from datetime import datetime

from pytask.taskapp.models import Profile, Task, Comment, Credit, Claim

def publishTask(task):

    """ set the task status to open """

    sub_tasks = task.subs.all()

    dependencies = task.deps.all()

    if sub_tasks or any(map(lambda t:t.status!="CM",dependencies)):

        task.status = "LO"

    else:

        task.status = "OP"

    task.save()

    return task

def addSubTask(main_task, sub_task):

    """ add the task to subs attribute of the task and update its status.

    sub task can be added only if a task is in UP/OP/LO state.

    """

    ## Shall modify after talking to pr about subtasks

    ## I think i might even remove the concept of subtasks

    main_task.subs.add(sub_task)

    sub_tasks = main_task.subs.all()

    if main_task.status == "OP":

        if any(map(lambda t:t.status!="CM",sub_tasks)):

            main_task.status = "LO"

        else:

            "CM"

    main_task.save()

def addDep(main_task, dependency):

    """ add the dependency task to deps attribute of the task.

    update the status of main_task accordingly.

    And also if the task doesn't have any subs.

    """

    main_task.deps.add(dependency)

    deps = main_task.deps.all()

    if main_task.status in ["OP", "LO"]: 

        if all(map(lambda t:t.status=="CM",deps)):

            main_task.status = "OP"

        else:

            main_task.status = "LO"

    main_task.save()

def addMentor(task,mentor):

    """ add the mentor to mentors list of the task """

    task.mentors.add(mentor)

    task.save()

    return task    

def createTask(title,desc,created_by,credits):

    """ creates a bare minimum task with title, description and credits.

    the creator of the task will be assigned as a mentor for the task.

    """

    try:

        task = Task.objects.get(title__iexact=title)

        return None

    except Task.DoesNotExist:

        task = Task(title=title)

    task.desc = desc

    task.created_by = created_by

    task.credits = credits

    task.creation_datetime = datetime.now()

    task.save()

    return task

def addClaim(task, message, user):

    """ add claim data to the database if it does not exist 

    and also update the claimed users field of the task.

    """

    task.claimed_users.add(user)

    task.save()

    claim = Claim()

    claim.message = message

    claim.task = task

    claim.user = user

    claim.creation_datetime = datetime.now()

    claim.save()

def assignTask(task, user):

    """ check for the status of task and assign it to the particular user """

    if task.status in ['OP', 'WR']:

        task.assigned_users.add(user)

        task.claimed_users.remove(user)

        task.status = "WR"

    task.save()

def getTask(tid):

    """ retreive the task from database.

    if the task has deps or subs, update its status correspondingly.

    """

    task = Task.objects.get(id=tid)

    deps = task.deps.all()

    subs = task.subs.all()

    if deps and task.status in ["OP", "LO"]:

        task.status = "OP" if all(map(lambda t:t.status=="CM",deps)) else "LO"

    if subs and task.status in ["OP", "LO", "CM"]:

        task.status = "CM" if all(map(lambda t:t.status=="CM",subs)) else "LO"

    task.save()

    return task

def updateTask(task, title=None, desc=None, credits=None, tags_field=None):

    """ update the property accordingly.

    while updating title, check for uniqueness of title.

    return None if any error. 

    """

    if title:

        try:

            task.title = title

            task.save()

        except Task.IntegrityError:

            return None

    if desc:task.desc = desc

    if credits:task.credits = credits

    if tags_field:task.tags_field = tags_field

    task.save()

    return task