# @file         helpers.py - Python->JS helpers for PythonMonkey
#               - typeof operator wrapper
#               - new operator wrapper
#
# @author       Wes Garland, wes@distributive.network
# @date         July 2023
#
# @copyright Copyright (c) 2023 Distributive Corp.

from . import pythonmonkey as pm
evalOpts = {'filename': __file__, 'fromPythonFrame': True}


def typeof(jsval):
  """
  typeof function - wraps JS typeof operator
  """
  return pm.eval("""'use strict'; (
function pmTypeof(jsval)
{
  return typeof jsval;
}
    )""", evalOpts)(jsval)


def new(ctor):
  """
  new function - emits function which wraps JS new operator, emitting a lambda which constructs a new
  JS object upon invocation.
  """
  if (typeof(ctor) == 'string'):
    ctor = pm.eval(ctor)

  newCtor = pm.eval("""'use strict'; (
function pmNewFactory(ctor)
{
  return function newCtor(args) {
    args = Array.from(args || []);
    return new ctor(...args);
  };
}
    )""", evalOpts)(ctor)
  return (lambda *args: newCtor(list(args)))


def simpleUncaughtExceptionHandler(loop, context):
  """
  A simple exception handler for uncaught JS Promise rejections sent to the Python event-loop

  See https://docs.python.org/3.11/library/asyncio-eventloop.html#error-handling-api
  """
  error = context["exception"]
  pm.eval("(err) => console.error('Uncaught', err)")(error)
  pm.stop()  # unblock `await pm.wait()` to gracefully exit the program


# List which symbols are exposed to the pythonmonkey module.
__all__ = ["new", "typeof", "simpleUncaughtExceptionHandler"]

# Add the non-enumerable properties of globalThis which don't collide with pythonmonkey.so as exports:
globalThis = pm.eval('globalThis')
pmGlobals = vars(pm)

exports = pm.eval("""
Object.getOwnPropertyNames(globalThis)
.filter(prop => Object.keys(globalThis).indexOf(prop) === -1);
""", evalOpts)

for index in range(0, len(exports)):
  name = exports[index]
  if (pmGlobals.get(name) is None):
    globals().update({name: globalThis[name]})
    __all__.append(name)