summaryrefslogtreecommitdiffstats
path: root/group_messaging/models.py
blob: 838134e7713450a4c99f51450e26310232cc3c8f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
from django.db import models
from django.contrib.auth.models import Group
from django.contrib.auth.models import User

MAX_TITLE_LENGTH = 80

#dummy parse message function
parse_message = lambda v: v

def get_personal_group_by_user_id(user_id):
    return Group.objects.get(name='_personal_%s' % user_id)


def get_personal_group(user):
    """returns personal group for the user"""
    return get_personal_group_by_user_id(user.id)


def create_personal_group(user):
    """creates a personal group for the user"""
    group = Group(name='_personal_%s' % user.id)
    group.save()
    return group


class SenderListManager(models.Manager):
    """model manager for the :class:`SenderList`"""

    def get_senders_for_user(self, user=None):
        """returns query set of :class:`User`"""
        user_groups = user.groups.all()
        lists = self.filter(recipient__in=user_groups)
        user_ids = lists.values_list(
                        'senders__id', flat=True
                    ).distinct()
        return User.objects.filter(id__in=user_ids)

class SenderList(models.Model):
    """a model to store denormalized data
    about who sends messages to any given person
    sender list is populated automatically
    as new messages are created
    """
    recipient = models.ForeignKey(Group, unique=True)
    senders = models.ManyToManyField(User)
    objects = SenderListManager()


class MessageMemo(models.Model):
    """A bridge between message recipients and messages
    these records are only created when user sees a message.
    The idea is that using groups as recipients, we can send
    messages to massive numbers of users, without cluttering
    the database.

    Instead we'll be creating a "seen" message after user
    reads the message.
    """
    SEEN = 0
    ARCHIVED = 1
    STATUS_CHOICES = (
        (SEEN, 'seen'),
        (ARCHIVED, 'archived')

    )
    user = models.ForeignKey(User)
    message = models.ForeignKey('Message')
    status = models.SmallIntegerField(
            choices=STATUS_CHOICES, default=SEEN
        )

    class Meta:
        unique_together = ('user', 'message')


class MessageManager(models.Manager):
    """model manager for the :class:`Message`"""

    def get_threads_for_user(self, user):
        user_groups = user.groups.all()
        return self.filter(
            root=None,
            message_type=Message.STORED,
            recipients__in=user_groups
        )

    def create(self, **kwargs):
        """creates a message"""
        root = kwargs.get('root', None)
        if root is None:
            parent = kwargs.get('parent', None)
            if parent:
                if parent.root:
                    root = parent.root
                else:
                    root = parent
        kwargs['root'] = root

        headline = kwargs.get('headline', kwargs['text'])
        kwargs['headline'] = headline[:MAX_TITLE_LENGTH]
        kwargs['html'] = parse_message(kwargs['text'])
        return super(MessageManager, self).create(**kwargs)

    def create_thread(self, sender=None, recipients=None, text=None):
        """creates a stored message and adds recipients"""
        message = self.create(
                    message_type=Message.STORED,
                    sender=sender,
                    text=text,
                )
        message.add_recipients(recipients)
        return message

    def create_response(self, sender=None, text=None, parent=None):
        message = self.create(
                    parent=parent,
                    message_type=Message.STORED,
                    sender=sender,
                    text=text,
                )
        #recipients are parent's recipients + sender
        #creator of response gets memo in the "read" status
        recipients = set(parent.recipients.all())
        senders_group = get_personal_group(parent.sender)
        recipients.add(senders_group)
        message.add_recipients(recipients, ignore_user=sender)
        #add author of the parent as a recipient to parent
        #but make sure to mute the message
        parent.add_recipients([senders_group], ignore_user=parent.sender)
        return message


class Message(models.Model):
    """the message model allowing users to send
    messages to other users and groups, via
    personal groups.
    """
    STORED = 0
    TEMPORARY = 1
    ONE_TIME = 2
    MESSAGE_TYPE_CHOICES = (
        (STORED, 'email-like message, stored in the inbox'),
        (ONE_TIME, 'will be shown just once'),
        (TEMPORARY, 'will be shown until certain time')
    )

    message_type = models.SmallIntegerField(
        choices=MESSAGE_TYPE_CHOICES,
        default=STORED,
    )
    
    sender = models.ForeignKey(User, related_name='sent_messages')
    recipients = models.ManyToManyField(Group)
    root = models.ForeignKey(
        'self', null=True,
        blank=True, related_name='descendants'
    )
    parent = models.ForeignKey(
        'self', null=True,
        blank=True, related_name='children'
    )
    headline = models.CharField(max_length=MAX_TITLE_LENGTH)
    text = models.TextField(
        null=True, blank=True,
        help_text='source text for the message, e.g. in markdown format'
    )
    html = models.TextField(
        null=True, blank=True,
        help_text='rendered html of the message'
    )
    sent_at = models.DateTimeField(auto_now_add=True)
    last_active_at = models.DateTimeField(auto_now_add=True)
    active_until = models.DateTimeField(blank=True, null=True)

    objects = MessageManager()

    def add_recipients(self, recipients, ignore_user=None):
        """adds recipients to the message
        and updates the sender lists for all recipients
        todo: sender lists may be updated in a lazy way - per user

        `ignore_user` parameter is used to mark a specific user
        as not needing to receive a message as new, even if that
        user is a member of any of the recipient groups
        """
        if ignore_user:
            #crate a "seen" memo for the sender, because we
            #don't want to inform the user about his/her own post
            MessageMemo.objects.create(
                message=self, user=self.sender, status=MessageMemo.SEEN
            )

        self.recipients.add(*recipients)
        for recipient in recipients:
            sender_list, created = SenderList.objects.get_or_create(recipient=recipient)
            sender_list.senders.add(self.sender)