import json 
import os.path

from manifold.manifoldresult import ManifoldResult
from manifold.manifoldapi import ManifoldAPI

from django.contrib                     import messages

debug=False
#debug=True

class MetaData:

    def __init__ (self, auth):
        self.auth=auth
        self.hash_by_object={}

    def fetch (self, request):
        manifold_api = ManifoldAPI(self.auth)
        fields = ['table', 'column.name', 'column.qualifier', 'column.type', 
                  'column.is_array', 'column.description', 'column.default', 'key', 'capability']
        #fields = ['table', 'column.column',
        #          'column.description','column.header', 'column.title',
        #          'column.unit', 'column.info_type',
        #          'column.resource_type', 'column.value_type',
        #          'column.allowed_values', 'column.platforms.platform',
        #          'column.platforms.platform_url']
        request={ 'action': 'get',
                  'object': 'local:object', # proposed to replace metadata:table
                  'fields':  fields ,
                  }
        result = manifold_api.forward(request)

        # xxx need a way to export error messages to the UI
        if result['code'] == 1: # warning
            # messages.warning(request, result['description'])
            print ("METADATA WARNING -",request,result['description'])
        elif result['code'] == 2:
            # messages.error(request, result['description'])
            print ("METADATA ERROR -",request,result['description'])
            # XXX FAIL HERE XXX
            return

        rows = result.ok_value()
# API errors will be handled by the outer logic
#        if not rows:
#            print "Failed to retrieve metadata",rows_result.error()
#            rows=[]
        self.hash_by_object = dict ( [ (row['table'], row) for row in rows ] )

    def to_json(self):
        return json.dumps(self.hash_by_object)

    def details_by_object (self, object):
        return self.hash_by_object[object]

    def sorted_fields_by_object (self, object):
        return self.hash_by_object[object]['column'].sort()

    def get_field_type(self, object, field):
        if debug: print "Temp fix for metadata::get_field_type() -> consider moving to manifold.core.metadata soon"
        return field