/*
 * Copyright 2004-present the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.security.web.access;

import jakarta.servlet.ServletContext;
import jakarta.servlet.http.HttpServletRequest;
import org.jspecify.annotations.Nullable;

import org.springframework.security.authorization.AuthorizationManager;
import org.springframework.security.authorization.AuthorizationResult;
import org.springframework.security.core.Authentication;
import org.springframework.security.web.FilterInvocation;
import org.springframework.util.Assert;
import org.springframework.web.context.ServletContextAware;

/**
 * An implementation of {@link WebInvocationPrivilegeEvaluator} which delegates the checks
 * to an instance of {@link AuthorizationManager}
 *
 * @author Marcus Da Coregio
 * @since 5.5.5
 */
public final class AuthorizationManagerWebInvocationPrivilegeEvaluator
		implements WebInvocationPrivilegeEvaluator, ServletContextAware {

	private final AuthorizationManager<HttpServletRequest> authorizationManager;

	private @Nullable ServletContext servletContext;

	private HttpServletRequestTransformer requestTransformer = HttpServletRequestTransformer.IDENTITY;

	public AuthorizationManagerWebInvocationPrivilegeEvaluator(
			AuthorizationManager<HttpServletRequest> authorizationManager) {
		Assert.notNull(authorizationManager, "authorizationManager cannot be null");
		this.authorizationManager = authorizationManager;
	}

	@Override
	public boolean isAllowed(String uri, @Nullable Authentication authentication) {
		return isAllowed(null, uri, null, authentication);
	}

	@Override
	public boolean isAllowed(@Nullable String contextPath, String uri, @Nullable String method,
			@Nullable Authentication authentication) {
		FilterInvocation filterInvocation = new FilterInvocation(contextPath, uri, method, this.servletContext);
		HttpServletRequest httpRequest = this.requestTransformer.transform(filterInvocation.getHttpRequest());
		AuthorizationResult result = this.authorizationManager.authorize(() -> authentication, httpRequest);
		return result == null || result.isGranted();
	}

	@Override
	public void setServletContext(ServletContext servletContext) {
		this.servletContext = servletContext;
	}

	/**
	 * Set a {@link HttpServletRequestTransformer} to be used prior to passing to the
	 * {@link AuthorizationManager}.
	 * @param requestTransformer the {@link HttpServletRequestTransformer} to use.
	 */
	public void setRequestTransformer(HttpServletRequestTransformer requestTransformer) {
		Assert.notNull(requestTransformer, "requestTransformer cannot be null");
		this.requestTransformer = requestTransformer;
	}

	/**
	 * Used to transform the {@link HttpServletRequest} prior to passing it into the
	 * {@link AuthorizationManager}.
	 */
	public interface HttpServletRequestTransformer {

		HttpServletRequestTransformer IDENTITY = (request) -> request;

		/**
		 * Return the {@link HttpServletRequest} that is passed into the
		 * {@link AuthorizationManager}
		 * @param request the {@link HttpServletRequest} created by the
		 * {@link WebInvocationPrivilegeEvaluator}
		 * @return the {@link HttpServletRequest} that is passed into the
		 * {@link AuthorizationManager}
		 */
		HttpServletRequest transform(HttpServletRequest request);

	}

}
