#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2011 Yesudeep Mangalapilly <yesudeep@gmail.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""
:module: watchdog.events
:synopsis: File system events and event handlers.
:author: Yesudeep Mangalapilly <yesudeep@gmail.com>

Event Classes
-------------
.. autoclass:: FileSystemEvent
   :members:
   :show-inheritance:
   :inherited-members:

.. autoclass:: FileSystemMovedEvent
   :members:
   :show-inheritance:

.. autoclass:: FileMovedEvent
   :members:
   :show-inheritance:

.. autoclass:: DirMovedEvent
   :members:
   :show-inheritance:

.. autoclass:: FileModifiedEvent
   :members:
   :show-inheritance:

.. autoclass:: DirModifiedEvent
   :members:
   :show-inheritance:

.. autoclass:: FileCreatedEvent
   :members:
   :show-inheritance:

.. autoclass:: DirCreatedEvent
   :members:
   :show-inheritance:

.. autoclass:: FileDeletedEvent
   :members:
   :show-inheritance:

.. autoclass:: DirDeletedEvent
   :members:
   :show-inheritance:


Event Handler Classes
---------------------
.. autoclass:: FileSystemEventHandler
   :members:
   :show-inheritance:

.. autoclass:: PatternMatchingEventHandler
   :members:
   :show-inheritance:

.. autoclass:: LoggingEventHandler
   :members:
   :show-inheritance:

"""

import os.path
import logging

from pathtools.path import absolute_path
from pathtools.patterns import match_any_paths
from watchdog.utils import has_attribute


EVENT_TYPE_MOVED = 'moved'
EVENT_TYPE_DELETED = 'deleted'
EVENT_TYPE_CREATED = 'created'
EVENT_TYPE_MODIFIED = 'modified'

class FileSystemEvent(object):
    """
    Immutable type that represents a file system event that is triggered
    when a change occurs on the monitored file system.

    All FileSystemEvent objects are required to be immutable and hence
    can be used as keys in dictionaries or be added to sets.
    """

    def __init__(self, event_type, src_path, is_directory=False):
        self._src_path = src_path
        self._is_directory = is_directory
        self._event_type = event_type

    @property
    def is_directory(self):
        """True if event was emitted for a directory; False otherwise."""
        return self._is_directory

    @property
    def src_path(self):
        """Source path of the file system object that triggered this event."""
        return self._src_path

    @property
    def event_type(self):
        """The type of the event as a string."""
        return self._event_type

    def __str__(self):
        return self.__repr__()

    def __repr__(self):
        return "<%(class_name)s: event_type=%(event_type)s, \
src_path=%(src_path)s, is_directory=%(is_directory)s>" %\
               dict(class_name=self.__class__.__name__,
                    event_type=self.event_type,
                    src_path=self.src_path,
                    is_directory=self.is_directory)

    # Used for comparison of events.
    @property
    def key(self):
        return (self.event_type,
                self.src_path,
                self.is_directory)

    def __eq__(self, event):
        return self.key == event.key

    def __ne__(self, event):
        return self.key != event.key

    def __hash__(self):
        return hash(self.key)


class FileSystemMovedEvent(FileSystemEvent):
    """
    File system event representing any kind of file system movement.
    """

    def __init__(self, src_path, dest_path, is_directory):
        super(FileSystemMovedEvent, self).__init__(event_type=EVENT_TYPE_MOVED,
                                                   src_path=src_path,
                                                   is_directory=is_directory)

        self._dest_path = dest_path

    @property
    def dest_path(self):
        """The destination path of the move event."""
        return self._dest_path

    # Used for hashing this as an immutable object.
    def _key(self):
        return (self.event_type,
                self.src_path,
                self.dest_path,
                self.is_directory)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s, dest_path=%(dest_path)s, \
is_directory=%(is_directory)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path,
                    dest_path=self.dest_path,
                    is_directory=self.is_directory)


    # File events.

class FileDeletedEvent(FileSystemEvent):
    """File system event representing file deletion on the file system."""

    def __init__(self, src_path):
        super(FileDeletedEvent, self).__init__(event_type=EVENT_TYPE_DELETED,
                                               src_path=src_path)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path)

class FileModifiedEvent(FileSystemEvent):
    """File system event representing file modification on the file system."""

    def __init__(self, src_path):
        super(FileModifiedEvent, self).__init__(event_type=EVENT_TYPE_MODIFIED,
                                                src_path=src_path)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path)


class FileCreatedEvent(FileSystemEvent):
    """File system event representing file creation on the file system."""

    def __init__(self, src_path):
        super(FileCreatedEvent, self).__init__(event_type=EVENT_TYPE_CREATED,
                                               src_path=src_path)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path)


class FileMovedEvent(FileSystemMovedEvent):
    """File system event representing file movement on the file system."""

    def __init__(self, src_path, dest_path):
        super(FileMovedEvent, self).__init__(src_path=src_path,
                                             dest_path=dest_path,
                                             is_directory=False)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s, \
dest_path=%(dest_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path,
                    dest_path=self.dest_path)


    # Directory events.

class DirDeletedEvent(FileSystemEvent):
    """File system event representing directory deletion on the file system."""

    def __init__(self, src_path):
        super(DirDeletedEvent, self).__init__(event_type=EVENT_TYPE_DELETED,
                                              src_path=src_path,
                                              is_directory=True)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path)


class DirModifiedEvent(FileSystemEvent):
    """
    File system event representing directory modification on the file system.
    """

    def __init__(self, src_path):
        super(DirModifiedEvent, self).__init__(event_type=EVENT_TYPE_MODIFIED,
                                               src_path=src_path,
                                               is_directory=True)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path)


class DirCreatedEvent(FileSystemEvent):
    """File system event representing directory creation on the file system."""

    def __init__(self, src_path):
        super(DirCreatedEvent, self).__init__(event_type=EVENT_TYPE_CREATED,
                                              src_path=src_path,
                                              is_directory=True)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path)


class DirMovedEvent(FileSystemMovedEvent):
    """File system event representing directory movement on the file system."""

    def __init__(self, src_path, dest_path):
        super(DirMovedEvent, self).__init__(src_path=src_path,
                                            dest_path=dest_path,
                                            is_directory=True)

    def __repr__(self):
        return "<%(class_name)s: src_path=%(src_path)s, \
dest_path=%(dest_path)s>" %\
               dict(class_name=self.__class__.__name__,
                    src_path=self.src_path,
                    dest_path=self.dest_path)


    def sub_moved_events(self, _walker=os.walk):
        """Generates moved events for file sytem objects within the
        moved directory.

        :param _walker:
            Walker used to walk directory trees :func:`os.walk` style. Sanity
            tests use this parameter to inject a mock walker that behaves like
            :func:`os.walk`.
        :returns:
            iterable of event objects of type :class:`FileMovedEvent` and
            :class:`DirMovedEvent`.
        """
        return list(
                _generate_sub_moved_events_for(self.src_path, self.dest_path,
                                               _walker=_walker))


class FileSystemEventHandler(object):
    """Base file system event handler that you can override methods from.
    """

    def dispatch(self, event):
        """Dispatches events to the appropriate methods.

        :param event:
            The event object representing the file system event.
        :type event:
            :class:`FileSystemEvent`
        """
        self.on_any_event(event)
        _method_map = {
            EVENT_TYPE_MODIFIED: self.on_modified,
            EVENT_TYPE_MOVED: self.on_moved,
            EVENT_TYPE_CREATED: self.on_created,
            EVENT_TYPE_DELETED: self.on_deleted,
        }
        event_type = event.event_type
        _method_map[event_type](event)

    def on_any_event(self, event):
        """Catch-all event handler.

        :param event:
            The event object representing the file system event.
        :type event:
            :class:`FileSystemEvent`
        """

    def on_moved(self, event):
        """Called when a file or a directory is moved or renamed.

        :param event:
            Event representing file/directory movement.
        :type event:
            :class:`DirMovedEvent` or :class:`FileMovedEvent`
        """

    def on_created(self, event):
        """Called when a file or directory is created.

        :param event:
            Event representing file/directory creation.
        :type event:
            :class:`DirCreatedEvent` or :class:`FileCreatedEvent`
        """


    def on_deleted(self, event):
        """Called when a file or directory is deleted.

        :param event:
            Event representing file/directory deletion.
        :type event:
            :class:`DirDeletedEvent` or :class:`FileDeletedEvent`
        """

    def on_modified(self, event):
        """Called when a file or directory is modified.

        :param event:
            Event representing file/directory modification.
        :type event:
            :class:`DirModifiedEvent` or :class:`FileModifiedEvent`
        """


class PatternMatchingEventHandler(FileSystemEventHandler):
    """
    Matches given patterns with file paths associated with occurring events.
    """

    def __init__(self, patterns=None, ignore_patterns=None,
                 ignore_directories=False, case_sensitive=False):
        super(PatternMatchingEventHandler, self).__init__()

        self._patterns = patterns
        self._ignore_patterns = ignore_patterns
        self._ignore_directories = ignore_directories
        self._case_sensitive = case_sensitive

    @property
    def patterns(self):
        """
        (Read-only)
        Patterns to allow matching event paths.
        """
        return self._patterns

    @property
    def ignore_patterns(self):
        """
        (Read-only)
        Patterns to ignore matching event paths.
        """
        return self._ignore_patterns

    @property
    def ignore_directories(self):
        """
        (Read-only)
        ``True`` if directories should be ignored; ``False`` otherwise.
        """
        return self._ignore_directories

    @property
    def case_sensitive(self):
        """
        (Read-only)
        ``True`` if path names should be matched sensitive to case; ``False``
        otherwise.
        """
        return self._case_sensitive

    def dispatch(self, event):
        """Dispatches events to the appropriate methods.

        :param event:
            The event object representing the file system event.
        :type event:
            :class:`FileSystemEvent`
        """
        if self.ignore_directories and event.is_directory:
            return

        if has_attribute(event, 'dest_path'):
            paths = [event.src_path, event.dest_path]
        else:
            paths = [event.src_path]

        if match_any_paths(paths,
                           included_patterns=self.patterns,
                           excluded_patterns=self.ignore_patterns,
                           case_sensitive=self.case_sensitive):
            self.on_any_event(event)
            _method_map = {
                EVENT_TYPE_MODIFIED: self.on_modified,
                EVENT_TYPE_MOVED: self.on_moved,
                EVENT_TYPE_CREATED: self.on_created,
                EVENT_TYPE_DELETED: self.on_deleted,
            }
            event_type = event.event_type
            _method_map[event_type](event)


class LoggingEventHandler(FileSystemEventHandler):
    """Logs all the events captured."""

    def on_moved(self, event):
        super(LoggingEventHandler, self).on_moved(event)

        what = 'directory' if event.is_directory else 'file'
        logging.info("Moved %s: from %s to %s", what, event.src_path,
                     event.dest_path)

    def on_created(self, event):
        super(LoggingEventHandler, self).on_created(event)

        what = 'directory' if event.is_directory else 'file'
        logging.info("Created %s: %s", what, event.src_path)

    def on_deleted(self, event):
        super(LoggingEventHandler, self).on_deleted(event)

        what = 'directory' if event.is_directory else 'file'
        logging.info("Deleted %s: %s", what, event.src_path)

    def on_modified(self, event):
        super(LoggingEventHandler, self).on_modified(event)

        what = 'directory' if event.is_directory else 'file'
        logging.info("Modified %s: %s", what, event.src_path)


class LoggingFileSystemEventHandler(LoggingEventHandler):
    """For backwards-compatibility. Please use :class:`LoggingEventHandler` instead."""


def _generate_sub_moved_events_for(src_dir_path, dest_dir_path,
                                   _walker=os.walk):
    """Generates an event list of :class:`DirMovedEvent` and :class:`FileMovedEvent`
    objects for all the files and directories within the given moved directory
    that were moved along with the directory.

    :param src_dir_path:
        The source path of the moved directory.
    :param dest_dir_path:
        The destination path of the moved directory.
    :param _walker:
        Walker used to walk directory trees :func:`os.walk` style. Sanity tests
        use this parameter to inject a mock walker that behaves like
        :func:`os.walk`.
    :returns:
        An iterable of file system events of type :class:`DirMovedEvent` and
        :class:`FileMovedEvent`.
    """
    src_dir_path = absolute_path(src_dir_path)
    dest_dir_path = absolute_path(dest_dir_path)
    for root, directories, filenames in _walker(dest_dir_path):
        for directory in directories:
            full_path = os.path.join(root, directory)
            renamed_path = full_path.replace(dest_dir_path, src_dir_path)
            yield DirMovedEvent(renamed_path, full_path)
        for filename in filenames:
            full_path = os.path.join(root, filename)
            renamed_path = full_path.replace(dest_dir_path, src_dir_path)
            yield FileMovedEvent(renamed_path, full_path)