import collections

from django import forms
from django.utils.translation import ugettext_lazy

from openslides.mediafile.models import Mediafile
from openslides.utils.forms import (CleanHtmlFormMixin, CssClassMixin,
                                    CSVImportForm, LocalizedModelChoiceField)
from openslides.users.models import User

from ckeditor.widgets import CKEditorWidget

from .models import Category, Motion, Workflow, Tag


class BaseMotionForm(CleanHtmlFormMixin, CssClassMixin, forms.ModelForm):
    """
    Base FormClass for a Motion.

    For it's own, it append the version data to the fields.

    The class can be mixed with the following mixins to add fields for the
    submitter, supporters etc.
    """
    clean_html_fields = ('text', 'reason')

    title = forms.CharField(widget=forms.TextInput(), label=ugettext_lazy("Title"))
    """
    Title of the motion. Will be saved in a MotionVersion object.
    """

    text = forms.CharField(widget=CKEditorWidget(), label=ugettext_lazy("Text"))
    """
    Text of the motion. Will be saved in a MotionVersion object.
    """

    reason = forms.CharField(
        widget=CKEditorWidget(), required=False, label=ugettext_lazy("Reason"))
    """
    Reason of the motion. will be saved in a MotionVersion object.
    """

    attachments = forms.ModelMultipleChoiceField(
        queryset=Mediafile.objects.all(),
        required=False,
        label=ugettext_lazy('Attachments'))
    """
    Attachments of the motion.
    """

    tags = forms.ModelMultipleChoiceField(
        queryset=Tag.objects.all(),
        required=False,
        label=ugettext_lazy('Tags'))

    key_order = ('identifier',
                 'title',
                 'text',
                 'reason',
                 'submitter',
                 'supporter',
                 'category',
                 'tags',
                 'attachments',
                 'workflow',
                 'disable_versioning',)
    """
    Order of fields, including optional fields from mixins (for example MotionSupporterMixin)
    """

    class Meta:
        model = Motion
        fields = ()

    def __init__(self, *args, **kwargs):
        """
        Fill the FormFields related to the version data with initial data.
        Fill also the initial data for attachments and tags.
        """
        self.motion = kwargs.get('instance', None)
        self.initial = kwargs.setdefault('initial', {})
        if self.motion is not None:
            last_version = self.motion.get_last_version()
            self.initial['title'] = last_version.title
            self.initial['text'] = last_version.text
            self.initial['reason'] = last_version.reason
            self.initial['attachments'] = self.motion.attachments.all()
            self.initial['tags'] = self.motion.tags.all()
        super(BaseMotionForm, self).__init__(*args, **kwargs)

        keys = self.fields.keys()
        keys_order = [key for key in self.key_order if key in keys]
        keys_order.extend(set(keys) - set(keys_order))
        self.fields = collections.OrderedDict([(key, self.fields[key]) for key in keys_order])


class MotionSubmitterMixin(forms.ModelForm):
    """Mixin to append the submitter field to a MotionForm."""

    submitter = forms.ModelMultipleChoiceField(
        User.objects, label=ugettext_lazy("Submitter"), required=False)
    """Submitter of the motion. Can be one or more persons."""

    def __init__(self, *args, **kwargs):
        """Fill in the submitter of the motion as default value."""
        if self.motion is not None:
            submitter = [submitter.person.id for submitter in self.motion.submitter.all()]
            self.initial['submitter'] = submitter
        super(MotionSubmitterMixin, self).__init__(*args, **kwargs)


class MotionSupporterMixin(forms.ModelForm):
    """Mixin to append the supporter field to a Motionform."""

    supporter = forms.ModelMultipleChoiceField(
        User.objects, required=False, label=ugettext_lazy("Supporters"))
    """Supporter of the motion. Can be one or more persons."""

    def __init__(self, *args, **kwargs):
        """Fill in the supporter of the motions as default value."""
        if self.motion is not None:
            supporter = [supporter.person.id for supporter in self.motion.supporter.all()]
            self.initial['supporter'] = supporter
        super(MotionSupporterMixin, self).__init__(*args, **kwargs)


class MotionDisableVersioningMixin(forms.ModelForm):
    """Mixin to add the option to the form to choose to disable versioning."""

    disable_versioning = forms.BooleanField(
        required=False, label=ugettext_lazy("Don't create a new version"),
        help_text=ugettext_lazy("Don't create a new version. Useful e.g. for trivial changes."))
    """BooleanField to decide, if a new version will be created, or the
    last_version will be used."""


# TODO: Add category and identifier to the form as normal fields (the django way),
# not as 'new' field from 'new' forms.

class MotionCategoryMixin(forms.ModelForm):
    """
    Mixin to let the user choose the category for the motion.
    """

    category = forms.ModelChoiceField(queryset=Category.objects.all(), required=False, label=ugettext_lazy("Category"))
    """
    Category of the motion.
    """

    def __init__(self, *args, **kwargs):
        """
        Fill in the category of the motion as default value.
        """
        if self.motion is not None:
            category = self.motion.category
            self.initial['category'] = category
        super(MotionCategoryMixin, self).__init__(*args, **kwargs)


class MotionIdentifierMixin(forms.ModelForm):
    """
    Mixin to let the user choose the identifier for the motion.
    """

    identifier = forms.CharField(required=False, label=ugettext_lazy('Identifier'))

    class Meta:
        model = Motion
        fields = ('identifier',)


class MotionWorkflowMixin(forms.ModelForm):
    """
    Mixin to let the user change the workflow of the motion.
    """

    workflow = LocalizedModelChoiceField(
        queryset=Workflow.objects.all(),
        empty_label=None,
        label=ugettext_lazy('Workflow'),
        help_text=ugettext_lazy('Set a specific workflow to switch to it. '
                                'If you do so, the state of the motion will be reset.'))


class MotionCSVImportForm(CSVImportForm):
    """
    Form for motion import via csv file.
    """
    override = forms.BooleanField(
        required=False,
        label=ugettext_lazy('Override existing motions with the same identifier'),
        help_text=ugettext_lazy('If this is active, every motion with the same identifier as in your csv file will be overridden.'))
    """
    Flag to decide whether existing motions (according to the identifier)
    should be overridden.
    """

    default_submitter = forms.ModelChoiceField(
        User.objects.all(),
        required=True,
        label=ugettext_lazy('Default submitter'),
        help_text=ugettext_lazy('This person is used as submitter for any line of your csv file which does not contain valid submitter data.'))
    """
    Person which is used as submitter, if the line of the csv file does
    not contain valid submitter data.
    """