# Copyright (c) 2013 AnsibleWorks, Inc.
#
# This file is part of Ansible Commander.
# 
# Ansible Commander 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, version 3 of the License. 
#
# Ansible Commander 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 Ansible Commander. If not, see <http://www.gnu.org/licenses/>.


import os
from django.conf import settings
from django.db import models, DatabaseError
from django.db.models import CASCADE, SET_NULL, PROTECT
from django.db.models.signals import post_save
from django.dispatch import receiver
from django.utils.translation import ugettext_lazy as _
from django.core.urlresolvers import reverse
from django.contrib.auth.models import User
from django.utils.timezone import now
import exceptions
from jsonfield import JSONField
from djcelery.models import TaskMeta
from rest_framework.authtoken.models import Token
import yaml

# TODO: jobs and events model TBD
# TODO: reporting model TBD

PERM_INVENTORY_ADMIN  = 'admin'
PERM_INVENTORY_READ   = 'read'
PERM_INVENTORY_WRITE  = 'write'
PERM_INVENTORY_DEPLOY = 'run'
PERM_INVENTORY_CHECK  = 'check'

JOB_TYPE_CHOICES = [
    (PERM_INVENTORY_DEPLOY, _('Run')),
    (PERM_INVENTORY_CHECK, _('Check')),
]

PERMISSION_TYPES = [
    PERM_INVENTORY_ADMIN,
    PERM_INVENTORY_READ,
    PERM_INVENTORY_WRITE,
    PERM_INVENTORY_DEPLOY,
    PERM_INVENTORY_CHECK,
]

PERMISSION_TYPES_ALLOWING_INVENTORY_READ = [
    PERM_INVENTORY_ADMIN,
    PERM_INVENTORY_WRITE,
    PERM_INVENTORY_READ,
]

PERMISSION_TYPES_ALLOWING_INVENTORY_WRITE = [
    PERM_INVENTORY_ADMIN,
    PERM_INVENTORY_WRITE,
]

PERMISSION_TYPES_ALLOWING_INVENTORY_ADMIN = [
    PERM_INVENTORY_ADMIN,
]

# FIXME: TODO: make sure all of these are used and consistent
PERMISSION_TYPE_CHOICES = [
    (PERM_INVENTORY_READ, _('Read Inventory')),
    (PERM_INVENTORY_WRITE, _('Edit Inventory')),
    (PERM_INVENTORY_ADMIN, _('Administrate Inventory')),
    (PERM_INVENTORY_DEPLOY, _('Deploy To Inventory')),
    (PERM_INVENTORY_CHECK, _('Deploy To Inventory (Dry Run)')),
]

class EditHelper(object):

    @classmethod
    def illegal_changes(cls, request, obj, model_class):
        ''' have any illegal changes been made (for a PUT request)? '''
        can_admin = model_class.can_user_administrate(request.user, obj, request.DATA)
        if (not can_admin) or (can_admin == 'partial'):
            check_fields = model_class.admin_only_edit_fields
            changed = cls.fields_changed(check_fields, obj, request.DATA)
            if len(changed.keys()) > 0:
                return True
        return False

    @classmethod
    def fields_changed(cls, fields, obj, data):
        ''' return the fields that would be changed by a prospective PUT operation '''
        changed = {}
        for f in fields:
            left = getattr(obj, f, None)
            if left is None:
                raise Exception("internal error, %s is not a member of %s" % (f, obj))
            right = data.get(f, None)
            if (right is not None) and (left != right):
                changed[f] = (left, right)
        return changed

class UserHelper(object):

    # fields that the user themselves cannot edit, but are not actually read only
    admin_only_edit_fields = ('last_name', 'first_name', 'username', 'is_active', 'is_superuser')

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        ''' a user can be administrated if they are themselves, or by org admins or superusers '''
        if user == obj:
            return 'partial'
        if user.is_superuser:
            return True
        matching_orgs = obj.organizations.filter(admins__in = [user]).count()
        return matching_orgs

    @classmethod
    def can_user_read(cls, user, obj):
        ''' a user can be read if they are on the same team or can be administrated '''
        matching_teams = user.teams.filter(users__in = [ user ]).count()
        return matching_teams or cls.can_user_administrate(user, obj, None)

    @classmethod
    def can_user_delete(cls, user, obj):
        if user.is_superuser:
            return True
        matching_orgs = obj.organizations.filter(admins__in = [user]).count()
        return matching_orgs

    @classmethod
    def can_user_attach(cls, user, obj, sub_obj, relationship_type, data):
        if type(sub_obj) != User:
            if not sub_obj.can_user_read(user, sub_obj):
                return False
        rc = cls.can_user_administrate(user, obj, None)
        if not rc:
            return False
        return sub_obj.__class__.can_user_read(user, sub_obj)

    @classmethod
    def can_user_unattach(cls, user, obj, sub_obj, relationship_type):
        return cls.can_user_administrate(user, obj, None)

class PrimordialModel(models.Model):
    '''
    common model for all object types that have these standard fields
    must use a subclass CommonModel or CommonModelNameNotUnique though
    as this lacks a name field.
    '''

    class Meta:
        abstract = True

    description   = models.TextField(blank=True, default='')
    created_by    = models.ForeignKey('auth.User', on_delete=SET_NULL, null=True, related_name='%s(class)s_created', editable=False) # not blank=False on purpose for admin!
    creation_date = models.DateField(auto_now_add=True)
    tags          = models.ManyToManyField('Tag', related_name='%(class)s_by_tag', blank=True)
    audit_trail   = models.ManyToManyField('AuditTrail', related_name='%(class)s_by_audit_trail', blank=True)
    active        = models.BooleanField(default=True)

    def __unicode__(self):
        return unicode("%s-%s"% (self.name, self.id))

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        # FIXME: do we want a seperate method to override put?  This is kind of general purpose
        raise exceptions.NotImplementedError()

    @classmethod
    def can_user_delete(cls, user, obj):
        raise exceptions.NotImplementedError()

    @classmethod
    def can_user_read(cls, user, obj):
        raise exceptions.NotImplementedError()

    @classmethod
    def can_user_add(cls, user, data):
        return user.is_superuser

    @classmethod
    def can_user_attach(cls, user, obj, sub_obj, relationship_type, data):
        ''' whether you can add sub_obj to obj using the relationship type in a subobject view '''
        if type(sub_obj) != User:
            if not sub_obj.can_user_read(user, sub_obj):
                return False
        rc = cls.can_user_administrate(user, obj, None)
        if not rc:
            return False

        # in order to attach something you also be able to read what you are attaching
        if type(sub_obj) == User:
            return UserHelper.can_user_read(user, sub_obj)
        else:
            return sub_obj.__class__.can_user_read(user, sub_obj)

    @classmethod
    def can_user_unattach(cls, user, obj, sub_obj, relationship):
        return cls.can_user_administrate(user, obj, None)

class CommonModel(PrimordialModel):
    ''' a base model where the name is unique '''

    class Meta:
        abstract = True

    name          = models.CharField(max_length=512, unique=True)

class CommonModelNameNotUnique(PrimordialModel):
    ''' a base model where the name is not unique '''

    class Meta:
        abstract = True

    name          = models.CharField(max_length=512, unique=False)

class Tag(models.Model):
    '''
    any type of object can be given a search tag
    '''

    class Meta:
        app_label = 'main'

    name = models.CharField(max_length=512)

    def __unicode__(self):
        return unicode(self.name)

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_TagsDetail, args=(self.pk,))

    @classmethod
    def can_user_add(cls, user, data):
        # anybody can make up tags
        return True

    @classmethod
    def can_user_read(cls, user, obj):
        # anybody can read tags, we won't show much detail other than the names
        return True


class AuditTrail(models.Model):
    '''
    changing any object records the change
    '''

    class Meta:
        app_label = 'main'

    resource_type = models.CharField(max_length=64)
    modified_by   = models.ForeignKey('auth.User', on_delete=SET_NULL, null=True, blank=True)
    delta         = models.TextField() # FIXME: switch to JSONField
    detail        = models.TextField()
    comment       = models.TextField()

    # FIXME: this looks like this should be a ManyToMany
    tag           = models.ForeignKey('Tag', on_delete=SET_NULL, null=True, blank=True)

class Organization(CommonModel):
    '''
    organizations are the basic unit of multi-tenancy divisions
    '''

    class Meta:
        app_label = 'main'

    users    = models.ManyToManyField('auth.User', blank=True, related_name='organizations')
    admins   = models.ManyToManyField('auth.User', blank=True, related_name='admin_of_organizations')
    projects = models.ManyToManyField('Project', blank=True, related_name='organizations')

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_OrganizationsDetail, args=(self.pk,))

    @classmethod
    def can_user_delete(cls, user, obj):
        return user in obj.admins.all()

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        # FIXME: super user checks should be higher up so we don't have to repeat them
        if user.is_superuser:
            return True
        if obj.created_by == user:
            return True
        rc = user in obj.admins.all()
        return rc

    @classmethod
    def can_user_read(cls, user, obj):
        return cls.can_user_administrate(user,obj,None) or user in obj.users.all()

    @classmethod
    def can_user_delete(cls, user, obj):
        return cls.can_user_administrate(user, obj, None)

    def __unicode__(self):
        return self.name

class Inventory(CommonModel):
    '''
    an inventory source contains lists and hosts.
    '''

    class Meta:
        app_label = 'main'
        verbose_name_plural = _('inventories')
        unique_together = (("name", "organization"),)

    organization = models.ForeignKey(Organization, null=False, related_name='inventories')

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_InventoryDetail, args=(self.pk,))

    @classmethod
    def _has_permission_types(cls, user, obj, allowed):
        if user.is_superuser:
            return True
        by_org_admin = obj.organization.admins.filter(pk = user.pk).count()
        by_team_permission = obj.permissions.filter(
            team__in = user.teams.all(),
            permission_type__in = allowed
        ).count()
        by_user_permission = obj.permissions.filter(
            user = user,
            permission_type__in = allowed
        ).count()

        result = (by_org_admin + by_team_permission + by_user_permission)
        return result > 0

    @classmethod
    def _has_any_inventory_permission_types(cls, user, allowed):
        '''
        rather than checking for a permission on a specific inventory, return whether we have
        permissions on any inventory.  This is primarily used to decide if the user can create
        host or group objects
        '''

        if user.is_superuser:
            return True
        by_org_admin = user.organizations.filter(
            admins__in = [ user ]
        ).count()
        by_team_permission = Permission.objects.filter(
            team__in = user.teams.all(),
            permission_type__in = allowed
        ).count()
        by_user_permission = user.permissions.filter(
            permission_type__in = allowed
        ).count()

        result = (by_org_admin + by_team_permission + by_user_permission)
        return result > 0

    @classmethod
    def can_user_add(cls, user, data):
        if not 'organization' in data:
            return True
        if user.is_superuser:
            return True
        if not user.is_superuser:
            org = Organization.objects.get(pk=data['organization'])
            if user in org.admins.all():
                return True
        return False

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        return cls._has_permission_types(user, obj, PERMISSION_TYPES_ALLOWING_INVENTORY_ADMIN)

    @classmethod
    def can_user_attach(cls, user, obj, sub_obj, relationship_type, data):
        ''' whether you can add sub_obj to obj using the relationship type in a subobject view '''
        if not sub_obj.can_user_read(user, sub_obj):
            return False
        return cls._has_permission_types(user, obj, PERMISSION_TYPES_ALLOWING_INVENTORY_WRITE)

    @classmethod
    def can_user_unattach(cls, user, obj, sub_obj, relationship):
        return cls._has_permission_types(user, obj, PERMISSION_TYPES_ALLOWING_INVENTORY_WRITE)

    @classmethod
    def can_user_read(cls, user, obj):
        return cls._has_permission_types(user, obj, PERMISSION_TYPES_ALLOWING_INVENTORY_READ)

    @classmethod
    def can_user_delete(cls, user, obj):
        return cls._has_permission_types(user, obj, PERMISSION_TYPES_ALLOWING_INVENTORY_ADMIN)

class Host(CommonModelNameNotUnique):
    '''
    A managed node
    '''

    class Meta:
        app_label = 'main'
        unique_together = (("name", "inventory"),)

    variable_data  = models.OneToOneField('VariableData', null=True, default=None, blank=True, on_delete=SET_NULL, related_name='host')
    inventory      = models.ForeignKey('Inventory', null=False, related_name='hosts')

    def __unicode__(self):
        return self.name

    @classmethod
    def can_user_read(cls, user, obj):
        return Inventory.can_user_read(user, obj.inventory)

    @classmethod
    def can_user_add(cls, user, data):
        if not 'inventory' in data:
            return False
        inventory = Inventory.objects.get(pk=data['inventory'])
        rc =  Inventory._has_permission_types(user, inventory, PERMISSION_TYPES_ALLOWING_INVENTORY_WRITE)
        return rc

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_HostsDetail, args=(self.pk,))

    # relationship to LaunchJobStatus
    # relationship to LaunchJobStatusEvent
    # last_job_status

class Group(CommonModelNameNotUnique):

    '''
    A group of managed nodes.  May belong to multiple groups
    '''

    class Meta:
        app_label = 'main'
        unique_together = (("name", "inventory"),)

    inventory     = models.ForeignKey('Inventory', null=False, related_name='groups')
    parents       = models.ManyToManyField('self', symmetrical=False, related_name='children', blank=True)
    variable_data = models.OneToOneField('VariableData', null=True, default=None, blank=True, on_delete=SET_NULL, related_name='group')
    hosts         = models.ManyToManyField('Host', related_name='groups', blank=True)

    def __unicode__(self):
        return self.name

    @classmethod
    def can_user_add(cls, user, data):
        if not 'inventory' in data:
            return False
        inventory = Inventory.objects.get(pk=data['inventory'])
        return Inventory._has_permission_types(user, inventory, PERMISSION_TYPES_ALLOWING_INVENTORY_WRITE)


    @classmethod
    def can_user_administrate(cls, user, obj, data):
        # here this controls whether the user can attach subgroups
        return Inventory._has_permission_types(user, obj.inventory, PERMISSION_TYPES_ALLOWING_INVENTORY_WRITE)

    @classmethod
    def can_user_read(cls, user, obj):
        return Inventory.can_user_read(user, obj.inventory)

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_GroupsDetail, args=(self.pk,))

# FIXME: audit nullables
# FIXME: audit cascades

class VariableData(CommonModelNameNotUnique):
    '''
    A set of host or group variables
    '''

    class Meta:
        app_label = 'main'
        verbose_name_plural = _('variable data')

    #host  = models.OneToOneField('Host', null=True, default=None, blank=True, on_delete=SET_NULL, related_name='variable_data')
    #group = models.OneToOneField('Group', null=True, default=None, blank=True, on_delete=SET_NULL, related_name='variable_data')
    data  = models.TextField() # FIXME: JsonField

    def __unicode__(self):
        return '%s = %s' % (self.name, self.data)

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_VariableDetail, args=(self.pk,))

    @classmethod
    def can_user_read(cls, user, obj):
        ''' a user can be read if they are on the same team or can be administrated '''
        if obj.host is not None:
            return Inventory.can_user_read(user, obj.host.inventory)
        if obj.group is not None:
            return Inventory.can_user_read(user, obj.group.inventory)
        return False

class Credential(CommonModelNameNotUnique):
    '''
    A credential contains information about how to talk to a remote set of hosts
    Usually this is a SSH key location, and possibly an unlock password.
    If used with sudo, a sudo password should be set if required.
    '''

    class Meta:
        app_label = 'main'

    user            = models.ForeignKey('auth.User', null=True, default=None, blank=True, on_delete=SET_NULL, related_name='credentials')
    team            = models.ForeignKey('Team', null=True, default=None, blank=True, on_delete=SET_NULL, related_name='credentials')

    # IF ssh_key_path is SET
    #
    # STAGE 1: SSH KEY SUPPORT
    #
    # ssh-agent bash &
    # save keyfile to tempdir in /var/tmp (permissions guarded)
    # ssh-add path-to-keydata
    # key could locked or unlocked, so use 'expect like' code to enter it at the prompt
    #    if key is locked:
    #       if ssh_key_unlock is provided provide key password
    #       if not provided, FAIL
    #
    # default_username if set corresponds to -u on ansible-playbook, if unset -u root
    #
    # STAGE 2:
    # OR if ssh_password is set instead, do not use SSH agent
    #    set ANSIBLE_SSH_PASSWORD
    #
    # STAGE 3:
    #
    # MICHAEL: modify ansible/ansible-playbook such that
    # if ANSIBLE_PASSWORD or ANSIBLE_SUDO_PASSWORD is set
    # you do not have to use --ask-pass and --ask-sudo-pass, so we don't have to do interactive
    # stuff with that.
    #
    # ansible-playbook foo.yml ...

    ssh_key_data     = models.TextField(blank=True, default='')
    ssh_key_unlock   = models.CharField(blank=True, default='', max_length=1024)
    default_username = models.CharField(blank=True, default='', max_length=1024)
    ssh_password     = models.CharField(blank=True, default='', max_length=1024)
    sudo_password    = models.CharField(blank=True, default='', max_length=1024)

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        if user.is_superuser:
            return True
        if user == obj.user:
            return True

        if obj.user:
            if (obj.user.organizations.filter(admins__in = [user]).count()):
                return True
        if obj.team:
            if user in obj.team.organization.admins.all():
                return True
        return False

    @classmethod
    def can_user_delete(cls, user, obj):
        if obj.user is None and obj.team is None:
            # unassociated credentials may be marked deleted by anyone
            return True
        return cls.can_user_administrate(user,obj,None)

    @classmethod
    def can_user_read(cls, user, obj):
        ''' a user can be read if they are on the same team or can be administrated '''
        return cls.can_user_administrate(user, obj, None)

    @classmethod
    def can_user_add(cls, user, data):
        if user.is_superuser:
            return True
        if 'user' in data:
            user_obj = User.objects.get(pk=data['user'])
            return UserHelper.can_user_administrate(user, user_obj, data)
        if 'team' in data:
            team_obj = Team.objects.get(pk=data['team'])
            return Team.can_user_administrate(user, team_obj, data)

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_CredentialsDetail, args=(self.pk,))

class Team(CommonModel):
    '''
    A team is a group of users that work on common projects.
    '''

    class Meta:
        app_label = 'main'

    projects        = models.ManyToManyField('Project', blank=True, related_name='teams')
    users           = models.ManyToManyField('auth.User', blank=True, related_name='teams')
    organization    = models.ForeignKey('Organization', blank=False, null=True, on_delete=SET_NULL, related_name='teams')

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_TeamsDetail, args=(self.pk,))

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        # FIXME -- audit when this is called explicitly, if any
        if user.is_superuser:
            return True
        if user in obj.organization.admins.all():
            return True
        return False

    @classmethod
    def can_user_read(cls, user, obj):
        if cls.can_user_administrate(user, obj, None):
            return True
        if obj.users.filter(pk__in = [ user.pk ]).count():
            return True
        return False

    @classmethod
    def can_user_add(cls, user, data):
        if user.is_superuser:
            return True
        if Organization.objects.filter(admins__in = [user]).count():
            # team assignment to organizations is handled elsewhere, this just creates
            # a blank team
            return True
        return False

    @classmethod
    def can_user_delete(cls, user, obj):
        return cls.can_user_administrate(user, obj, None)

class Project(CommonModel):
    '''
    A project represents a playbook git repo that can access a set of inventories
    '''

    # this is not part of the project, but managed with perms
    # inventories      = models.ManyToManyField('Inventory', blank=True, related_name='projects')

    local_path = models.FilePathField(
        path=settings.PROJECTS_ROOT,
        recursive=False,
        allow_files=False,
        allow_folders=True,
        max_length=1024,
        unique=True,
        help_text=_('Local path (relative to PROJECTS_ROOT) containing '
                    'playbooks and related files for this project.')
    )
    #scm_type         = models.CharField(max_length=64)
    #default_playbook = models.CharField(max_length=1024)

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_ProjectsDetail, args=(self.pk,))

    @classmethod
    def can_user_administrate(cls, user, obj, data):
        if user.is_superuser:
            return True
        if obj.created_by == user:
            return True
        organizations = Organization.objects.filter(admins__in = [ user ], projects__in = [ obj ])
        for org in organizations:
            if org in project.organizations():
                return True
        return False

    @classmethod
    def can_user_read(cls, user, obj):
        if cls.can_user_administrate(user, obj, None):
            return True
        # and also if I happen to be on a team inside the project
        # FIXME: add this too
        return False

    @classmethod
    def can_user_delete(cls, user, obj):
        return cls.can_user_administrate(user, obj, None)

    @property
    def available_playbooks(self):
        playbooks = []
        if self.local_path and os.path.exists(self.local_path):
            for dirpath, dirnames, filenames in os.walk(self.local_path):
                for filename in filenames:
                    if os.path.splitext(filename)[-1] != '.yml':
                        continue
                    playbook = os.path.join(dirpath, filename)
                    # Filter any invalid YAML files.
                    try:
                        data = yaml.safe_load(file(playbook).read())
                    except (IOError, yaml.YAMLError):
                        continue
                    # Filter files that do not have either hosts or top-level
                    # includes.
                    try:
                        if 'hosts' not in data[0] and 'include' not in data[0]:
                            continue
                    except (IndexError, KeyError):
                        continue
                    playbook = os.path.relpath(playbook, self.local_path)
                    # Filter files in a roles subdirectory.
                    if 'roles' in playbook.split(os.sep):
                        continue
                    # Filter files in a tasks subdirectory.
                    if 'tasks' in playbook.split(os.sep):
                        continue
                    playbooks.append(playbook)
        return playbooks

class Permission(CommonModelNameNotUnique):
    '''
    A permission allows a user, project, or team to be able to use an inventory source.
    '''

    class Meta:
        app_label = 'main'

    # permissions are granted to either a user or a team:
    user            = models.ForeignKey('auth.User', null=True, on_delete=SET_NULL, blank=True, related_name='permissions')
    team            = models.ForeignKey('Team', null=True, on_delete=SET_NULL, blank=True, related_name='permissions')

    # to be used against a project or inventory (or a project and inventory in conjunction):
    project         = models.ForeignKey('Project', null=True, on_delete=SET_NULL, blank=True, related_name='permissions')
    inventory       = models.ForeignKey('Inventory', null=True, on_delete=SET_NULL, related_name='permissions')

    # permission system explanation:
    #
    # for example, user A on inventory X has write permissions                 (PERM_INVENTORY_WRITE)
    #              team C on inventory X has read permissions                  (PERM_INVENTORY_READ)
    #              team C on inventory X and project Y has launch permissions  (PERM_INVENTORY_DEPLOY)
    #              team C on inventory X and project Z has dry run permissions (PERM_INVENTORY_CHECK)
    #
    # basically for launching, permissions can be awarded to the whole inventory source or just the inventory source
    # in context of a given project.
    #
    # the project parameter is not used when dealing with READ, WRITE, or ADMIN permissions.

    permission_type = models.CharField(max_length=64, choices=PERMISSION_TYPE_CHOICES)

    def __unicode__(self):
        return unicode("Permission(name=%s,ON(user=%s,team=%s),FOR(project=%s,inventory=%s,type=%s))" % (
            self.name,
            self.user,
            self.team,
            self.project,
            self.inventory,
            self.permission_type
        ))

# TODO: other job types (later)

class JobTemplate(CommonModel):
    '''
    A job template is a reusable job definition for applying a project (with
    playbook) to an inventory source with a given credential.
    '''

    class Meta:
        app_label = 'main'

    job_type = models.CharField(
        max_length=64,
        choices=JOB_TYPE_CHOICES,
    )
    inventory = models.ForeignKey(
        'Inventory',
        related_name='job_templates',
        null=True,
        on_delete=models.SET_NULL,
    )
    project = models.ForeignKey(
        'Project',
        related_name='job_templates',
        null=True,
        on_delete=models.SET_NULL,
    )
    playbook = models.CharField(
        max_length=1024,
        default='',
    )
    credential = models.ForeignKey(
        'Credential',
        related_name='job_templates',
        blank=True,
        null=True,
        default=None,
        on_delete=models.SET_NULL,
    )

    def create_job(self, **kwargs):
        '''
        Create a new job based on this template.
        '''
        start_job = kwargs.pop('start', False)
        save_job = kwargs.pop('save', True) or start_job # Start implies save.
        kwargs['job_template'] = self
        kwargs.setdefault('name', '%s %s' % (self.name, now().isoformat()))
        kwargs.setdefault('description', self.description)
        kwargs.setdefault('job_type', self.job_type)
        kwargs.setdefault('inventory', self.inventory)
        kwargs.setdefault('project', self.project)
        kwargs.setdefault('playbook', self.playbook)
        kwargs.setdefault('credential', self.credential)
        job = Job(**kwargs)
        if save_job:
            job.save()
        if start_job:
            job.start()
        return job

    # project has one default playbook but really should have a list of playbooks and flags ...
    # ssh-agent bash
    # ssh-add ... < key entry
    #
    # playbook in source control is already on the disk

    # we'll extend ansible core to have callback context like
    #    self.context.playbook
    #    self.context.runner
    #    and the callback will read the environment for ACOM_CELERY_JOB_ID or similar
    #    and log tons into the database

    # the ansible commander setup instructions will include installing the database logging callback
    # inventory script is going to need some way to load Django models
    #    it is documented on ansible.cc under API docs and takes two parameters
    #    --list
    #    -- host <hostname>

    def get_absolute_url(self):
        import lib.urls
        return reverse(lib.urls.views_JobTemplateDetail, args=(self.pk,))

    @classmethod
    def can_user_read(cls, user, obj):
        # you can only see the job templates that you have permission to launch.
        data = dict(
            inventory = obj.inventory.pk,
            project = obj.project.pk,
            job_type = obj.job_type
        )
        return cls.can_user_add(user, data)

    @classmethod
    def can_user_add(cls, user, data):
        ''' 
        a user can create a job template if they are a superuser, an org admin of any org
        that the project is a member, or if they have user or team based permissions tying
        the project to the inventory source for the given action.
   
        users who are able to create deploy jobs can also make check (dry run) jobs
        '''

        if user.is_superuser:
            return True
        project = Project.objects.get(pk=data['project'])
        inventory = Inventory.objects.get(pk=data['inventory'])

        admin_of_orgs = project.organizations.filter(admins__in = [ user ])
        if admin_of_orgs.count() > 0:
            return True
        job_type = data['job_type']

        has_launch_permission = False
        user_permissions = Permission.objects.filter(inventory=inventory, project=project, user=user)
        for perm in user_permissions:
            if job_type == PERM_INVENTORY_CHECK:
                # if you have run permissions, you can also create check jobs
                has_launch_permission = True
            elif job_type == PERM_INVENTORY_DEPLOY and perm.permission_type == PERM_INVENTORY_DEPLOY:
                # you need explicit run permissions to make run jobs
                has_launch_permission = True
        team_permissions = Permission.objects.filter(inventory=inventory, project=project, team__users__in = [user])
        for perm in team_permissions:
            if job_type == PERM_INVENTORY_CHECK:
                # if you have run permissions, you can also create check jobs
                has_launch_permission = True
            elif job_type == PERM_INVENTORY_DEPLOY and perm.permission_type == PERM_INVENTORY_DEPLOY:
                # you need explicit run permissions to make run jobs
                has_launch_permission = True

        if not has_launch_permission:
            return False

        # make sure user owns the credentials they are using
        if data.has_key('credential'):
            has_credential = False
            credential = Credential.objects.get(pk=data['credential'])
            if credential.team and credential.team.users.filter(id = user.pk).count():
               has_credential = True
            if credential.user and credential.user == user:
               has_credential = True
            if not has_credential:
               return False

        # shouldn't really matter with permissions given, but make sure the user
        # is also currently on the team in case they were added a per-user permission and then removed
        # from the project.
        if project.teams.filter(users__in = [ user ]).count():
            return False

        return True


class Job(CommonModel):
    '''
    A job applies a project (with playbook) to an inventory source with a given
    credential.  It represents a single invocation of ansible-playbook with the
    given parameters.
    '''

    STATUS_CHOICES = [
        ('new', _('New')),                  # Job has been created, but not started.
        ('pending', _('Pending')),          # Job has been queued, but is not yet running.
        ('running', _('Running')),          # Job is currently running.
        ('successful', _('Successful')),    # Job completed successfully.
        ('failed', _('Failed')),            # Job completed, but with failures.
        ('error', _('Error')),              # The job was unable to run.
    ]

    class Meta:
        app_label = 'main'

    job_template = models.ForeignKey(
        'JobTemplate',
        related_name='jobs',
        blank=True,
        null=True,
        default=None,
        on_delete=models.SET_NULL,
    )
    job_type = models.CharField(
        max_length=64,
        choices=JOB_TYPE_CHOICES,
    )
    inventory = models.ForeignKey(
        'Inventory',
        related_name='jobs',
        null=True,
        on_delete=models.SET_NULL,
    )
    credential = models.ForeignKey(
        'Credential',
        related_name='jobs',
        null=True,
        on_delete=models.SET_NULL,
    )
    project = models.ForeignKey(
        'Project',
        related_name='jobs',
        null=True,
        on_delete=models.SET_NULL,
    )
    playbook = models.CharField(
        max_length=1024,
    )
    status = models.CharField(
        max_length=20,
        choices=STATUS_CHOICES,
        default='new',
        editable=False,
    )
    result_stdout = models.TextField(
        blank=True,
        default='',
        editable=False,
    )
    result_stderr = models.TextField(
        blank=True,
        default='',
        editable=False,
    )
    result_traceback = models.TextField(
        blank=True,
        default='',
        editable=False,
    )
    celery_task_id = models.CharField(
        max_length=100,
        blank=True,
        default='',
        editable=False,
    )
    hosts = models.ManyToManyField(
        'Host',
        related_name='jobs',
        blank=True,
        editable=False,
        through='JobHostSummary',
    )

    @property
    def celery_task(self):
        try:
            if self.celery_task_id:
                return TaskMeta.objects.get(task_id=self.celery_task_id)
        except TaskMeta.DoesNotExist:
            pass

    def start(self):
        from lib.main.tasks import run_job
        if self.status != 'new':
            return
        self.status = 'pending'
        self.save(update_fields=['status'])
        task_result = run_job.delay(self.pk)
        # The TaskMeta instance in the database isn't created until the worker
        # starts processing the task, so we can only store the task ID here.
        self.celery_task_id = task_result.task_id
        self.save(update_fields=['celery_task_id'])

    @property
    def successful_hosts(self):
        return Host.objects.filter(job_host_summaries__job__pk=self.pk,
                                   job_host_summaries__ok__gt=0)

    @property
    def failed_hosts(self):
        return Host.objects.filter(job_host_summaries__job__pk=self.pk,
                                   job_host_summaries__failures__gt=0)

    @property
    def changed_hosts(self):
        return Host.objects.filter(job_host_summaries__job__pk=self.pk,
                                   job_host_summaries__changed__gt=0)

    @property
    def dark_hosts(self):
        return Host.objects.filter(job_host_summaries__job__pk=self.pk,
                                   job_host_summaries__dark__gt=0)

    @property
    def unreachable_hosts(self):
        return self.dark_hosts

    @property
    def skipped_hosts(self):
        return Host.objects.filter(job_host_summaries__job__pk=self.pk,
                                   job_host_summaries__skipped__gt=0)

    @property
    def processed_hosts(self):
        return Host.objects.filter(job_host_summaries__job__pk=self.pk,
                                   job_host_summaries__processed__gt=0)

class JobHostSummary(models.Model):
    '''
    Per-host statistics for each job.
    '''

    class Meta:
        unique_together = [('job', 'host')]
        verbose_name_plural = _('Job Host Summaries')
        ordering = ('-pk',)

    job = models.ForeignKey(
        'Job',
        related_name='job_host_summaries',
        on_delete=models.CASCADE,
    )
    host = models.ForeignKey('Host',
        related_name='job_host_summaries',
        on_delete=models.CASCADE,
    )

    changed = models.PositiveIntegerField(default=0)
    dark = models.PositiveIntegerField(default=0)
    failures = models.PositiveIntegerField(default=0)
    ok = models.PositiveIntegerField(default=0)
    processed = models.PositiveIntegerField(default=0)
    skipped = models.PositiveIntegerField(default=0)

    def __unicode__(self):
        return '%s changed=%d dark=%d failures=%d ok=%d processed=%d skipped=%s' % \
            (self.host.name, self.changed, self.dark, self.failures, self.ok,
             self.processed, self.skipped)

class JobEvent(models.Model):
    '''
    An event/message logged from the callback when running a job.
    '''

    EVENT_TYPES = [
        ('runner_on_failed', _('Runner on Failed')),
        ('runner_on_ok', _('Runner on OK')),
        ('runner_on_error', _('Runner on Error')),
        ('runner_on_skipped', _('Runner on Skipped')),
        ('runner_on_unreachable', _('Runner on Unreachable')),
        ('runner_on_no_hosts', _('Runner on No Hosts')),
        ('runner_on_async_poll', _('Runner on Async Poll')),
        ('runner_on_async_ok', _('Runner on Async OK')),
        ('runner_on_async_failed', _('Runner on Async Failed')),
        ('playbook_on_start', _('Playbook on Start')),
        ('playbook_on_notify', _('Playbook on Notify')),
        ('playbook_on_task_start', _('Playbook on Task Start')),
        ('playbook_on_vars_prompt', _('Playbook on Vars Prompt')),
        ('playbook_on_setup', _('Playbook on Setup')),
        ('playbook_on_import_for_host', _('Playbook on Import for Host')),
        ('playbook_on_not_import_for_host', _('Playbook on Not Import for Host')),
        ('playbook_on_play_start', _('Playbook on Play Start')),
        ('playbook_on_stats', _('Playbook on Stats')),
    ]

    class Meta:
        app_label = 'main'

    job = models.ForeignKey(
        'Job',
        related_name='job_events',
        on_delete=models.CASCADE,
    )
    created = models.DateTimeField(
        auto_now_add=True,
    )
    event = models.CharField(
        max_length=100,
        choices=EVENT_TYPES,
    )
    event_data = JSONField(
        blank=True,
        default='',
    )
    host = models.ForeignKey(
        'Host',
        related_name='job_events',
        blank=True,
        null=True,
        default=None,
        on_delete=models.SET_NULL,
    )

    def __unicode__(self):
        return u'%s @ %s' % (self.get_event_display(), self.created.isoformat())

    def save(self, *args, **kwargs):
        try:
            if not self.host and self.event_data.get('host', ''):
                self.host = self.job.inventory.hosts.get(name=self.event_data['host'])
        except (Host.DoesNotExist, AttributeError):
            pass
        super(JobEvent, self).save(*args, **kwargs)
        self.update_host_summary_from_stats()

    def update_host_summary_from_stats(self):
        if self.event != 'playbook_on_stats':
            return
        hostnames = set()
        try:
            for v in self.event_data.values():
                hostnames.update(v.keys())
        except AttributeError: # In case event_data or v isn't a dict.
            pass
        for hostname in hostnames:
            try:
                host = self.job.inventory.hosts.get(name=hostname)
            except Host.DoesNotExist:
                continue
            host_summary = self.job.job_host_summaries.get_or_create(host=host)[0]
            host_summary_changed = False
            for stat in ('changed', 'dark', 'failures', 'ok', 'processed', 'skipped'):
                try:
                    value = self.event_data.get(stat, {}).get(hostname, 0)
                    if getattr(host_summary, stat) != value:
                        setattr(host_summary, stat, value)
                        host_summary_changed = True
                except AttributeError: # in case event_data[stat] isn't a dict.
                    pass
            if host_summary_changed:
                host_summary.save()

# TODO: reporting (MPD)

@receiver(post_save, sender=User)
def create_auth_token_for_user(sender, **kwargs):
    instance = kwargs.get('instance', None)
    if instance:
        try:
            Token.objects.get_or_create(user=instance)
        except DatabaseError:
            pass    # Only fails when creating a new superuser from syncdb on a
                    # new database (before migrate has been called).