	DestinationKey    string
	DestinationBucket Bucket
	IsDestination     bool
}

type GridFSOptions struct {
	Name         string
	Prefix       string
	Database     string
	MongoDBURI   string
	DryRun       bool
	DeleteOnSync bool
	DeleteOnPush bool
	DeleteOnPull bool
	Verbose      bool
}

type LocalOptions struct {
	Path   string
	Prefix string
	// UseSlash sets the prefix separator to the slash ('/') character
	// instead of the OS specific separator.
	UseSlash     bool
	DryRun       bool
	DeleteOnSync bool
	DeleteOnPush bool
	DeleteOnPull bool
	Verbose      bool
}

type ParallelBucketOptions struct {
	// Workers sets the number of worker threads.
	Workers int
	// DryRun enables running in a mode that will not execute any
	// operations that modify the bucket.
	DryRun bool
	// DeleteOnSync will delete all objects from the target that do not
	// exist in the source after the completion of a sync operation
	// (Push/Pull).
	DeleteOnSync bool
	// DeleteOnPush will delete all objects from the target that do not
	// exist in the source after the completion of Push.
	DeleteOnPush bool
	// DeleteOnPull will delete all objects from the target that do not
	// exist in the source after the completion of Pull.
	DeleteOnPull bool
}

type PreSignRequestParams struct {
	Bucket          string
	FileKey         string
	AwsKey          string
	AwsSecret       string
	AwsSessionToken string
	Region          string
}

type S3Options struct {
	// DryRun enables running in a mode that will not execute any
	// operations that modify the bucket.
	DryRun bool
	// DeleteOnSync will delete all objects from the target that do not
	// exist in the destination after the completion of a sync operation
	// (Push/Pull).
	DeleteOnSync bool
	// DeleteOnPush will delete all objects from the target that do not
	// exist in the source after the completion of Push.
	DeleteOnPush bool
	// DeleteOnPull will delete all objects from the target that do not
	// exist in the source after the completion of Pull.
	DeleteOnPull bool
	// Compress enables gzipping of uploaded objects.
	Compress bool
	// UseSingleFileChecksums forces the bucket to checksum files before
	// running uploads and download operation (rather than doing these
	// operations independently.) Useful for large files, particularly in
	// coordination with the parallel sync bucket implementations.
	UseSingleFileChecksums bool
	// Verbose sets the logging mode to "debug".
	Verbose bool
	// MaxRetries sets the number of retry attempts for S3 operations.
	// By default it defers to the AWS SDK's default.
	MaxRetries *int
	// Credentials allows the passing in of explicit AWS credentials. These
	// will override the default credentials chain. (Optional)
	Credentials *credentials.Credentials
	// SharedCredentialsFilepath, when not empty, will override the default
	// credentials chain and the Credentials value (see above). (Optional)
	SharedCredentialsFilepath string
	// SharedCredentialsProfile, when not empty, will fetch the given
	// credentials profile from the shared credentials file. (Optional)
	SharedCredentialsProfile string
	// AssumeRoleARN specifies an IAM role ARN. When not empty, it will be
	// used to assume the given role for this session. See
	// `https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html` for
	// more information. (Optional)
	AssumeRoleARN string
	// AssumeRoleOptions provide a mechanism to override defaults by
	// applying changes to the AssumeRoleProvider struct created with this
	// session. This field is ignored if AssumeRoleARN is not set.
	// (Optional)
	AssumeRoleOptions []func(*stscreds.AssumeRoleProvider)
	// Region specifies the AWS region.
	Region string
	// Name specifies the name of the bucket.
	Name string
	// Prefix specifies the prefix to use. (Optional)
	Prefix string
	// Permissions sets the S3 permissions to use for each object. Defaults
	// to FULL_CONTROL. See
	// `https://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html`
	// for more information.
	Permissions S3Permissions
	// ContentType sets the standard MIME type of the objet data. Defaults
	// to nil. See
	//`https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.17`
	// for more information.
	ContentType string
}

type S3Permissions string

type SyncBucket interface {
	// Sync methods: these methods are the recursive, efficient
	// copy methods of files from S3 to the local file
	// system.
	Push(context.Context, SyncOptions) error
	Pull(context.Context, SyncOptions) error
}

type SyncOptions struct {
	Local   string
	Remote  string
	Exclude string
}