/*
 * 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.web.reactive.result.condition;

import java.util.Map;

import org.springframework.http.MediaType;
import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.server.NotAcceptableStatusException;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.UnsupportedMediaTypeStatusException;

/**
 * Supports media type expressions as described in:
 * {@link RequestMapping#consumes()} and {@link RequestMapping#produces()}.
 *
 * @author Rossen Stoyanchev
 * @since 5.0
 */
abstract class AbstractMediaTypeExpression implements Comparable<AbstractMediaTypeExpression>, MediaTypeExpression {

	private final MediaType mediaType;

	private final boolean isNegated;


	AbstractMediaTypeExpression(String expression) {
		if (expression.startsWith("!")) {
			this.isNegated = true;
			expression = expression.substring(1);
		}
		else {
			this.isNegated = false;
		}
		this.mediaType = MediaType.parseMediaType(expression);
	}

	AbstractMediaTypeExpression(MediaType mediaType, boolean negated) {
		this.mediaType = mediaType;
		this.isNegated = negated;
	}


	@Override
	public MediaType getMediaType() {
		return this.mediaType;
	}

	@Override
	public boolean isNegated() {
		return this.isNegated;
	}


	public final boolean match(ServerWebExchange exchange) {
		try {
			boolean match = matchMediaType(exchange);
			return (!this.isNegated == match);
		}
		catch (NotAcceptableStatusException | UnsupportedMediaTypeStatusException ex) {
			return false;
		}
	}

	protected abstract boolean matchMediaType(ServerWebExchange exchange)
			throws NotAcceptableStatusException, UnsupportedMediaTypeStatusException;

	protected boolean matchParameters(MediaType contentType) {
		for (Map.Entry<String, String> entry : getMediaType().getParameters().entrySet()) {
			if (StringUtils.hasText(entry.getValue())) {
				String value = contentType.getParameter(entry.getKey());
				if (StringUtils.hasText(value) && !entry.getValue().equalsIgnoreCase(value)) {
					return false;
				}
			}
		}
		return true;
	}

	@Override
	public int compareTo(AbstractMediaTypeExpression other) {
		MediaType mediaType1 = this.getMediaType();
		MediaType mediaType2 = other.getMediaType();
		if (mediaType1.isMoreSpecific(mediaType2)) {
			return -1;
		}
		else if (mediaType1.isLessSpecific(mediaType2)) {
			return 1;
		}
		else {
			return 0;
		}
	}

	@Override
	public boolean equals(@Nullable Object other) {
		if (this == other) {
			return true;
		}
		if (other == null || getClass() != other.getClass()) {
			return false;
		}
		AbstractMediaTypeExpression otherExpr = (AbstractMediaTypeExpression) other;
		return (this.mediaType.equals(otherExpr.mediaType) && this.isNegated == otherExpr.isNegated);
	}

	@Override
	public int hashCode() {
		return this.mediaType.hashCode();
	}

	@Override
	public String toString() {
		if (this.isNegated) {
			return '!' + this.mediaType.toString();
		}
		return this.mediaType.toString();
	}

}
