/*
 * Copyright 2020-2030 码匠君<herodotus@aliyun.com>
 *
 * Dante Engine 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
 *
 *    http://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.
 *
 * Dante Engine 是 Dante Cloud 系统核心组件库，采用 APACHE LICENSE 2.0 开源协议，您在使用过程中，需要注意以下几点：
 *
 * 1. 请不要删除和修改根目录下的LICENSE文件。
 * 2. 请不要删除和修改 Dante Engine 源码头部的版权声明。
 * 3. 请保留源码和相关描述文件的项目出处，作者声明等。
 * 4. 分发源码时候，请注明软件出处 <https://gitee.com/dromara/dante-cloud>
 * 5. 在修改包名，模块名称，项目代码等时，请注明软件出处 <https://gitee.com/dromara/dante-cloud>
 * 6. 若您的项目无法满足以上几点，可申请商业授权
 */

package org.dromara.dante.webmvc.autoconfigure.crypto;

import cn.hutool.v7.core.io.IoUtil;
import cn.hutool.v7.core.util.ByteUtil;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Strings;
import org.dromara.dante.core.jackson.JacksonUtils;
import org.dromara.dante.web.support.crypto.DigitalEnvelopeProcessor;
import org.dromara.dante.web.annotation.Crypto;
import org.dromara.dante.web.exception.SessionInvalidException;
import org.dromara.dante.web.servlet.utils.SessionUtils;
import org.jspecify.annotations.Nullable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.MethodParameter;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice;
import tools.jackson.databind.JsonNode;
import tools.jackson.databind.node.StringNode;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Type;
import java.util.Map;
import java.util.Set;

/**
 * <p>Description: RequestBody 解密 Advice</p>
 *
 * @author : gengwei.zheng
 * @date : 2021/10/4 12:15
 */
@RestControllerAdvice
public class DecryptRequestBodyAdvice implements RequestBodyAdvice {

    private static final Logger log = LoggerFactory.getLogger(DecryptRequestBodyAdvice.class);

    private final DigitalEnvelopeProcessor digitalEnvelopeProcessor;

    public DecryptRequestBodyAdvice(DigitalEnvelopeProcessor digitalEnvelopeProcessor) {
        this.digitalEnvelopeProcessor = digitalEnvelopeProcessor;
    }

    @Override
    public boolean supports(MethodParameter methodParameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {

        String methodName = methodParameter.getMethod().getName();
        Crypto crypto = methodParameter.getMethodAnnotation(Crypto.class);

        boolean isSupports = ObjectUtils.isNotEmpty(crypto) && crypto.requestDecrypt();

        log.trace("[Herodotus] |- Is DecryptRequestBodyAdvice supports method [{}] ? Status is [{}].", methodName, isSupports);
        return isSupports;
    }

    @Override
    public HttpInputMessage beforeBodyRead(HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) throws IOException {

        String sessionId = SessionUtils.analyseSessionId(httpInputMessage);

        if (SessionUtils.isCryptoEnabled(httpInputMessage, sessionId)) {

            log.info("[Herodotus] |- DecryptRequestBodyAdvice begin decrypt data.");

            String methodName = methodParameter.getMethod().getName();
            String className = methodParameter.getDeclaringClass().getName();

            String content = IoUtil.read(httpInputMessage.getBody()).toString();

            if (StringUtils.isNotBlank(content)) {
                String data = digitalEnvelopeProcessor.decrypt(sessionId, content);
                if (Strings.CS.equals(data, content)) {
                    data = decrypt(sessionId, content);
                }
                log.debug("[Herodotus] |- Decrypt request body for rest method [{}] in [{}] finished.", methodName, className);
                return new DecryptHttpInputMessage(httpInputMessage, ByteUtil.toUtf8Bytes(data));
            } else {
                return httpInputMessage;
            }
        } else {
            log.warn("[Herodotus] |- Cannot find Herodotus Cloud custom session header. Use interface crypto founction need add X_HERODOTUS_SESSION_ID to request header.");
            return httpInputMessage;
        }
    }

    private String decrypt(String sessionKey, String content) throws SessionInvalidException {
        JsonNode jsonNode = JacksonUtils.toNode(content);
        if (ObjectUtils.isNotEmpty(jsonNode)) {
            decrypt(sessionKey, jsonNode);
            return JacksonUtils.toJson(jsonNode);
        }

        return content;
    }

    private void decrypt(String sessionKey, JsonNode jsonNode) throws SessionInvalidException {
        if (jsonNode.isObject()) {
            Set<Map.Entry<String, JsonNode>> it = jsonNode.properties();
            for (Map.Entry<String, JsonNode> entry : it) {
                if (entry.getValue() instanceof JsonNode t && entry.getValue().isValueNode()) {
                    String value = digitalEnvelopeProcessor.decrypt(sessionKey, t.asString());
                    entry.setValue(new StringNode(value));
                }
                decrypt(sessionKey, entry.getValue());
            }
        }

        if (jsonNode.isArray()) {
            for (JsonNode node : jsonNode) {
                decrypt(sessionKey, node);
            }
        }
    }

    @Override
    public Object afterBodyRead(Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
        return body;
    }

    @Override
    public @Nullable Object handleEmptyBody(@Nullable Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
        return body;
    }

    public static class DecryptHttpInputMessage implements HttpInputMessage {

        private final HttpInputMessage httpInputMessage;
        private final byte[] data;

        public DecryptHttpInputMessage(HttpInputMessage httpInputMessage, byte[] data) {
            this.httpInputMessage = httpInputMessage;
            this.data = data;
        }

        @Override
        public InputStream getBody() throws IOException {
            return new ByteArrayInputStream(this.data);
        }

        @Override
        public HttpHeaders getHeaders() {
            return this.httpInputMessage.getHeaders();
        }
    }
}
