import os
import wsgiref.handlers
 
from google.appengine.ext.webapp import template
from google.appengine.api import users
from google.appengine.ext import db
from google.appengine.ext import webapp
 
class Post(db.Model):
    title = db.StringProperty()
    author = db.UserProperty()
    body = db.TextProperty()
    date = db.DateTimeProperty(auto_now_add=True)
    comments = db.IntegerProperty(default=0)
    
class Comment(db.Model):
    comment = db.StringProperty()
    author = db.UserProperty()
    reference = db.ReferenceProperty(Post)
    date = db.DateTimeProperty(auto_now_add=True)
  
def render_page(webob, tmpl_file, params):
    params['user'] = users.get_current_user()    
    if params['user']:
        params['url'] = '<a href="%s">Sign out</a>' % \
              users.create_logout_url(webob.request.uri)
    else: 
        params['url'] = '<a href="%s">Sign in</a>' % \
              users.create_login_url(webob.request.uri)
    params['admin'] = users.is_current_user_admin()
    
    path = os.path.join(os.path.dirname(__file__), tmpl_file)
    webob.response.out.write(template.render(path, params))
    
class MainPage(webapp.RequestHandler):
    def get(self):
        posts = Post.all().order('-date')[:5]
        
        params = { 'posts': posts, }
        render_page(self, 'index.html', params)
        
class BlogPost(webapp.RequestHandler):
    def get(self):
        if not users.get_current_user():
            self.redirect(users.create_login_url("/"))
        
        render_page(self, 'post.html', {})
        
    def post(self):
        if users.get_current_user():
            p = Post()
            p.author = users.get_current_user()
            p.title = self.request.get('title')
            p.body = self.request.get('body')
            p.put()
            self.redirect('/')
        else:
            self.redirect(users.create_login_url(self.request.uri))
 
class ViewPost(webapp.RequestHandler):
    def get(self):
        try:
            p = Post.get(self.request.get('key'))
        except db.BadKeyError:
            self.redirect("/")
        else:
            c = None
            if p:
                c = db.GqlQuery("SELECT * FROM Comment WHERE reference=:1", 
                            p.key())
            params = { 'post': p, 'comments': c, }
            render_page(self, 'view.html', params)
 
    def post(self):
        p = Post.get(self.request.get('key'))
        
        comment = Comment()
        comment.reference = p.key()
        comment.comment = self.request.get('comment')
        comment.author = users.get_current_user()
        comment.put()
        p.comments += 1
        p.put()
        
        self.redirect(self.request.referrer)
        
class DeletePost(webapp.RequestHandler):
    def get(self):
        if users.is_current_user_admin():
            try:
                p = Post.get(self.request.get('key'))
            except db.BadKeyError:
                self.redirect(self.request.referrer)
            else:
                c = db.GqlQuery("SELECT * FROM Comment WHERE reference=:1",
                        p.key())
                p.delete()
                db.delete(c)
        
                self.redirect('/')
 
class DeleteComment(webapp.RequestHandler):
    def get(self):
        if users.is_current_user_admin():
            try:
                c = Comment.get(self.request.get('key'))
            except db.BadKeyError:
                self.redirect(self.request.referrer)
            else:
                p = Post.get(c.reference.key())
                c.delete()
                p.comments -= 1
                p.put()
                
                self.redirect(self.request.referrer)
                
        
def main():
    application = webapp.WSGIApplication([
        ('/', MainPage), 
        ('/post', BlogPost),
        ('/view', ViewPost),
        ('/delete', DeletePost),
        ('/deletecomment', DeleteComment),
        ], debug=True)
    
    wsgiref.handlers.CGIHandler().run(application)
 
if __name__ == "__main__":
    main()