/*
	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
	Copyright (C) 2023 Spacebar and Spacebar Contributors

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published
	by the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program 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 Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import { route, verifyCaptcha } from "@spacebar/api";
import { Config, FieldErrors, Invite, User, ValidRegistrationToken, generateToken, IpDataClient, AbuseIpDbClient, TimeSpan, Stopwatch } from "@spacebar/util";
import bcrypt from "bcrypt";
import { Request, Response, Router } from "express";
import { HTTPError } from "lambert-server";
import { MoreThan } from "typeorm";
import { RegisterSchema } from "@spacebar/schemas";

const router: Router = Router({ mergeParams: true });

const recentlyBlockedIps: {
    [ip: string]: {
        firstHit: Date;
        lastHit: Date;
        hits: number;
        reason: string;
    };
} = {};

router.post(
    "/",
    route({
        requestBody: "RegisterSchema",
        responses: {
            200: { body: "TokenOnlyResponse" },
            400: { body: "APIErrorOrCaptchaResponse" },
        },
    }),
    async (req: Request, res: Response) => {
        const totalSw = Stopwatch.startNew();
        const incSw = Stopwatch.startNew();
        const logTrace = (...data: unknown[]) => {
            if (process.env.LOG_VERBOSE_TRACES !== "true") return;
            console.log("[Register]", ...data, `[${totalSw.elapsed().toString()} (+${incSw.getElapsedAndReset().totalMilliseconds}ms)]`);
        };

        const body = req.body as RegisterSchema;
        const { register, security, limits } = Config.get();
        const ip = req.ip!;

        // Reg tokens
        // They're a one time use token that bypasses registration limits ( rates, disabled reg, etc )
        let regTokenUsed = false;
        if (req.get("Referrer") && req.get("Referrer")?.includes("token=")) {
            // eg theyre on https://staging.spacebar.chat/register?token=whatever
            const token = req.get("Referrer")?.split("token=")[1].split("&")[0];
            if (token) {
                const regToken = await ValidRegistrationToken.findOneOrFail({
                    where: { token, expires_at: MoreThan(new Date()) },
                });
                await regToken.remove();
                regTokenUsed = true;
                console.log(`[REGISTER] Registration token ${token} used for registration!`);
            } else {
                console.log(`[REGISTER] Invalid registration token ${token} used for registration by ${ip}!`);
            }
        }

        // check if registration is allowed
        if (!regTokenUsed && !register.allowNewRegistration) {
            throw FieldErrors({
                email: {
                    code: "REGISTRATION_DISABLED",
                    message: req.t("auth:register.REGISTRATION_DISABLED"),
                },
            });
        }

        // check if the user agreed to the Terms of Service
        if (!body.consent) {
            throw FieldErrors({
                consent: {
                    code: "CONSENT_REQUIRED",
                    message: req.t("auth:register.CONSENT_REQUIRED"),
                },
            });
        }

        if (!regTokenUsed && register.disabled) {
            throw FieldErrors({
                email: {
                    code: "DISABLED",
                    message: "Registration is disabled on this instance",
                },
            });
        }

        if (!regTokenUsed && register.requireCaptcha && security.captcha.enabled) {
            const { sitekey, service } = security.captcha;
            if (!body.captcha_key) {
                return res?.status(400).json({
                    captcha_key: ["captcha-required"],
                    captcha_sitekey: sitekey,
                    captcha_service: service,
                });
            }

            const verify = await verifyCaptcha(body.captcha_key, ip);
            if (!verify.success) {
                return res.status(400).json({
                    captcha_key: verify["error-codes"],
                    captcha_sitekey: sitekey,
                    captcha_service: service,
                });
            }
        }

        if (!regTokenUsed && !register.allowMultipleAccounts) {
            // TODO: check if fingerprint was eligible generated
            const exists = await User.findOne({
                where: { fingerprints: body.fingerprint },
                select: { id: true },
            });

            if (exists) {
                throw FieldErrors({
                    email: {
                        code: "EMAIL_ALREADY_REGISTERED",
                        message: req.t("auth:register.EMAIL_ALREADY_REGISTERED"),
                    },
                });
            }
        }

        logTrace("Basic checks");

        //region IP checks
        const cacheBlockedIp = (ip: string, reason: string) => {
            recentlyBlockedIps[ip] = {
                firstHit: new Date(),
                lastHit: new Date(),
                hits: 0,
                reason,
            };
            console.log(`[Register] ${ip} blocked from registration:`, reason);
        };

        if (!regTokenUsed && recentlyBlockedIps[ip]) {
            if (new TimeSpan(recentlyBlockedIps[ip].firstHit.getTime(), new Date().getTime()).totalHours >= 24) delete recentlyBlockedIps[ip];
            else {
                recentlyBlockedIps[ip].lastHit = new Date();
                recentlyBlockedIps[ip].hits++;
                console.log(
                    `[Register] ${ip} blocked from registration: blocked since ${recentlyBlockedIps[ip].firstHit} with ${recentlyBlockedIps[ip].hits} hits and reason:`,
                    recentlyBlockedIps[ip].reason,
                );
                throw new HTTPError("Your IP is blocked from registration");
            }
        }

        if (!regTokenUsed && register.enableAbuseIpDb) {
            const blacklist = await AbuseIpDbClient.getBlacklist();
            if (blacklist) {
                const entry = blacklist.data.find((e) => e.ipAddress === ip);

                if (entry && entry.abuseConfidenceScore >= register.blockAbuseIpDbAboveScore) {
                    cacheBlockedIp(ip, `AbuseIPDB score ${entry.abuseConfidenceScore} >= ${register.blockAbuseIpDbAboveScore} (BLACKLIST)`);
                    throw new HTTPError("Your IP is blocked from registration");
                }
            }

            const checkIp = await AbuseIpDbClient.checkIpAddress(ip);
            if (checkIp?.data && checkIp.data.abuseConfidenceScore >= register.blockAbuseIpDbAboveScore) {
                cacheBlockedIp(ip, `AbuseIPDB score ${checkIp.data.abuseConfidenceScore} >= ${register.blockAbuseIpDbAboveScore} (CHECK)`);
                throw new HTTPError("Your IP is blocked from registration");
            }
        }

        if (!regTokenUsed && register.enableIpData) {
            const ipData = await IpDataClient.getIpInfo(ip);
            if (ipData) {
                if (!ipData.threat) {
                    console.log("Invalid IPData.co response, missing threat field", ipData);
                }
                const categories = Object.entries(ipData.threat)
                    .filter(([key, value]) => key.startsWith("is_") && value === true)
                    .map(([key]) => key.replace("is_", ""));
                const blockedCategories = new Set(categories).intersection(new Set(register.blockIpDataCoThreatTypes));
                if (blockedCategories.size > 0) {
                    cacheBlockedIp(ip, `IPData.co threat types ${Array.from(blockedCategories).join(", ")}`);
                    throw new HTTPError("Your IP is blocked from registration");
                }

                if (ipData.asn.type && register.blockAsnTypes.includes(ipData.asn.type)) {
                    cacheBlockedIp(ip, `IPData.co ASN type ${ipData.asn.type} is blocked`);
                    throw new HTTPError("Your IP is blocked from registration");
                } else if (!ipData.asn.type) {
                    console.log("[Register] IPData.co response missing asn.type field", ipData);
                }

                if (ipData.asn.asn && register.blockAsns.includes(ipData.asn.asn)) {
                    cacheBlockedIp(ip, `IPData.co ASN ${ipData.asn.name} is blocked`);
                    throw new HTTPError("Your IP is blocked from registration");
                } else if (!ipData.asn.asn) {
                    console.log("[Register] IPData.co response missing asn.asn field", ipData);
                }
            }
        }
        //endregion
        logTrace("IP checks");

        // TODO: gift_code_sku_id?
        // TODO: check password strength

        const email = body.email;
        if (email) {
            // replace all dots and chars after +, if its a gmail.com email
            if (!email) {
                throw FieldErrors({
                    email: {
                        code: "INVALID_EMAIL",
                        message: req?.t("auth:register.INVALID_EMAIL"),
                    },
                });
            }

            // check if there is already an account with this email
            const exists = await User.findOne({ where: { email: email } });

            if (exists) {
                throw FieldErrors({
                    email: {
                        code: "EMAIL_ALREADY_REGISTERED",
                        message: req.t("auth:register.EMAIL_ALREADY_REGISTERED"),
                    },
                });
            }
        } else if (register.email.required) {
            throw FieldErrors({
                email: {
                    code: "BASE_TYPE_REQUIRED",
                    message: req.t("common:field.BASE_TYPE_REQUIRED"),
                },
            });
        }

        logTrace("Email checks");

        if (register.dateOfBirth.required && !body.date_of_birth) {
            throw FieldErrors({
                date_of_birth: {
                    code: "BASE_TYPE_REQUIRED",
                    message: req.t("common:field.BASE_TYPE_REQUIRED"),
                },
            });
        } else if (register.dateOfBirth.required && register.dateOfBirth.minimum) {
            const minimum = new Date();
            minimum.setFullYear(minimum.getFullYear() - register.dateOfBirth.minimum);

            let parsedDob;
            try {
                parsedDob = new Date(body.date_of_birth as Date);
                if (isNaN(parsedDob.getTime())) {
                    throw new Error("Invalid date");
                }
            } catch (e) {
                throw FieldErrors({
                    date_of_birth: {
                        code: "DATE_OF_BIRTH_INVALID",
                        message: req.t("auth:register.DATE_OF_BIRTH_INVALID"),
                    },
                });
            }

            // higher is younger
            if (parsedDob > minimum) {
                throw FieldErrors({
                    date_of_birth: {
                        code: "DATE_OF_BIRTH_UNDERAGE",
                        message: req.t("auth:register.DATE_OF_BIRTH_UNDERAGE", {
                            years: register.dateOfBirth.minimum,
                        }),
                    },
                });
            }
        }

        if (body.password) {
            const min = register.password.minLength ?? 8;

            if (body.password.length < min) {
                throw FieldErrors({
                    password: {
                        code: "PASSWORD_REQUIREMENTS_MIN_LENGTH",
                        message: req.t("auth:register.PASSWORD_REQUIREMENTS_MIN_LENGTH", { min: min }),
                    },
                });
            }
            // the salt is saved in the password refer to bcrypt docs
            body.password = await bcrypt.hash(body.password, 12);
        } else if (register.password.required) {
            throw FieldErrors({
                password: {
                    code: "BASE_TYPE_REQUIRED",
                    message: req.t("common:field.BASE_TYPE_REQUIRED"),
                },
            });
        }
        logTrace("Password checks");

        if (!regTokenUsed && !body.invite && (register.requireInvite || (register.guestsRequireInvite && !register.email))) {
            // require invite to register -> e.g. for organizations to send invites to their employees
            throw FieldErrors({
                email: {
                    code: "INVITE_ONLY",
                    message: req.t("auth:register.INVITE_ONLY"),
                },
            });
        }

        if (
            !regTokenUsed &&
            limits.absoluteRate.register.enabled &&
            (await User.count({
                where: {
                    created_at: MoreThan(new Date(Date.now() - limits.absoluteRate.register.window)),
                },
            })) >= limits.absoluteRate.register.limit
        ) {
            console.log(`Global register ratelimit exceeded for ${req.ip}, ${req.body.username}, ${req.body.invite || "No invite given"}`);
            throw FieldErrors({
                email: {
                    code: "TOO_MANY_REGISTRATIONS",
                    message: req.t("auth:register.TOO_MANY_REGISTRATIONS"),
                },
            });
        }
        logTrace("Absolute register rate checks");

        const { maxUsername } = Config.get().limits.user;
        if (body.username.length > maxUsername) {
            throw FieldErrors({
                username: {
                    code: "BASE_TYPE_BAD_LENGTH",
                    message: `Must be between 2 and ${maxUsername} in length.`,
                },
            });
        }

        const user = await User.register({ ...body, req });
        logTrace("Register user");

        if (body.invite) {
            // await to fail if the invite doesn't exist (necessary for requireInvite to work properly) (username only signups are possible)
            await Invite.joinGuild(user.id, body.invite);
            logTrace("Accept invite");
        }

        res.json({ token: await generateToken(user.id) });
        logTrace("Generate token");
    },
);

export default router;

/**
 * POST /auth/register
 * @argument { "fingerprint":"805826570869932034.wR8vi8lGlFBJerErO9LG5NViJFw", "email":"qo8etzvaf@gmail.com", "username":"qp39gr98", "password":"wtp9gep9gw", "invite":null, "consent":true, "date_of_birth":"2000-04-04", "gift_code_sku_id":null, "captcha_key":null}
 *
 * Field Error
 * @returns { "code": 50035, "errors": { "consent": { "_errors": [{ "code": "CONSENT_REQUIRED", "message": "You must agree to Discord's Terms of Service and Privacy Policy." }]}}, "message": "Invalid Form Body"}
 *
 * Success 200:
 * @returns {token: "OMITTED"}
 */