# Copyright 2015 Google Inc. All Rights Reserved.
#
# 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.

import datetime
import logging
import os
import socket

from flask import Flask, request
from flask.ext.sqlalchemy import SQLAlchemy


app = Flask(__name__)


def is_ipv6(addr):
    """Checks if a given address is an IPv6 address."""
    try:
        socket.inet_pton(socket.AF_INET6, addr)
        return True
    except socket.error:
        return False


# [START example]
# Environment variables are defined in app.yaml.
app.config['SQLALCHEMY_DATABASE_URI'] = os.environ['SQLALCHEMY_DATABASE_URI']
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)


class Visit(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    timestamp = db.Column(db.DateTime())
    user_ip = db.Column(db.String(46))

    def __init__(self, timestamp, user_ip):
        self.timestamp = timestamp
        self.user_ip = user_ip


@app.route('/')
def index():
    user_ip = request.remote_addr

    # Keep only the first two octets of the IP address.
    if is_ipv6(user_ip):
        user_ip = ':'.join(user_ip.split(':')[:2])
    else:
        user_ip = '.'.join(user_ip.split('.')[:2])

    visit = Visit(
        user_ip=user_ip,
        timestamp=datetime.datetime.utcnow()
    )

    db.session.add(visit)
    db.session.commit()

    visits = Visit.query.order_by(-Visit.timestamp).limit(10)

    results = [
        'Time: {} Addr: {}'.format(x.timestamp, x.user_ip)
        for x in visits]

    output = 'Last 10 visits:\n{}'.format('\n'.join(results))

    return output, 200, {'Content-Type': 'text/plain; charset=utf-8'}
# [END example]


@app.errorhandler(500)
def server_error(e):
    logging.exception('An error occurred during a request.')
    return """
    An internal error occurred: <pre>{}</pre>
    See logs for full stacktrace.
    """.format(e), 500


if __name__ == '__main__':
    # This is used when running locally. Gunicorn is used to run the
    # application on Google App Engine. See entrypoint in app.yaml.
    app.run(host='127.0.0.1', port=8080, debug=True)