/*******************************************************************************
 * Copyright (c) 2013, 2016 Association for Decentralized 
 * Information Management in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the THTH Simantics 
 * Division Member Component License which accompanies this 
 * distribution, and is available at
 * http://www.simantics.org/legal/sdmcl-v10.html
 *
 * Contributors:
 *     Semantum Oy - initial API and implementation
 *******************************************************************************/
package org.simantics.scl.rest;

import java.io.IOException;

import javax.ws.rs.NotAuthorizedException;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;

public class AuthorizationFilter implements ContainerRequestFilter {

    private final String token;

    public AuthorizationFilter(String token) {
        this.token = token;
    }

    @Override
    public void filter(ContainerRequestContext requestContext) throws IOException {
        // Get the HTTP Authorization header from the request
        String authorizationHeader =  requestContext.getHeaderString(HttpHeaders.AUTHORIZATION);

        // Check if the HTTP Authorization header is present and formatted correctly 
        if (authorizationHeader == null || !authorizationHeader.startsWith("SCLRESTServer-Bearer ")) {
            throw new NotAuthorizedException("Authorization header must be provided");
        }

        // Extract the token from the HTTP Authorization header
        String token = authorizationHeader.substring("SCLRESTServer-Bearer".length()).trim();
        try {
            // Validate the token
            validateToken(token);
        } catch (Exception e) {
            requestContext.abortWith(Response.status(Status.UNAUTHORIZED).build());
        }
    }

    private void validateToken(String token) throws Exception {
        if (!this.token.equals(token)) {
            throw new Exception("Wrong token!");
        }
    }

}