from __future__ import absolute_import

from django.core.urlresolvers import reverse
from django.utils.html import escape, mark_safe

from sentry import options
from sentry.models import (
    GroupSubscription, GroupSubscriptionReason, ProjectOption, UserAvatar,
    UserOption
)
from sentry.utils.assets import get_asset_url
from sentry.utils.avatar import get_email_avatar
from sentry.utils.email import MessageBuilder, group_id_to_email
from sentry.utils.http import absolute_uri
from sentry.utils.linksign import generate_signed_link


class ActivityEmail(object):
    def __init__(self, activity):
        self.activity = activity
        self.project = activity.project
        self.organization = self.project.organization
        self.group = activity.group

    def _get_subject_prefix(self):
        prefix = ProjectOption.objects.get_value(
            project=self.project,
            key='mail:subject_prefix',
        )
        if not prefix:
            prefix = options.get('mail.subject-prefix')
        return prefix

    def should_email(self):
        return True

    def get_participants(self):
        # TODO(dcramer): not used yet today except by Release's
        if not self.group:
            return []

        participants = GroupSubscription.objects.get_participants(group=self.group)

        if self.activity.user is not None and self.activity.user in participants:
            receive_own_activity = UserOption.objects.get_value(
                user=self.activity.user,
                key='self_notifications',
                default='0'
            ) == '1'

            if not receive_own_activity:
                del participants[self.activity.user]

        return participants

    def get_template(self):
        return 'sentry/emails/activity/generic.txt'

    def get_html_template(self):
        return 'sentry/emails/activity/generic.html'

    def get_project_link(self):
        return absolute_uri('/{}/{}/'.format(
            self.organization.slug,
            self.project.slug,
        ))

    def get_group_link(self):
        return absolute_uri('/{}/{}/issues/{}/'.format(
            self.organization.slug,
            self.project.slug,
            self.group.id,
        ))

    def get_base_context(self):
        activity = self.activity

        context = {
            'data': activity.data,
            'author': activity.user,
            'project': self.project,
            'project_link': self.get_project_link(),
        }
        if activity.group:
            context.update(self.get_group_context())
        return context

    def get_group_context(self):
        group_link = self.get_group_link()
        activity_link = '{}activity/'.format(group_link)

        return {
            'group': self.group,
            'link': group_link,
            'activity_link': activity_link,
        }

    def get_email_type(self):
        return 'notify.activity.{}'.format(
            self.activity.get_type_display(),
        )

    def get_subject(self):
        group = self.group

        return u'[%s] %s: %s' % (
            self.project.get_full_name(),
            group.get_level_display(),
            group.title
        )

    def get_subject_with_prefix(self):
        return u'{}{}'.format(
            self._get_subject_prefix(),
            self.get_subject(),
        ).encode('utf-8')

    def get_context(self):
        description = self.get_description()
        try:
            description, params, html_params = description
        except ValueError:
            try:
                description, params = description
                html_params = params
            except ValueError:
                params, html_params = {}, {}

        return {
            'activity_name': self.get_activity_name(),
            'text_description': self.description_as_text(
                description, params),
            'html_description': self.description_as_html(
                description, html_params),
        }

    def get_user_context(self, user):
        # use in case context of email changes depending on user
        return {}

    def get_headers(self):
        project = self.project
        group = self.group

        headers = {
            'X-Sentry-Team': project.team.slug,
            'X-Sentry-Project': project.slug,
        }

        if group:
            headers.update({
                'X-Sentry-Logger': group.logger,
                'X-Sentry-Logger-Level': group.get_level_display(),
                'X-Sentry-Reply-To': group_id_to_email(group.id),
            })

        return headers

    def get_description(self):
        raise NotImplementedError

    def avatar_as_html(self):
        user = self.activity.user
        if not user:
            return '<img class="avatar" src="{}" width="20px" height="20px" />'.format(
                escape(self._get_sentry_avatar_url())
            )
        avatar_type = user.get_avatar_type()
        if avatar_type == 'upload':
            return '<img class="avatar" src="{}" />'.format(
                escape(self._get_user_avatar_url(user))
            )
        elif avatar_type == 'letter_avatar':
            return get_email_avatar(
                user.get_display_name(), user.get_label(), 20, False)
        else:
            return get_email_avatar(
                user.get_display_name(), user.get_label(), 20, True)

    def _get_sentry_avatar_url(self):
        url = '/images/sentry-email-avatar.png'
        return get_asset_url('sentry', url)

    def _get_user_avatar_url(self, user, size=20):
        try:
            avatar = UserAvatar.objects.get(user=user)
        except UserAvatar.DoesNotExist:
            return ''

        url = reverse('sentry-user-avatar-url', args=[avatar.ident])
        if size:
            url = '{}?s={}'.format(url, int(size))
        return absolute_uri(url)

    def description_as_text(self, description, params):
        user = self.activity.user
        if user:
            name = user.name or user.email
        else:
            name = u'Sentry'

        context = {
            'author': name,
            'an issue': u'an issue',
        }
        context.update(params)

        return description.format(**context)

    def description_as_html(self, description, params):
        user = self.activity.user
        if user:
            name = user.get_display_name()
        else:
            name = 'Sentry'

        fmt = u'<span class="avatar-container">{}</span> <strong>{}</strong>'

        author = mark_safe(fmt.format(
            self.avatar_as_html(),
            escape(name),
        ))

        an_issue = u'<a href="{}">an issue</a>'.format(
            escape(self.get_group_link()),
        )

        context = {
            'author': author,
            'an issue': an_issue,
        }
        context.update(params)

        return mark_safe(description.format(**context))

    def send(self):
        if not self.should_email():
            return

        participants = self.get_participants()
        if not participants:
            return

        activity = self.activity
        project = self.project
        group = self.group

        context = self.get_base_context()
        context.update(self.get_context())

        template = self.get_template()
        html_template = self.get_html_template()
        email_type = self.get_email_type()
        headers = self.get_headers()

        for user, reason in participants.items():
            if group:
                context.update({
                    'reason': GroupSubscriptionReason.descriptions.get(
                        reason,
                        "are subscribed to this issue",
                    ),
                    'unsubscribe_link': generate_signed_link(
                        user.id,
                        'sentry-account-email-unsubscribe-issue',
                        kwargs={'issue_id': group.id},
                    ),
                })
            user_context = self.get_user_context(user)
            if user_context:
                user_context.update(context)
            else:
                user_context = context

            msg = MessageBuilder(
                subject=self.get_subject_with_prefix(),
                template=template,
                html_template=html_template,
                headers=headers,
                type=email_type,
                context=user_context,
                reference=activity,
                reply_reference=group,
            )
            msg.add_users([user.id], project=project)
            msg.send_async()
