es_filesystem

type Connector interface {
	// Copy source to target system. Target path must include file name.
	// Connector callbacks onSuccess or onFailure to tell an result.
	// Copy operation may block to wait I/O.
	Copy(source Entry,
		target Path,
		onSuccess func(pair CopyPair, copied Entry),
		onFailure func(pair CopyPair, err FileSystemError))

	// Start up the connector
	Startup(qd eq_queue.Definition) (err FileSystemError)

	// Clean up connector
	Shutdown() (err FileSystemError)
}

type CopyPair struct {
	Source Entry
	Target Path
}

type Entry interface {
	// Name of the entry.
	Name() string

	// Path of the entry.
	Path() Path

	// Size of the entry.
	Size() int64

	// Modification time.
	ModTime() time.Time

	// Content hash.
	ContentHash() (string, FileSystemError)

	// True when the entry is a file.
	IsFile() bool

	// True when the entry is a folder.
	IsFolder() bool

	// Convert as serializable data
	AsData() EntryData
}

type EntryData struct {
	FileSystemType string                 `json:"file_system_type"`
	EntryName      string                 `json:"name"`
	EntryPath      string                 `json:"path"`
	EntrySize      int64                  `json:"size"`
	EntryModTime   time.Time              `json:"mod_time"`
	EntryIsFile    bool                   `json:"is_file"`
	EntryIsFolder  bool                   `json:"is_folder"`
	Attributes     map[string]interface{} `json:"attributes,omitempty"`
}

type FileSystem interface {
	// List entries of the path.
	List(path Path) (entries []Entry, err FileSystemError)

	// Retrieve entry of the path.
	Info(path Path) (entry Entry, err FileSystemError)

	// Delete path.
	Delete(path Path) (err FileSystemError)

	// Create folder. Returns created entry on success, otherwise returns nil for entry.
	CreateFolder(path Path) (entry Entry, err FileSystemError)

	// Deserialize entry from entry data.
	// Returns err if the format is not valid for this file system.
	Entry(data EntryData) (entry Entry, err FileSystemError)

	// Deserialize path from path data.
	Path(data PathData) (path Path, err FileSystemError)

	// Deserialize shard from shard data.
	Shard(data ShardData) (shard Shard, err FileSystemError)

	// Type of file system
	FileSystemType() string

	// Operation complexity parameter in this file system
	OperationalComplexity(entries []Entry) (complexity int64)
}

type FileSystemError interface {
	error

	// True if a path is not found.
	IsPathNotFound() bool

	// True if an operation detect conflict of the path.
	IsConflict() bool

	// True if the user doesn't have permissions to write to the target.
	IsNoPermission() bool

	// True if the file system doesn't have enough available space to write more data.
	IsInsufficientSpace() bool

	// True if the file system doesn't allow name of the entry.
	IsDisallowedName() bool

	// True if the entry data is not valid for this file system.
	IsInvalidEntryDataFormat() bool

	// True if the error is for testing
	IsMockError() bool
}

type MockEntry struct {
	EntryData
	MockHash string `json:"content_hash"`
}

type MockPath struct {
	PathData
}

type Path interface {
	// Base name of the path entry.
	Base() string

	// Cleaned absolute path in the file system.
	Path() string

	// Shard of the path.
	Shard() Shard

	// Ancestor path. Returns root path if this instance is root.
	Ancestor() Path

	// Returns descendant path with pathFragment.
	Descendant(pathFragment ...string) Path

	// True if the path indicates root path of the namespace.
	IsRoot() bool

	// Serialize
	AsData() PathData
}

type PathData struct {
	FileSystemType string                 `json:"file_system_type"`
	EntryPath      string                 `json:"entry_path"`
	EntryShard     ShardData              `json:"entry_shard"`
	Attributes     map[string]interface{} `json:"attributes"`
}

type Shard interface {
	// string representation of Shard ID.
	// Drive letter, or server name for windows file system (e.g. C:, \\SERVER\).
	// Or namespace ID (shared_folder_id/team_folder_id) of Dropbox file system.
	Id() string

	// Serialize
	AsData() ShardData
}

type ShardData struct {
	FileSystemType string                 `json:"file_system_type"`
	ShardId        string                 `json:"shard_id"`
	Attributes     map[string]interface{} `json:"attributes"`
}