import inspect, operator
import urllib
import re

from django.utils import simplejson as json
from google.appengine.ext import db
from google.appengine.api import users
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app

def createEntity(className, jsonObj):
    if className[0] == "_":
        raise Exception("Class name must not start with _")
    #Return an empty instance if no jsonObj present
    if jsonObj == None:
        objClass = type(className,(db.Model,),{})
        return objClass()
    if not type(jsonObj) == dict:
        raise Exception("JSON object must start as a dictionary (as opposed to an array or string value)")
    
    #Create entity
    propertyDict = dict()
    for k in jsonObj.keys():
        propertyDict[str(k)] = db.StringProperty()
    
    objClass = type(className,(db.Model,),propertyDict)
    objEntity = objClass()
    for k in jsonObj.keys():
        objEntity.__setattr__(str(k), json.dumps(jsonObj[k]))
        
    return objEntity

class MainPage(webapp.RequestHandler):
  def get(self):
    self.redirect("index.html")

class Add(webapp.RequestHandler):
  def get(self):
    if self.request.get('jsonp') and len(self.request.GET.keys()) >= 2:
        className = str(self.request.GET.keys()[0])
        jsonStr = urllib.unquote(str(self.request.get(className)))
        jsonObj = json.loads(jsonStr)
        objEntity = createEntity(className, jsonObj)
        self.response.out.write(self.request.get('jsonp') + "(\"" + str(objEntity.put()) + "\");")

class Get(webapp.RequestHandler):
  def get(self):
    
    if self.request.get('jsonp') and len(self.request.GET.keys()) >= 2:
        className = str(self.request.GET.keys()[0])
        if str.lower(className) == "jsonp":
            raise Exception("Expected JSON object name as first parameter.")
        classString = str(self.request.get(className))
        if classString == "*":
            #Process get request for all objects of a type
            objEntity = createEntity(className, None)
            query = objEntity.all()
            objArr = list()
            for ent in query:
                objDict = dict()
                for k in ent.__dict__["_entity"].keys():
                        objDict[str(k)] = json.loads(ent.__dict__["_entity"][k])
                objArr.append(objDict)
            self.response.out.write(str(self.request.get('jsonp')) + "(" + json.dumps(objArr) + ");")
        elif not re.compile('\W').match(classString):
            #Query for object based on a unique key
            objClass = type(className, (db.Model,), {})
            keyStr = classString
            ent = db.get(keyStr)
            if ent:
                objDict = dict()
                for k in ent.__dict__["_entity"].keys():
                        objDict[str(k)] = json.loads(ent.__dict__["_entity"][k])
                self.response.out.write(str(self.request.get('jsonp')) + "(" + json.dumps(objDict) + ");")
        else:
            jsonStr = urllib.unquote(classString)
            jsonObj = json.loads(jsonStr)
            objEntity = createEntity(className, jsonObj)
            query = objEntity.all()
            #Querying based on filtered information for an object
            #Loop through the keys sent in the object and add query filters
            
            for k in jsonObj.keys():
                query.filter(str(k) + " =", json.dumps(jsonObj.get(k)))
            
            #Return results
            objArr = list()
            for ent in query:
                objDict = dict()
                for k in ent.__dict__["_entity"].keys():
                        objDict[str(k)] = json.loads(ent.__dict__["_entity"][k])
                objArr.append(objDict)
            
            self.response.out.write(str(self.request.get('jsonp')) + "(" + json.dumps(objArr) + ");")

application = webapp.WSGIApplication(
                                     [('/', MainPage),
                                      ('/add', Add),
                                      ('/get', Get)],
                                     debug=True)

def main():
  run_wsgi_app(application)

if __name__ == "__main__":
  main()