from django.utils.translation import ugettext_lazy as _
from django.utils.translation import ugettext
from django.core.urlresolvers import reverse
from django.utils.safestring import mark_safe

from metadata.classes import MetadataObject

#from filesystem_serving.conf.settings import MAX_RENAME_COUNT

from document_indexing.models import Index, IndexInstance
from document_indexing.conf.settings import AVAILABLE_INDEXING_FUNCTIONS


def evaluate_index(eval_dict, document, node, parent_index_instance=None):
    warnings = []
    if node.enabled:
        try:
            result = eval(node.expression, eval_dict, AVAILABLE_INDEXING_FUNCTIONS)
            index_instance, created = IndexInstance.objects.get_or_create(index=node, value=result, parent=parent_index_instance)
            if node.link_documents:
                index_instance.documents.add(document)
                
            for children in node.get_children():
                children_warnings = evaluate_index(eval_dict, document, children, index_instance)
                warnings.extend(children_warnings)
            
        except NameError, exc:
            warnings.append(_(u'Error in metadata indexing expression: %s') % exc)
            #raise NameError()
            #This should be a warning not an error
            #pass
        except Exception, exc:
            warnings.append(_(u'Unable to create metadata indexing directory: %s') % exc)
            
    return warnings


def update_indexes(document):
    print 'update_indexes'
    warnings = []

    eval_dict = {}
    eval_dict['document'] = document
    metadata_dict = dict([(metadata.metadata_type.name, metadata.value) for metadata in document.documentmetadata_set.all() if metadata.value])
    eval_dict['metadata'] = MetadataObject(metadata_dict)

    for root in Index.objects.filter(parent=None):
        index_warnings = evaluate_index(eval_dict, document, root)
        warnings.extend(index_warnings)

    return warnings
    
    
def delete_indexes(document):
    print 'delete_indexes'


def get_instance_link(index_instance=None, text=None, simple=False):
    if simple:
        # Just display the instance's value or overrided text, no
        # HTML anchor
        template = u'%(value)s'
    else:
        template = u'<a href="%(url)s">%(value)s</a>'
    if index_instance:
        return template % {
            'url': index_instance.get_absolute_url(), 'value': text if text else index_instance
        }
    else:
        # Root node
        return template % {
            'url': reverse('index_instance_list'), 'value': ugettext(u'root')
        }
        

def get_breadcrumbs(index_instance, simple=False, single_link=False):
    result = []
    if single_link:
        # Return the entire breadcrumb as a single HTML anchor
        simple = True
    
    result.append(get_instance_link(simple=simple))

    for instance in index_instance.get_ancestors():
        result.append(get_instance_link(instance, simple=simple))

    result.append(get_instance_link(index_instance, simple=simple))

    if single_link:
        return mark_safe(get_instance_link(index_instance=index_instance, text=(u' / '.join(result))))
    else:
        return mark_safe(u' / '.join(result))