extends Node
## Client for the MusicServer REST API.
##
## Registered as the [code]MusicServerClient[/code] autoload, so every script can call it
## directly, e.g. [code]MusicServerClient.fetch_song_list(on_done)[/code]. All HTTP traffic
## goes through [member transport]; tests replace it with a fake to answer requests
## without a running server.

## Sends the actual HTTP requests. Swap it out in tests.
var transport: HttpTransport


func _ready() -> void:
	if transport == null:
		transport = HttpTransport.new(self)


## Fetches the songs already in the server playlist, as an Array of
## [code]{SongNo, Soundtrack, Song}[/code] dictionaries.
func fetch_song_list(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_json("/music/list", on_done, on_failed)


## Downloads a random song as MP3 bytes. With [param low_played] the server prefers
## soundtracks that have been played the least.
func fetch_random_song(
		low_played: bool, on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_bytes("/music/rand/low" if low_played else "/music/rand", on_done, on_failed)


## Adds the most recently fetched random song to the server playlist.
func add_to_queue(on_done: Callable, on_failed: Callable = Callable()) -> void:
	send("/music/addQue", on_done, on_failed)


## Fetches [code]{SongNo, Soundtrack, Song}[/code] for the most recently queued song.
func fetch_song_info(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_json("/music/info", on_done, on_failed)


## Downloads a song from the server playlist as MP3 bytes.
func fetch_song(song_no: int, on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_bytes("/music?song=" + str(song_no), on_done, on_failed)


## Downloads the sound test song as MP3 bytes.
func fetch_sound_test_song(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_bytes("/music/soundTest", on_done, on_failed)


## Clears the server playlist.
func reset_playlist(on_done: Callable, on_failed: Callable = Callable()) -> void:
	send("/music/reset", on_done, on_failed)


## Fetches every soundtrack name as an Array of Strings.
func fetch_all_soundtracks(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_json("/music/all", on_done, on_failed)


## Fetches every soundtrack name, sorted, as an Array of Strings.
func fetch_all_soundtracks_ordered(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_json("/music/all/order", on_done, on_failed)


## Records in the server statistics that a song has been played.
func mark_song_played(song_no: int) -> void:
	send("/music/played?song=" + str(song_no), Callable(), Callable(), HTTPClient.METHOD_PUT)


## Fetches the names of all character images.
func fetch_character_list(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_json("/characters", on_done, on_failed)


## Downloads a character image as PNG bytes.
func fetch_character_image(
		character_name: String, on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_bytes("/character?name=" + character_name.uri_encode(), on_done, on_failed)


## Starts syncing the server's soundtrack library with its music folder.
func start_sync(on_done: Callable, on_failed: Callable = Callable()) -> void:
	send("/sync", on_done, on_failed)


## Fetches the sync state: [code]{progress, time_spent}[/code] while running, or the
## sync result once finished.
func fetch_sync_progress(on_done: Callable, on_failed: Callable = Callable()) -> void:
	get_json("/sync/progress", on_done, on_failed)


## Requests [param path] and calls [param on_done] with the parsed JSON.
## [param on_failed] is called with no arguments if the request fails or the body is
## not valid JSON.
func get_json(path: String, on_done: Callable, on_failed: Callable = Callable()) -> void:
	_request(path, HTTPClient.METHOD_GET, func(body: PackedByteArray) -> void:
		var json: JSON = JSON.new()
		if json.parse(body.get_string_from_utf8()) != OK:
			push_warning("Invalid JSON from %s: %s" % [path, json.get_error_message()])
			_call_if_valid(on_failed)
			return
		on_done.call(json.data)
	, on_failed)


## Requests [param path] and calls [param on_done] with the raw response body, or
## [param on_failed] with no arguments if the request fails.
func get_bytes(path: String, on_done: Callable, on_failed: Callable = Callable()) -> void:
	_request(path, HTTPClient.METHOD_GET, on_done, on_failed)


## Requests [param path] and calls [param on_done] with no arguments when it succeeds,
## or [param on_failed] when it fails. Either may be an empty Callable.
func send(
		path: String,
		on_done: Callable,
		on_failed: Callable = Callable(),
		method: int = HTTPClient.METHOD_GET,
) -> void:
	_request(path, method, func(_body: PackedByteArray) -> void:
		_call_if_valid(on_done)
	, on_failed)


func _request(path: String, method: int, on_success: Callable, on_failed: Callable) -> void:
	var url: String = Settings.default_path + path
	transport.request(url, method, func(response_code: int, body: PackedByteArray) -> void:
		if response_code != 200:
			push_warning("Request to %s failed with response code %d" % [url, response_code])
			_call_if_valid(on_failed)
			return
		on_success.call(body)
	)


static func _call_if_valid(callback: Callable) -> void:
	if callback.is_valid():
		callback.call()