"""Endpoints for the authorisation stuff."""
import uuid
import traceback
from typing import Tuple, Optional

import sqlite3
from flask import request, jsonify, Response, current_app

from gn3.auth import db
from gn3.auth.dictify import dictify
from gn3.auth.blueprint import oauth2

from .errors import NotFoundError, UserRegistrationError
from .resources import user_resources as _user_resources
from .roles import user_role, assign_default_roles, user_roles as _user_roles
from .groups import (
    all_groups, GroupCreationError, user_group as _user_group,
    group_users as _group_users, create_group as _create_group)

from ..authentication.oauth2.resource_server import require_oauth
from ..authentication.users import save_user, set_user_password
from ..authentication.oauth2.models.oauth2token import token_by_access_token

@oauth2.route("/user", methods=["GET"])
@require_oauth("profile")
def user_details():
    """Return user's details."""
    with require_oauth.acquire("profile") as the_token:
        user = the_token.user
        user_dets = {
            "user_id": user.user_id, "email": user.email, "name": user.name,
            "group": False
        }
        with db.connection(current_app.config["AUTH_DB"]) as conn, db.cursor(conn) as cursor:
            return jsonify(_user_group(cursor, user).maybe(
                user_dets,
                lambda group: {**user_dets, "group": dictify(group)}))

@oauth2.route("/user-roles", methods=["GET"])
@require_oauth("role")
def user_roles():
    """Return the non-resource roles assigned to the user."""
    with require_oauth.acquire("role") as token:
        with db.connection(current_app.config["AUTH_DB"]) as conn:
            return jsonify(_user_roles(conn, token.user).maybe(
                tuple(), lambda roles: tuple(dictify(role) for role in roles)))

def __email_valid__(email: str) -> Tuple[bool, Optional[str]]:
    """Validate the email address."""
    if email == "":
        return False, "Empty email address"

    ## Check that the address is a valid email address
    ## Review use of `email-validator` or `pyIsEmail` python packages for
    ## validating the emails, if it turns out this is important.

    ## Success
    return True, None

def __password_valid__(password, confirm_password) -> Tuple[bool, Optional[str]]:
    if password == "" or confirm_password == "":
        return False, "Empty password value"

    if password != confirm_password:
        return False, "Mismatched password values"

    return True, None

def __user_name_valid__(name: str) -> Tuple[bool, Optional[str]]:
    if name == "":
        return False, "User's name not provided."

    return True, None

def __assert_not_logged_in__(conn: db.DbConnection):
    bearer = request.headers.get('Authorization')
    if bearer:
        token = token_by_access_token(conn, bearer.split(None)[1]).maybe(# type: ignore[misc]
            False, lambda tok: tok)
        if token:
            raise UserRegistrationError(
                "Cannot register user while authenticated")

@oauth2.route("/register-user", methods=["POST"])
def register_user():
    """Register a user."""
    with db.connection(current_app.config["AUTH_DB"]) as conn:
        __assert_not_logged_in__(conn)

        form = request.form
        email = form.get("email", "").strip()
        password = form.get("password", "").strip()
        user_name = form.get("user_name", "").strip()
        errors = tuple(
                error for valid,error in
            [__email_valid__(email),
             __password_valid__(
                 password, form.get("confirm_password", "").strip()),
             __user_name_valid__(user_name)]
            if not valid)
        if len(errors) > 0:
            raise UserRegistrationError(*errors)

        try:
            with db.cursor(conn) as cursor:
                user, _hashed_password = set_user_password(
                    cursor, save_user(cursor, email, user_name), password)
                assign_default_roles(cursor, user)
                return jsonify(
                    {
                        "user_id": user.user_id,
                        "email": user.email,
                        "name": user.name
                    }), 200
        except sqlite3.IntegrityError as sq3ie:
            current_app.logger.debug(traceback.format_exc())
            raise UserRegistrationError(
                "A user with that email already exists") from sq3ie

    raise Exception(
        "unknown_error", "The system experienced an unexpected error.")

@oauth2.route("/groups", methods=["GET"])
@require_oauth("profile group")
def groups():
    """Return the list of groups that exist."""
    with db.connection(current_app.config["AUTH_DB"]) as conn:
        the_groups = all_groups(conn)

    return jsonify(the_groups.maybe(
        [], lambda grps: [dictify(grp) for grp in grps]))

@oauth2.route("/create-group", methods=["POST"])
@require_oauth("profile group")
def create_group():
    """Create a new group."""
    with require_oauth.acquire("profile group") as the_token:
        group_name=request.form.get("group_name", "").strip()
        if not bool(group_name):
            raise GroupCreationError("Could not create the group.")

        db_uri = current_app.config["AUTH_DB"]
        with db.connection(db_uri) as conn:
            user = the_token.user
            new_group = _create_group(
                conn, group_name, user, request.form.get("group_description"))
            return jsonify({
                **dictify(new_group), "group_leader": dictify(user)
            })

@oauth2.route("/role/<uuid:role_id>", methods=["GET"])
@require_oauth("role")
def role(role_id: uuid.UUID) -> Response:
    """Retrieve a user role with id `role_id`"""
    def __error__(exc: Exception):
        raise exc
    with require_oauth.acquire("profile role") as the_token:
        db_uri = current_app.config["AUTH_DB"]
        with db.connection(db_uri) as conn:
            the_role = user_role(conn, the_token.user, role_id)
            return the_role.either(
                __error__, lambda a_role: jsonify(dictify(a_role)))

@oauth2.route("/user-group", methods=["GET"])
@require_oauth("profile group")
def user_group():
    """Retrieve the group in which the user is a member."""
    with require_oauth.acquire("profile group") as the_token:
        db_uri = current_app.config["AUTH_DB"]
        with db.connection(db_uri) as conn, db.cursor(conn) as cursor:
            group = _user_group(cursor, the_token.user).maybe(
                False, lambda grp: grp)

        if group:
            return jsonify(dictify(group))
        raise NotFoundError("User is not a member of any group.")

@oauth2.route("/user-resources")
@require_oauth("profile resource")
def user_resources():
    """Retrieve the resources a user has access to."""
    with require_oauth.acquire("profile resource") as the_token:
        db_uri = current_app.config["AUTH_DB"]
        with db.connection(db_uri) as conn:
            return jsonify([
                dictify(resource) for resource in
                _user_resources(conn, the_token.user)])

@oauth2.route("/group-users/<uuid:group_id>", methods=["GET"])
@require_oauth("profile group")
def group_users(group_id: uuid.UUID) -> Response:
    """Retrieve all the members of a group."""
    with require_oauth.acquire("profile group") as the_token:
        db_uri = current_app.config["AUTH_DB"]
        with db.connection(db_uri) as conn:
            return jsonify(tuple(
                dictify(user) for user in _group_users(conn, group_id)))