# Copyright (C) 2006-2007 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import os

import gobject

from sugar.bundle.activitybundle import ActivityBundle
from sugar.bundle.bundle import MalformedBundleException
from sugar import env
from sugar import util

# http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html
def _get_data_dirs():
    if os.environ.has_key('XDG_DATA_DIRS'):
        return os.environ['XDG_DATA_DIRS'].split(':')
    else:
        return [ '/usr/local/share/', '/usr/share/' ]

def _load_mime_defaults():
    defaults = {}

    f = open(env.get_data_path('mime.defaults'), 'r')
    for line in f.readlines():
        line = line.strip()
        if line and not line.startswith('#'):
            mime = line[:line.find(' ')]
            handler = line[line.rfind(' ') + 1:]
            defaults[mime] = handler
    f.close()

    return defaults

class _ServiceManager(object):
    """Internal class responsible for creating dbus service files
    
    DBUS services are defined in files which bind a service name 
    to the name of an executable which provides the service name.
    
    In Sugar, the service files are automatically generated from 
    the activity registry (by this class).  When an activity's 
    dbus launch service is requested, dbus will launch the 
    specified executable in order to allow it to provide the 
    requested activity-launching service.
    
    In the case of activities which provide a "class", instead of 
    an "exec" attribute in their activity.info, the 
    sugar-activity-factory script is used with an appropriate 
    argument to service that bundle.
    """
    SERVICE_DIRECTORY = '~/.local/share/dbus-1/services'
    def __init__(self):
        service_dir = os.path.expanduser(self.SERVICE_DIRECTORY)
        if not os.path.isdir(service_dir):
            os.makedirs(service_dir)

        self._path = service_dir

    def add(self, bundle):
        util.write_service(bundle.get_service_name(),
                           bundle.get_command(), self._path)

class BundleRegistry(gobject.GObject):
    """Service that tracks the available activity bundles"""

    __gsignals__ = {
        'bundle-added': (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
                        ([gobject.TYPE_PYOBJECT]))
    }

    def __init__(self):
        gobject.GObject.__init__(self)
        
        self._bundles = []
        self._search_path = []
        self._service_manager = _ServiceManager()
        self._mime_defaults = _load_mime_defaults()

    def get_bundle(self, service_name):
        """Returns an bundle given his service name"""
        for bundle in self._bundles:
            if bundle.get_service_name() == service_name:
                return bundle
        return None

    def add_search_path(self, path):
        """Add a directory to the bundles search path"""
        self._search_path.append(path)
        self._scan_directory(path)
    
    def __iter__(self):
        return self._bundles.__iter__()

    def _scan_directory(self, path):
        if not os.path.isdir(path):
            return

        # Sort by mtime to ensure a stable activity order
        bundles = {}
        for f in os.listdir(path):
            if not f.endswith('.activity'):
                continue
            bundle_dir = os.path.join(path, f)
            if os.path.isdir(bundle_dir):
                bundles[bundle_dir] = os.stat(bundle_dir).st_mtime

        bundle_dirs = bundles.keys()
        bundle_dirs.sort(lambda d1,d2: cmp(bundles[d1], bundles[d2]))
        for dir in bundle_dirs:
            self.add_bundle(dir)

    def add_bundle(self, bundle_path):
        try:
            bundle = ActivityBundle(bundle_path)
        except MalformedBundleException:
            return False

        self._bundles.append(bundle)
        self._service_manager.add(bundle)
        self.emit('bundle-added', bundle)
        return True

    def get_activities_for_type(self, mime_type):
        result = []
        for bundle in self._bundles:
            if bundle.get_mime_types() and mime_type in bundle.get_mime_types():
                if self.get_default_for_type(mime_type) == bundle.get_service_name():
                    result.insert(0, bundle)
                else:
                    result.append(bundle)
        return result

    def get_default_for_type(self, mime_type):
        if self._mime_defaults.has_key(mime_type):
            return self._mime_defaults[mime_type]
        else:
            return None

def get_registry():
    return _bundle_registry

_bundle_registry = BundleRegistry()

for path in _get_data_dirs():
    bundles_path = os.path.join(path, 'activities')
    _bundle_registry.add_search_path(bundles_path)

_bundle_registry.add_search_path(env.get_user_activities_path())