"""Moonchess practice server: play against the computer.

Stateless: the page sends the current position with every request and gets the new
position back, so there's no session to lose. The page decides whose turn belongs to
the computer; this server only applies moves and picks them.
"""

import argparse
import logging

from aiohttp import web

from game import Game
from server import STATIC_DIR, no_cache
from solver import Solver

solver = Solver()  # solves every position up front; takes about a second


async def index(request):
    return web.FileResponse(STATIC_DIR / "practice.html")


async def play(request):
    """Body: {history, turn, cell} to play `cell`, or {history, turn, accuracy} for a
    computer move, where accuracy (0-1) is the chance it plays a perfect move. A computer
    move's reply also says how it was chosen, as computerMove: {cell, how}."""
    try:
        body = await request.json()
        game = Game.from_history(body["history"], body["turn"])
        cell = body.get("cell")
        accuracy = float(body.get("accuracy", 1))
    except (ValueError, KeyError, TypeError, AttributeError):
        return web.json_response({"error": "Invalid request"}, status=400)

    computer_move = None
    if cell is None and game.winner is None:
        cell, how = solver.choose(game, accuracy)
        computer_move = {"cell": cell, "how": how}
    error = game.play(game.turn, cell)
    if error:
        return web.json_response({"error": error}, status=400)
    return web.json_response({**game.to_dict(), "computerMove": computer_move})


def make_app():
    app = web.Application(middlewares=[no_cache])
    app.router.add_get("/", index)
    app.router.add_post("/api/play", play)
    app.router.add_static("/static", STATIC_DIR)
    return app


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Moonchess practice server")
    parser.add_argument("--host", default="127.0.0.1")
    parser.add_argument("--port", type=int, default=8081)
    args = parser.parse_args()
    logging.basicConfig(level=logging.INFO, format="%(asctime)s %(message)s")
    web.run_app(make_app(), host=args.host, port=args.port)