# This file is part of GNU TALER.
# Copyright (C) 2017 Taler Systems SA
#
# TALER is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free Software
# Foundation; either version 2.1, or (at your option) any later version.
#
# TALER is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License along with
# GNU TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
#
# @author Marcello Stanisci

import os
import base64
import logging
import json
from urllib.parse import urljoin
import flask
import requests
from ..talerconfig import TalerConfig
from .amount import Amount

BASE_DIR = os.path.dirname(os.path.abspath(__file__))
app = flask.Flask(__name__, template_folder=BASE_DIR)
app.debug = True
app.secret_key = base64.b64encode(os.urandom(64)).decode('utf-8')
TC = TalerConfig.from_env()
BACKEND_URL = TC["frontends"]["backend"].value_string(required=True)
CURRENCY = TC["taler"]["currency"].value_string(required=True)
app.config.from_object(__name__)
LOGGER = logging.getLogger(__name__)


def backend_error(requests_response):
    LOGGER.error("Backend error: status code: "
                 + str(requests_response.status_code))
    try:
        return flask.jsonify(requests_response.json()), requests_response.status_code
    except json.decoder.JSONDecodeError:
        LOGGER.error("Backend error (NO JSON returned): status code: "
                     + str(requests_response.status_code))
        return flask.jsonify(dict(error="Backend died, no JSON got from it")), 502


@app.context_processor
def utility_processor():

    def join_urlparts(*parts):
        ret = ""
        part = 0
        while part < len(parts):
            buf = parts[part]
            part += 1
            if ret.endswith("/"):
                buf = buf.lstrip("/")
            elif ret and not buf.startswith("/"):
                buf = "/" + buf
            ret += buf
        return ret

    def url(my_url):
        return join_urlparts(flask.request.script_root, my_url)
    def env(name, default=None):
        return os.environ.get(name, default)
    return dict(url=url, env=env)


@app.route("/tip-pickup", methods=["POST"])
def pick():
    body = flask.request.get_json()
    resp = requests.post(urljoin(BACKEND_URL, 'tip-pickup'),
                         json=body)
    if resp.status_code != 200:
        return backend_error(resp)
    return flask.jsonify(resp.json())

@app.route("/submit-survey", methods=["POST"])
def submit_survey():
    tip_spec = dict(pickup_url=urljoin(flask.request.base_url, "/tip-pickup"),
                    amount=Amount(CURRENCY, 1).dump(),
                    instance="default",
                    justification="Payment methods survey")
    resp = requests.post(urljoin(BACKEND_URL, 'tip-authorize'),
                         json=tip_spec)
    if resp.status_code != 200:
        return backend_error(resp)

    response = flask.make_response(
        flask.render_template("templates/wait.html", success=True),
        402)
    response.headers["X-Taler-Tip"] = resp.json()["tip_token"]

    return response


@app.route("/", methods=["GET"])
def survey():
    return flask.render_template("templates/index.html", merchant_currency=CURRENCY)