"""A simple number and datetime addition JSON API.
Run the app:

    $ python examples/aiohttp_example.py

Try the following with httpie (a cURL-like utility, http://httpie.org):

    $ pip install httpie
    $ http GET :5001/
    $ http GET :5001/ name==Ada
    $ http POST :5001/add x=40 y=2
    $ http POST :5001/dateadd value=1973-04-10 addend=63
    $ http POST :5001/dateadd value=2014-10-23 addend=525600 unit=minutes
"""
import asyncio
import datetime as dt

from aiohttp import web
from aiohttp.web import json_response
from webargs import fields, validate
from webargs.aiohttpparser import use_args, use_kwargs

hello_args = {"name": fields.Str(missing="Friend")}


@use_args(hello_args)
async def index(request, args):
    """A welcome page."""
    return json_response({"message": "Welcome, {}!".format(args["name"])})


add_args = {"x": fields.Float(required=True), "y": fields.Float(required=True)}


@use_kwargs(add_args)
async def add(request, x, y):
    """An addition endpoint."""
    return json_response({"result": x + y})


dateadd_args = {
    "value": fields.Date(required=False),
    "addend": fields.Int(required=True, validate=validate.Range(min=1)),
    "unit": fields.Str(missing="days", validate=validate.OneOf(["minutes", "days"])),
}


@use_kwargs(dateadd_args)
async def dateadd(request, value, addend, unit):
    """A datetime adder endpoint."""
    value = value or dt.datetime.utcnow()
    if unit == "minutes":
        delta = dt.timedelta(minutes=addend)
    else:
        delta = dt.timedelta(days=addend)
    result = value + delta
    return json_response({"result": result.isoformat()})


def create_app():
    app = web.Application()
    app.router.add_route("GET", "/", index)
    app.router.add_route("POST", "/add", add)
    app.router.add_route("POST", "/dateadd", dateadd)
    return app


def run(app, port=5001):
    loop = asyncio.get_event_loop()
    handler = app.make_handler()
    f = loop.create_server(handler, "0.0.0.0", port)
    srv = loop.run_until_complete(f)
    print("serving on", srv.sockets[0].getsockname())
    try:
        loop.run_forever()
    except KeyboardInterrupt:
        pass
    finally:
        loop.run_until_complete(handler.finish_connections(1.0))
        srv.close()
        loop.run_until_complete(srv.wait_closed())
        loop.run_until_complete(app.finish())
    loop.close()


if __name__ == "__main__":
    app = create_app()
    run(app)