"""This module contains functions and classes for creating and issuing events.
For a list of the events that are built into Spyral, check the
:ref:`Event List<ref.events>`.

    .. attribute:: keys

        A special attribute for accessing the constants associated with a given
        key. For instance, ``spyral.keys.down`` and ``spyral.keys.f``. This is
        useful for testing for keyboard events. A complete list of all the key
        constants can be found in the
        :ref:`Keyboard Keys <ref.keys>` appendix.

    .. attribute:: mods

        A special attribute for accessing the constants associated with a given
        mod key. For instance, ``spyral.mods.lshift`` (left shift) and
        ``spyral.mods.ralt`` (Right alt). This is useful for testing for keyboard
        events. A complete list of all the key
        constants can be found in the
        :ref:`Keyboard Modifiers <ref.mods>` appendix.

"""

import pygame
try:
    import json
except ImportError:
    import simplejson as json
import spyral
import os
import random
import base64
from weakmethod import WeakMethod as _wm

def WeakMethod(func):
    try:
        return _wm(func)
    except TypeError:
        return func

_TYPE_TO_ATTRS = None
_TYPE_TO_TYPE = None

class Event(object):
    """
    A class for building for attaching data to an event.
    Keyword arguments will be named attributes of the Event when it is passed
    into :func:`queue <spyral.event.queue>`::

        collision_event = Event(ball=ball, paddle=paddle)
        spyral.event.queue("ball.collides.paddle", collision_event)
    """
    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)

# This might actually be unused!
_EVENT_NAMES = ['QUIT', 'ACTIVEEVENT', 'KEYDOWN', 'KEYUP', 'MOUSEMOTION',
                'MOUSEBUTTONUP', 'VIDEORESIZE', 'VIDEOEXPOSE', 'USEREVENT',
                'MOUSEBUTTONDOWN']
MOUSE_MAP = ['left', 'middle', 'right', 'scroll_up', 'scroll_down']

def _init():
    """
    Initializes the Event system, which requires mapping the Pygame event
    constants to Spyral strings.
    """
    global _TYPE_TO_ATTRS
    global _TYPE_TO_TYPE

    _TYPE_TO_ATTRS = {
        pygame.QUIT: tuple(),
        pygame.ACTIVEEVENT: ('gain', 'state'),
        pygame.KEYDOWN: ('unicode', 'key', 'mod'),
        pygame.KEYUP: ('key', 'mod'),
        pygame.MOUSEMOTION: ('pos', 'rel', 'buttons'),
        pygame.MOUSEBUTTONUP: ('pos', 'button'),
        pygame.MOUSEBUTTONDOWN: ('pos', 'button'),
        pygame.VIDEORESIZE: ('size', 'w', 'h'),
        pygame.VIDEOEXPOSE: tuple(),
    }
    _TYPE_TO_TYPE = {
        pygame.QUIT: "system.quit",
        pygame.ACTIVEEVENT: "system.focus_change",
        pygame.KEYDOWN: "input.keyboard.down",
        pygame.KEYUP: "input.keyboard.up",
        pygame.MOUSEMOTION: "input.mouse.motion",
        pygame.MOUSEBUTTONUP: "input.mouse.up",
        pygame.MOUSEBUTTONDOWN: "input.mouse.down",
        pygame.VIDEORESIZE: "system.video_resize",
        pygame.VIDEOEXPOSE: "system.video_expose",
    }

def queue(event_name, event=None, scene=None):
    """
    Queues a new event in the system, meaning that it will be run at the next
    available opportunity.

    :param str event_name: The type of event (e.g., ``"system.quit"``,
                           ``"input.mouse.up"``, or ``"pong.score"``.
    :param event: An Event object that holds properties for the event.
    :type event: :class:`Event <spyral.event.Event>`
    :param scene: The scene to queue this event on; if `None` is given, the
                   currently executing scene will be used.
    :type scene: :class:`Scene <spyral.Scene>` or `None`.
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._queue_event(event_name, event)

def handle(event_name, event=None, scene=None):
    """
    Instructs spyral to execute the handlers for this event right now. When you
    have a custom event, this is the function you call to have the event occur.

    :param str event_name: The type of event (e.g., ``"system.quit"``,
                           ``"input.mouse.up"``, or ``"pong.score"``.
    :param event: An Event object that holds properties for the event.
    :type event: :class:`Event <spyral.event.Event>`
    :param scene: The scene to queue this event on; if ``None`` is given, the
                   currently executing scene will be used.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``.
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._handle_event(event_name, event)

def register(event_namespace, handler,
             args=None, kwargs=None, priority=0, scene=None):
    """
    Registers an event `handler` to a namespace. Whenever an event in that
    `event_namespace` is fired, the event `handler` will execute with that
    event.

    :param event_namespace: the namespace of the event, e.g.
                            ``"input.mouse.left.click"`` or ``"pong.score"``.
    :type event_namespace: str
    :param handler: A function that will handle the event. The first
                    argument to the function will be the event.
    :type handler: function
    :param args: any additional arguments that need to be passed in
                 to the handler.
    :type args: sequence
    :param kwargs: any additional keyword arguments that need to be
                   passed into the handler.
    :type kwargs: dict
    :param int priority: the higher the `priority`, the sooner this handler will
                         be called in reaction to the event, relative to the
                         other event handlers registered.
    :param scene: The scene to register this event on; if it is ``None``, then
                  it will be attached to the currently running scene.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._reg_internal(event_namespace, (WeakMethod(handler),),
                        args, kwargs, priority, False)

def register_dynamic(event_namespace, handler_string,
                     args=None, kwargs=None, priority=0, scene=None):
    """
    Similar to :func:`spyral.event.register` function, except that instead
    of passing in a function, you pass in the name of a property of this
    scene that holds a function.

    Example::

        class MyScene(Scene):
            def __init__(self):
                ...
                self.register_dynamic("orc.dies", "future_function")
                ...

    :param str event_namespace: The namespace of the event, e.g.
                                ``"input.mouse.left.click"`` or ``"pong.score"``.
    :param str handler: The name of an attribute on this scene that will hold
                        a function. The first argument to the function will be
                        the event.
    :param args: any additional arguments that need to be passed in
                 to the handler.
    :type args: sequence
    :param kwargs: any additional keyword arguments that need to be
                   passed into the handler.
    :type kwargs: dict
    :param int priority: the higher the `priority`, the sooner this handler will
                         be called in reaction to the event, relative to the
                         other event handlers registered.
    :param scene: The scene to register this event on; if it is ``None``, then
                  it will be attached to the currently running scene.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._reg_internal(event_namespace, (handler_string,),
                        args, kwargs, priority, True)

def register_multiple(event_namespace, handlers, args=None,
                      kwargs=None, priority=0, scene=None):
    """
    Similar to :func:`spyral.event.register` function, except a sequence of
    `handlers` are be given instead of just one.

    :param str event_namespace: the namespace of the event, e.g.
                            ``"input.mouse.left.click"`` or ``"pong.score"``.
    :type event_namespace: string
    :param handler: A list of functions that will be run on this event.
    :type handler: list of functions
    :param args: any additional arguments that need to be passed in
                 to the handler.
    :type args: sequence
    :param kwargs: any additional keyword arguments that need to be
                   passed into the handler.
    :type kwargs: dict
    :param int priority: the higher the `priority`, the sooner this handler will
                         be called in reaction to the event, relative to the
                         other event handlers registered.
    :param scene: The scene to register this event on; if it is ``None``, then
                  it will be attached to the currently running scene.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._reg_internal(event_namespace, map(WeakMethod, handlers),
                        args, kwargs, priority, False)

def register_multiple_dynamic(event_namespace, handler_strings, args=None,
                              kwargs=None, priority=0, scene=None):
    """
    Similar to :func:`spyral.Scene.register` function, except a sequence of
    strings representing handlers can be given instead of just one.

    :param event_namespace: the namespace of the event, e.g.
                            ``"input.mouse.left.click"`` or ``"pong.score"``.
    :type event_namespace: string
    :param handler: A list of names of an attribute on this scene that will
                    hold a function. The first argument to the function will
                    be the event.
    :type handler: list of strings
    :param args: any additional arguments that need to be passed in
                 to the handler.
    :type args: sequence
    :param kwargs: any additional keyword arguments that need to be
                   passed into the handler.
    :type kwargs: dict
    :param int priority: the higher the `priority`, the sooner this handler will
                         be called in reaction to the event, relative to the
                         other event handlers registered.
    :param scene: The scene to register this event on; if it is ``None``, then
                  it will be attached to the currently running scene.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._reg_internal(event_namespace, handler_strings,
                        args, kwargs, priority, True)

def unregister(event_namespace, handler, scene=None):
    """
    Unregisters a registered handler for that namespace. Dynamic handler
    strings are supported as well.

    :param str event_namespace: An event namespace
    :param handler: The handler to unregister.
    :type handler: a function or string.
    :param scene: The scene to unregister the event; if it is ``None``, then
                  it will be attached to the currently running scene.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._unregister(event_namespace, handler)

def clear_namespace(namespace, scene=None):
    """
    Clears all handlers from namespaces that are at least as specific as the
    provided `namespace`.

    :param str namespace: The complete namespace.
    :param scene: The scene to clear the namespace of; if it is ``None``, then
                  it will be attached to the currently running scene.
    :type scene: :class:`Scene <spyral.Scene>` or ``None``
    """
    if scene is None:
        scene = spyral._get_executing_scene()
    scene._clear_namespace(namespace)

def _pygame_to_spyral(event):
    """
    Convert a Pygame event to a Spyral event, correctly converting arguments to
    attributes.
    """
    event_attrs = _TYPE_TO_ATTRS[event.type]
    event_type = _TYPE_TO_TYPE[event.type]
    e = Event()
    for attr in event_attrs:
        setattr(e, attr, getattr(event, attr))
    if event_type.startswith("input"):
        setattr(e, "type", event_type.split(".")[-1])
    if event_type.startswith('input.keyboard'):
        k = keys.reverse_map.get(event.key, 'unknown')
        event_type += '.' + k
    if event_type.startswith('input.mouse.motion'):
        e.left, e.middle, e.right = map(bool, event.buttons)
    elif event_type.startswith('input.mouse'):
        try:
            m = MOUSE_MAP[event.button-1]
            setattr(e, "button", m)
        except IndexError:
            m = str(event.button)
        event_type += '.' + m
    if event_type.startswith('input.mouse'):
        e.pos = spyral.Vec2D(e.pos) / spyral.director.get_scene()._scale

    return (event_type, e)

class EventHandler(object):
    """
    Base event handler class.
    """
    def __init__(self):
        self._events = []
        self._mouse_pos = (0, 0)

    def tick(self):
        """
        Should be called at the beginning of update cycle. For the
        event handler which is part of a scene, this function will be
        called automatically. For any additional event handlers, you
        must call this function manually.
        """
        pass

    def get(self, types=[]):
        """
        Gets events from the event handler. Types is an optional
        iterable which has types which you would like to get.
        """
        try:
            types[0]
        except IndexError:
            pass
        except TypeError:
            types = (types,)

        if types == []:
            ret = self._events
            self._events = []
            return ret

        ret = [e for e in self._events if e['type'] in types]
        self._events = [e for e in self._events if e['type'] not in types]
        return ret


class LiveEventHandler(EventHandler):
    """
    An event handler which pulls events from the operating system.

    The optional output_file argument specifies the path to a file
    where the event handler will save a custom json file that can
    be used with the `ReplayEventHandler` to show replays of a
    game in action, or be used for other clever purposes.

    .. note::

        If you use the output_file parameter, this function will
        reseed the random number generator, save the seed used. It
        will then be restored by the ReplayEventHandler.
    """
    def __init__(self, output_file=None):
        EventHandler.__init__(self)
        self._save = output_file is not None
        if self._save:
            self._file = open(output_file, 'w')
            seed = os.urandom(4)
            info = {'random_seed': base64.encodestring(seed)}
            random.seed(seed)
            self._file.write(json.dumps(info) + "\n")

    def tick(self):
        mouse = pygame.mouse.get_pos()
        events = pygame.event.get()
        self._mouse_pos = mouse
        self._events.extend(events)
        # if self._save:
        #     d = {'mouse': mouse, 'events': events}
        #     self._file.write(json.dumps(d) + "\n")

    def __del__(self):
        if self._save:
            self._file.close()


class ReplayEventHandler(EventHandler):
    """
    An event handler which replays the events from a custom json
    file saved by the `LiveEventHandler`.
    """
    def __init__(self, input_file):
        EventHandler.__init__(self)
        self._file = open(input_file)
        info = json.loads(self._file.readline())
        random.seed(base64.decodestring(info['random_seed']))
        self.paused = False

    def pause(self):
        """
        Pauses the replay of the events, making tick() a noop until
        resume is called.
        """
        self.paused = True

    def resume(self):
        """
        Resumes the replay of events.
        """
        self.paused = False

    def tick(self):
        if self.paused:
            return
        try:
            d = json.loads(self._file.readline())
        except ValueError:
            spyral.director.pop()
        events = d['events']
        events = [EventDict(e) for e in events]
        self._mouse_pos = d['mouse']
        self._events.extend(events)

class Mods(object):
    def __init__(self):
        self.none = pygame.KMOD_NONE
        self.lshift = pygame.KMOD_LSHIFT
        self.rshift = pygame.KMOD_RSHIFT
        self.shift = pygame.KMOD_SHIFT
        self.caps = pygame.KMOD_CAPS
        self.ctrl = pygame.KMOD_CTRL
        self.lctrl = pygame.KMOD_LCTRL
        self.rctrl = pygame.KMOD_RCTRL
        self.lalt = pygame.KMOD_LALT
        self.ralt = pygame.KMOD_RALT
        self.alt = pygame.KMOD_ALT

class Keys(object):

    def __init__(self):
        self.reverse_map = {}
        self.load_keys_from_file(spyral._get_spyral_path() +
                                 'resources/default_key_mappings.txt')
        self._fix_bad_names([("return", "enter"),
                             ("break", "brk")])

    def _fix_bad_names(self, renames):
        """
        Used to replace any binding names with non-python keywords.
        """
        for original, new in renames:
            setattr(self, new, getattr(self, original))
            delattr(self, original)


    def load_keys_from_file(self, filename):
        fp = open(filename)
        key_maps = fp.readlines()
        fp.close()
        for single_mapping in key_maps:
            mapping = single_mapping[:-1].split(' ')
            if len(mapping) == 2:
                if mapping[1][0:2] == '0x':
                    setattr(self, mapping[0], int(mapping[1], 16))
                    self.reverse_map[int(mapping[1], 16)] = mapping[0]
                else:
                    setattr(self, mapping[0], int(mapping[1]))
                    self.reverse_map[int(mapping[1])] = mapping[0]

    def add_key_mapping(self, name, number):
        setattr(self, name, number)

keys = Keys()
mods = Mods()