"""JQuery-Ajax Autocomplete fields for Django Forms"""
__version__ = "1.2.4"
__author__ = "crucialfelix"
__contact__ = "crucialfelix@gmail.com"
__homepage__ = "http://code.google.com/p/django-ajax-selects/"

from django.conf import settings
from django.core.exceptions import ImproperlyConfigured, PermissionDenied
from django.db.models.fields.related import ForeignKey, ManyToManyField
from django.contrib.contenttypes.models import ContentType
from django.forms.models import ModelForm
from django.utils.text import capfirst
from django.utils.translation import ugettext_lazy as _, ugettext


class LookupChannel(object):

    """Subclass this, setting model and overiding the methods below to taste"""
    
    model = None
    min_length = 1
    
    def get_query(self,q,request):
        """ return a query set searching for the query string q 
            either implement this method yourself or set the search_field
            in the LookupChannel class definition
        """
        kwargs = { "%s__icontains" % self.search_field : q }
        return self.model.objects.filter(**kwargs).order_by(self.search_field)

    def get_result(self,obj):
        """ The text result of autocompleting the entered query """
        return unicode(obj)

    def format_match(self,obj):
        """ (HTML) formatted item for displaying item in the dropdown """
        return unicode(obj)

    def format_item_display(self,obj):
        """ (HTML) formatted item for displaying item in the selected deck area """
        return unicode(obj)

    def get_objects(self,ids):
        """ Get the currently selected objects when editing an existing model """
        # return in the same order as passed in here
        # this will be however the related objects Manager returns them
        # which is not guaranteed to be the same order they were in when you last edited
        # see OrdredManyToMany.md
        ids = [int(id) for id in ids]
        things = self.model.objects.in_bulk(ids)
        return [things[aid] for aid in ids if things.has_key(aid)]

    def can_add(self,user,argmodel):
        """ Check if the user has permission to add 
            one of these models. This enables the green popup +
            Default is the standard django permission check
        """
        ctype = ContentType.objects.get_for_model(argmodel)
        return user.has_perm("%s.add_%s" % (ctype.app_label,ctype.model))

    def check_auth(self,request):
        """ to ensure that nobody can get your data via json simply by knowing the URL.
            public facing forms should write a custom LookupChannel to implement as you wish.
            also you could choose to return HttpResponseForbidden("who are you?")
            instead of raising PermissionDenied (401 response)
         """
        if not request.user.is_staff:
            raise PermissionDenied



def make_ajax_form(model,fieldlist,superclass=ModelForm,show_help_text=False,**kwargs):
    """ Creates a ModelForm subclass with autocomplete fields
            
        usage:
            class YourModelAdmin(Admin):
                ...
                form = make_ajax_form(YourModel,{'contacts':'contact','author':'contact'})

        where 
            'contacts' is a ManyToManyField specifying to use the lookup channel 'contact'
        and
            'author' is a ForeignKeyField specifying here to also use the lookup channel 'contact'
    """
    # will support previous arg name for several versions before deprecating
    if 'show_m2m_help' in kwargs:
        show_help_text = kwargs.pop('show_m2m_help')
        
    class TheForm(superclass):
        
        class Meta:
            pass
        setattr(Meta, 'model', model)

    for model_fieldname,channel in fieldlist.iteritems():
        f = make_ajax_field(model,model_fieldname,channel,show_help_text)

        TheForm.declared_fields[model_fieldname] = f
        TheForm.base_fields[model_fieldname] = f
        setattr(TheForm,model_fieldname,f)

    return TheForm


def make_ajax_field(model,model_fieldname,channel,show_help_text = False,**kwargs):
    """ Makes a single autocomplete field for use in a Form

        optional args:
            help_text - default is the model db field's help_text. 
                None will disable all help text
            label     - default is the model db field's verbose name
            required  - default is the model db field's (not) blank
        
            show_help_text - 
                Django will show help text below the widget, but not for ManyToMany inside of admin inlines
                This setting will show the help text inside the widget itself.
    """
    # will support previous arg name for several versions before deprecating
    if 'show_m2m_help' in kwargs:
        show_help_text = kwargs.pop('show_m2m_help')

    from ajax_select.fields import AutoCompleteField, \
                                   AutoCompleteSelectMultipleField, \
                                   AutoCompleteSelectField

    field = model._meta.get_field(model_fieldname)
    if kwargs.has_key('label'):
        label = kwargs.pop('label')
    else:
        label = _(capfirst(unicode(field.verbose_name)))

    if kwargs.has_key('help_text'):
        help_text = kwargs.pop('help_text')
    else:
        if isinstance(field.help_text,basestring) and field.help_text:
            help_text = _(field.help_text)
        else:
            help_text = field.help_text
    if kwargs.has_key('required'):
        required = kwargs.pop('required')
    else:
        required = not field.blank

    kwargs['show_help_text'] = show_help_text
    if isinstance(field,ManyToManyField):
        f = AutoCompleteSelectMultipleField(
            channel,
            required=required,
            help_text=help_text,
            label=label,
            **kwargs
            )
    elif isinstance(field,ForeignKey):
        f = AutoCompleteSelectField(
            channel,
            required=required,
            help_text=help_text,
            label=label,
            **kwargs
            )
    else:
        f = AutoCompleteField(
            channel,
            required=required,
            help_text=help_text,
            label=label,
            **kwargs
            )
    return f


####################  private  ##################################################

def get_lookup(channel):
    """ find the lookup class for the named channel.  this is used internally """
    try:
        lookup_label = settings.AJAX_LOOKUP_CHANNELS[channel]
    except AttributeError:
        raise ImproperlyConfigured("settings.AJAX_LOOKUP_CHANNELS is not configured")
    except KeyError:
        raise ImproperlyConfigured("settings.AJAX_LOOKUP_CHANNELS not configured correctly for %r" % channel)

    if isinstance(lookup_label,dict):
        # 'channel' : dict(model='app.model', search_field='title' )
        #  generate a simple channel dynamically
        return make_channel( lookup_label['model'], lookup_label['search_field'] )
    else: # a tuple
        # 'channel' : ('app.module','LookupClass')
        #  from app.module load LookupClass and instantiate
        lookup_module = __import__( lookup_label[0],{},{},[''])
        lookup_class = getattr(lookup_module,lookup_label[1] )

        # monkeypatch older lookup classes till 1.3
        if not hasattr(lookup_class,'format_match'):
            setattr(lookup_class, 'format_match',
                getattr(lookup_class,'format_item',
                    lambda self,obj: unicode(obj)))
        if not hasattr(lookup_class,'format_item_display'):
            setattr(lookup_class, 'format_item_display',
                getattr(lookup_class,'format_item', 
                    lambda self,obj: unicode(obj)))
        if not hasattr(lookup_class,'get_result'):
            setattr(lookup_class, 'get_result',
                getattr(lookup_class,'format_result', 
                    lambda self,obj: unicode(obj)))

        return lookup_class()


def make_channel(app_model,arg_search_field):
    """ used in get_lookup
            app_model :   app_name.model_name
            search_field :  the field to search against and to display in search results 
    """
    from django.db import models
    app_label, model_name = app_model.split(".")
    themodel = models.get_model(app_label, model_name)
    
    class MadeLookupChannel(LookupChannel):
        
        model = themodel
        search_field = arg_search_field
        
    return MadeLookupChannel()