internal

type Checker struct {
	// Content holds the expected content values.
	Content Content

	// SizeTracker tracks the number of bytes read.
	SizeTracker SizeTracker

	// ChecksumWriter tracks the checksum of the read bytes.
	ChecksumWriter ChecksumWriter
}

type ChecksumWriter interface {
	io.Writer

	// Fingerprint is the fingerprint for the tracked checksum.
	Fingerprint() charmresource.Fingerprint
}

type Content struct {
	// Data holds the resouce content, ready to be read (once).
	Data io.Reader

	// Size is the byte count of the data.
	Size int64

	// Fingerprint holds the checksum of the data.
	Fingerprint charmresource.Fingerprint
}

type ContentChecker interface {
	// WrapReader wraps the provided reader in another reader
	// that tracks the read data.
	WrapReader(io.Reader) io.Reader

	// Verify fails if the tracked data does not match
	// the expected data.
	Verify() error
}

type ContentSource interface {
	// Content returns the content for the opened resource.
	Content() Content

	// Info returns the info for the opened resource.
	Info() resource.Resource
}

type ContextDirectorySpec interface {
	Resolver

	// Initializeprepares the target directory and returns it.
	Initialize() (DownloadDirectory, error)

	// IsUpToDate indicates whether or not the resource dir is in sync
	// with the content.
	IsUpToDate(Content) (bool, error)
}

type ContextDownloadDeps interface {
	// NewContextDirectorySpec returns the dir spec for the resource
	// in the hook context.
	NewContextDirectorySpec() ContextDirectorySpec

	// OpenResource reads the resource info and opens the resource
	// content for reading.
	OpenResource() (ContextOpenedResource, error)

	// CloseAndLog closes the closer and logs any error.
	CloseAndLog(io.Closer, string)

	// Download writes the remote to the target directory.
	Download(DownloadTarget, ContextOpenedResource) error
}

type ContextDownloadDirectory struct {
	*TempDirectorySpec
}

type ContextOpenedResource interface {
	ContentSource
	io.Closer
}

type Directory struct {
	*DirectorySpec

	// Deps holds the external dependencies of the directory.
	Deps DirectoryDeps
}

type DirectoryDeps interface {
	// CreateWriter creates a new writer to which the resource file
	// will be written.
	CreateWriter(string) (io.WriteCloser, error)

	// CloseAndLog closes the closer and logs any error.
	CloseAndLog(io.Closer, string)

	// WriteContent writes the content to the directory.
	WriteContent(io.Writer, Content) error
}

type DirectorySpec struct {
	// Name is the resource name.
	Name string

	// Dirname is the path to the resource directory.
	Dirname string

	// Deps is the external dependencies of DirectorySpec.
	Deps DirectorySpecDeps
}

type DirectorySpecDeps interface {
	DirectoryDeps

	// FingerprintMatches determines whether or not the identified file
	// exists and has the provided fingerprint.
	FingerprintMatches(filename string, fp charmresource.Fingerprint) (bool, error)

	// Join exposes the functionality of filepath.Join().
	Join(...string) string

	// MkdirAll exposes the functionality of os.MkdirAll().
	MkdirAll(string) error
}

type DownloadDirectory interface {
	Resolver

	// Write writes all the relevant files for the provided source
	// to the directory.
	Write(ContentSource) error
}

type DownloadIndirectDeps interface {
	// NewTempDirSpec returns a directory spec for the resource under a temporary datadir.
	NewTempDirSpec() (DownloadTempTarget, error)

	// CloseAndLog closes the closer and logs any error.
	CloseAndLog(io.Closer, string)

	// DownloadDirect downloads the source into the target.
	DownloadDirect(DownloadTarget, ContentSource) error

	// ReplaceDirectory moves the source directory path to the target
	// path. If the target path already exists then it is replaced atomically.
	ReplaceDirectory(tgt, src string) error
}

type DownloadTarget interface {
	// Initialize prepares the target directory and returns it.
	Initialize() (DownloadDirectory, error)
}

type DownloadTempTarget interface {
	DownloadTarget
	Resolver
	io.Closer
}

type Logger interface {
	// Errorf formats the provided log message and writes it to the log.
	Errorf(string, ...interface{})
}

type NewContextContentCheckerDeps interface {
	// NewSizeTracker returns a new size tracker.
	NewSizeTracker() SizeTracker

	// NewChecksumWriter returns a new checksum writer.
	NewChecksumWriter() ChecksumWriter
}

type NopChecker struct{}

type OpenedResource struct {
	resource.Resource
	io.ReadCloser
}

type OpenedResourceClient interface {
	// GetResource returns the resource info and content for the given
	// name (and unit-implied application).
	GetResource(resourceName string) (resource.Resource, io.ReadCloser, error)
}

type ReplaceDirectoryDeps interface {
	// RemoveDir deletes the directory at the given path.
	RemoveDir(dirname string) error

	// Move moves the directory at the source path to the target path.
	Move(target, source string) error
}

type Resolver interface {
	// Resolve returns the fully resolved path for the provided path items.
	Resolve(...string) string
}

type SizeTracker interface {
	io.Writer

	// Size returns the number of bytes written.
	Size() int64
}

type TempDirDeps interface {
	DirectorySpecDeps

	// NewTempDir returns the path to a new temporary directory.
	NewTempDir() (string, error)

	// RemoveDir deletes the specified directory.
	RemoveDir(string) error
}

type TempDirectorySpec struct {
	*DirectorySpec

	// CleanUp cleans up the temp directory in which the resource
	// directory is placed.
	CleanUp func() error
}

type WriteContentDeps interface {
	//NewChecker provides a content checker for the given content.
	NewChecker(Content) ContentChecker

	// Copy copies the data from the reader into the writer.
	Copy(io.Writer, io.Reader) error
}