#pylint: disable=E1103, E1101

from django.conf import settings
from xmodule.modulestore import Location
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.exceptions import ItemNotFoundError
from django.core.urlresolvers import reverse
import copy
import logging
import re
from xmodule.modulestore.draft import DIRECT_ONLY_CATEGORIES
from django.utils.translation import ugettext as _

log = logging.getLogger(__name__)

# In order to instantiate an open ended tab automatically, need to have this data
OPEN_ENDED_PANEL = {"name": _("Open Ended Panel"), "type": "open_ended"}
NOTES_PANEL = {"name": _("My Notes"), "type": "notes"}
EXTRA_TAB_PANELS = dict([(p['type'], p) for p in [OPEN_ENDED_PANEL, NOTES_PANEL]])


def get_modulestore(category_or_location):
    """
    Returns the correct modulestore to use for modifying the specified location
    """
    if isinstance(category_or_location, Location):
        category_or_location = category_or_location.category

    if category_or_location in DIRECT_ONLY_CATEGORIES:
        return modulestore('direct')
    else:
        return modulestore()


def get_course_location_for_item(location):
    '''
    cdodge: for a given Xmodule, return the course that it belongs to
    NOTE: This makes a lot of assumptions about the format of the course location
    Also we have to assert that this module maps to only one course item - it'll throw an
    assert if not
    '''
    item_loc = Location(location)

    # check to see if item is already a course, if so we can skip this
    if item_loc.category != 'course':
        # @hack! We need to find the course location however, we don't
        # know the 'name' parameter in this context, so we have
        # to assume there's only one item in this query even though we are not specifying a name
        course_search_location = ['i4x', item_loc.org, item_loc.course, 'course', None]
        courses = modulestore().get_items(course_search_location)

        # make sure we found exactly one match on this above course search
        found_cnt = len(courses)
        if found_cnt == 0:
            raise Exception('Could not find course at {0}'.format(course_search_location))

        if found_cnt > 1:
            raise Exception('Found more than one course at {0}. There should only be one!!! Dump = {1}'.format(course_search_location, courses))

        location = courses[0].location

    return location


def get_course_for_item(location):
    '''
    cdodge: for a given Xmodule, return the course that it belongs to
    NOTE: This makes a lot of assumptions about the format of the course location
    Also we have to assert that this module maps to only one course item - it'll throw an
    assert if not
    '''
    item_loc = Location(location)

    # @hack! We need to find the course location however, we don't
    # know the 'name' parameter in this context, so we have
    # to assume there's only one item in this query even though we are not specifying a name
    course_search_location = ['i4x', item_loc.org, item_loc.course, 'course', None]
    courses = modulestore().get_items(course_search_location)

    # make sure we found exactly one match on this above course search
    found_cnt = len(courses)
    if found_cnt == 0:
        raise BaseException('Could not find course at {0}'.format(course_search_location))

    if found_cnt > 1:
        raise BaseException('Found more than one course at {0}. There should only be one!!! Dump = {1}'.format(course_search_location, courses))

    return courses[0]


def get_lms_link_for_item(location, preview=False, course_id=None):
    if course_id is None:
        course_id = get_course_id(location)

    if settings.LMS_BASE is not None:
        if preview:
            lms_base = settings.MITX_FEATURES.get('PREVIEW_LMS_BASE')
        else:
            lms_base = settings.LMS_BASE

        lms_link = "//{lms_base}/courses/{course_id}/jump_to/{location}".format(
            lms_base=lms_base,
            course_id=course_id,
            location=Location(location)
        )
    else:
        lms_link = None

    return lms_link


def get_lms_link_for_about_page(location):
    """
    Returns the url to the course about page from the location tuple.
    """
    if settings.MITX_FEATURES.get('ENABLE_MKTG_SITE', False):
        if not hasattr(settings, 'MKTG_URLS'):
            log.exception("ENABLE_MKTG_SITE is True, but MKTG_URLS is not defined.")
            about_base = None
        else:
            marketing_urls = settings.MKTG_URLS
            if marketing_urls.get('ROOT', None) is None:
                log.exception('There is no ROOT defined in MKTG_URLS')
                about_base = None
            else:
                # Root will be "https://www.edx.org". The complete URL will still not be exactly correct,
                # but redirects exist from www.edx.org to get to the Drupal course about page URL.
                about_base = marketing_urls.get('ROOT')
                # Strip off https:// (or http://) to be consistent with the formatting of LMS_BASE.
                about_base = re.sub(r"^https?://", "", about_base)
    elif settings.LMS_BASE is not None:
        about_base = settings.LMS_BASE
    else:
        about_base = None

    if about_base is not None:
        lms_link = "//{about_base_url}/courses/{course_id}/about".format(
            about_base_url=about_base,
            course_id=get_course_id(location)
        )
    else:
        lms_link = None

    return lms_link


def get_course_id(location):
    """
    Returns the course_id from a given the location tuple.
    """
    # TODO: These will need to be changed to point to the particular instance of this problem in the particular course
    return modulestore().get_containing_courses(Location(location))[0].id


class UnitState(object):
    draft = 'draft'
    private = 'private'
    public = 'public'


def compute_unit_state(unit):
    """
    Returns whether this unit is 'draft', 'public', or 'private'.

    'draft' content is in the process of being edited, but still has a previous
        version visible in the LMS
    'public' content is locked and visible in the LMS
    'private' content is editabled and not visible in the LMS
    """

    if getattr(unit, 'is_draft', False):
        try:
            modulestore('direct').get_item(unit.location)
            return UnitState.draft
        except ItemNotFoundError:
            return UnitState.private
    else:
        return UnitState.public


def update_item(location, value):
    """
    If value is None, delete the db entry. Otherwise, update it using the correct modulestore.
    """
    if value is None:
        get_modulestore(location).delete_item(location)
    else:
        get_modulestore(location).update_item(location, value)


def add_extra_panel_tab(tab_type, course):
    """
    Used to add the panel tab to a course if it does not exist.
    @param tab_type: A string representing the tab type.
    @param course: A course object from the modulestore.
    @return: Boolean indicating whether or not a tab was added and a list of tabs for the course.
    """
    # Copy course tabs
    course_tabs = copy.copy(course.tabs)
    changed = False
    # Check to see if open ended panel is defined in the course

    tab_panel = EXTRA_TAB_PANELS.get(tab_type)
    if tab_panel not in course_tabs:
        # Add panel to the tabs if it is not defined
        course_tabs.append(tab_panel)
        changed = True
    return changed, course_tabs


def remove_extra_panel_tab(tab_type, course):
    """
    Used to remove the panel tab from a course if it exists.
    @param tab_type: A string representing the tab type.
    @param course: A course object from the modulestore.
    @return: Boolean indicating whether or not a tab was added and a list of tabs for the course.
    """
    # Copy course tabs
    course_tabs = copy.copy(course.tabs)
    changed = False
    # Check to see if open ended panel is defined in the course

    tab_panel = EXTRA_TAB_PANELS.get(tab_type)
    if tab_panel in course_tabs:
        # Add panel to the tabs if it is not defined
        course_tabs = [ct for ct in course_tabs if ct != tab_panel]
        changed = True
    return changed, course_tabs