import express, {Request, Response} from 'express';
import * as InvitationsService from './invitations.service.js';
import * as UsersService from '../users/users.admin.service.js';
import {toPermissions} from '../admin.schema.js';
import {sendInvitationMail} from '../admin.mail.js';
import {ADMIN_APP_URL, LOG_INVITE_LINKS} from '../admin.config.js';
import {sendServerError} from '../admin.errors.js';
import logger from '../../../middleware/logger.js';

export const invitationsRouter = express.Router();

/**
 * The admin-facing half of invitations (create, resend, revoke). The public
 * half - preview and accept - lives in invitations.plugin.ts, because
 * redeeming an invitation has to create a user through better-auth internals.
 *
 * Mounted behind requireAppAccess('admin').
 */

const EMAIL_PATTERN = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;

/**
 * With the mail relay off (the normal local setup) the invitation mail never
 * arrives, and only the token's hash is stored, so there would be no way to
 * walk through the accept flow. Logging the link closes that.
 *
 * Gated on an explicit opt-in rather than on NODE_ENV: the link is a live
 * account-creation credential, and "not production" is too weak a condition to
 * hang that on. See LOG_INVITE_LINKS in admin.config.ts.
 */
const logInviteLinkInDev = (token: string): void => {
	if (LOG_INVITE_LINKS) {
		logger.info(`Admin: invitation link ${ADMIN_APP_URL}/accept-invite?token=${encodeURIComponent(token)}`);
	}
};

/**
 * @swagger
 * /admin/invitations:
 *      get:
 *          summary: List open (unaccepted, unrevoked, unexpired) invitations
 *          tags: [admin]
 *          responses:
 *              200:
 *                  description: Success
 */
invitationsRouter.get('/', async (req: Request, res: Response) => {
	try {
		res.status(200).send(await InvitationsService.listOpenInvitations());
	} catch (e: any) {
		sendServerError(res, e);
	}
});

/**
 * @swagger
 * /admin/invitations:
 *      post:
 *          summary: Invite someone and mail them an acceptance link
 *          tags: [admin]
 *          requestBody:
 *              required: true
 *              content:
 *                  application/json:
 *                      schema:
 *                          type: object
 *                          required: [email, name, permissions]
 *                          properties:
 *                              email:
 *                                  type: string
 *                              name:
 *                                  type: string
 *                              permissions:
 *                                  type: array
 *                                  description: >
 *                                      One entry per (app, role). A plain array of app names is
 *                                      accepted too and means the same at the `access` role.
 *                                  items:
 *                                      type: object
 *                                      properties:
 *                                          app:
 *                                              type: string
 *                                          role:
 *                                              type: string
 *          responses:
 *              201:
 *                  description: Invitation created and mailed
 *              400:
 *                  description: Invalid input
 *              409:
 *                  description: A user with this address already exists
 */
invitationsRouter.post('/', async (req: Request, res: Response) => {
	try {
		const email = String(req.body?.email || '').trim().toLowerCase();
		const name = String(req.body?.name || '').trim();

		// Same two accepted shapes as PUT /admin/users/:id/permissions.
		const permissions = toPermissions(req.body?.permissions ?? req.body?.apps);

		if (!EMAIL_PATTERN.test(email) || name.length === 0 || !permissions) {
			res.status(400).send({
				status: 'BAD_REQUEST',
				message: 'E-Mail, Name und Berechtigungen sind erforderlich.'
			});
			return;
		}

		// Inviting someone who already has an account would strand them on an
		// accept page that can only fail. Granting permissions on the existing
		// user is the operation they actually want.
		if (await UsersService.findUserByEmail(email)) {
			res.status(409).send({
				status: 'CONFLICT',
				message: 'Für diese E-Mail-Adresse gibt es bereits ein Konto. Vergib dort die Berechtigungen.'
			});
			return;
		}

		const invitation = await InvitationsService.createInvitation(
			email,
			name,
			permissions,
			res.locals.admin.id
		);

		const mailed = await sendInvitationMail(email, name, invitation.token, invitation.expiresAt);
		if (!mailed) {
			logger.warn('Admin: invitation created but the mail was not accepted', {email});
		}
		logInviteLinkInDev(invitation.token);

		res.status(201).send({id: invitation.id, email, name, expiresAt: invitation.expiresAt, mailed});
	} catch (e: any) {
		sendServerError(res, e);
	}
});

/**
 * @swagger
 * /admin/invitations/{invitationId}/resend:
 *      post:
 *          summary: Issue a new token for an open invitation and mail it again
 *          description: The previous link stops working.
 *          tags: [admin]
 *          responses:
 *              200:
 *                  description: Resent
 *              404:
 *                  description: No open invitation with this id
 */
invitationsRouter.post('/:invitationId/resend', async (req: Request, res: Response) => {
	try {
		const invitationId = parseInt(req.params.invitationId, 10);
		if (Number.isNaN(invitationId)) {
			res.status(400).send({status: 'BAD_REQUEST', message: 'Ungültige Einladungs-ID.'});
			return;
		}

		const resent = await InvitationsService.resendInvitation(invitationId);
		if (!resent) {
			res.status(404).send({status: 'NOT_FOUND', message: 'Einladung nicht gefunden.'});
			return;
		}

		const mailed = await sendInvitationMail(resent.email, resent.name, resent.token, resent.expiresAt);
		if (!mailed) {
			logger.warn('Admin: invitation resent but the mail was not accepted', {email: resent.email});
		}
		logInviteLinkInDev(resent.token);

		res.status(200).send({id: invitationId, expiresAt: resent.expiresAt, mailed});
	} catch (e: any) {
		sendServerError(res, e);
	}
});

/**
 * @swagger
 * /admin/invitations/{invitationId}:
 *      delete:
 *          summary: Revoke an open invitation
 *          tags: [admin]
 *          responses:
 *              204:
 *                  description: Revoked
 *              404:
 *                  description: No open invitation with this id
 */
invitationsRouter.delete('/:invitationId', async (req: Request, res: Response) => {
	try {
		const invitationId = parseInt(req.params.invitationId, 10);
		if (Number.isNaN(invitationId)) {
			res.status(400).send({status: 'BAD_REQUEST', message: 'Ungültige Einladungs-ID.'});
			return;
		}

		const revoked = await InvitationsService.revokeInvitation(invitationId);
		if (!revoked) {
			res.status(404).send({status: 'NOT_FOUND', message: 'Einladung nicht gefunden.'});
			return;
		}

		res.status(204).send();
	} catch (e: any) {
		sendServerError(res, e);
	}
});