import base64

import requests
from flask import Blueprint
from flask import current_app as app
from flask import redirect, render_template, request, session, url_for
from itsdangerous.exc import BadSignature, BadTimeSignature, SignatureExpired

from CTFd.models import Teams, Users, db
from CTFd.utils import config, email, get_app_config, get_config
from CTFd.utils import user as current_user
from CTFd.cache import clear_user_session, clear_team_session
from CTFd.utils import validators
from CTFd.utils.config import is_teams_mode
from CTFd.utils.config.integrations import mlc_registration
from CTFd.utils.config.visibility import registration_visible
from CTFd.utils.crypto import verify_password
from CTFd.utils.decorators import ratelimit
from CTFd.utils.decorators.visibility import check_registration_visibility
from CTFd.utils.helpers import error_for, get_errors
from CTFd.utils.logging import log
from CTFd.utils.modes import TEAMS_MODE
from CTFd.utils.security.auth import login_user, logout_user
from CTFd.utils.security.signing import unserialize

auth = Blueprint("auth", __name__)


@auth.route("/confirm", methods=["POST", "GET"])
@auth.route("/confirm/<data>", methods=["POST", "GET"])
@ratelimit(method="POST", limit=10, interval=60)
def confirm(data=None):
    if not get_config("verify_emails"):
        # If the CTF doesn't care about confirming email addresses then redierct to challenges
        return redirect(url_for("challenges.listing"))

    # User is confirming email account
    if data and request.method == "GET":
        try:
            user_email = unserialize(data, max_age=1800)
        except (BadTimeSignature, SignatureExpired):
            return render_template(
                "confirm.html", errors=["Your confirmation link has expired"]
            )
        except (BadSignature, TypeError, base64.binascii.Error):
            return render_template(
                "confirm.html", errors=["Your confirmation token is invalid"]
            )

        user = Users.query.filter_by(email=user_email).first_or_404()
        if user.verified:
            return redirect(url_for("views.settings"))

        user.verified = True
        log(
            "registrations",
            format="[{date}] {ip} - successful confirmation for {name}",
            name=user.name,
        )
        db.session.commit()
        clear_user_session(user_id=user.id)
        email.successful_registration_notification(user.email)
        db.session.close()
        if current_user.authed():
            return redirect(url_for("challenges.listing"))
        return redirect(url_for("auth.login"))

    # User is trying to start or restart the confirmation flow
    if not current_user.authed():
        return redirect(url_for("auth.login"))

    user = Users.query.filter_by(id=session["id"]).first_or_404()
    if user.verified:
        return redirect(url_for("views.settings"))

    if data is None:
        if request.method == "POST":
            # User wants to resend their confirmation email
            email.verify_email_address(user.email)
            log(
                "registrations",
                format="[{date}] {ip} - {name} initiated a confirmation email resend",
            )
            return render_template(
                "confirm.html",
                user=user,
                infos=["Your confirmation email has been resent!"],
            )
        elif request.method == "GET":
            # User has been directed to the confirm page
            return render_template("confirm.html", user=user)


@auth.route("/reset_password", methods=["POST", "GET"])
@auth.route("/reset_password/<data>", methods=["POST", "GET"])
@ratelimit(method="POST", limit=10, interval=60)
def reset_password(data=None):
    if data is not None:
        try:
            email_address = unserialize(data, max_age=1800)
        except (BadTimeSignature, SignatureExpired):
            return render_template(
                "reset_password.html", errors=["Your link has expired"]
            )
        except (BadSignature, TypeError, base64.binascii.Error):
            return render_template(
                "reset_password.html", errors=["Your reset token is invalid"]
            )

        if request.method == "GET":
            return render_template("reset_password.html", mode="set")
        if request.method == "POST":
            password = request.form.get("password", "").strip()
            user = Users.query.filter_by(email=email_address).first_or_404()
            if user.oauth_id:
                return render_template(
                    "reset_password.html",
                    errors=[
                        "Your account was registered via an authentication provider and does not have an associated password. Please login via your authentication provider."
                    ],
                )

            pass_short = len(password) == 0
            if pass_short:
                return render_template(
                    "reset_password.html", errors=["Please pick a longer password"]
                )

            user.password = password
            db.session.commit()
            clear_user_session(user_id=user.id)
            log(
                "logins",
                format="[{date}] {ip} -  successful password reset for {name}",
                name=user.name,
            )
            db.session.close()
            email.password_change_alert(user.email)
            return redirect(url_for("auth.login"))

    if request.method == "POST":
        email_address = request.form["email"].strip()
        user = Users.query.filter_by(email=email_address).first()

        get_errors()

        if config.can_send_mail() is False:
            return render_template(
                "reset_password.html",
                errors=["Email could not be sent due to server misconfiguration"],
            )

        if not user:
            return render_template(
                "reset_password.html",
                errors=[
                    "If that account exists you will receive an email, please check your inbox"
                ],
            )

        if user.oauth_id:
            return render_template(
                "reset_password.html",
                errors=[
                    "The email address associated with this account was registered via an authentication provider and does not have an associated password. Please login via your authentication provider."
                ],
            )

        email.forgot_password(email_address)

        return render_template(
            "reset_password.html",
            errors=[
                "If that account exists you will receive an email, please check your inbox"
            ],
        )
    return render_template("reset_password.html")


@auth.route("/register", methods=["POST", "GET"])
@check_registration_visibility
@ratelimit(method="POST", limit=10, interval=5)
def register():
    errors = get_errors()
    if request.method == "POST":
        name = request.form.get("name", "").strip()
        email_address = request.form.get("email", "").strip().lower()
        password = request.form.get("password", "").strip()

        name_len = len(name) == 0
        names = Users.query.add_columns("name", "id").filter_by(name=name).first()
        emails = (
            Users.query.add_columns("email", "id")
            .filter_by(email=email_address)
            .first()
        )
        pass_short = len(password) == 0
        pass_long = len(password) > 128
        valid_email = validators.validate_email(email_address)
        team_name_email_check = validators.validate_email(name)

        if not valid_email:
            errors.append("Please enter a valid email address")
        if email.check_email_is_whitelisted(email_address) is False:
            errors.append(
                "Only email addresses under {domains} may register".format(
                    domains=get_config("domain_whitelist")
                )
            )
        if names:
            errors.append("That user name is already taken")
        if team_name_email_check is True:
            errors.append("Your user name cannot be an email address")
        if emails:
            errors.append("That email has already been used")
        if pass_short:
            errors.append("Pick a longer password")
        if pass_long:
            errors.append("Pick a shorter password")
        if name_len:
            errors.append("Pick a longer user name")

        if len(errors) > 0:
            return render_template(
                "register.html",
                errors=errors,
                name=request.form["name"],
                email=request.form["email"],
                password=request.form["password"],
            )
        else:
            with app.app_context():
                user = Users(name=name, email=email_address, password=password)
                db.session.add(user)
                db.session.commit()
                db.session.flush()

                login_user(user)

                if config.can_send_mail() and get_config(
                    "verify_emails"
                ):  # Confirming users is enabled and we can send email.
                    log(
                        "registrations",
                        format="[{date}] {ip} - {name} registered (UNCONFIRMED) with {email}",
                    )
                    email.verify_email_address(user.email)
                    db.session.close()
                    return redirect(url_for("auth.confirm"))
                else:  # Don't care about confirming users
                    if (
                        config.can_send_mail()
                    ):  # We want to notify the user that they have registered.
                        email.successful_registration_notification(user.email)

        log("registrations", "[{date}] {ip} - {name} registered with {email}")
        db.session.close()

        if is_teams_mode():
            return redirect(url_for("teams.private"))

        return redirect(url_for("challenges.listing"))
    else:
        return render_template("register.html", errors=errors)


@auth.route("/login", methods=["POST", "GET"])
@ratelimit(method="POST", limit=10, interval=5)
def login():
    errors = get_errors()
    if request.method == "POST":
        name = request.form["name"]

        # Check if the user submitted an email address or a team name
        if validators.validate_email(name) is True:
            user = Users.query.filter_by(email=name).first()
        else:
            user = Users.query.filter_by(name=name).first()

        if user:
            if user and verify_password(request.form["password"], user.password):
                session.regenerate()

                login_user(user)
                log("logins", "[{date}] {ip} - {name} logged in")

                db.session.close()
                if request.args.get("next") and validators.is_safe_url(
                    request.args.get("next")
                ):
                    return redirect(request.args.get("next"))
                return redirect(url_for("challenges.listing"))

            else:
                # This user exists but the password is wrong
                log("logins", "[{date}] {ip} - submitted invalid password for {name}")
                errors.append("Your username or password is incorrect")
                db.session.close()
                return render_template("login.html", errors=errors)
        else:
            # This user just doesn't exist
            log("logins", "[{date}] {ip} - submitted invalid account information")
            errors.append("Your username or password is incorrect")
            db.session.close()
            return render_template("login.html", errors=errors)
    else:
        db.session.close()
        return render_template("login.html", errors=errors)


@auth.route("/oauth")
def oauth_login():
    endpoint = (
        get_app_config("OAUTH_AUTHORIZATION_ENDPOINT")
        or get_config("oauth_authorization_endpoint")
        or "https://auth.majorleaguecyber.org/oauth/authorize"
    )

    if get_config("user_mode") == "teams":
        scope = "profile team"
    else:
        scope = "profile"

    client_id = get_app_config("OAUTH_CLIENT_ID") or get_config("oauth_client_id")

    if client_id is None:
        error_for(
            endpoint="auth.login",
            message="OAuth Settings not configured. "
            "Ask your CTF administrator to configure MajorLeagueCyber integration.",
        )
        return redirect(url_for("auth.login"))

    redirect_url = "{endpoint}?response_type=code&client_id={client_id}&scope={scope}&state={state}".format(
        endpoint=endpoint, client_id=client_id, scope=scope, state=session["nonce"]
    )
    return redirect(redirect_url)


@auth.route("/redirect", methods=["GET"])
@ratelimit(method="GET", limit=10, interval=60)
def oauth_redirect():
    oauth_code = request.args.get("code")
    state = request.args.get("state")
    if session["nonce"] != state:
        log("logins", "[{date}] {ip} - OAuth State validation mismatch")
        error_for(endpoint="auth.login", message="OAuth State validation mismatch.")
        return redirect(url_for("auth.login"))

    if oauth_code:
        url = (
            get_app_config("OAUTH_TOKEN_ENDPOINT")
            or get_config("oauth_token_endpoint")
            or "https://auth.majorleaguecyber.org/oauth/token"
        )

        client_id = get_app_config("OAUTH_CLIENT_ID") or get_config("oauth_client_id")
        client_secret = get_app_config("OAUTH_CLIENT_SECRET") or get_config(
            "oauth_client_secret"
        )
        headers = {"content-type": "application/x-www-form-urlencoded"}
        data = {
            "code": oauth_code,
            "client_id": client_id,
            "client_secret": client_secret,
            "grant_type": "authorization_code",
        }
        token_request = requests.post(url, data=data, headers=headers)

        if token_request.status_code == requests.codes.ok:
            token = token_request.json()["access_token"]
            user_url = (
                get_app_config("OAUTH_API_ENDPOINT")
                or get_config("oauth_api_endpoint")
                or "https://api.majorleaguecyber.org/user"
            )

            headers = {
                "Authorization": "Bearer " + str(token),
                "Content-type": "application/json",
            }
            api_data = requests.get(url=user_url, headers=headers).json()

            user_id = api_data["id"]
            user_name = api_data["name"]
            user_email = api_data["email"]

            user = Users.query.filter_by(email=user_email).first()
            if user is None:
                # Check if we are allowing registration before creating users
                if registration_visible() or mlc_registration():
                    user = Users(
                        name=user_name,
                        email=user_email,
                        oauth_id=user_id,
                        verified=True,
                    )
                    db.session.add(user)
                    db.session.commit()
                else:
                    log("logins", "[{date}] {ip} - Public registration via MLC blocked")
                    error_for(
                        endpoint="auth.login",
                        message="Public registration is disabled. Please try again later.",
                    )
                    return redirect(url_for("auth.login"))

            if get_config("user_mode") == TEAMS_MODE:
                team_id = api_data["team"]["id"]
                team_name = api_data["team"]["name"]

                team = Teams.query.filter_by(oauth_id=team_id).first()
                if team is None:
                    team = Teams(name=team_name, oauth_id=team_id, captain_id=user.id)
                    db.session.add(team)
                    db.session.commit()
                    clear_team_session(team_id=team.id)

                team_size_limit = get_config("team_size", default=0)
                if team_size_limit and len(team.members) >= team_size_limit:
                    plural = "" if team_size_limit == 1 else "s"
                    size_error = "Teams are limited to {limit} member{plural}.".format(
                        limit=team_size_limit, plural=plural
                    )
                    error_for(endpoint="auth.login", message=size_error)
                    return redirect(url_for("auth.login"))

                team.members.append(user)
                db.session.commit()

            if user.oauth_id is None:
                user.oauth_id = user_id
                user.verified = True
                db.session.commit()
                clear_user_session(user_id=user.id)

            login_user(user)

            return redirect(url_for("challenges.listing"))
        else:
            log("logins", "[{date}] {ip} - OAuth token retrieval failure")
            error_for(endpoint="auth.login", message="OAuth token retrieval failure.")
            return redirect(url_for("auth.login"))
    else:
        log("logins", "[{date}] {ip} - Received redirect without OAuth code")
        error_for(
            endpoint="auth.login", message="Received redirect without OAuth code."
        )
        return redirect(url_for("auth.login"))


@auth.route("/logout")
def logout():
    if current_user.authed():
        logout_user()
    return redirect(url_for("views.static_html"))