import datetime
from urllib.parse import urlsplit
from urllib.parse import urlunsplit

from authlib.integrations.flask_oauth2 import current_token
from authlib.jose import jwk
from authlib.jose import jwt
from authlib.oauth2 import OAuth2Error
from flask import abort
from flask import Blueprint
from flask import current_app
from flask import flash
from flask import jsonify
from flask import redirect
from flask import request
from flask import session
from flask import url_for
from flask_babel import gettext
from flask_babel import lazy_gettext as _
from flask_themer import render_template
from werkzeug.datastructures import CombinedMultiDict

from ..flaskutils import current_user
from ..forms import FullLoginForm
from ..models import User
from .forms import LogoutForm
from .models import Client
from .models import Consent
from .oauth2utils import authorization
from .oauth2utils import DEFAULT_JWT_ALG
from .oauth2utils import DEFAULT_JWT_KTY
from .oauth2utils import generate_user_info
from .oauth2utils import IntrospectionEndpoint
from .oauth2utils import require_oauth
from .oauth2utils import RevocationEndpoint


bp = Blueprint("oauth", __name__, url_prefix="/oauth")

CLAIMS = {
    "profile": (
        "id card outline",
        _("Personnal information about yourself, such as your name or your gender."),
    ),
    "email": ("at", _("Your email address.")),
    "address": ("envelope open outline", _("Your postal address.")),
    "phone": ("phone", _("Your phone number.")),
    "groups": ("users", _("Groups you are belonging to")),
}


def get_public_key():
    with open(current_app.config["JWT"]["PUBLIC_KEY"]) as fd:
        return fd.read()


@bp.route("/authorize", methods=["GET", "POST"])
def authorize():
    current_app.logger.debug(
        "authorization endpoint request:\nGET: %s\nPOST: %s",
        request.args.to_dict(flat=False),
        request.form.to_dict(flat=False),
    )

    if "client_id" not in request.args:
        abort(400)

    client = Client.get(request.args["client_id"])
    if not client:
        abort(400)

    user = current_user()
    scopes = request.args.get("scope", "").split(" ")

    # LOGIN

    if not user:
        if request.args.get("prompt") == "none":
            return jsonify({"error": "login_required"})

        form = FullLoginForm(request.form or None)
        if request.method == "GET":
            return render_template("login.html", form=form, menu=False)

        if not form.validate() or not User.authenticate(
            form.login.data, form.password.data, True
        ):
            flash(gettext("Login failed, please check your information"), "error")
            return render_template("login.html", form=form, menu=False)

        return redirect(request.url)

    if not user.can_use_oidc:
        abort(400)

    # CONSENT

    consents = Consent.filter(
        client=client.dn,
        subject=user.dn,
    )
    consents = [c for c in consents if not c.revokation_date]
    consent = consents[0] if consents else None

    if request.method == "GET":
        if client.preconsent or (
            consent and all(scope in set(consent.scope) for scope in scopes)
        ):
            return authorization.create_authorization_response(grant_user=user.dn)

        elif request.args.get("prompt") == "none":
            response = {"error": "consent_required"}
            current_app.logger.debug("authorization endpoint response: %s", response)
            return jsonify(response)

        try:
            grant = authorization.get_consent_grant(end_user=user)
        except OAuth2Error as error:
            response = dict(error.get_body())
            current_app.logger.debug("authorization endpoint response: %s", response)
            return jsonify(response)

        return render_template(
            "oidc/user/authorize.html",
            user=user,
            grant=grant,
            client=client,
            claims=CLAIMS,
            menu=False,
            ignored_claims=["openid"],
        )

    if request.method == "POST":
        if request.form["answer"] == "logout":
            del session["user_dn"]
            flash(gettext("You have been successfully logged out."), "success")
            return redirect(request.url)

        if request.form["answer"] == "deny":
            grant_user = None

        if request.form["answer"] == "accept":
            grant_user = user.dn

            if consent:
                consent.scope = list(set(scopes + consents[0].scope))
            else:

                consent = Consent(
                    client=client.dn,
                    subject=user.dn,
                    scope=scopes,
                    issue_date=datetime.datetime.now(),
                )
            consent.save()

        response = authorization.create_authorization_response(grant_user=grant_user)
        current_app.logger.debug(
            "authorization endpoint response: %s", response.location
        )
        return response


@bp.route("/token", methods=["POST"])
def issue_token():
    current_app.logger.debug(
        "token endpoint request: POST: %s", request.form.to_dict(flat=False)
    )
    response = authorization.create_token_response()
    current_app.logger.debug("token endpoint response: %s", response.json)
    return response


@bp.route("/introspect", methods=["POST"])
def introspect_token():
    current_app.logger.debug(
        "introspection endpoint request: POST: %s", request.form.to_dict(flat=False)
    )
    response = authorization.create_endpoint_response(
        IntrospectionEndpoint.ENDPOINT_NAME
    )
    current_app.logger.debug("introspection endpoint response: %s", response.json)
    return response


@bp.route("/revoke", methods=["POST"])
def revoke_token():
    current_app.logger.debug(
        "revokation endpoint request: POST: %s", request.form.to_dict(flat=False)
    )
    response = authorization.create_endpoint_response(RevocationEndpoint.ENDPOINT_NAME)
    current_app.logger.debug("revokation endpoint response: %s", response.json)
    return response


@bp.route("/jwks.json")
def jwks():
    obj = jwk.dumps(
        get_public_key(), current_app.config["JWT"].get("KTY", DEFAULT_JWT_KTY)
    )
    return jsonify(
        {
            "keys": [
                {
                    "kid": None,
                    "use": "sig",
                    "alg": current_app.config["JWT"].get("ALG", DEFAULT_JWT_ALG),
                    **obj,
                }
            ]
        }
    )


@bp.route("/userinfo")
@require_oauth("profile")
def userinfo():
    current_app.logger.debug("userinfo endpoint request: %s", request.args)
    response = generate_user_info(current_token.subject, current_token.scope[0])
    current_app.logger.debug("userinfo endpoint response: %s", response)
    return jsonify(response)


def set_parameter_in_url_query(url, **kwargs):
    split = list(urlsplit(url))

    parameters = "&".join(f"{key}={value}" for key, value in kwargs.items())

    if split[3]:
        split[3] = f"{split[3]}&{parameters}"
    else:
        split[3] = parameters

    return urlunsplit(split)


@bp.route("/end_session", methods=["GET", "POST"])
def end_session():
    data = CombinedMultiDict((request.args, request.form))
    user = current_user()

    form = LogoutForm(request.form)
    form.action = url_for("oidc.oauth.end_session_submit")

    client = None
    valid_uris = []

    if "client_id" in data:
        client = Client.get(data["client_id"])
        if client:
            valid_uris = client.post_logout_redirect_uris

    if (
        not data.get("id_token_hint")
        or (data.get("logout_hint") and data["logout_hint"] != user.uid[0])
    ) and not session.get("end_session_confirmation"):
        session["end_session_data"] = data
        return render_template(
            "oidc/user/logout.html", form=form, client=client, menu=False
        )

    if data.get("id_token_hint"):
        id_token = jwt.decode(data["id_token_hint"], get_public_key())
        if not id_token["iss"] == current_app.config["JWT"]["ISS"]:
            return jsonify(
                {
                    "status": "error",
                    "message": "id_token_hint has not been issued here",
                }
            )

        if "client_id" in data:
            if (
                data["client_id"] != id_token["aud"]
                and data["client_id"] not in id_token["aud"]
            ):
                return jsonify(
                    {
                        "status": "error",
                        "message": "id_token_hint and client_id don't match",
                    }
                )

        else:
            client_ids = (
                id_token["aud"]
                if isinstance(id_token["aud"], list)
                else [id_token["aud"]]
            )
            for client_id in client_ids:
                client = Client.get(client_id)
                if client:
                    valid_uris.extend(client.post_logout_redirect_uris)

        if user.uid[0] != id_token["sub"] and not session.get(
            "end_session_confirmation"
        ):
            session["end_session_data"] = data
            return render_template(
                "oidc/user/logout.html", form=form, client=client, menu=False
            )

    user.logout()

    if "end_session_confirmation" in session:
        del session["end_session_confirmation"]

    if (
        "post_logout_redirect_uri" in data
        and data["post_logout_redirect_uri"] in valid_uris
    ):
        url = data["post_logout_redirect_uri"]
        if "state" in data:
            url = set_parameter_in_url_query(url, state=data["state"])
        return redirect(data["post_logout_redirect_uri"])

    flash(_("You have been disconnected"), "success")
    return redirect(url_for("account.index"))


@bp.route("/end_session_confirm", methods=["POST"])
def end_session_submit():
    form = LogoutForm(request.form)
    if not form.validate():
        flash(_("An error happened during the logout"), "error")
        client = Client.get(session.get("end_session_data", {}).get("client_id"))
        return render_template("oidc/user/logout.html", form=form, client=client)

    data = session["end_session_data"]
    del session["end_session_data"]

    if request.form["answer"] == "logout":
        session["end_session_confirmation"] = True
        url = set_parameter_in_url_query(url_for("oidc.oauth.end_session"), **data)
        return redirect(url)

    flash(_("You have not been disconnected"), "info")

    return redirect(url_for("account.index"))