from collections import namedtuple

from ietf.doc.models import Document, TelechatDocEvent, STATUSCHANGE_RELATIONS
from ietf.iesg.agenda import get_doc_section

TelechatPageCount = namedtuple('TelechatPageCount',['for_approval','for_action','related'])

def telechat_page_count(date):

    candidates = Document.objects.filter(docevent__telechatdocevent__telechat_date=date).distinct() 
    
    docs = [ doc for doc in candidates if doc.latest_event(TelechatDocEvent,type='scheduled_for_telechat').telechat_date==date ]

    for_action =[d for d in docs if get_doc_section(d).endswith('.3')]

    for_approval = set(docs)-set(for_action)

    drafts = [d for d in for_approval if d.type_id == 'draft']

    pages_for_approval = sum([d.pages or 0 for d in drafts])

    pages_for_action = 0
    for d in for_action:
        if d.type_id == 'draft':
            pages_for_action += d.pages or 0
        elif d.type_id == 'statchg':
            for rel in d.related_that_doc(STATUSCHANGE_RELATIONS):
                pages_for_action += rel.document.pages or 0
        elif d.type_id == 'conflrev':
            for rel in d.related_that_doc('conflrev'):
                pages_for_action += rel.document.pages or 0
        else:
            pass

    related_pages = 0
    for d in for_approval-set(drafts):
        if d.type_id == 'statchg':
            for rel in d.related_that_doc(STATUSCHANGE_RELATIONS):
                related_pages += rel.document.pages or 0
        elif d.type_id == 'conflrev':
            for rel in d.related_that_doc('conflrev'):
                related_pages += rel.document.pages or 0
        else:
            # There's really nothing to rely on to give a reading load estimate for charters
            pass
    
    return TelechatPageCount(for_approval=pages_for_approval,
                             for_action=pages_for_action,
                             related=related_pages)