from datetime import datetime

from django.contrib.auth.models import User

from pytask.taskapp.models import Notification, RIGHTS_CHOICES

def create_notification(role, sent_to, sent_from=None, reply=None, task=None, remarks=None, requested_by=None, receiving_user=None, pynts=None):

    """

    creates a notification based on the passed arguments.

        role: role of the notification - look at choices in models 

        sent_to: a user to which the notification is to be sent

        sent_from : a user from which the message has originated

            A user who approves/rejects in case of request

            A mentor who closes/complets the task

        reply: A boolean

        task: a task if applicable

        requested_by: a user makes the request

            A mentor who assigns credits in case of pynts

            A mentor who requests to act as a mentor

        remarks: any remarks for rejecting

        receiving_user: user receiving pynts

        pynts: the obvious

    """

    notification = Notification(sent_date = datetime.now())

    notification.role = role

    notification.sent_to = sent_to

    notification.save()

    if role == "PY":

        notification.sent_from = sent_from

        notification.task = task

        notification.pynts = pynts

        task_url= '<a href="/task/view/tid=%s">%s</a>'%(task.id, task.title)

        credits_url = '<a href="/task/assigncredits/tid=%s">%s</a>'%(task.id, "click here")

        mentor_url = '<a href="/user/view/uid=%s">%s</a>'%(requested_by.id, requested_by.username)

        admin_url = '<a href="/user/view/uid=%s">%s</a>'%(sent_from.id, sent_from.username)

        user_url = '<a href="/user/view/uid=%s">%s</a>'%(receiving_user.id, receiving_user.username)

        if reply:

            notification.sub = "Approved request for assign of credits for %s"%task.title[:20]

            notification.message  = """ Request made by %s to assign %s pynts to %s for the task %s has been approved by %s<br />

                                    %s if you want the view/assign pynts page of the task.<br />"""%(mentor_url, pynts, user_url, task_url, admin_url, credits_url)

        else:

            notification.sub = "Rejected request for assign of credits for %s"%task.title[:20]

            notification.message = """ Request made by %s to assign %s pynts to %s for the task %s has been rejected by %s.<br /> """%(mentor_url, pynts, user_url, task_url, admin_url)

            if remarks:

                notification.remarks = remarks

                notification.message += "Reason: %s<br />"%remarks

            notification.message += "<br />"

    elif role == "MT":

        task_url= '<a href="/task/view/tid=%s">%s</a>'%(task.id, task.title)

        requested_mentor_url = '<a href="/user/view/uid=%s">%s</a>'%(requested_by.id, requested_by.username)

        new_mentor = sent_from

        new_mentor_url = '<a href="/user/view/uid=%s">%s</a>'%(new_mentor.id, new_mentor.username)

        if reply:

            notification.sub = "New mentor for the task %s"%task.title[:20]

            notification.message = "%s has accepted the request made by %s, asking him act as a mentor for the task %s<br />"%(new_mentor_url, requested_mentor_url, task_url)

            notification.message += "He can be contacted on %s"%new_mentor.email

        else:

            notification.sub = "Rejected request to act as a mentor for %s"%task.title[:20]

            notification.message = "%s has rejected your request asking him to act as a mentor for %s.<br />"%(new_mentor_url, task_url)

            if remarks:

                notification.message += "Remarks: %s<br />"%remarks

    elif role in ["DV", "MG", "AD"]:

        accepting_user = sent_from

        role_rights = dict(RIGHTS_CHOICES)[role]

        role_learn_url = "/about/%s"%role_rights.lower()

        if reply:

            notification.sub = "New %s for the site"%role_rights

        else:

            notification.sub = "Rejected your request to act as %s"%role_rights

            notification.message = "%s has rejected your request asking him to act as a %s.<br />"%(new_mentor_url, task_url)

            if remarks:

                notification.message += "Remarks: %s<br />"%remarks

    elif role == "NT":

        new_mentor = sent_to

        mentor_learn_url = '<sup><a href="/about/mentor">learn more</a></sup>'

        task_url= '<a href="/task/view/tid=%s">%s</a>'%(task.id, task.title)

        notification.sub = "You are mentoring the task %s"%task.title[:20]

        notification.message = "You have accepted to act as a mentor%s for the task %s.<br />"%(mentor_learn_url, task_url)

        notification.message += " Here is a list of other mentors and their email addresses.<br /> <ul>"

        for a_mentor in task.mentors.exclude(id=new_mentor.id):

            notification.message += "<li> %s - %s </li>"%(a_mentor.username, a_mentor.email)

        notification.message += "</ul> List of users working on the task.<br />"

        working_users = task.assigned_users.all()

        if working_users:

            notification_message += "<ul>"

            for a_user in working_users:

                notification.message += "<li> %s - %s </li>"%(a_user.username, a_user.email)

            notification.message += "</ul><br />"

        notification.message += "Happy Mentoring."

    notification.save()

def mark_notification_read(notification_id):

    """

    makes a notification identified by the notification_id read.

    arguments:

        notification_id - a number denoting the id of the Notification object

    """

    try:

        notification = Notification.objects.get(id = notification_id)

    except Notification.DoesNotExist:

        return False

    notification.is_read = True

    notification.save()

    return True

def delete_notification(notification_id):

    """

    deletes a notification identified by the notification_id.

    arguments:

        notification_id - a number denoting the id of the Notification object

    """

    try:

        notification = Notification.objects.get(id = notification_id)

    except Notification.DoesNotExist:

        return False

    notification.is_deleted = True

    notification.save()

    return True

def get_notification(nid, user):

    """ if notification exists, and belongs to the current user, return it.

    else return None.

    """

    user_notifications = user.notification_sent_to.filter(is_deleted=False).order_by('sent_date')

    current_notifications = user_notifications.filter(id=nid)

    if user_notifications:

        current_notification = current_notifications[0]

        try:

            newer_notification = current_notification.get_next_by_sent_date(sent_to=user, is_deleted=False)

            newest_notification = user_notifications.reverse()[0]

            if newest_notification == newer_notification:

                newest_notification = None

        except Notification.DoesNotExist:

            newest_notification, newer_notification = None, None

        try:

            older_notification = current_notification.get_previous_by_sent_date(sent_to=user, is_deleted=False)

            oldest_notification = user_notifications[0]

            if oldest_notification == older_notification:

                oldest_notification = None

        except:

            oldest_notification, older_notification = None, None

        return newest_notification, newer_notification, current_notification, older_notification, oldest_notification

    else:

        return None, None, None, None, None