1 files changed, 226 insertions, 0 deletions
diff --git a/src/EventManager.py b/src/EventManager.py
new file mode 100644
index 00000000..604ae337
--- /dev/null
+++ b/src/EventManager.py
@@ -0,0 +1,226 @@
+import itertools, time, traceback
+
+PRIORITY_URGENT = 0
+PRIORITY_HIGH = 1
+PRIORITY_MEDIUM = 2
+PRIORITY_LOW = 3
+PRIORITY_MONITOR = 4
+
+DEFAULT_PRIORITY = PRIORITY_MEDIUM
+DEFAULT_DELIMITER = "."
+
+class Event(object):
+    def __init__(self, bot, name, **kwargs):
+        self.bot = bot
+        self.name = name
+        self.kwargs = kwargs
+        self.eaten = False
+    def __getitem__(self, key):
+        return self.kwargs[key]
+    def get(self, key, default=None):
+        return self.kwargs.get(key, default)
+    def __contains__(self, key):
+        return key in self.kwargs
+    def eat(self):
+        self.eaten = True
+
+class EventCallback(object):
+    def __init__(self, function, bot, priority, kwargs):
+        self.function = function
+        self.bot = bot
+        self.priority = priority
+        self.kwargs = kwargs
+    def call(self, event):
+        return self.function(event)
+
+class MultipleEventHook(object):
+    def __init__(self):
+        self._event_hooks = set([])
+    def _add(self, event_hook):
+        self._event_hooks.add(event_hook)
+
+    def hook(self, function, **kwargs):
+        for event_hook in self._event_hooks:
+            event_hook.hook(function, **kwargs)
+
+    def call_limited(self, maximum, **kwargs):
+        returns = []
+        for event_hook in self._event_hooks:
+            returns.append(event_hook.call_limited(maximum, **kwargs))
+        return returns
+    def call(self, **kwargs):
+        returns = []
+        for event_hook in self._event_hooks:
+            returns.append(event_hook.call(**kwargs))
+        return returns
+
+class EventHookContext(object):
+    def __init__(self, parent, context):
+        self._parent = parent
+        self.context = context
+    def hook(self, function, priority=DEFAULT_PRIORITY, replay=False,
+            **kwargs):
+        self._parent._context_hook(self.context, function, priority, replay,
+            kwargs)
+    def on(self, subevent, *extra_subevents, delimiter=DEFAULT_DELIMITER):
+        return self._parent._context_on(self.context, subevent,
+            extra_subevents, delimiter)
+    def call_for_result(self, default=None, **kwargs):
+        return self._parent.call_for_result(default, **kwargs)
+    def assure_call(self, **kwargs):
+        self._parent.assure_call(**kwargs)
+    def call(self, **kwargs):
+        return self._parent.call(**kwargs)
+    def call_limited(self, maximum, **kwargs):
+        return self._parent.call_limited(maximum, **kwargs)
+    def get_hooks(self):
+        return self._parent.get_hooks()
+    def get_children(self):
+        return self._parent.get_children()
+
+class EventHook(object):
+    def __init__(self, bot, name=None, parent=None):
+        self.bot = bot
+        self.name = name
+        self.parent = parent
+        self._children = {}
+        self._hooks = []
+        self._stored_events = []
+        self._context_hooks = {}
+
+    def _make_event(self, kwargs):
+        return Event(self.bot, self.name, **kwargs)
+
+    def _get_path(self):
+        path = []
+        parent = self
+        while not parent == None and not parent.name == None:
+            path.append(parent.name)
+            parent = parent.parent
+        return DEFAULT_DELIMITER.join(path[::-1])
+
+    def new_context(self, context):
+        return EventHookContext(self, context)
+
+    def hook(self, function, priority=DEFAULT_PRIORITY, replay=False,
+            **kwargs):
+        self._hook(function, None, priority, replay, kwargs)
+    def _context_hook(self, context, function, priority, replay, kwargs):
+        self._hook(function, context, priority, replay, kwargs)
+    def _hook(self, function, context, priority, replay, kwargs):
+        callback = EventCallback(function, self.bot, priority, kwargs)
+
+        if context == None:
+            self._hooks.append(callback)
+        else:
+            if not context in self._context_hooks:
+                self._context_hooks[context] = []
+            self._context_hooks[context].append(callback)
+
+        if replay and not self._stored_events == None:
+            for kwargs in self._stored_events:
+                self._call(kwargs)
+        self._stored_events = None
+
+    def on(self, subevent, *extra_subevents, delimiter=DEFAULT_DELIMITER):
+        return self._on(subevent, extra_subevents, None, delimiter)
+    def _context_on(self, context, subevent, extra_subevents,
+            delimiter=DEFAULT_DELIMITER):
+        return self._on(subevent, extra_subevents, context, delimiter)
+    def _on(self, subevent, extra_subevents, context, delimiter):
+        if delimiter in subevent:
+            event_chain = subevent.split(delimiter)
+            event_obj = self
+            for event_name in event_chain:
+                event_obj = event_obj.get_child(event_name)
+            if not context == None:
+                return event_obj.new_context(context)
+            return event_obj
+
+        if extra_subevents:
+            multiple_event_hook = MultipleEventHook()
+            for extra_subevent in (subevent,)+extra_subevents:
+                child = self.get_child(extra_subevent)
+                if not context == None:
+                    child = child.new_context(context)
+                multiple_event_hook._add(child)
+            return multiple_event_hook
+
+        child = self.get_child(subevent)
+        if not context == None:
+            child = child.new_context(context)
+        return child
+
+    def call_for_result(self, default=None, **kwargs):
+        results = self.call_limited(1, **kwargs)
+        return default if not len(results) else results[0]
+    def assure_call(self, **kwargs):
+        if not self._stored_events == None:
+            self._stored_events.append(kwargs)
+        else:
+            self._call(kwargs)
+    def call(self, **kwargs):
+        return self._call(kwargs)
+    def call_limited(self, maximum, **kwargs):
+        return self._call(kwargs, maximum=maximum)
+    def _call(self, kwargs, maximum=None):
+        event_path = self._get_path()
+        self.bot.log.debug("calling event: \"%s\" (params: %s)",
+            [event_path, kwargs])
+        start = time.monotonic()
+
+        event = self._make_event(kwargs)
+        returns = []
+        for hook in self.get_hooks()[:maximum]:
+            if event.eaten:
+                break
+            try:
+                returns.append(hook.call(event))
+            except Exception as e:
+                traceback.print_exc()
+                self.bot.log.error("failed to call event \"%s\"", [
+                    event_path], exc_info=True)
+
+        total_milliseconds = (time.monotonic() - start) * 1000
+        self.bot.log.debug("event \"%s\" called in %fms", [
+            event_path, total_milliseconds])
+
+        self.check_purge()
+
+        return returns
+
+    def get_child(self, child_name):
+        child_name_lower = child_name.lower()
+        if not child_name_lower in self._children:
+            self._children[child_name_lower] = EventHook(self.bot,
+                child_name_lower, self)
+        return self._children[child_name_lower]
+    def remove_child(self, child_name):
+        child_name_lower = child_name.lower()
+        if child_name_lower in self._children:
+            del self._children[child_name_lower]
+
+    def check_purge(self):
+        if self.is_empty() and not self.parent == None:
+            self.parent.remove_child(self.name)
+            self.parent.check_purge()
+
+    def remove_context(self, context):
+        del self._context_hooks[context]
+    def has_context(self, context):
+        return context in self._context_hooks
+    def purge_context(self, context):
+        if self.has_context(context):
+            self.remove_context(context)
+
+        for child_name in self.get_children()[:]:
+            child = self.get_child(child_name)
+            child.purge_context(context)
+
+    def get_hooks(self):
+        return sorted(self._hooks + sum(self._context_hooks.values(), []),
+            key=lambda e: e.priority)
+    def get_children(self):
+        return list(self._children.keys())
+    def is_empty(self):
+        return len(self.get_hooks() + self.get_children()) == 0