from google.appengine.ext import webapp
from google.appengine.ext import db
from google.appengine.ext.webapp.util import run_wsgi_app
from models.Message import Message
import jinja2
import os
import re

jinja_environment = jinja2.Environment(
    loader=jinja2.FileSystemLoader(os.path.dirname(__file__)))


def authenticate(username):
    return username in ['Alice', 'Bob']


class Handler(webapp.RequestHandler):
    def render(self, template, vals={}):
        template = jinja_environment.get_template(template)
        self.response.out.write(template.render(vals))


class WelcomePage(Handler):
    def get(self):
        template_values = {'login_url' : '/login'}
        self.render('templates/index.html', template_values)


class LoginPage(Handler):
    def get(self):
        self.render('templates/login.html')

    def post(self):
        username = self.request.get("username")
        if authenticate(username):
            self.redirect('/users/%s' % username)
        else:
            self.response.out.write("User doesn't exist. Login as Alice or Bob!")


class UserPage(Handler):
    def get(self):
        user = re.search(r".+/users/(.+)", self.request.url).group(1)
        template_values = {'user' : user,
                           'inbox_link' : '/users/%s/messages?show=recived' % user}
        self.render('templates/userpage.html', template_values)


class Messages(Handler):
    def get(self):
        """Display specific message if message key is given in url
           otherwise get show param and display inbox, outbox or
           render form for new message"""
        match  = re.search(r".+/users/(.+)/messages(/?)([0-9]*)", self.request.url)
        user   = match.group(1)
        msg_id = match.group(3)
        show   = self.request.get('show')

        if msg_id:
            msg_id = int(msg_id)
            self.displayMessage(msg_id)
        else:
            if show == 'recived' or not show:
                self.showInbox(user)
            elif show == 'sent':
                self.showOutbox(user)
            elif show == 'new':
                self.showFormForNewMsg()
            else:
                self.response.out.write("Error in Message.get()")

    def showInbox(self, user):
        messages = list(db.GqlQuery("""SELECT * FROM Message
                                  WHERE msg_to=:u
                                  ORDER BY timestamp DESC""", u = user))
        welcome  = "inbox"
        self.displayMessages(messages, welcome, user)

    def showOutbox(self, user):
        messages = list(db.GqlQuery("""SELECT * FROM Message
                                  WHERE msg_from=:u
                                  ORDER BY timestamp DESC""", u = user))
        welcome = "outbox"
        self.displayMessages(messages, welcome, user)

    def displayMessages(self, messages, welcome, user):
        """Inbox and Outbox use the same template
           hash other contains values for making link
           from inbox to outbox and vice versa"""
        if welcome == 'inbox':
            other = { 'name' : 'outbox', 'get_param' : 'sent' }
        else:
            other = { 'name' : 'inbox',  'get_param' : 'recived' }
        template_values = {'welcome' : welcome,
                           'messages' : messages,
                           'user' : user,
                           'other' : other}
        self.render('templates/displayMessages.html', template_values)

    def displayMessage(self, msg_id):
        message = Message.get_by_id(msg_id)
        template_values = { 'message' : message }
        self.render('templates/displayMessage.html', template_values)

    def showFormForNewMsg(self):
        self.render('templates/newMessage.html')

    def post(self):
        msg_from = re.search(r".+/users/(.+)/messages", self.request.url).group(1)
        msg_to   = self.request.get('msg_to')
        title    = self.request.get('title')
        message  = self.request.get('message')

        if msg_to and title and message:
            msg = Message(msg_from = msg_from,
                      msg_to   = msg_to,
                      title    = title,
                      message  = message)
            msg.put()
            self.redirect('/')
        else:
            self.response.out.write("Error in Messages.post()")


msgapp = webapp.WSGIApplication([('/', WelcomePage),
                     ('/login', LoginPage),
                 (r'/users/[a-zA-Z0-9]+$', UserPage),
                 (r'/users/[a-zA-Z0-9]+/messages.*', Messages)])




def main():
  run_wsgi_app(msgapp)

if __name__=="__main__":
  main()