/*
 * Copyright 2002-2022 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.server.csrf;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import reactor.core.publisher.Mono;
import reactor.test.StepVerifier;
import reactor.test.publisher.PublisherProbe;

import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
import org.springframework.mock.web.server.MockServerWebExchange;
import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatcher;
import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatcher.MatchResult;
import org.springframework.test.web.reactive.server.WebTestClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilterChain;
import org.springframework.web.server.WebSession;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.BDDMockito.given;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;

/**
 * @author Rob Winch
 * @author Parikshit Dutta
 * @since 5.0
 */
@ExtendWith(MockitoExtension.class)
public class CsrfWebFilterTests {

	@Mock
	private WebFilterChain chain;

	@Mock
	private ServerCsrfTokenRepository repository;

	private CsrfToken token = new DefaultCsrfToken("csrf", "CSRF", "a");

	private CsrfWebFilter csrfFilter = new CsrfWebFilter();

	private MockServerWebExchange get = MockServerWebExchange.from(MockServerHttpRequest.get("/"));

	private MockServerWebExchange post = MockServerWebExchange.from(MockServerHttpRequest.post("/"));

	@Test
	public void setRequestHandlerWhenNullThenThrowsIllegalArgumentException() {
		// @formatter:off
		assertThatIllegalArgumentException()
				.isThrownBy(() -> this.csrfFilter.setRequestHandler(null))
				.withMessage("requestHandler cannot be null");
		// @formatter:on
	}

	@Test
	public void filterWhenGetThenSessionNotCreatedAndChainContinues() {
		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		given(this.chain.filter(this.get)).willReturn(chainResult.mono());
		Mono<Void> result = this.csrfFilter.filter(this.get, this.chain);
		StepVerifier.create(result).verifyComplete();
		Mono<Boolean> isSessionStarted = this.get.getSession().map(WebSession::isStarted);
		StepVerifier.create(isSessionStarted).expectNext(false).verifyComplete();
		chainResult.assertWasSubscribed();
	}

	@Test
	public void filterWhenPostAndNoTokenThenCsrfException() {
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		assertThat(this.post.getResponse().getStatusCode()).isEqualTo(HttpStatus.FORBIDDEN);
	}

	@Test
	public void filterWhenPostAndEstablishedCsrfTokenAndRequestMissingTokenThenCsrfException() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		assertThat(this.post.getResponse().getStatusCode()).isEqualTo(HttpStatus.FORBIDDEN);
		StepVerifier.create(this.post.getResponse().getBodyAsString())
				.assertNext((body) -> assertThat(body).contains("An expected CSRF token cannot be found"));
	}

	@Test
	public void filterWhenPostAndEstablishedCsrfTokenAndRequestParamInvalidTokenThenCsrfException() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		this.post = MockServerWebExchange.from(MockServerHttpRequest.post("/")
				.body(this.token.getParameterName() + "=" + this.token.getToken() + "INVALID"));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		assertThat(this.post.getResponse().getStatusCode()).isEqualTo(HttpStatus.FORBIDDEN);
	}

	@Test
	public void filterWhenPostAndEstablishedCsrfTokenAndRequestParamValidTokenThenContinues() {
		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		given(this.chain.filter(any())).willReturn(chainResult.mono());
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		CsrfToken csrfToken = createXorCsrfToken();
		this.post = MockServerWebExchange
				.from(MockServerHttpRequest.post("/").contentType(MediaType.APPLICATION_FORM_URLENCODED)
						.body(csrfToken.getParameterName() + "=" + csrfToken.getToken()));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		chainResult.assertWasSubscribed();
	}

	@Test
	public void filterWhenPostAndEstablishedCsrfTokenAndHeaderInvalidTokenThenCsrfException() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		this.post = MockServerWebExchange.from(
				MockServerHttpRequest.post("/").header(this.token.getHeaderName(), this.token.getToken() + "INVALID"));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		assertThat(this.post.getResponse().getStatusCode()).isEqualTo(HttpStatus.FORBIDDEN);
	}

	@Test
	public void filterWhenPostAndEstablishedCsrfTokenAndHeaderValidTokenThenContinues() {
		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		given(this.chain.filter(any())).willReturn(chainResult.mono());
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		CsrfToken csrfToken = createXorCsrfToken();
		this.post = MockServerWebExchange
				.from(MockServerHttpRequest.post("/").header(csrfToken.getHeaderName(), csrfToken.getToken()));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		chainResult.assertWasSubscribed();
	}

	@Test
	public void filterWhenRequestHandlerSetThenUsed() {
		ServerCsrfTokenRequestHandler requestHandler = mock(ServerCsrfTokenRequestHandler.class);
		given(requestHandler.resolveCsrfTokenValue(any(ServerWebExchange.class), any(CsrfToken.class)))
				.willReturn(Mono.just(this.token.getToken()));
		this.csrfFilter.setRequestHandler(requestHandler);

		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		given(this.chain.filter(any())).willReturn(chainResult.mono());
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		this.post = MockServerWebExchange
				.from(MockServerHttpRequest.post("/").header(this.token.getHeaderName(), this.token.getToken()));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		chainResult.assertWasSubscribed();

		verify(requestHandler).handle(eq(this.post), any());
		verify(requestHandler).resolveCsrfTokenValue(this.post, this.token);
	}

	@Test
	public void filterWhenXorServerCsrfTokenRequestAttributeHandlerAndValidTokenThenSuccess() {
		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		given(this.chain.filter(any())).willReturn(chainResult.mono());
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));

		CsrfToken csrfToken = createXorCsrfToken();
		this.post = MockServerWebExchange
				.from(MockServerHttpRequest.post("/").header(csrfToken.getHeaderName(), csrfToken.getToken()));
		StepVerifier.create(this.csrfFilter.filter(this.post, this.chain)).verifyComplete();
		chainResult.assertWasSubscribed();
	}

	@Test
	public void filterWhenXorServerCsrfTokenRequestAttributeHandlerAndRawTokenThenAccessDeniedException() {
		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		XorServerCsrfTokenRequestAttributeHandler requestHandler = new XorServerCsrfTokenRequestAttributeHandler();
		this.csrfFilter.setRequestHandler(requestHandler);
		this.post = MockServerWebExchange
				.from(MockServerHttpRequest.post("/").header(this.token.getHeaderName(), this.token.getToken()));
		Mono<Void> result = this.csrfFilter.filter(this.post, this.chain);
		StepVerifier.create(result).verifyComplete();
		chainResult.assertWasNotSubscribed();
		assertThat(this.post.getResponse().getStatusCode()).isEqualTo(HttpStatus.FORBIDDEN);
	}

	@Test
	// gh-8452
	public void matchesRequireCsrfProtectionWhenNonStandardHTTPMethodIsUsed() {
		MockServerWebExchange nonStandardHttpExchange = MockServerWebExchange
				.from(MockServerHttpRequest.method("non-standard-http-method", "/"));
		ServerWebExchangeMatcher serverWebExchangeMatcher = CsrfWebFilter.DEFAULT_CSRF_MATCHER;
		assertThat(serverWebExchangeMatcher.matches(nonStandardHttpExchange).map(MatchResult::isMatch).block())
				.isTrue();
	}

	@Test
	public void doFilterWhenSkipExchangeInvokedThenSkips() {
		PublisherProbe<Void> chainResult = PublisherProbe.empty();
		given(this.chain.filter(any())).willReturn(chainResult.mono());
		ServerWebExchangeMatcher matcher = mock(ServerWebExchangeMatcher.class);
		this.csrfFilter.setRequireCsrfProtectionMatcher(matcher);
		MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.post("/post").build());
		CsrfWebFilter.skipExchange(exchange);
		this.csrfFilter.filter(exchange, this.chain).block();
		verifyNoMoreInteractions(matcher);
	}

	@Test
	public void filterWhenMultipartFormDataAndNotEnabledThenDenied() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		WebTestClient client = WebTestClient.bindToController(new OkController()).webFilter(this.csrfFilter).build();
		client.post().uri("/").contentType(MediaType.MULTIPART_FORM_DATA)
				.body(BodyInserters.fromMultipartData(this.token.getParameterName(), this.token.getToken())).exchange()
				.expectStatus().isForbidden();
	}

	@Test
	public void filterWhenMultipartFormDataAndEnabledThenGranted() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		ServerCsrfTokenRequestAttributeHandler requestHandler = new ServerCsrfTokenRequestAttributeHandler();
		requestHandler.setTokenFromMultipartDataEnabled(true);
		this.csrfFilter.setRequestHandler(requestHandler);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		WebTestClient client = WebTestClient.bindToController(new OkController()).webFilter(this.csrfFilter).build();
		client.post().uri("/").contentType(MediaType.MULTIPART_FORM_DATA)
				.body(BodyInserters.fromMultipartData(this.token.getParameterName(), this.token.getToken())).exchange()
				.expectStatus().is2xxSuccessful();
	}

	@Test
	public void filterWhenPostAndMultipartFormDataEnabledAndNoBodyProvided() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		ServerCsrfTokenRequestAttributeHandler requestHandler = new ServerCsrfTokenRequestAttributeHandler();
		requestHandler.setTokenFromMultipartDataEnabled(true);
		this.csrfFilter.setRequestHandler(requestHandler);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		WebTestClient client = WebTestClient.bindToController(new OkController()).webFilter(this.csrfFilter).build();
		client.post().uri("/").header(this.token.getHeaderName(), this.token.getToken()).exchange().expectStatus()
				.is2xxSuccessful();
	}

	@Test
	public void filterWhenFormDataAndEnabledThenGranted() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		ServerCsrfTokenRequestAttributeHandler requestHandler = new ServerCsrfTokenRequestAttributeHandler();
		requestHandler.setTokenFromMultipartDataEnabled(true);
		this.csrfFilter.setRequestHandler(requestHandler);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		given(this.repository.generateToken(any())).willReturn(Mono.just(this.token));
		WebTestClient client = WebTestClient.bindToController(new OkController()).webFilter(this.csrfFilter).build();
		client.post().uri("/").contentType(MediaType.APPLICATION_FORM_URLENCODED)
				.bodyValue(this.token.getParameterName() + "=" + this.token.getToken()).exchange().expectStatus()
				.is2xxSuccessful();
	}

	@Test
	public void filterWhenMultipartMixedAndEnabledThenNotRead() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		ServerCsrfTokenRequestAttributeHandler requestHandler = new ServerCsrfTokenRequestAttributeHandler();
		requestHandler.setTokenFromMultipartDataEnabled(true);
		this.csrfFilter.setRequestHandler(requestHandler);
		given(this.repository.loadToken(any())).willReturn(Mono.just(this.token));
		WebTestClient client = WebTestClient.bindToController(new OkController()).webFilter(this.csrfFilter).build();
		client.post().uri("/").contentType(MediaType.MULTIPART_MIXED)
				.bodyValue(this.token.getParameterName() + "=" + this.token.getToken()).exchange().expectStatus()
				.isForbidden();
	}

	// gh-9561

	@Test
	public void doFilterWhenTokenIsNullThenNoNullPointer() {
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		CsrfToken token = mock(CsrfToken.class);
		given(token.getToken()).willReturn(null);
		given(token.getHeaderName()).willReturn(this.token.getHeaderName());
		given(token.getParameterName()).willReturn(this.token.getParameterName());
		given(this.repository.loadToken(any())).willReturn(Mono.just(token));
		WebTestClient client = WebTestClient.bindToController(new OkController()).webFilter(this.csrfFilter).build();
		client.post().uri("/").contentType(MediaType.APPLICATION_FORM_URLENCODED)
				.bodyValue(this.token.getParameterName() + "=" + this.token.getToken()).exchange().expectStatus()
				.isForbidden();
	}
	// gh-9113

	@Test
	public void filterWhenSubscribingCsrfTokenMultipleTimesThenGenerateOnlyOnce() {
		PublisherProbe<CsrfToken> chainResult = PublisherProbe.empty();
		this.csrfFilter.setCsrfTokenRepository(this.repository);
		given(this.repository.loadToken(any())).willReturn(Mono.empty());
		given(this.repository.generateToken(any())).willReturn(chainResult.mono());
		given(this.chain.filter(any())).willReturn(Mono.empty());
		this.csrfFilter.filter(this.get, this.chain).block();
		Mono<CsrfToken> result = this.get.getAttribute(CsrfToken.class.getName());
		result.block();
		result.block();
		assertThat(chainResult.subscribeCount()).isEqualTo(1);
	}

	private CsrfToken createXorCsrfToken() {
		ServerCsrfTokenRequestHandler handler = new XorServerCsrfTokenRequestAttributeHandler();
		MockServerWebExchange exchange = MockServerWebExchange.from(MockServerHttpRequest.get("/"));
		handler.handle(exchange, Mono.just(this.token));
		Mono<CsrfToken> csrfToken = exchange.getAttribute(CsrfToken.class.getName());
		return csrfToken.block();
	}

	@RestController
	static class OkController {

		@RequestMapping("/**")
		String ok() {
			return "ok";
		}

	}

}
