from django.db.models import get_model
from regluit.core import cc

  
class BaseFacet(object):
    facet_name = 'all'
    
    def __init__(self, outer_facet):
        self.outer_facet = outer_facet if outer_facet else None
        self.model = get_model('core', 'Work')
    
    def _get_query_set(self):
        if self.outer_facet:
            return self.outer_facet.get_query_set()
        else:
            return self.model.objects.filter(is_free=True)
    
    def __unicode__(self):
        if self.facet_name == 'all':
            return 'Free eBooks'
        return unicode(self.facet_name)
    
    @property    
    def title(self):
        return self.__unicode__()
    
    @property    
    def label(self):
        return self.__unicode__()
    
    def get_query_set(self):
        return self._get_query_set()

    def get_facet_path(self):
        if self.outer_facet:
            return self.outer_facet.get_facet_path() + self.facet_name + '/'
        else:
            return self.facet_name + '/'
            
    def facets(self):
        facets=[self]
        if self.outer_facet:
            facets= self.outer_facet.facets() + facets
        return facets

    def context(self):
        return {}
    
    def template(self):
        return 'facets/default.html'
    
    _stash_others = None
    def get_other_groups(self):
        if self._stash_others != None:
            return self._stash_others
        others = []
        used = self.facets()
        for group in facet_groups:
            in_use = False
            for facet in used:
                if group.has_facet(facet.facet_name) :
                    in_use = True
                    break
            if not in_use:
                others.append(group)
        self._stash_others=others
        return others

    @property
    def description(self):
        return self.__unicode__()
        
class FacetGroup(object):
    # a FacetGroup should implement title, facets, has_facet(self, facet_name) and get_facet_class(self, facet_name)
    def has_facet(self, facet_name):
        return facet_name in self.facets
    def get_facets(self):
        for facet_name in self.facets:
            yield self.get_facet_class(facet_name)(None)
    
class NamedFacet(BaseFacet):
    # set_name() must be defined in classes implementing NamedFacet
    def __init__(self, outer_facet):
        super(NamedFacet, self).__init__( outer_facet )
        self.set_name() 
    
class FormatFacetGroup(FacetGroup):
    
    def __init__(self):
        super(FacetGroup,self).__init__()
        self.title = 'Format'
        self.facets = ['pdf', 'epub', 'mobi']
        
    
    def get_facet_class(self, facet_name):
        class FormatFacet(NamedFacet):
            def set_name(self):
                self.facet_name=facet_name
            def get_query_set(self):
                return self._get_query_set().filter(editions__ebooks__format=self.facet_name)
            def template(self):
                return 'facets/format.html'
            @property
            def title(self):
                return "eBooks available in format: " + self.facet_name
            @property
            def description(self):
                return  "These eBooks available in %s format." % self.facet_name
        return FormatFacet    
        
        
class LicenseFacetGroup(FacetGroup):

    def __init__(self):
        super(FacetGroup,self).__init__()
        self.title = 'License'
        self.licenses = cc.LICENSE_LIST_ALL
        self.facets = cc.FACET_LIST
        
        
    def get_facet_class(self, facet_name):
        class LicenseFacet(NamedFacet):
            def set_name(self):
                self.facet_name=facet_name
                self.license = cc.ccinfo(facet_name)
            def get_query_set(self):
                return self._get_query_set().filter(editions__ebooks__rights=self.license.license)
            def template(self):
                return 'facets/license.html'
            def context(self):
                return   {
                    'license': self.license,
                    }
            def label(self):
                return self.license.__str__()
            @property
            def title(self):
                return "license: " + self.license.title
            @property
            def description(self):
                return  "These eBooks are available under the %s license." % self.facet_name
        return LicenseFacet

TOPKW = ["Fiction", "Nonfiction", "Literature",  "History", "Classic Literature", 
    "Children's literature, English", "History and criticism", "Science", "Juvenile fiction", 
    "Sociology", "Software", "Science Fiction"]

class KeywordFacetGroup(FacetGroup):
    
    def __init__(self):
        super(FacetGroup,self).__init__()
        self.title = 'Keyword'
        # make facets in TOPKW available for display
        self.facets = [('kw.%s' % kw) for kw in TOPKW]
        
    def has_facet(self, facet_name):
    
        # recognize any facet_name that starts with "kw." as a valid facet name
        return facet_name.startswith('kw.')

    def get_facet_class(self, facet_name):
        class KeywordFacet(NamedFacet):
            def set_name(self):
                self.facet_name=facet_name
                # facet_names of the form 'kw.SUBJECT' and SUBJECT is therefore the 4th character on
                self.keyword=self.facet_name[3:]
            def get_query_set(self):
                return self._get_query_set().filter(subjects__name=self.keyword)
            def template(self):
                return 'facets/keyword.html'
            @property    
            def title(self):
                return self.keyword
            @property    
            def label(self):
                return self.keyword
            @property
            def description(self):
                return  "%s eBooks" % self.keyword
        return KeywordFacet    
    
# order of groups in facet_groups determines order of display on /free/    
facet_groups = [KeywordFacetGroup(), FormatFacetGroup(),  LicenseFacetGroup(), ]

def get_facet(facet_name):
    for facet_group in facet_groups:
        if facet_group.has_facet(facet_name):
            return facet_group.get_facet_class(facet_name)
    return BaseFacet

def get_all_facets(group='all'):
    facets=[]
    for facet_group in facet_groups:
        if group == 'all' or facet_group.title == group:
            facets = facets + facet_group.facets
    return facets

def get_facet_object(facet_path):
    facets = facet_path.replace('//','/').strip('/').split('/')
    facet_object = None
    for facet in facets:
        facet_object = get_facet(facet)(facet_object)
    return facet_object

order_by_keys = {
    'newest':['-featured', '-created'],
    'oldest':['created'],
    'featured':['-featured', '-num_wishes'],
    'popular':['-num_wishes'],
    'title':['title'],
}   
           
def get_order_by(order_by_key):
    # return the args to use as arguments for order_by
    return order_by_keys.get(order_by_key,'')