#!/usr/bin/env python
#
# Copyright 2010 ESHA Research, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
from google.appengine.ext import db
from google.appengine.api import urlfetch
from django.utils import simplejson as json
from operator import itemgetter
import time

API = "http://api.esha.com"
PUBLIC_KEY = "2s35wsxke74rcut8jqapbkyf"

def write(str, self):
    self.response.out.write(str+"\n")

def toUrl(path, key):
    delim = "?" if path.find("?") < 0 else "&"
    return API + path + delim + "apikey=" + key

def getJSON(path, key, cache):
    url = toUrl(path, key)
    latest = Cache.gql("WHERE url = :1", url).get();
    if cache and latest:
        return json.loads(latest.json)

    result = urlfetch.fetch(url)
    if result.status_code == 200:
        # rudimentary rate-limit support
        time.sleep(0.5)
        if cache:
            latest = Cache()
            latest.url = url
            latest.json = result.content
            latest.put()
        return json.loads(result.content)

def findIdForDescription(list, desc):
    for item in list:
        if item['description'] == desc:
            return item['id']

class Simple(webapp.RequestHandler):
    def get(self):
        self.response.headers['Content-Type'] = 'text/plain'
        key = self.request.get('apikey', default_value=PUBLIC_KEY)
        cache = not self.request.get('nocache')
        if not cache:
            write('Clearing cache...', self)

        q = self.request.get('query', default_value="pizza")
        write("Searching for '"+q+"'...", self)
        results = getJSON('/foods?query='+q, key, cache)
        write("Matches found: "+str(results['total']), self)
        if results['total'] == 0:
            return None

        write("Loading supported food units to identify id for 'Gram'...", self);
        units = getJSON('/food-units', key, cache)
        gramId = findIdForDescription(units, "Gram");
        write("Gram unit id: "+str(gramId), self);

        write("Selecting results that support 'Gram' as a unit...", self);
        selectedFoods = [];
        for result in results['items']:
            for unit in result['units']:
                if gramId == unit:
                    selectedFoods.append(result)
                    break
            if len(selectedFoods) == 10:
                write("Stopped selection after 10 results (to keep this short).", self)
                break

        write("Loading supported nutrients to identify id for 'Calories'...", self)
        nutrients = getJSON('/nutrients', key, cache)
        caloriesId = findIdForDescription(nutrients, "Calories")
        write("Calories nutrient id: "+str(caloriesId), self);

        for food in selectedFoods:
            write("Analyzing 100 grams of '"+food['description']+"'...", self)
            analysis = getJSON("/analysis?n="+str(caloriesId)+
                               "&f0="+food['id']+
                               "&q0=100"+
                               "&u0="+str(gramId), key, cache)
            #There will be only one nutrient result in the analysis (for Calories)
            food['calories'] = analysis['results'][0]['value']

        write("All "+str(len(selectedFoods))+" analyses have been returned.  Sorting results by calories...", self)
        foods = sorted(selectedFoods, key=itemgetter('calories'))
        for food in foods:
            write("There are "+str(round(food['calories'],1))+" calories in 100g of '"+food['description']+"'", self)

        write("\nFor source code go to: "+self.request.url+"src", self)

class Source(webapp.RequestHandler):
    def get(self):
        self.response.headers['Content-Type'] = 'text/plain'
        file = open('simple.py', "r")
        write(file.read(), self)

class Reset(webapp.RequestHandler):
    def get(self):
        self.response.headers['Content-Type'] = 'text/plain'
        for cache in Cache.all():
            cache.delete()
        write('Reset full cache.', self)

class Cache(db.Model):
    url = db.StringProperty()
    json = db.TextProperty()

def main():
    application = webapp.WSGIApplication([('/', Simple),
                                          ('/src', Source),
                                          ('/reset', Reset)], debug=True)
    run_wsgi_app(application)

if __name__ == '__main__':
    main()