#!/usr/bin/env python

import os
import flask
import hashlib
import functools
from boto.route53.record import ResourceRecordSets
from boto.route53.connection import Route53Connection


app = flask.Flask(__name__)
app.config.from_pyfile("/etc/ddns.cfg", silent=True)
app.config.from_pyfile("ddns.cfg", silent=True)
if "AMAZON_KEY_ID" not in app.config:
    raise Exception("Not configured")


def returns_plain_text(f):
    @functools.wraps(f)
    def wrapper(*args, **kwargs):
        return flask.Response(f(*args, **kwargs), content_type="text/plain")

    return wrapper


def update_record(zone, record, ip):
    conn = Route53Connection(app.config["AMAZON_KEY_ID"],
            app.config["AMAZON_SECRET_KEY"])
    change_set = ResourceRecordSets(conn, conn.get_zone(zone).id)
    change_set.add_change("UPSERT", record, type="A", ttl=60).add_value(ip)
    change_set.commit()


@app.errorhandler(404)
@app.errorhandler(405)
@app.errorhandler(500)
def handle_error(ex):
    response = flask.Response("Error", content_type="text/plain")
    response.status_code = getattr(ex, "code", 500)
    return response


@app.route("/new-secret", methods=["GET"])
@returns_plain_text
def new_secret():
    return hashlib.sha256(os.urandom(100)).hexdigest()


@app.route("/update", methods=["POST"])
def update_ip():
    key = flask.request.form.get("key")
    config = app.config["CLIENTS"].get(key)

    if not config:
        flask.abort(404)

    try:
        update_record(config["zone"], config["resource"],
                flask.request.remote_addr)
        return "OK"
    except:
        flask.abort(500)


@app.route("/", methods=["GET"])
@returns_plain_text
def get_ip():
    return flask.request.remote_addr


@app.route("/config")
@returns_plain_text
def get_config():
    return repr(app.config.items())


if __name__ == "__main__":
    app.debug = True
    app.run()