class_name FakeHttpTransport
extends HttpTransport
## Stands in for the MusicServer in tests.
##
## Register canned responses per path with [method respond_json] or
## [method respond_bytes], then install it with [method install]. Requests to paths
## without a response get a 404. Responses are delivered immediately.

## Paths requested so far, relative to [code]Settings.default_path[/code].
var requested_paths: Array[String] = []
## HTTP method of each request, in the same order as [member requested_paths].
var requested_methods: Array[int] = []

var _responses: Dictionary = {}
var _successes_left: Dictionary = {}
var _held_paths: Dictionary = {}
var _previous_transport: HttpTransport


func _init() -> void:
	super(null)


## Replaces the MusicServerClient transport with this fake.
func install() -> FakeHttpTransport:
	_previous_transport = MusicServerClient.transport
	MusicServerClient.transport = self
	return self


## Restores the transport that was active before [method install].
func uninstall() -> void:
	MusicServerClient.transport = _previous_transport


## Answers requests to [param path] with [param data] encoded as JSON.
func respond_json(path: String, data: Variant, response_code: int = 200) -> void:
	respond_bytes(path, JSON.stringify(data).to_utf8_buffer(), response_code)


## Answers requests to [param path] with [param body] as-is.
func respond_bytes(path: String, body: PackedByteArray, response_code: int = 200) -> void:
	_responses[path] = {"code": response_code, "body": body}
	_successes_left.erase(path)


## Lets [param successes] more requests to [param path] succeed, then answers 503 until
## a new response is registered for the path.
func fail_after(path: String, successes: int) -> void:
	_successes_left[path] = successes


## Holds back responses to [param path] until [method release] is called, like a slow
## server.
func hold(path: String) -> void:
	_held_paths[path] = []


## Delivers the responses held back for [param path] and stops holding it.
func release(path: String) -> void:
	var waiting: Array = _held_paths.get(path, [])
	_held_paths.erase(path)
	for pending: Callable in waiting:
		pending.call()


## Returns how many times [param path] has been requested.
func count(path: String) -> int:
	return requested_paths.count(path)


func request(url: String, method: int, on_complete: Callable) -> void:
	var path: String = url.trim_prefix(Settings.default_path)
	requested_paths.append(path)
	requested_methods.append(method)
	if _held_paths.has(path):
		_held_paths[path].append(_answer.bind(path, on_complete))
		return
	_answer(path, on_complete)


func _answer(path: String, on_complete: Callable) -> void:
	if _successes_left.has(path):
		if _successes_left[path] == 0:
			on_complete.call(503, PackedByteArray())
			return
		_successes_left[path] -= 1
	if _responses.has(path):
		on_complete.call(_responses[path].code, _responses[path].body)
	else:
		on_complete.call(404, PackedByteArray())