/*
 * Copyright (C)2005-2019 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package lua;

import haxe.extern.Rest;
import haxe.Constraints.Function;

/**
	Externs for native Lua coroutines.
**/
@:native("_G.coroutine")
extern class Coroutine<T:Function> extends Thread {
	/**
		Creates a new coroutine, with body `f`. `f` must be a Lua function.
	**/
	public static function create<T:Function>(f:T):Coroutine<T>;

	/**
		Returns the running coroutine plus a boolean, true when the running coroutine is the main one.
	**/
	public static function running():CoroutineRunning;

	/**
		Returns the status of coroutine.
	**/
	public static function status(c:Coroutine<Dynamic>):CoroutineState;

	/**
		Starts or continues the execution of coroutine.
		The first time you resume a coroutine, it starts running its body.
		The values `args` are passed as the arguments to the body function.
		If the coroutine has yielded, `resume` restarts it;
		the values `args` are passed as the results from the yield.

		If the coroutine runs without any errors, `resume` returns `true` plus any
		values passed to `yield` (if the coroutine yields) or any values returned
		by the body function (if the coroutine terminates). If there is any error,
		`resume` returns `false` plus the error message.
	**/
	public static function resume<A, B>(c:Coroutine<Dynamic>, args:Rest<A>):CoroutineResume<B>;

	/**
		Suspends the execution of the calling coroutine.
		The coroutine cannot be running a C function, a metamethod, or an iterator.
		Any arguments to `yield` are passed as extra results to `resume`.
	**/
	public static function yield<T>(args:Rest<Dynamic>):T;

	/**
		Creates a new coroutine, with body `f`.
		Returns a function that resumes the coroutine each time it is called.
		Any arguments passed to the function behave as the extra arguments to `resume`.
		Returns the same values returned by `resume`, except the first boolean.
		In case of error, propagates the error.
	**/
	public static function wrap<T:Function>(f:T):T;
}

/**
	A enumerator that describes the output of `Coroutine.status()`.
**/
enum abstract CoroutineState(String) {
	/**
		If the coroutine is suspended in a call to yield, or if it has not started
		running yet.
	**/
	var Suspended = "suspended";

	/**
		If the coroutine is running.
	**/
	var Running = "running";

	/**
		If the coroutine is active but not running. That is, it has resumed another
		coroutine.
	**/
	var Normal = "normal";

	/**
		If the coroutine has finished its body function or if it has stopped with
		an error.
	**/
	var Dead = "dead";
}

@:multiReturn
extern class CoroutineResume<T> {
	var success:Bool;
	var result:T;
}

@:multiReturn
extern class CoroutineRunning {
	var coroutine:Coroutine<Dynamic>;
	var status:Bool;
}
