from django.db import models
from django.utils.translation import ugettext_lazy as _

from mptt.models import MPTTModel, TreeForeignKey

from documents.models import Document

from document_indexing.conf.settings import AVAILABLE_INDEXING_FUNCTIONS

available_indexing_functions_string = (_(u'Available functions: %s') % u','.join([u'%s()' % name for name, function in AVAILABLE_INDEXING_FUNCTIONS.items()])) if AVAILABLE_INDEXING_FUNCTIONS else u''


class Index(MPTTModel):
    parent = TreeForeignKey('self', null=True, blank=True, related_name='index_meta_class')
    expression = models.CharField(max_length=128, verbose_name=_(u'indexing expression'), help_text=_(u'Enter a python string expression to be evaluated.'))
        # % available_indexing_functions_string)
    enabled = models.BooleanField(default=True, verbose_name=_(u'enabled'))
    link_document = models.BooleanField(default=False, verbose_name=_(u'link document'))
    
    def __unicode__(self):
        return self.expression if not self.link_document else u'%s/[document]' % self.expression

    class Meta:
        verbose_name = _(u'index')
        verbose_name_plural = _(u'indexes')


class IndexInstance(MPTTModel):
    parent = TreeForeignKey('self', null=True, blank=True, related_name='index_meta_instance')
    index = models.ForeignKey(Index, verbose_name=_(u'index'))
    value = models.CharField(max_length=128, blank=True, verbose_name=_(u'value'))
    documents = models.ManyToManyField(Document, verbose_name=_(u'documents'))
    
    def __unicode__(self):
        return self.value

    def get_document_list_display(self):
        return u', '.join([d.file_filename for d in self.documents.all()])
        

    class Meta:
        verbose_name = _(u'index instance')
        verbose_name_plural = _(u'indexes instances')


# TODO
# class DocumentRenameCount
# FK=IndexInstance