# Module:   notify
# Date:     2nd March 2009
# Author:   James Mills, prologic at shortcircuit dot net dot au

"""File Notification Support

A Component wrapping the inotify API using the pyinotify library.
"""

try:
    from pyinotify import IN_UNMOUNT
    from pyinotify import WatchManager, Notifier, ALL_EVENTS
    from pyinotify import IN_ACCESS, IN_MODIFY, IN_ATTRIB, IN_CLOSE_WRITE
    from pyinotify import IN_CREATE, IN_DELETE, IN_DELETE_SELF, IN_MOVE_SELF
    from pyinotify import IN_CLOSE_NOWRITE, IN_OPEN, IN_MOVED_FROM, IN_MOVED_TO
except ImportError:
    raise Exception("No pyinotify support available. Is pyinotify installed?")

from circuits.core.utils import findcmp
from circuits.core import handler, BaseComponent
from circuits.core.pollers import BasePoller, Poller

from .events import accessed, closed, created, deleted, modified, moved, opened, ready, unmounted

MASK = ALL_EVENTS

EVENT_MAP = {
    IN_MOVED_TO:        moved,
    IN_MOVE_SELF:       moved,
    IN_MOVED_FROM:      moved,
    IN_CLOSE_WRITE:     closed,
    IN_CLOSE_NOWRITE:   closed,
    IN_OPEN:            opened,
    IN_DELETE_SELF:     deleted,
    IN_DELETE:          deleted,
    IN_CREATE:          created,
    IN_ACCESS:          accessed,
    IN_MODIFY:          modified,
    IN_ATTRIB:          modified,
    IN_UNMOUNT:         unmounted,
}


class Notify(BaseComponent):

    channel = "notify"

    def __init__(self, channel=channel):
        super(Notify, self).__init__(channel=channel)

        self._poller = None
        self._wm = WatchManager()
        self._notifier = Notifier(self._wm, self._on_process_events)

    def _on_process_events(self, event):
        dir = event.dir
        mask = event.mask
        path = event.path
        name = event.name
        pathname = event.pathname

        for k, v in EVENT_MAP.items():
            if mask & k:
                self.fire(v(name, path, pathname, dir))

    def add_path(self, path, mask=None, recursive=False):
        mask = mask or MASK
        self._wm.add_watch(path, mask, rec=recursive)

    def remove_path(self, path, recursive=False):
        wd = self._wm.get_wd(path)
        if wd:
            self._wm.rm_watch(wd, rec=recursive)

    @handler("ready")
    def _on_ready(self, component):
        self._poller.addReader(self, self._notifier._fd)

    @handler("registered", channel="*")
    def _on_registered(self, component, manager):
        if self._poller is None:
            if isinstance(component, BasePoller):
                self._poller = component
                self.fire(ready(self))
            else:
                if component is not self:
                    return
                component = findcmp(self.root, BasePoller)
                if component is not None:
                    self._poller = component
                    self.fire(ready(self))
                else:
                    self._poller = Poller().register(self)
                    self.fire(ready(self))

    @handler("started", channel="*", priority=1)
    def _on_started(self, event, component):
        if self._poller is None:
            self._poller = Poller().register(self)
            self.fire(ready(self))
            event.stop()

    @handler("_read", priority=1)
    def __on_read(self, fd):
        self._notifier.read_events()
        self._notifier.process_events()