from datetime import datetime
from pytask.taskapp.models import Profile, Task, Comment, Credit, Claim, Map
from pytask.taskapp.utilities.request import create_request

def publishTask(task, rem_mentors=True, rem_comments=True):
    """ set the task status to open """

    if task.sub_type == 'D':
        deps, subs = task.map_subs.all(), []
    else:
        subs, deps = task.map_subs.all(), []
   
    if subs or any(map(lambda t:t.status!="CM",deps)):
        task.status = "LO"
    else:
        task.status = "OP"

    if rem_mentors:
        task.mentors.clear()
        task.mentors.add(task.created_by)

    if rem_comments:
        task.comment_set.update(is_deleted=True)
        task.comment_set.update(deleted_by=task.created_by)

    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.sub_type = "S"
    main_task.save()

    try:
        mapobj = Map.objects.get(main=main_task)
    except Map.DoesNotExist:
        mapobj = Map()
        mapobj.main = main_task
        mapobj.save()
    mapobj.subs.add(sub_task)
    mapobj.save()

    sub_tasks = getTask(main_task.id).subs
    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.
    note that deps can be added only if task is in UP/OP/LO state.
    And also if the task doesn't have any subs.
    """

    main_task.sub_type = "D"
    main_task.save()

    try:
        mapobj = Map.objects.get(main=main_task)
    except Map.DoesNotExist:
        mapobj = Map()
        mapobj.main = main_task
        mapobj.save()

    mapobj.subs.add(dependency)
    mapobj.save()

    deps = getTask(main_task.id).deps

    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 reqMentor(task, mentor, req_by):
    """ create a request object with role as MT.
    """

    create_request(sent_by=req_by, role="MT", sent_to=mentor, task=task) 

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)
    try:
        mapobj = Map.objects.get(main=task)
    except Map.DoesNotExist:
        mapobj = Map()
        mapobj.main = task
        mapobj.save()
        
    task_subs = mapobj.subs.all()

    if task.sub_type == "D":
        task.deps, task.subs = task_subs, []
    elif task.sub_type == "S":
        task.subs, task.deps = task_subs, []

    deps, subs = task.deps, task.subs
    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

def removeTask(main_task, sub_task):
    """ get the corresponding map object and remove the sub_task.
    """

    mapobj = Map.objects.get(main=main_task)
    mapobj.subs.remove(sub_task)
    mapobj.save()

def removeUser(main_task, rem_user):
    """ right now, just remove the user from the list of assigned_users.
    """

    main_task.assigned_users.remove(rem_user)
    main_task.save()

def completeTask(main_task):
    """ set the status of task to CP.
    """

    main_task.status = "CP"
    main_task.save()

def assignCredits(task, given_by, given_to, points):
    """ make a proper request object.
    """
    
    create_request(sent_by=given_by, role="PY", task=task, receiving_user=given_to, pynts=points ) 

def addCredits(task, given_by, given_to, points):
    """ add credit to the credits model.
    """

    creditobj = Credit()
    creditobj.task = task
    creditobj.given_by = given_by
    creditobj.given_to = given_to
    creditobj.points = points
    creditobj.given_time = datetime.now()
    creditobj.save()

def completeTask(task, marked_by):
    """ set the status of task as completed.
    We dont have to inform parent tasks.
    That part is taken care by getTask method.
    """

    task.status = "CM"
    task.save()

    ## generate notification appropriately using marked_by
    ## we also have to mark unread requests as invalid