# Copyright 2004-2025 Tom Rothamel <pytom@bishoujo.us>
#
# 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.

from __future__ import division, absolute_import, with_statement, print_function, unicode_literals
from renpy.compat import PY2, basestring, bchr, bord, chr, open, pystr, range, round, str, tobytes, unicode # *

import random

import renpy
from renpy.parameter import Signature, ValuedParameter
from renpy.pyanalysis import Analysis, NOT_CONST, GLOBAL_CONST

def compiling(loc):
    file, number = loc # @ReservedAssignment

    renpy.game.exception_info = "Compiling ATL code at %s:%d" % (file, number)


def executing(loc):
    file, number = loc # @ReservedAssignment

    renpy.game.exception_info = "Executing ATL code at %s:%d" % (file, number)


# A map from the name of a time warp function to the function itself.
warpers = { }


def atl_warper(f):
    name = f.__name__
    warpers[name] = f
    return f

# The pause warper is used internally when no other warper is
# specified.


@atl_warper
def pause(t):
    if t < 1.0:
        return 0.0
    else:
        return 1.0


@atl_warper
def instant(t):
    return 1.0



class position(object):
    """
    A combination of relative and absolute coordinates.
    """
    __slots__ = ('absolute', 'relative')

    def __new__(cls, absolute=0, relative=None):
        """
        If passed two parameters, takes them as an absolute and a relative.
        If passed only one parameter, converts it.
        Using __new__ so that passing a position returns it unchanged.
        """
        if relative is None:
            self = cls.from_any(absolute)
        else:
            self = object.__new__(cls)
            self.absolute = absolute
            self.relative = relative
        return self

    @classmethod
    def from_any(cls, other):
        if isinstance(other, cls):
            return other
        elif type(other) is float:
            return cls(0, other)
        else:
            return cls(other, 0)

    def simplify(self):
        """
        Tries to represent this position as an int, float, or absolute, if
        possible.
        """

        if self.relative == 0.0:
            if self.absolute == int(self.absolute):
                return int(self.absolute)
            else:
                return renpy.display.core.absolute(self.absolute)
        elif self.absolute == 0:
            return float(self.relative)
        else:
            return self

    def __add__(self, other):
        if isinstance(other, position):
            return position(self.absolute + other.absolute, self.relative + other.relative)
        # elif isinstance(other, (int, float)):
        #     return self + position.from_any(other)
        return NotImplemented

    __radd__ = __add__

    def __sub__(self, other):
        return self + -other

    def __rsub__(self, other):
        return other + -self

    def __mul__(self, other):
        if isinstance(other, (int, float)):
            return position(self.absolute * other, self.relative * other)
        return NotImplemented

    __rmul__ = __mul__

    def __truediv__(self, other):
        if isinstance(other, (int, float)):
            return self * (1/other)
        return NotImplemented

    __div__ = __truediv__ # PY2

    def __pos__(self):
        return position(renpy.display.core.absolute(self.absolute), float(self.relative))

    def __neg__(self):
        return -1 * self

    def __repr__(self):
        return "position(absolute={}, relative={})".format(self.absolute, self.relative)


class DualAngle(object):
    def __init__(self, absolute, relative): # for tests, convert to PY2 after
        self.absolute = absolute
        self.relative = relative

    @classmethod
    def from_any(cls, other):
        if isinstance(other, cls):
            return other
        elif type(other) is float:
            return cls(other, other)
        raise TypeError("Cannot convert {} to DualAngle".format(type(other)))

    def __add__(self, other):
        if isinstance(other, DualAngle):
            return DualAngle(self.absolute + other.absolute, self.relative + other.relative)
        return NotImplemented

    def __sub__(self, other):
        return self + -other

    def __mul__(self, other):
        if isinstance(other, (int, float)):
            return DualAngle(self.absolute * other, self.relative * other)
        return NotImplemented

    __rmul__ = __mul__

    def __neg__(self):
        return -1 * self


def position_or_none(x):
    if x is None:
        return None
    return position.from_any(x)


def any_object(x):
    return x


def bool_or_none(x):
    if x is None:
        return x
    return bool(x)


def float_or_none(x):
    if x is None:
        return x
    return float(x)


def matrix(x):
    if x is None:
        return None
    elif callable(x):
        return x
    else:
        return renpy.display.matrix.Matrix(x)


def mesh(x):
    if isinstance(x, (renpy.gl2.gl2mesh2.Mesh2, renpy.gl2.gl2mesh3.Mesh3, tuple)):
        return x

    return bool(x)


# A dictionary giving property names and the corresponding type or
# function. This is massively added to by renpy.display.transform.
PROPERTIES = { }


def interpolate(t, a, b, typ):
    """
    Linearly interpolate the arguments.
    """

    # Deal with booleans, nones, etc.
    if b is None or isinstance(b, (bool, basestring, renpy.display.matrix.Matrix, renpy.display.transform.Camera)):
        if t >= 1.0:
            return b
        else:
            return a

    # Recurse into tuples.
    elif isinstance(b, tuple):
        if a is None:
            a = [ None ] * len(b)

        if not isinstance(typ, tuple):
            typ = (typ,) * len(b)

        return tuple(interpolate(t, i, j, ty) for i, j, ty in zip(a, b, typ))

    # If something is callable, call it and return the result.
    elif callable(b):
        a_origin = getattr(a, "origin", None)
        rv = b(a_origin, t)
        rv.origin = b
        return rv

    # Interpolate everything else.
    else:
        if a is None:
            a = 0

        if typ in (position_or_none, position):
            if renpy.config.mixed_position:
                a = position.from_any(a)
                b = position.from_any(b)
                return (1-t)*a + t*b # same result, faster execution
            else:
                typ = type(b)

        return typ(a + t * (b - a))


# Interpolate the value of a spline. This code is based on Aenakume's code,
# from 00splines.rpy.

def interpolate_spline(t, spline, typ):

    if isinstance(spline[-1], tuple):
        return tuple(interpolate_spline(t, i, ty) for i, ty in zip(zip(*spline), typ))

    if spline[0] is None:
        return spline[-1]

    if renpy.config.mixed_position and typ in (position_or_none, position):
        spline = [position_or_none(i) for i in spline]

    lenspline = len(spline)

    if lenspline == 2:
        t_p = 1.0 - t

        rv = t_p * spline[0] + t * spline[-1]

    elif lenspline == 3:
        t_pp = (1.0 - t) ** 2
        t_p = 2 * t * (1.0 - t)
        t2 = t ** 2

        rv = t_pp * spline[0] + t_p * spline[1] + t2 * spline[2]

    elif lenspline == 4:
        t_ppp = (1.0 - t) ** 3
        t_pp = 3 * t * (1.0 - t) ** 2
        t_p = 3 * t ** 2 * (1.0 - t)
        t3 = t ** 3

        rv = t_ppp * spline[0] + t_pp * spline[1] + t_p * spline[2] + t3 * spline[3]

    elif t <= 0.0:
        rv = spline[0]
    elif t >= 1.0:
        rv = spline[-1]

    else:
        # Catmull-Rom (re-adjust the control points)
        spline = [
            spline[1],
            spline[0]
        ] + list(spline[2:-2]) + [
            spline[-1],
            spline[-2]
        ]

        inner_spline_count = float(lenspline - 3)

        # determine which spline values are relevant
        sector = int(t // (1.0 / inner_spline_count) + 1)

        # determine t for this sector
        t = (t % (1.0 / inner_spline_count)) * inner_spline_count

        rv = get_catmull_rom_value(t, *spline[sector - 1:sector + 3])

    if rv is None:
        return None
    else:
        return type(spline[-1])(rv)


def get_catmull_rom_value(t, p_1, p0, p1, p2):
    """
    Very basic Catmull-Rom calculation with no alpha or handling
    of multi-dimensional points
    """
    t = float(max(0.0, min(1.0, t)))
    return type(p0)(
        (t * ((2 - t) * t - 1) * p_1
        +(t * t * (3 * t - 5) + 2) * p0
        +t * ((4 - 3 * t) * t + 1) * p1
        +(t - 1) * t * t * p2) / 2)


# A list of atl transforms that may need to be compiled.
compile_queue = [ ]


def compile_all():
    """
    Called after the init phase is finished and transforms are compiled,
    to compile all constant transforms.
    """

    global compile_queue

    for i in compile_queue:

        if i.atl.constant == GLOBAL_CONST:
            i.compile()

    compile_queue = [ ]


# Used to indicate that a variable is not in the context.
NotInContext = renpy.object.Sentinel("NotInContext")


# This is the context used when compiling an ATL statement. It stores the
# scopes that are used to evaluate the various expressions in the statement,
# and has a method to do the evaluation and return a result.
class Context(object):

    def __init__(self, context):
        self.context = context

    def eval(self, expr): # @ReservedAssignment
        return renpy.python.py_eval(expr, locals=self.context)

    def __eq__(self, other):
        if not isinstance(other, Context):
            return False

        return self.context == other.context

    def __ne__(self, other):
        return not (self == other)


class ATLTransformBase(renpy.object.Object):
    """
    This is intended to be subclassed by ATLTransform. It takes care of
    managing ATL execution, which allows ATLTransform itself to not care
    much about the contents of this file.
    """

    __version__ = 1

    # Compatibility with older saves.
    parameters = renpy.ast.EMPTY_PARAMETERS
    parent_transform = None # type: ATLTransformBase|None
    atl_st_offset = 0

    # The block, as first compiled for prediction.
    predict_block = None

    nosave = [ 'parent_transform' ]

    def after_upgrade(self, version):
        if version < 1:
            # any value in the inner scope was treated as a valid keyword parameter
            # so, we turn any inner scope value into a keyword parameter
            rv_parameters = []
            for name, value in self.context.context.items():
                if name not in self.parameters.parameters:
                    rv_parameters.append(ValuedParameter(name, ValuedParameter.KEYWORD_ONLY, value))
            if rv_parameters:
                rv_parameters = list(self.parameters.parameters.values()) + rv_parameters
                rv_parameters.sort(key=lambda p: p.kind)
                self.parameters = Signature(rv_parameters)

    def __init__(self, atl, context, parameters):

        # The constructor will be called by atltransform.
        if parameters is None:
            parameters = ATLTransformBase.parameters
        else:
            context = context.copy()
            # Apply the default parameters.
            parameters.apply_defaults(context, scope=context)

        # The parameters that we take.
        self.parameters = parameters

        # The raw code that makes up this ATL statement.
        self.atl = atl

        # The context in which execution occurs.
        self.context = Context(context)

        # The code after it has been compiled into a block.
        self.block = None

        # The same thing, but only if the code was compiled into a block
        # for prediction purposes only.
        self.predict_block = None

        # The properties of the block, if it contains only an
        # Interpolation.
        self.properties = None

        # The state of the statement we are executing. As this can be
        # shared between more than one object (in the case of a hide),
        # the data must not be altered.
        self.atl_state = None

        # Are we done?
        self.done = False

        # The transform event we are going to process.
        self.transform_event = None

        # The transform event we last processed.
        self.last_transform_event = None

        # The child transform event we last processed.
        self.last_child_transform_event = None

        # The child, without any transformations.
        self.raw_child = None

        # The parent transform that was called to create this transform.
        self.parent_transform = None

        # The offset between st and when this ATL block first executed.
        if renpy.config.atl_start_on_show:
            self.atl_st_offset = None
        else:
            self.atl_st_offset = 0

        if renpy.game.context().init_phase:
            compile_queue.append(self)

    @property
    def transition(self):
        """
        Returns true if this is likely to be an ATL transition.
        """

        return "new_widget" in self.context.context

    def _handles_event(self, event):

        if (event == "replaced") and (self.atl_state is None):
            return True

        if (self.block is not None) and (self.block._handles_event(event)):
            return True

        if self.child is None:
            return False

        return self.child._handles_event(event)

    def get_block(self):
        """
        Returns the compiled block to use.
        """

        if self.block:
            return self.block
        elif self.predict_block and renpy.display.predict.predicting:
            return self.predict_block
        else:
            return None

    def take_execution_state(self, t):
        """
        Updates self to begin executing from the same point as t. This
        requires that t.atl is self.atl.
        """

        super(ATLTransformBase, self).take_execution_state(t) # type: ignore

        self.atl_st_offset = None
        self.atl_state = None

        if self is t:
            return
        elif not isinstance(t, ATLTransformBase):
            return
        elif t.atl is not self.atl:
            return

        # Only take the execution state if the contexts haven't changed in
        # a way that would affect the execution of the ATL.

        if t.atl.constant != GLOBAL_CONST:

            block = self.get_block()
            if block is None:
                block = self.compile()

            if not deep_compare(self.block, t.block):
                return

        self.done = t.done
        self.block = t.block
        self.atl_state = t.atl_state
        self.transform_event = t.transform_event
        self.last_transform_event = t.last_transform_event
        self.last_child_transform_event = t.last_child_transform_event

        self.st = t.st
        self.at = t.at
        self.st_offset = t.st_offset
        self.at_offset = t.at_offset
        self.atl_st_offset = t.atl_st_offset

        if self.child is renpy.display.motion.null:

            if t.child and t.child._duplicatable:
                self.child = t.child._duplicate(None)
            else:
                self.child = t.child

            self.raw_child = t.raw_child

    def __call__(self, *args, **kwargs):

        _args = kwargs.pop("_args", None)

        scope = self.context.context.copy()
        signature = self.parameters
        child = None

        if renpy.config.atl_pos_only_as_pos_or_kw:
            signature = signature.with_pos_only_as_pos_or_kw()

        present_kinds = {p.kind for p in signature.parameters.values()}

        child_param = signature.parameters.get("child", None)
        old_widget_param = signature.parameters.get("old_widget", None)
        # args_param_name = None
        # if ValuedParameter.VAR_POSITIONAL in present_kinds:
        #     for param in signature.parameters.values():
        #         if param.kind == ValuedParameter.VAR_POSITIONAL:
        #             args_param_name = param.name
        #             break
        # kwargs_param_name = None
        # if ValuedParameter.VAR_KEYWORD in present_kinds:
        #     for param in signature.parameters.values():
        #         if param.kind == ValuedParameter.VAR_KEYWORD:
        #             kwargs_param_name = param.name
        #             break

        ## if a single arg is passed and no positional parameter is there to catch it, set it to be the child
        if args and (present_kinds <= {ValuedParameter.KEYWORD_ONLY, ValuedParameter.VAR_KEYWORD}):
            try:
                child, = args
            except Exception:
                raise Exception("Too many arguments passed to ATL transform.")
            args = ()

        if (child_param is None) or (child_param.kind not in {ValuedParameter.POSITIONAL_OR_KEYWORD, ValuedParameter.KEYWORD_ONLY}):
            # if kwargs_param_name is None:
                child = kwargs.pop("child", child)
        else:
            child = kwargs.get("child", child)
        if (old_widget_param is not None) and (old_widget_param.kind in {ValuedParameter.POSITIONAL_OR_KEYWORD, ValuedParameter.KEYWORD_ONLY}):
            # if getattr(signature.parameters.get("new_widget", None), "kind", None) in {ValuedParameter.POSITIONAL_OR_KEYWORD, ValuedParameter.KEYWORD_ONLY}: # Gamma-ter
            child = kwargs.get("old_widget", child)

        new_scope = signature.apply(args, kwargs, partial=True, apply_defaults=False)

        ## when *args and **kwargs are enabled
        # if args_param_name:
        #     var_args = new_scope.pop(args_param_name, ())
        #     if args_param_name in scope:
        #         scope[args_param_name] += var_args
        #     else:
        #         scope[args_param_name] = var_args
        # if kwargs_param_name:
        #     var_kwargs = new_scope.pop(kwargs_param_name, {})
        #     if kwargs_param_name in scope:
        #         scope[kwargs_param_name].update(var_kwargs)
        #     else:
        #         scope[kwargs_param_name] = var_kwargs

        scope.update(new_scope)

        if child is None:
            ## if a child parameter gets a value by a positional argument
            if child_param and (child_param.kind in {ValuedParameter.POSITIONAL_ONLY, ValuedParameter.POSITIONAL_OR_KEYWORD}):
                child = new_scope.get("child", child)

        rv_parameters = []
        for name, param in signature.parameters.items():
            passed = name in new_scope
            pkind = param.kind

            ## when *args and **kwargs are enabled
            # if name in (args_param_name, kwargs_param_name):
            #     pass

            ## when positional-only parameters are enabled
            # elif passed and (pkind == param.POSITIONAL_ONLY):
            #     continue

            if passed: # turn into elif when possible
                param = ValuedParameter(name, param.KEYWORD_ONLY, scope[name])

            elif param.has_default:
                param = ValuedParameter(name, pkind, scope[name])

            else:
                ## not passed and no default value
                pass

            rv_parameters.append(param)

        rv_parameters.sort(key=lambda p: p.kind)

        if child is None:
            child = self.child

        if getattr(child, '_duplicatable', False):
            child = child._duplicate(_args)

        rv = renpy.display.motion.ATLTransform(
            atl=self.atl,
            child=child,
            style=self.style_arg, # type: ignore
            context=scope,
            parameters=Signature(rv_parameters),
            _args=_args,
        )

        rv.parent_transform = self
        rv.take_state(self)

        return rv

    def compile(self): # @ReservedAssignment
        """
        Compiles the ATL code into a block. As necessary, updates the
        properties.
        """

        constant = (self.atl.constant == GLOBAL_CONST)

        if not constant:
            missing = set(self.parameters.parameters) - set(self.context.context)
            if missing:
                last = missing.pop()
                raise Exception("Cannot compile ATL Transform at {}:{}, as it's missing parameters {}.".format(
                    self.atl.loc[0],
                    self.atl.loc[1],
                    "{} and {!r}".format(", ".join(map(repr, missing)), last) if missing else repr(last),
                ))

        if constant and self.parent_transform:
            if self.parent_transform.block:
                self.block = self.parent_transform.block
                self.properties = self.parent_transform.properties
                self.parent_transform = None
                return self.block

        old_exception_info = renpy.game.exception_info

        if constant and self.atl.compiled_block is not None:
            block = self.atl.compiled_block
        else:
            block = self.atl.compile(self.context)

        if all(
            isinstance(statement, Interpolation) and statement.duration == 0
            for statement in block.statements
        ):
            self.properties = []
            for interp in block.statements:
                self.properties.extend(interp.properties)

        if not constant and renpy.display.predict.predicting:
            self.predict_block = block
        else:
            self.block = block
            self.predict_block = None

        renpy.game.exception_info = old_exception_info

        if constant and self.parent_transform:
            self.parent_transform.block = self.block
            self.parent_transform.properties = self.properties
            self.parent_transform = None

        return block

    def execute(self, trans, st, at):

        if self.done:
            return None

        block = self.get_block()
        if block is None:
            block = self.compile()

        events = [ ]

        # Hide request.
        if trans.hide_request:
            self.transform_event = "hide"

        if trans.replaced_request:
            self.transform_event = "replaced"

        # Notice transform events.
        if renpy.config.atl_multiple_events:
            if self.transform_event != self.last_transform_event:
                events.append(self.transform_event)
                self.last_transform_event = self.transform_event

        # Propagate transform_events from children.
        if (self.child is not None) and self.child.transform_event != self.last_child_transform_event:
            self.last_child_transform_event = self.child.transform_event

            if self.child.transform_event is not None:
                self.transform_event = self.child.transform_event

        # Notice transform events, again.
        if self.transform_event != self.last_transform_event:
            events.append(self.transform_event)
            self.last_transform_event = self.transform_event

        if self.transform_event in renpy.config.repeat_transform_events:
            self.transform_event = None
            self.last_transform_event = None

        old_exception_info = renpy.game.exception_info

        if (self.atl_st_offset is None) or (st - self.atl_st_offset) < 0:
            self.atl_st_offset = st

        if self.atl.animation or self.transition:
            timebase = at
        else:
            timebase = st - self.atl_st_offset

        action, arg, pause = block.execute(trans, timebase, self.atl_state, events)

        renpy.game.exception_info = old_exception_info

        if action == "continue" and not renpy.display.predict.predicting:
            self.atl_state = arg
        else:
            self.done = True

        return pause

    def predict_one(self):
        self.atl.predict(self.context)

    def visit(self):
        block = self.get_block()

        if block is None:
            block = self.compile()

        return self.children + block.visit() # type: ignore


# The base class for raw ATL statements.


class RawStatement(object):

    constant = None

    def __init__(self, loc):
        super(RawStatement, self).__init__()
        self.loc = loc

    # Compiles this RawStatement into a Statement, by using ctx to
    # evaluate expressions as necessary.
    def compile(self, ctx): # @ReservedAssignment
        raise Exception("Compile not implemented.")

    # Predicts the images used by this statement.
    def predict(self, ctx):
        return

    # RawBlock also has an analysis method which creates an Analysis
    # object, applies passed parameters and calls mark_constant

    def mark_constant(self, analysis):
        """
        Sets self.constant to GLOBAL_CONST if all expressions used in
        this statement and its children are constant.
        `analysis`
            A pyanalysis.Analysis object containing the analysis of this ATL.
        """

        self.constant = NOT_CONST


# The base class for compiled ATL Statements.


class Statement(renpy.object.Object):

    def __init__(self, loc):
        super(Statement, self).__init__()
        self.loc = loc

    # trans is the transform we're working on.
    # st is the time since this statement started executing.
    # state is the state stored by this statement, or None if
    # we've just started executing this statement.
    # event is an event we're triggering.
    #
    # "continue", state, pause - Causes this statement to execute
    # again, with the given state passed in the second time around.
    #
    #
    # "next", timeleft, pause - Causes the next statement to execute,
    # with timeleft being the amount of time left after this statement
    # finished.
    #
    # "event", (name, timeleft), pause - Causes an event to be reported,
    # and control to head up to the event handler.
    #
    # "repeat", (count, timeleft), pause - Causes the repeat behavior
    # to occur.
    #
    # As the Repeat statement can only appear in a block, only Block
    # needs to deal with the repeat behavior.
    #
    # Pause is the amount of time until execute should be called again,
    # or None if there's no need to call execute ever again.
    def execute(self, trans, st, state, events):
        raise Exception("Not implemented.")

    # Return a list of displayable children.
    def visit(self):
        return [ ]

    # Does this respond to an event?
    def _handles_event(self, event):
        return False

# This represents a Raw ATL block.


class RawBlock(RawStatement):

    # Should we use the animation timebase or the showing timebase?
    animation = False

    # If this block uses only constant values we can once compile it
    # and use this value for all ATLTransform that use us as an atl.
    compiled_block = None


    def __init__(self, loc, statements, animation):

        super(RawBlock, self).__init__(loc)

        # A list of RawStatements in this block.
        self.statements = statements

        self.animation = animation

    def compile(self, ctx): # @ReservedAssignment
        compiling(self.loc)

        statements = [ i.compile(ctx) for i in self.statements ]

        return Block(self.loc, statements)

    def predict(self, ctx):
        for i in self.statements:
            i.predict(ctx)

    def analyze(self, parameters=None):
        analysis = Analysis(None)

        # Apply the passed parameters to take into account
        # the names that are not constant in this context
        if parameters is not None:
            analysis.parameters(parameters)

        self.mark_constant(analysis)

        # We can only be a constant if we do not use values
        # from parameters or do not have them at all.
        # So we can pass an empty context for compilation.
        if self.constant == GLOBAL_CONST:
            self.compile_block()

    def compile_block(self):
        # This may failed if we use another transfrom
        # which use non constant value.
        # In this case we also non constant.
        old_exception_info = renpy.game.exception_info
        try:
            block = self.compile(Context({}))
        except RuntimeError:  # PY3: RecursionError
            raise Exception("This transform refers to itself in a cycle.")
        except Exception:
            self.constant = NOT_CONST
        else:
            self.compiled_block = block
        renpy.game.exception_info = old_exception_info

    def mark_constant(self, analysis):

        constant = GLOBAL_CONST

        for i in self.statements:
            i.mark_constant(analysis)
            constant = min(constant, i.constant)

        self.constant = constant


# A compiled ATL block.
class Block(Statement):

    def __init__(self, loc, statements):

        super(Block, self).__init__(loc)

        # A list of statements in the block.
        self.statements = statements

        # The start times of various statements.
        self.times = [ ]

        for i, s in enumerate(statements):
            if isinstance(s, Time):
                self.times.append((s.time, i + 1))

        self.times.sort()

    def _handles_event(self, event):

        for i in self.statements:
            if i._handles_event(event):
                return True

        return False

    def execute(self, trans, st, state, events):

        executing(self.loc)

        # Unpack the state.
        if state is not None:
            index, start, loop_start, repeats, times, child_state = state
        else:
            index, start, loop_start, repeats, times, child_state = 0, 0, 0, 0, self.times[:], None

        # What we might be returning.
        action = "continue"
        arg = None
        pause = None

        while action == "continue":

            # Target is the time we're willing to execute to.
            # Max_pause is how long we'll wait before executing again.

            # If we have times queued up, then use them to inform target
            # and time.
            if times:
                time, tindex = times[0]
                target = min(time, st)
                max_pause = time - target

            # Otherwise, take the defaults.
            else:
                target = st
                max_pause = 15

            while True:

                # If we've hit the last statement, it's the end of
                # this block.
                if index >= len(self.statements):
                    return "next", target - start, None

                # Find the statement and try to run it.
                stmt = self.statements[index]
                action, arg, pause = stmt.execute(trans, target - start, child_state, events)

                # On continue, persist our state.
                if action == "continue":
                    if pause is None:
                        pause = max_pause

                    action, arg, pause = "continue", (index, start, loop_start, repeats, times, arg), min(max_pause, pause)
                    break

                elif action == "event":
                    return action, arg, pause

                # On next, advance to the next statement in the block.
                elif action == "next":
                    index += 1
                    start = target - arg
                    child_state = None

                # On repeat, either terminate the block, or go to
                # the first statement.
                elif action == "repeat":

                    count, arg = arg
                    loop_end = target - arg
                    duration = loop_end - loop_start

                    if (state is None) and (duration <= 0):
                        raise Exception("ATL appears to be in an infinite loop.")

                    # Figure how many durations can occur between the
                    # start of the loop and now.

                    if duration:
                        new_repeats = int((target - loop_start) / duration)
                    else:
                        new_repeats = 0

                    if count is not None:
                        if repeats + new_repeats >= count:
                            new_repeats = count - repeats
                            loop_start += new_repeats * duration
                            return "next", target - loop_start, None

                    repeats += new_repeats
                    loop_start = loop_start + new_repeats * duration
                    start = loop_start
                    index = 0
                    child_state = None

            if times:
                time, tindex = times[0]
                if time <= target:
                    times.pop(0)

                    index = tindex
                    start = time
                    child_state = None

                    continue

            return action, arg, pause

    def visit(self):
        return [ j for i in self.statements for j in i.visit() ]

# A list of properties
incompatible_props = {
    "alignaround" : {"xaround", "yaround", "xanchoraround", "yanchoraround"},
    "align" : {"xanchor", "yanchor", "xpos", "ypos"},
    "anchor" : {"xanchor", "yanchor"},
    "angle" : {"xpos", "ypos"},
    "anchorangle" : {"xangle", "yangle"},
    "around" : {"xaround", "yaround", "xanchoraround", "yanchoraround"},
    "offset" : {"xoffset", "yoffset"},
    "pos" : {"xpos", "ypos"},
    "radius" : {"xpos", "ypos"},
    "anchorradius" : {"xanchor", "yanchor"},
    "size" : {"xsize", "ysize"},
    "xalign" : {"xpos", "xanchor"},
    "xcenter" : {"xpos", "xanchor"},
    "xycenter" : {"xpos", "ypos", "xanchor", "yanchor"},
    "xysize" : {"xsize", "ysize"},
    "yalign" : {"ypos", "yanchor"},
    "ycenter" : {"ypos", "yanchor"},
    }

# A list of sets of pairs of properties that do not conflict.
compatible_pairs = [
    {"radius", "angle"},
    {"anchorradius", "anchorangle"}
]

# This can become one of four things:
#
# - A pause.
# - An interpolation (which optionally can also reference other
# blocks, as long as they're not time-dependent, and have the same
# arity as the interpolation).
# - A call to another block.
# - A command to change the image, perhaps with a transition.
#
# We won't decide which it is until runtime, as we need the
# values of the variables here.


def check_spline_types(value):
    if isinstance(value, (position, int, float)):
        return True

    if isinstance(value, tuple):
        return all(check_spline_types(i) for i in value)

    return False


class RawMultipurpose(RawStatement):

    warp_function = None

    def __init__(self, loc):

        super(RawMultipurpose, self).__init__(loc)

        self.warper = None
        self.duration = None
        self.properties = [ ]
        self.expressions = [ ]
        self.splines = [ ]
        self.revolution = None
        self.circles = "0"

    def add_warper(self, name, duration, warp_function):
        self.warper = name
        self.duration = duration
        self.warp_function = warp_function

    def add_property(self, name, exprs):
        """
        Checks if the property is compatible with any previously included, and
        sets it.
        Either returns the previously-set property, if any, or None.
        """
        newly_set = incompatible_props.get(name, set()) | {name}

        for old, _e in self.properties:
            if newly_set.intersection(incompatible_props.get(old, (old,))):
                break
        else:
            old = None

        self.properties.append((name, exprs))

        if old is not None:
            pair = { old, name }

            for i in compatible_pairs:
                if pair == i:
                    old = None

        return old

    def add_expression(self, expr, with_clause):
        self.expressions.append((expr, with_clause))

    def add_revolution(self, revolution):
        self.revolution = revolution

    def add_circles(self, circles):
        self.circles = circles

    def add_spline(self, name, exprs):
        self.splines.append((name, exprs))

    def compile(self, ctx): # @ReservedAssignment

        compiling(self.loc)

        # Figure out what kind of statement we have. If there's no
        # interpolator, and no properties, than we have either a
        # call, or a child statement.
        if (self.warper is None and
            self.warp_function is None and
            not self.properties and
            not self.splines and
                len(self.expressions) == 1):

            expr, withexpr = self.expressions[0]

            child = ctx.eval(expr)
            if withexpr:
                transition = ctx.eval(withexpr)
            else:
                transition = None

            if isinstance(child, (int, float)):
                return Interpolation(self.loc, "pause", child, [ ], None, 0, [ ])

            child = renpy.easy.displayable(child)

            if isinstance(child, ATLTransformBase) and (child.child is None):
                child.compile()
                return child.get_block()
            else:
                return Child(self.loc, child, transition)

        compiling(self.loc)

        # Otherwise, we probably have an interpolation statement.

        if self.warp_function:
            warper = ctx.eval(self.warp_function)
        else:
            warper = self.warper or "instant"

            if warper not in warpers:
                raise Exception("ATL Warper %s is unknown at runtime." % warper)

        properties = [ ]

        for name, expr in self.properties:
            if name not in PROPERTIES:
                raise Exception("ATL Property %s is unknown at runtime." % name)

            value = ctx.eval(expr)
            properties.append((name, value))

        splines = [ ]

        for name, exprs in self.splines:
            if name not in PROPERTIES:
                raise Exception("ATL Property %s is unknown at runtime." % name)

            values = [ ctx.eval(i) for i in exprs ]

            if not all(check_spline_types(i) for i in values):
                if name in { "matrixtransform", "matrixcolor" }:
                    raise Exception("%s: Spline interpolation requires position types. (You may want to use SplineMatrix.)" % name)
                else:
                    raise Exception("%s: Spline interpolation requires position types." % name)

            splines.append((name, values))

        for expr, _with in self.expressions:
            try:
                value = ctx.eval(expr)
            except Exception:
                raise Exception("Could not evaluate expression %r when compiling ATL." % expr)

            if not isinstance(value, ATLTransformBase):
                raise Exception("Expression %r is not an ATL transform, and so cannot be included in an ATL interpolation." % expr)

            value.compile()

            if value.properties is None:
                raise Exception("ATL transform %r is too complicated to be included in interpolation." % expr)

            properties.extend(value.properties)

        duration = ctx.eval(self.duration)
        circles = ctx.eval(self.circles)

        return Interpolation(self.loc, warper, duration, properties, self.revolution, circles, splines)

    def mark_constant(self, analysis):
        constant = GLOBAL_CONST
        is_constant_expr = analysis.is_constant_expr

        constant = min(constant, is_constant_expr(self.warp_function))
        constant = min(constant, is_constant_expr(self.duration))
        constant = min(constant, is_constant_expr(self.circles))

        for _name, expr in self.properties:
            constant = min(constant, is_constant_expr(expr))

        for _name, exprs in self.splines:
            for expr in exprs:
                constant = min(constant, is_constant_expr(expr))

        for expr, withexpr in self.expressions:
            constant = min(constant, is_constant_expr(expr))
            constant = min(constant, is_constant_expr(withexpr))

        self.constant = constant

    def predict(self, ctx):

        for i, _j in self.expressions:

            try:
                i = ctx.eval(i)
            except Exception:
                continue

            if isinstance(i, ATLTransformBase) and (i.child is None):
                i.atl.predict(ctx)
                return

            try:
                renpy.easy.predict(i)
            except Exception:
                continue

# This lets us have an ATL transform as our child.
class RawContainsExpr(RawStatement):

    def __init__(self, loc, expr):

        super(RawContainsExpr, self).__init__(loc)

        self.expression = expr

    def compile(self, ctx): # @ReservedAssignment
        compiling(self.loc)
        child = ctx.eval(self.expression)
        return Child(self.loc, child, None)

    def mark_constant(self, analysis):
        self.constant = analysis.is_constant_expr(self.expression)


# This allows us to have multiple ATL transforms as children.
class RawChild(RawStatement):

    def __init__(self, loc, child):

        super(RawChild, self).__init__(loc)

        self.children = [ child ]

    def compile(self, ctx): # @ReservedAssignment

        children = [ ]

        for i in self.children:
            children.append(renpy.display.motion.ATLTransform(i, context=ctx.context))

        box = renpy.display.layout.MultiBox(layout='fixed')

        for i in children:
            box.add(i)

        return Child(self.loc, box, None)

    def mark_constant(self, analysis):

        constant = GLOBAL_CONST

        for i in self.children:
            i.mark_constant(analysis)
            constant = min(constant, i.constant)

        self.constant = constant


# This changes the child of this statement, optionally with a transition.
class Child(Statement):

    def __init__(self, loc, child, transition):

        super(Child, self).__init__(loc)

        self.child = child
        self.transition = transition

    def execute(self, trans, st, state, events):

        executing(self.loc)

        old_child = trans.raw_child

        child = self.child

        if child._duplicatable:
            child = self.child._duplicate(trans._args)
            child._unique()

        if (old_child is not None) and (old_child is not renpy.display.motion.null) and (self.transition is not None):
            child = self.transition(old_widget=old_child,
                                    new_widget=child)
            child._unique()

        trans.set_child(child, duplicate=False)
        trans.raw_child = self.child

        return "next", st, None

    def visit(self):
        return [ self.child ]


# This causes interpolation to occur.
class Interpolation(Statement):

    def __init__(self, loc, warper, duration, properties, revolution, circles, splines):

        super(Interpolation, self).__init__(loc)

        self.warper = warper
        self.duration = duration
        self.properties = properties
        self.splines = splines

        # The direction we revolve in: cw, ccw, or None.
        self.revolution = revolution

        # The number of complete circles we make.
        self.circles = circles

    def execute(self, trans, st, state, events):

        executing(self.loc)

        warper = warpers.get(self.warper, self.warper)

        # Special case `pause 0` to always display a frame. This is intended to
        # support single-frame animations that shouldn't skip.
        if state is None and self.warper == "pause" and self.duration == 0 and renpy.config.atl_one_frame:
            force_frame = True
        else:
            force_frame = False

        if self.duration:
            complete = min(1.0, st / self.duration)
        else:
            complete = 1.0

        if complete < 0.0:
            complete = 0.0
        elif complete > 1.0:
            complete = 1.0

        complete = warper(complete)

        if state is None or len(state) != 6:

            # Create a new transform state, and apply the property
            # changes to it.
            newts = renpy.display.motion.TransformState()
            newts.take_state(trans.state)

            has_angle = False
            has_radius = False
            has_anchorangle = False
            has_anchorradius = False

            for k, v in self.properties:
                setattr(newts, k, v)

                if k == "angle":
                    has_angle = True

                elif k == "radius":
                    has_radius = True

                elif k == "anchorangle":
                    has_anchorangle = True

                elif k == "anchorradius":
                    has_anchorradius = True

            # Now, the things we change linearly are in the difference
            # between the new and old states.
            linear = trans.state.diff(newts)

            # Angle and radius need to go after the linear changes, as
            # around or alignaround must be set first.
            angles = None
            radii = None
            anchorangles = None
            anchorradii = None

            splines = [ ]

            revdir = self.revolution
            circles = self.circles

            if revdir or ((has_angle or has_radius) and renpy.config.automatic_polar_motion) or has_anchorangle or has_anchorradius:

                # Remove various irrelevant motions.
                for i in [ 'xpos', 'ypos',
                           'xanchor', 'yanchor',
                           'xaround', 'yaround',
                           'xanchoraround', 'yanchoraround',
                           ]:

                    linear.pop(i, None)

                if revdir is not None:

                    # Ensure we rotate around the new point.
                    trans.state.xaround = newts.xaround or .0
                    trans.state.yaround = newts.yaround or .0
                    trans.state.xanchoraround = newts.xanchoraround
                    trans.state.yanchoraround = newts.yanchoraround

                    # Get the start and end angles and radii.
                    startangle = trans.state.angle
                    endangle = newts.angle
                    startradius = trans.state.radius
                    endradius = newts.radius

                    startanchorangle = trans.state.anchorangle
                    startanchorangle_absolute = startanchorangle.absolute
                    startanchorangle_relative = startanchorangle.relative
                    endanchorangle = newts.anchorangle
                    endanchorangle_absolute = endanchorangle.absolute
                    endanchorangle_relative = endanchorangle.relative
                    startanchorradius = trans.state.anchorradius
                    endanchorradius = newts.anchorradius

                    # Make sure the angle is in the appropriate direction,
                    # and contains an appropriate number of circles.

                    if revdir == "clockwise":
                        if endangle < startangle:
                            startangle -= 360

                        if endanchorangle_absolute < startanchorangle_absolute:
                            endanchorangle_absolute -= 360
                        if endanchorangle_relative < startanchorangle_relative:
                            endanchorangle_relative -= 360

                        startangle -= circles * 360
                        startanchorangle_absolute -= circles * 360
                        startanchorangle_relative -= circles * 360

                    elif revdir == "counterclockwise":
                        if endangle > startangle:
                            startangle += 360

                        if endanchorangle_absolute > startanchorangle_absolute:
                            endanchorangle_absolute += 360
                        if endanchorangle_relative > startanchorangle_relative:
                            endanchorangle_relative += 360

                        startangle += circles * 360
                        startanchorangle_absolute += circles * 360
                        startanchorangle_relative += circles * 360

                    radii = (startradius, endradius)
                    angles = (startangle, endangle)
                    anchorradii = (startanchorradius, endanchorradius)
                    anchorangles = (
                        DualAngle(startanchorangle_absolute, startanchorangle_relative),
                        DualAngle(endanchorangle_absolute, endanchorangle_relative),
                    )

                else:

                    if has_angle:
                        start = trans.state.angle
                        end = newts.last_angle

                        if end - start > 180:
                            start += 360
                        if end - start < -180:
                            start -= 360

                        angles = (start, end)

                    if has_radius:
                        radii = (trans.state.radius, newts.radius)

                    if has_anchorangle:
                        start = trans.state.anchorangle
                        start_absolute = start.absolute
                        start_relative = start.relative
                        end_absolute = newts.last_absolute_anchorangle
                        end_relative = newts.last_relative_anchorangle

                        if end_absolute - start_absolute > 180:
                            start_absolute += 360
                        if end_absolute - start_absolute < -180:
                            start_absolute -= 360
                        if end_relative - start_relative > 180:
                            start_relative += 360
                        if end_relative - start_relative < -180:
                            start_relative -= 360

                        anchorangles = (
                            DualAngle(start_absolute, start_relative),
                            DualAngle(end_absolute, end_relative),
                        )

                    if has_anchorradius:
                        anchorradii = (trans.state.anchorradius, newts.anchorradius)

            # Figure out the splines.
            for name, values in self.splines:
                splines.append((name, [ trans.state.get(name) ] + values))

            state = (linear, angles, radii, anchorangles, anchorradii, splines)

            # Ensure that we set things, even if they don't actually
            # change from the old state.
            for k, v in self.properties:
                if k not in linear:
                    setattr(trans.state, k, v)

        else:
            linear, angles, radii, anchorangles, anchorradii, splines = state

        # Linearly interpolate between the things in linear.
        for k, (old, new) in linear.items():

            if k == "orientation":
                if old is None:
                    old = (0.0, 0.0, 0.0)
                if new is not None:
                    value = renpy.display.quaternion.euler_slerp(complete, old, new)
                elif complete >= 1:
                    value = None
                else:
                    value = old

            else:
                value = interpolate(complete, old, new, PROPERTIES[k])

            setattr(trans.state, k, value)

        # Handle the angle.
        if angles is not None:
            startangle, endangle = angles[:2]

            angle = interpolate(complete, startangle, endangle, float)
            trans.state.angle = angle

        if radii is not None:
            startradius, endradius = radii
            trans.state.radius = interpolate(complete, startradius, endradius, position_or_none)

        if anchorangles is not None:
            startangle, endangle = anchorangles[:2]

            anchorangle = interpolate(complete, startangle, endangle, DualAngle.from_any)
            trans.state.anchorangle = anchorangle

        if anchorradii is not None:
            startradius, endradius = anchorradii
            trans.state.anchorradius = interpolate(complete, startradius, endradius, position_or_none)

        # Handle any splines we might have.
        for name, values in splines:
            value = interpolate_spline(complete, values, PROPERTIES[name])
            setattr(trans.state, name, value)

        if (st >= self.duration) and (not force_frame):
            return "next", st - self.duration, None
        else:
            if not self.properties and not self.revolution and not self.splines:
                return "continue", state, max(0, self.duration - st)
            else:
                return "continue", state, 0


# Implementation of the repeat statement.
class RawRepeat(RawStatement):

    def __init__(self, loc, repeats):

        super(RawRepeat, self).__init__(loc)

        self.repeats = repeats

    def compile(self, ctx): # @ReservedAssignment

        compiling(self.loc)

        repeats = self.repeats

        if repeats is not None:
            repeats = ctx.eval(repeats)

        return Repeat(self.loc, repeats)

    def mark_constant(self, analysis):
        self.constant = analysis.is_constant_expr(self.repeats)

class Repeat(Statement):

    def __init__(self, loc, repeats):

        super(Repeat, self).__init__(loc)

        self.repeats = repeats

    def execute(self, trans, st, state, events):
        return "repeat", (self.repeats, st), 0

# Parallel statement.


class RawParallel(RawStatement):

    def __init__(self, loc, block):

        super(RawParallel, self).__init__(loc)
        self.blocks = [ block ]

    def compile(self, ctx): # @ReservedAssignment
        return Parallel(self.loc, [i.compile(ctx) for i in self.blocks])

    def predict(self, ctx):
        for i in self.blocks:
            i.predict(ctx)

    def mark_constant(self, analysis):
        constant = GLOBAL_CONST

        for i in self.blocks:
            i.mark_constant(analysis)
            constant = min(constant, i.constant)

        self.constant = constant



class Parallel(Statement):

    def __init__(self, loc, blocks):
        super(Parallel, self).__init__(loc)
        self.blocks = blocks

    def _handles_event(self, event):

        for i in self.blocks:
            if i._handles_event(event):
                return True

        return False

    def execute(self, trans, st, state, events):

        executing(self.loc)

        if state is None:
            state = [ (i, None) for i in self.blocks ]

        # The amount of time left after finishing this block.
        left = [ ]

        # The duration of the pause.
        pauses = [ ]

        # The new state structure.
        newstate = [ ]

        for i, istate in state:

            action, arg, pause = i.execute(trans, st, istate, events)

            if pause is not None:
                pauses.append(pause)

            if action == "continue":
                newstate.append((i, arg))
            elif action == "next":
                left.append(arg)
            elif action == "event":
                return action, arg, pause

        if newstate:
            return "continue", newstate, min(pauses)
        else:
            return "next", min(left), None

    def visit(self):
        return [ j for i in self.blocks for j in i.visit() ]

# The choice statement.


class RawChoice(RawStatement):

    def __init__(self, loc, chance, block):
        super(RawChoice, self).__init__(loc)

        self.choices = [ (chance, block) ]

    def compile(self, ctx): # @ReservedAssignment
        compiling(self.loc)
        return Choice(self.loc, [ (ctx.eval(chance), block.compile(ctx)) for chance, block in self.choices])

    def predict(self, ctx):
        for _i, j in self.choices:
            j.predict(ctx)

    def mark_constant(self, analysis):
        constant = GLOBAL_CONST

        for _chance, block in self.choices:
            block.mark_constant(analysis)
            constant = min(constant, block.constant)

        self.constant = constant


class Choice(Statement):

    def __init__(self, loc, choices):

        super(Choice, self).__init__(loc)

        self.choices = choices

    def _handles_event(self, event):

        for i in self.choices:
            if i[1]._handles_event(event):
                return True

        return False

    def execute(self, trans, st, state, events):

        executing(self.loc)

        choice = None # For typing purposes.

        if state is None:

            total = 0

            for chance, choice in self.choices:
                total += chance

            n = random.uniform(0, total)

            for chance, choice in self.choices:
                if n < chance:
                    break
                n -= chance

            cstate = None

        else:
            choice, cstate = state

        action, arg, pause = choice.execute(trans, st, cstate, events)

        if action == "continue":
            return "continue", (choice, arg), pause
        else:
            return action, arg, None

    def visit(self):
        return [ j for i in self.choices for j in i[1].visit() ]

# The Time statement.


class RawTime(RawStatement):

    def __init__(self, loc, time):

        super(RawTime, self).__init__(loc)
        self.time = time

    def compile(self, ctx): # @ReservedAssignment
        compiling(self.loc)
        return Time(self.loc, ctx.eval(self.time))

    def mark_constant(self, analysis):
        self.constant = analysis.is_constant_expr(self.time)


class Time(Statement):

    def __init__(self, loc, time):
        super(Time, self).__init__(loc)

        self.time = time

    def execute(self, trans, st, state, events):
        return "continue", None, None

# The On statement.


class RawOn(RawStatement):

    def __init__(self, loc, names, block):
        super(RawOn, self).__init__(loc)

        self.handlers = { }

        for i in names:
            self.handlers[i] = block

    def compile(self, ctx): # @ReservedAssignment
        compiling(self.loc)

        handlers = { }

        for k, v in self.handlers.items():
            handlers[k] = v.compile(ctx)

        return On(self.loc, handlers)

    def predict(self, ctx):
        for i in self.handlers.values():
            i.predict(ctx)

    def mark_constant(self, analysis):
        constant = GLOBAL_CONST

        for block in self.handlers.values():
            block.mark_constant(analysis)
            constant = min(constant, block.constant)

        self.constant = constant

class On(Statement):

    def __init__(self, loc, handlers):
        super(On, self).__init__(loc)

        self.handlers = handlers

    def _handles_event(self, event):
        if event in self.handlers:
            return True
        else:
            return False

    def execute(self, trans, st, state, events):

        executing(self.loc)

        # If it's our first time through, start in the start state.
        if state is None:
            name, start, cstate = ("start", st, None)
        else:
            name, start, cstate = state

        # If we have an external event, and we have a handler for it,
        # handle it.
        for event in events:

            while event:
                if event in self.handlers:
                    break

                event = event.partition("_")[2]

            if not event:
                continue

            # Do not allow people to abort the hide or replaced event.
            lock_event = (name == "hide" and trans.hide_request) or (name == "replaced" and trans.replaced_request)

            if not lock_event:
                name = event
                start = st
                cstate = None

        while True:

            # If we don't have a handler, return until we change event.
            if name not in self.handlers:
                return "continue", (name, start, cstate), None

            action, arg, pause = self.handlers[name].execute(trans, st - start, cstate, events)

            # If we get a continue, save our state.
            if action == "continue":

                # If it comes from a hide block, indicate that.
                if name == "hide" or name == "replaced":
                    trans.hide_response = False
                    trans.replaced_response = False

                return "continue", (name, start, arg), pause

            # If we get a next, then try going to the default
            # event, unless we're already in default, in which case we
            # go to None.
            elif action == "next":
                if name == "default" or name == "hide" or name == "replaced":
                    name = None
                else:
                    name = "default"

                start = st - arg
                cstate = None

                continue

            # If we get an event, then either handle it if we can, or
            # pass it up the stack if we can't.
            elif action == "event":

                name, arg = arg

                if name in self.handlers:
                    start = max(st - arg, st - 30)
                    cstate = None
                    continue

                return "event", (name, arg), None

    def visit(self):
        return [ j for i in self.handlers.values() for j in i.visit() ]

# Event statement.


class RawEvent(RawStatement):

    def __init__(self, loc, name):
        super(RawEvent, self).__init__(loc)

        self.name = name

    def compile(self, ctx): # @ReservedAssignment
        return Event(self.loc, self.name)

    def mark_constant(self, analysis):
        self.constant = GLOBAL_CONST


class Event(Statement):

    def __init__(self, loc, name):
        super(Event, self).__init__(loc)

        self.name = name

    def execute(self, trans, st, state, events):
        return "event", (self.name, st), None


class RawFunction(RawStatement):

    def __init__(self, loc, expr):
        super(RawFunction, self).__init__(loc)

        self.expr = expr

    def compile(self, ctx): # @ReservedAssignment
        compiling(self.loc)
        return Function(self.loc, ctx.eval(self.expr))

    def mark_constant(self, analysis):
        self.constant = analysis.is_constant_expr(self.expr)


class Function(Statement):

    def __init__(self, loc, function):
        super(Function, self).__init__(loc)

        self.function = function

    def _handles_event(self, event):
        return True

    def execute(self, trans, st, state, events):
        block = state or renpy.config.atl_function_always_blocks

        fr = self.function(trans, st if block else 0, trans.at)

        if (not block) and (fr is not None):
            block = True
            fr = self.function(trans, st, trans.at)

        if fr is not None:
            return "continue", True, fr
        else:
            return "next", 0 if block else st, None


# This parses an ATL block.
def parse_atl(l):

    l.advance()
    block_loc = l.get_location()

    statements = [ ]

    animation = False

    while not l.eob:

        loc = l.get_location()

        if l.keyword('repeat'):

            repeats = l.simple_expression()
            statements.append(RawRepeat(loc, repeats))

        elif l.keyword('block'):
            l.require(':')
            l.expect_eol()
            l.expect_block('block')

            block = parse_atl(l.subblock_lexer())
            statements.append(block)

        elif l.keyword('contains'):

            expr = l.simple_expression()

            if expr:

                l.expect_noblock('contains expression')
                statements.append(RawContainsExpr(loc, expr))

            else:

                l.require(':')
                l.expect_eol()
                l.expect_block('contains')

                block = parse_atl(l.subblock_lexer())
                statements.append(RawChild(loc, block))

        elif l.keyword('parallel'):
            l.require(':')
            l.expect_eol()
            l.expect_block('parallel')

            block = parse_atl(l.subblock_lexer())
            statements.append(RawParallel(loc, block))

        elif l.keyword('choice'):

            chance = l.simple_expression()
            if not chance:
                chance = "1.0"

            l.require(':')
            l.expect_eol()
            l.expect_block('choice')

            block = parse_atl(l.subblock_lexer())
            statements.append(RawChoice(loc, chance, block))

        elif l.keyword('on'):

            names = [ l.require(l.word) ]

            while l.match(','):
                name = l.word()

                if name is None:
                    break

                names.append(name)

            l.require(':')
            l.expect_eol()
            l.expect_block('on')

            block = parse_atl(l.subblock_lexer())
            statements.append(RawOn(loc, names, block))

        elif l.keyword('time'):
            time = l.require(l.simple_expression)
            l.expect_noblock('time')

            statements.append(RawTime(loc, time))

        elif l.keyword('function'):
            expr = l.require(l.simple_expression)
            l.expect_noblock('function')

            statements.append(RawFunction(loc, expr))

        elif l.keyword('event'):
            name = l.require(l.word)
            l.expect_noblock('event')

            statements.append(RawEvent(loc, name))

        elif l.keyword('pass'):
            l.expect_noblock('pass')
            statements.append(None)

        elif l.keyword('animation'):
            l.expect_noblock('animation')
            animation = True

        else:

            # If we can't assign it it a statement more specifically,
            # we try to parse it into a RawMultipurpose. That will
            # then be turned into another statement, as appropriate.

            # The RawMultipurpose we add things to.
            rm = renpy.atl.RawMultipurpose(loc)

            # Is the last clause an expression?
            last_expression = False

            # Is this clause an expression?
            this_expression = False

            # First, look for a warper.
            cp = l.checkpoint()
            warper = l.name()

            if warper in warpers:
                duration = l.require(l.simple_expression)
                warp_function = None

            elif warper == "warp":

                warper = None
                warp_function = l.require(l.simple_expression)
                duration = l.require(l.simple_expression)

            else:
                l.revert(cp)

                warper = None
                warp_function = None
                duration = "0"

            rm.add_warper(warper, duration, warp_function)

            ll = l
            has_block = False

            # Now, look for properties and simple_expressions.
            while True:

                if ((warper is not None) or (warp_function is not None)) and (not has_block) and ll.match(':'):
                    ll.expect_eol()
                    ll.expect_block("ATL")
                    has_block = True
                    ll = l.subblock_lexer()
                    ll.advance()
                    ll.expect_noblock("ATL")

                if has_block and ll.eol():
                    ll.advance()
                    ll.expect_noblock("ATL")

                # Update expression status.
                last_expression = this_expression
                this_expression = False

                if ll.keyword('pass'):
                    continue

                # Parse revolution keywords.
                if ll.keyword('clockwise'):
                    rm.add_revolution('clockwise')
                    continue

                if ll.keyword('counterclockwise'):
                    rm.add_revolution('counterclockwise')
                    continue

                if ll.keyword('circles'):
                    expr = l.require(l.simple_expression)
                    rm.add_circles(expr)
                    continue

                # Try to parse a property.
                cp = ll.checkpoint()

                prop = ll.name()

                if (prop in PROPERTIES) or (prop and prop.startswith("u_")):

                    expr = ll.require(ll.simple_expression)

                    # We either have a property or a spline. It's the
                    # presence of knots that determine which one it is.

                    knots = [ ]

                    while ll.keyword('knot'):
                        knots.append(ll.require(ll.simple_expression))

                    if knots:
                        if prop == "orientation":
                            raise Exception("Orientation doesn't support spline.")
                        knots.append(expr)
                        rm.add_spline(prop, knots)
                    else:
                        addprop_rv = rm.add_property(prop, expr)
                        if addprop_rv == prop:
                            ll.deferred_error("check_conflicting_properties", "property {!r} is given a value more than once".format(prop))
                        elif addprop_rv:
                            ll.deferred_error("check_conflicting_properties", "properties {!r} and {!r} conflict with each other".format(prop, addprop_rv))

                    continue

                # Otherwise, try to parse it as a simple expressoon,
                # with an optional with clause.

                ll.revert(cp)

                expr = ll.simple_expression()

                if not expr:
                    break

                if last_expression:
                    ll.error('ATL statement contains two expressions in a row; is one of them a misspelled property? If not, separate them with pass.')

                this_expression = True

                if ll.keyword("with"):
                    with_expr = ll.require(ll.simple_expression)
                else:
                    with_expr = None

                rm.add_expression(expr, with_expr)

            if not has_block:
                l.expect_noblock('ATL')

            statements.append(rm)

        if l.eol():
            l.advance()
            continue

        l.require(",", "comma or end of line")

    # Merge together statements that need to be merged together.

    merged = [ ]
    old = None

    for new in statements:

        if isinstance(old, RawParallel) and isinstance(new, RawParallel):
            old.blocks.extend(new.blocks)
            continue

        elif isinstance(old, RawChoice) and isinstance(new, RawChoice):
            old.choices.extend(new.choices)
            continue

        elif isinstance(old, RawChild) and isinstance(new, RawChild):
            old.children.extend(new.children)
            continue

        elif isinstance(old, RawOn) and isinstance(new, RawOn):
            old.handlers.update(new.handlers)
            continue

        # None is a pause statement, which gets skipped, but also
        # prevents things from combining.
        elif new is None:
            old = new
            continue

        merged.append(new)
        old = new

    return RawBlock(block_loc, merged, animation)

def deep_compare(a, b):
    """
    Compares two trees of ATL statements for equality.
    """

    if type(a) != type(b):
        return False

    if isinstance(a, (list, tuple)):
        return all(deep_compare(i, j) for i, j in zip(a, b))

    if isinstance(a, dict):
        if len(a) != len(b):
            return False

        return all((k in b) and deep_compare(a[k], b[k]) for k in a)

    if isinstance(a, Statement):
        return deep_compare(a.__dict__, b.__dict__)

    try:
        return a == b
    except Exception:
        return True
