from django.core.exceptions import ValidationError
from django.utils.module_loading import import_string
from django.utils.translation import gettext as _
from django.utils.translation import ngettext

from misago.categories import THREADS_ROOT_NAME
from misago.categories.models import Category
from misago.categories.permissions import can_browse_category, can_see_category
from misago.conf import settings
from misago.core.validators import validate_sluggable

from .threadtypes import trees_map


def validate_category(user_acl, category_id, allow_root=False):
    try:
        threads_tree_id = trees_map.get_tree_id_for_root(THREADS_ROOT_NAME)
        category = Category.objects.get(tree_id=threads_tree_id, id=category_id)
    except Category.DoesNotExist:
        category = None

    # Skip ACL validation for root category?
    if allow_root and category and not category.level:
        return category

    if not category or not can_see_category(user_acl, category):
        raise ValidationError(_("Requested category could not be found."))

    if not can_browse_category(user_acl, category):
        raise ValidationError(_("You don't have permission to access this category."))
    return category


def validate_thread_title(settings, title):
    validate_thread_title_length(settings, title)

    error_not_sluggable = _("Thread title should contain alpha-numeric characters.")
    error_slug_too_long = _("Thread title is too long.")
    validate_sluggable(error_not_sluggable, error_slug_too_long)(title)


def validate_thread_title_length(settings, value):
    value_len = len(value)

    if not value_len:
        raise ValidationError(_("You have to enter an thread title."))

    if value_len < settings.thread_title_length_min:
        message = ngettext(
            "Thread title should be at least %(limit_value)s character long (it has %(show_value)s).",
            "Thread title should be at least %(limit_value)s characters long (it has %(show_value)s).",
            settings.thread_title_length_min,
        )
        raise ValidationError(
            message
            % {"limit_value": settings.thread_title_length_min, "show_value": value_len}
        )

    if value_len > settings.thread_title_length_max:
        message = ngettext(
            "Thread title cannot be longer than %(limit_value)s character (it has %(show_value)s).",
            "Thread title cannot be longer than %(limit_value)s characters (it has %(show_value)s).",
            settings.thread_title_length_max,
        )
        raise ValidationError(
            message
            % {"limit_value": settings.thread_title_length_max, "show_value": value_len}
        )


def validate_post_length(settings, value):
    value_len = len(value)

    if not value_len:
        raise ValidationError(_("You have to enter a message."))

    if value_len < settings.post_length_min:
        message = ngettext(
            "Posted message should be at least %(limit_value)s character long (it has %(show_value)s).",
            "Posted message should be at least %(limit_value)s characters long (it has %(show_value)s).",
            settings.post_length_min,
        )
        raise ValidationError(
            message % {"limit_value": settings.post_length_min, "show_value": value_len}
        )

    if settings.post_length_max and value_len > settings.post_length_max:
        message = ngettext(
            "Posted message cannot be longer than %(limit_value)s character (it has %(show_value)s).",
            "Posted message cannot be longer than %(limit_value)s characters (it has %(show_value)s).",
            settings.post_length_max,
        )
        raise ValidationError(
            message % {"limit_value": settings.post_length_max, "show_value": value_len}
        )


# Post validation framework
validators_list = settings.MISAGO_POST_VALIDATORS
POST_VALIDATORS = list(map(import_string, validators_list))


def validate_post(context, data, validators=None):
    validators = validators or POST_VALIDATORS

    for validator in validators:
        data = validator(context, data) or data

    return data