text: # Released under the MIT License. See LICENSE for details.
  #
  """Utility snippets applying to generic Python code."""
  from __future__ import annotations
  
  import gc
  import types
  import weakref
  import random
  import inspect
  from typing import TYPE_CHECKING, TypeVar, Protocol
  
  from efro.terminal import Clr
  import _ba
  from ba._error import print_error, print_exception
  from ba._enums import TimeType
  
  if TYPE_CHECKING:
      from types import FrameType
      from typing import Any, Type, Optional
      from efro.call import Call as Call  # 'as Call' so we re-export.
      from weakref import ReferenceType
  
  
  class Existable(Protocol):
      """A Protocol for objects supporting an exists() method.
  
      Category: Protocols
      """
  
      def exists(self) -> bool:
          """Whether this object exists."""
          ...
  
  
  ExistableType = TypeVar('ExistableType', bound=Existable)
  T = TypeVar('T')
  
  
  def existing(obj: Optional[ExistableType]) -> Optional[ExistableType]:
      """Convert invalid references to None for any ba.Existable object.
  
      Category: Gameplay Functions
  
      To best support type checking, it is important that invalid references
      not be passed around and instead get converted to values of None.
      That way the type checker can properly flag attempts to pass dead
      objects (Optional[FooType]) into functions expecting only live ones
      (FooType), etc. This call can be used on any 'existable' object
      (one with an exists() method) and will convert it to a None value
      if it does not exist.
  
      For more info, see notes on 'existables' here:
      https://ballistica.net/wiki/Coding-Style-Guide
      """
      assert obj is None or hasattr(obj, 'exists'), f'No "exists" on {obj}'
      return obj if obj is not None and obj.exists() else None
  
  
  def getclass(name: str, subclassof: Type[T]) -> Type[T]:
      """Given a full class name such as foo.bar.MyClass, return the class.
  
      Category: General Utility Functions
  
      The class will be checked to make sure it is a subclass of the provided
      'subclassof' class, and a TypeError will be raised if not.
      """
      import importlib
      splits = name.split('.')
      modulename = '.'.join(splits[:-1])
      classname = splits[-1]
      module = importlib.import_module(modulename)
      cls: Type = getattr(module, classname)
  
      if not issubclass(cls, subclassof):
          raise TypeError(f'{name} is not a subclass of {subclassof}.')
      return cls
  
  
  def json_prep(data: Any) -> Any:
      """Return a json-friendly version of the provided data.
  
      This converts any tuples to lists and any bytes to strings
      (interpreted as utf-8, ignoring errors). Logs errors (just once)
      if any data is modified/discarded/unsupported.
      """
  
      if isinstance(data, dict):
          return dict((json_prep(key), json_prep(value))
                      for key, value in list(data.items()))
      if isinstance(data, list):
          return [json_prep(element) for element in data]
      if isinstance(data, tuple):
          print_error('json_prep encountered tuple', once=True)
          return [json_prep(element) for element in data]
      if isinstance(data, bytes):
          try:
              return data.decode(errors='ignore')
          except Exception:
              from ba import _error
              print_error('json_prep encountered utf-8 decode error', once=True)
              return data.decode(errors='ignore')
      if not isinstance(data, (str, float, bool, type(None), int)):
          print_error('got unsupported type in json_prep:' + str(type(data)),
                      once=True)
      return data
  
  
  def utf8_all(data: Any) -> Any:
      """Convert any unicode data in provided sequence(s) to utf8 bytes."""
      if isinstance(data, dict):
          return dict((utf8_all(key), utf8_all(value))
                      for key, value in list(data.items()))
      if isinstance(data, list):
          return [utf8_all(element) for element in data]
      if isinstance(data, tuple):
          return tuple(utf8_all(element) for element in data)
      if isinstance(data, str):
          return data.encode('utf-8', errors='ignore')
      return data
  
  
  def print_refs(obj: Any) -> None:
      """Print a list of known live references to an object."""
  
      # Hmmm; I just noticed that calling this on an object
      # seems to keep it alive. Should figure out why.
      print('REFERENCES FOR', obj, ':')
      refs = list(gc.get_referrers(obj))
      i = 1
      for ref in refs:
          print('     ref', i, ':', ref)
          i += 1
  
  
  def get_type_name(cls: Type) -> str:
      """Return a full type name including module for a class."""
      return cls.__module__ + '.' + cls.__name__
  
  
  class _WeakCall:
      """Wrap a callable and arguments into a single callable object.
  
      Category: General Utility Classes
  
      When passed a bound method as the callable, the instance portion
      of it is weak-referenced, meaning the underlying instance is
      free to die if all other references to it go away. Should this
      occur, calling the WeakCall is simply a no-op.
  
      Think of this as a handy way to tell an object to do something
      at some point in the future if it happens to still exist.
  
      # EXAMPLE A: this code will create a FooClass instance and call its
      # bar() method 5 seconds later; it will be kept alive even though
      # we overwrite its variable with None because the bound method
      # we pass as a timer callback (foo.bar) strong-references it
      foo = FooClass()
      ba.timer(5.0, foo.bar)
      foo = None
  
      # EXAMPLE B: this code will *not* keep our object alive; it will die
      # when we overwrite it with None and the timer will be a no-op when it
      # fires
      foo = FooClass()
      ba.timer(5.0, ba.WeakCall(foo.bar))
      foo = None
  
      Note: additional args and keywords you provide to the WeakCall()
      constructor are stored as regular strong-references; you'll need
      to wrap them in weakrefs manually if desired.
      """
  
      def __init__(self, *args: Any, **keywds: Any) -> None:
          """Instantiate a WeakCall.
  
          Pass a callable as the first arg, followed by any number of
          arguments or keywords.
  
          # Example: wrap a method call with some positional and
          # keyword args:
          myweakcall = ba.WeakCall(myobj.dostuff, argval1, namedarg=argval2)
  
          # Now we have a single callable to run that whole mess.
          # The same as calling myobj.dostuff(argval1, namedarg=argval2)
          # (provided my_obj still exists; this will do nothing otherwise)
          myweakcall()
          """
          if hasattr(args[0], '__func__'):
              self._call = WeakMethod(args[0])
          else:
              app = _ba.app
              if not app.did_weak_call_warning:
                  print(('Warning: callable passed to ba.WeakCall() is not'
                         ' weak-referencable (' + str(args[0]) +
                         '); use ba.Call() instead to avoid this '
                         'warning. Stack-trace:'))
                  import traceback
                  traceback.print_stack()
                  app.did_weak_call_warning = True
              self._call = args[0]
          self._args = args[1:]
          self._keywds = keywds
  
      def __call__(self, *args_extra: Any) -> Any:
          return self._call(*self._args + args_extra, **self._keywds)
  
      def __str__(self) -> str:
          return ('<ba.WeakCall object; _call=' + str(self._call) + ' _args=' +
                  str(self._args) + ' _keywds=' + str(self._keywds) + '>')
  
  
  class _Call:
      """Wraps a callable and arguments into a single callable object.
  
      Category: General Utility Classes
  
      The callable is strong-referenced so it won't die until this
      object does.
  
      Note that a bound method (ex: myobj.dosomething) contains a reference
      to 'self' (myobj in that case), so you will be keeping that object
      alive too. Use ba.WeakCall if you want to pass a method to callback
      without keeping its object alive.
      """
  
      def __init__(self, *args: Any, **keywds: Any):
          """Instantiate a Call.
  
          Pass a callable as the first arg, followed by any number of
          arguments or keywords.
  
          # Example: wrap a method call with 1 positional and 1 keyword arg:
          mycall = ba.Call(myobj.dostuff, argval1, namedarg=argval2)
  
          # Now we have a single callable to run that whole mess.
          # ..the same as calling myobj.dostuff(argval1, namedarg=argval2)
          mycall()
          """
          self._call = args[0]
          self._args = args[1:]
          self._keywds = keywds
  
      def __call__(self, *args_extra: Any) -> Any:
          return self._call(*self._args + args_extra, **self._keywds)
  
      def __str__(self) -> str:
          return ('<ba.Call object; _call=' + str(self._call) + ' _args=' +
                  str(self._args) + ' _keywds=' + str(self._keywds) + '>')
  
  
  if TYPE_CHECKING:
      WeakCall = Call
      Call = Call
  else:
      WeakCall = _WeakCall
      WeakCall.__name__ = 'WeakCall'
      Call = _Call
      Call.__name__ = 'Call'
  
  
  class WeakMethod:
      """A weak-referenced bound method.
  
      Wraps a bound method using weak references so that the original is
      free to die. If called with a dead target, is simply a no-op.
      """
  
      def __init__(self, call: types.MethodType):
          assert isinstance(call, types.MethodType)
          self._func = call.__func__
          self._obj = weakref.ref(call.__self__)
  
      def __call__(self, *args: Any, **keywds: Any) -> Any:
          obj = self._obj()
          if obj is None:
              return None
          return self._func(*((obj, ) + args), **keywds)
  
      def __str__(self) -> str:
          return '<ba.WeakMethod object; call=' + str(self._func) + '>'
  
  
  def verify_object_death(obj: object) -> None:
      """Warn if an object does not get freed within a short period.
  
      Category: General Utility Functions
  
      This can be handy to detect and prevent memory/resource leaks.
      """
      try:
          ref = weakref.ref(obj)
      except Exception:
          print_exception('Unable to create weak-ref in verify_object_death')
  
      # Use a slight range for our checks so they don't all land at once
      # if we queue a lot of them.
      delay = random.uniform(2.0, 5.5)
      with _ba.Context('ui'):
          _ba.timer(delay,
                    lambda: _verify_object_death(ref),
                    timetype=TimeType.REAL)
  
  
  def print_active_refs(obj: Any) -> None:
      """Print info about things referencing a given object.
  
      Category: General Utility Functions
  
      Useful for tracking down cyclical references and causes for zombie objects.
      """
      # pylint: disable=too-many-nested-blocks
      from types import FrameType, TracebackType
      refs = list(gc.get_referrers(obj))
      print(f'{Clr.YLW}Active referrers to {obj}:{Clr.RST}')
      for i, ref in enumerate(refs):
          print(f'{Clr.YLW}#{i+1}:{Clr.BLU} {ref}{Clr.RST}')
  
          # For certain types of objects such as stack frames, show what is
          # keeping *them* alive too.
          if isinstance(ref, FrameType):
              print(f'{Clr.YLW}  Active referrers to #{i+1}:{Clr.RST}')
              refs2 = list(gc.get_referrers(ref))
              for j, ref2 in enumerate(refs2):
                  print(f'{Clr.YLW}  #a{j+1}:{Clr.BLU} {ref2}{Clr.RST}')
  
                  # Can go further down the rabbit-hole if needed...
                  if bool(False):
                      if isinstance(ref2, TracebackType):
                          print(f'{Clr.YLW}    '
                                f'Active referrers to #a{j+1}:{Clr.RST}')
                          refs3 = list(gc.get_referrers(ref2))
                          for k, ref3 in enumerate(refs3):
                              print(f'{Clr.YLW}    '
                                    f'#b{k+1}:{Clr.BLU} {ref3}{Clr.RST}')
  
                              if isinstance(ref3, BaseException):
                                  print(f'{Clr.YLW}      Active referrers to'
                                        f' #b{k+1}:{Clr.RST}')
                                  refs4 = list(gc.get_referrers(ref3))
                                  for x, ref4 in enumerate(refs4):
                                      print(f'{Clr.YLW}      #c{x+1}:{Clr.BLU}'
                                            f' {ref4}{Clr.RST}')
  
  
  def _verify_object_death(wref: ReferenceType) -> None:
      obj = wref()
      if obj is None:
          return
  
      try:
          name = type(obj).__name__
      except Exception:
          print(f'Note: unable to get type name for {obj}')
          name = 'object'
  
      print(f'{Clr.RED}Error: {name} not dying when expected to:'
            f' {Clr.BLD}{obj}{Clr.RST}')
      print_active_refs(obj)
  
  
  def storagename(suffix: str = None) -> str:
      """Generate a unique name for storing class data in shared places.
  
      Category: General Utility Functions
  
      This consists of a leading underscore, the module path at the
      call site with dots replaced by underscores, the containing class's
      qualified name, and the provided suffix. When storing data in public
      places such as 'customdata' dicts, this minimizes the chance of
      collisions with other similarly named classes.
  
      Note that this will function even if called in the class definition.
  
      # Example: generate a unique name for storage purposes:
      class MyThingie:
  
          # This will give something like '_mymodule_submodule_mythingie_data'.
          _STORENAME = ba.storagename('data')
  
          # Use that name to store some data in the Activity we were passed.
          def __init__(self, activity):
              activity.customdata[self._STORENAME] = {}
      """
      frame = inspect.currentframe()
      if frame is None:
          raise RuntimeError('Cannot get current stack frame.')
      fback = frame.f_back
  
      # Note: We need to explicitly clear frame here to avoid a ref-loop
      # that keeps all function-dicts in the stack alive until the next
      # full GC cycle (the stack frame refers to this function's dict,
      # which refers to the stack frame).
      del frame
  
      if fback is None:
          raise RuntimeError('Cannot get parent stack frame.')
      modulepath = fback.f_globals.get('__name__')
      if modulepath is None:
          raise RuntimeError('Cannot get parent stack module path.')
      assert isinstance(modulepath, str)
      qualname = fback.f_locals.get('__qualname__')
      if qualname is not None:
          assert isinstance(qualname, str)
          fullpath = f'_{modulepath}_{qualname.lower()}'
      else:
          fullpath = f'_{modulepath}'
      if suffix is not None:
          fullpath = f'{fullpath}_{suffix}'
      return fullpath.replace('.', '_')
  