package com.ard.web.controller.sample.media;

import com.ard.oss.model.CredentialsDTO;
import com.ard.oss.service.impl.OssServiceContext;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import okhttp3.*;
import okio.BufferedSink;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.net.ssl.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;
import java.util.Enumeration;
import java.util.concurrent.TimeUnit;

/**
 * MinIO STS代理控制器（适配分块上传全流程：初始化/传块/合并）
 * 解决SSL连接重置、鉴权透传、分块合并XML透传问题
 */
@Api(tags = "机场上传minio")
@Slf4j
@RestController
@RequestMapping("/minioTransfer")
public class MinioStsProxyController {

    // ==================== 常量配置 ====================
    private static final String PROXY_PREFIX = "/minioTransfer";
    private static final int BUFFER_SIZE = 65536; // 64K缓冲区
    private static final long MAX_MEMORY_SIZE = 1024 * 1024 * 100; // 100MB（小文件阈值）
    private static final String X_AMZ_SECURITY_TOKEN = "X-Amz-Security-Token";
    private static final String TRANSFER_ENCODING = "Transfer-Encoding";
    private static final String HOST = "Host";

    // 配置注入（支持yml配置，避免硬编码）
    @Value("${oss.endpoint}")
    private String minioEndpoint;
    private static final Integer connectTimeout = 30;
    private static final Integer readWriteTimeout = 1800;

    @Autowired
    private OssServiceContext ossService;

    // OkHttp客户端（全局单例，优化SSL/TCP）
    private static OkHttpClient httpClient;

    // 静态初始化：SSL/TCP优化（适配MinIO内网环境）
    static {
        try {
            // 1. 全局信任所有SSL证书（内网专用，生产需替换合法证书）
            TrustManager[] trustAllCerts = new TrustManager[]{
                    new X509TrustManager() {
                        @Override
                        public void checkClientTrusted(X509Certificate[] chain, String authType) {}
                        @Override
                        public void checkServerTrusted(X509Certificate[] chain, String authType) {}
                        @Override
                        public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[0]; }
                    }
            };

            // 2. 强制TLS 1.2（解决MinIO SSL版本兼容问题）
            SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
            sslContext.init(null, trustAllCerts, new SecureRandom());

            // 3. 构建高兼容性OkHttp客户端
            httpClient = new OkHttpClient.Builder()
                    .sslSocketFactory(sslContext.getSocketFactory(), (X509TrustManager) trustAllCerts[0])
                    .hostnameVerifier((hostname, session) -> true) // 禁用主机名校验
                    .connectTimeout(30, TimeUnit.SECONDS)
                    .readTimeout(1800, TimeUnit.SECONDS) // 30分钟读超时（适配大文件）
                    .writeTimeout(1800, TimeUnit.SECONDS) // 30分钟写超时
                    .connectionPool(new ConnectionPool(30, 10, TimeUnit.MINUTES)) // 扩大连接池
                    .retryOnConnectionFailure(true) // 开启连接重试
                    .pingInterval(10, TimeUnit.SECONDS) // TCP保活（防止连接被重置）
                    .callTimeout(60, TimeUnit.SECONDS)
                    .build();

            log.info("OkHttp客户端初始化完成（适配MinIO分块上传）");
        } catch (Exception e) {
            log.error("OkHttp初始化失败，降级为默认客户端", e);
            httpClient = new OkHttpClient();
        }
    }

    /**
     * 核心代理方法：适配MinIO分块上传全流程（POST初始化/PUT传块/POST合并）
     */
    @ApiOperation("MinIO STS临时凭证通用代理（支持分块上传）")
    @RequestMapping("/**")
    public void proxyRequest(HttpServletRequest request, HttpServletResponse response) {
        String method = request.getMethod();
        String requestUri = request.getRequestURI();
        String queryString = request.getQueryString();
        long contentLength = request.getContentLengthLong();

        // 日志增强：区分分块上传阶段
        String uploadStage = getUploadStage(queryString);
        log.info("STS代理请求开始 | 阶段:{} | 方法:{} | URI:{} | 参数:{} | 内容长度:{}B",
                uploadStage, method, requestUri, queryString, contentLength);

        // 1. 构造MinIO目标地址
        String targetUrl = buildTargetUrl(requestUri, queryString);
        if (targetUrl == null) {
            sendError(response, HttpServletResponse.SC_BAD_REQUEST, "请求路径非法（缺失MinIO前缀）");
            return;
        }

        // 2. 获取并校验STS凭证（鉴权核心）
        CredentialsDTO credentials = getCredentials();
        if (credentials == null) {
            sendError(response, HttpServletResponse.SC_FORBIDDEN, "STS凭证无效/缺失");
            return;
        }

        // 3. 构建请求+转发响应（核心逻辑）
        try {
            Request okRequest = buildRequest(request, method, targetUrl, credentials);
            forwardResponse(okRequest, response);
            log.info("STS代理请求成功 | 阶段:{} | 目标地址:{}", uploadStage, targetUrl);
        } catch (Exception e) {
            log.error("STS代理请求执行异常 | 阶段:{}", uploadStage, e);
            // 友好错误提示：区分SSL/分块/鉴权错误
            String errorMsg = e.getMessage().contains("SSL") ? "SSL连接异常（请检查MinIO HTTPS配置）" :
                    e.getMessage().contains("Credentials") ? "STS凭证异常" : "代理服务异常";
            sendError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, errorMsg);
        }
    }

    /**
     * 识别分块上传阶段（日志优化）
     */
    private String getUploadStage(String queryString) {
        if (queryString == null) return "普通请求";
        if (queryString.contains("uploads") && !queryString.contains("uploadId")) return "分块初始化";
        if (queryString.contains("partNumber") && queryString.contains("uploadId")) return "分块上传";
        if (queryString.contains("uploadId") && !queryString.contains("partNumber")) return "分块合并";
        return "普通请求";
    }

    /**
     * 构造MinIO目标地址（兼容分块参数透传）
     */
    private String buildTargetUrl(String requestUri, String queryString) {
        try {
            // 截取代理前缀后的路径（/minioTransfer/xxx → xxx）
            String targetPath = requestUri.substring(PROXY_PREFIX.length());
            StringBuilder urlBuilder = new StringBuilder(minioEndpoint).append(targetPath);
            // 透传分块参数（uploads/uploadId/partNumber）
            if (queryString != null && !queryString.isBlank()) {
                urlBuilder.append("?").append(queryString);
            }
            return urlBuilder.toString();
        } catch (Exception e) {
            log.error("构造MinIO目标地址失败", e);
            return null;
        }
    }

    /**
     * 获取并校验STS凭证（确保AK/SK/Token完整）
     */
    private CredentialsDTO getCredentials() {
        try {
            CredentialsDTO dto = ossService.getCredentials();
            // 严格校验核心字段（避免鉴权失败）
            if (dto == null || dto.getAccessKeyId() == null || dto.getAccessKeySecret() == null || dto.getSecurityToken() == null) {
                log.error("STS凭证核心字段缺失：AK/SK/Token不能为空");
                return null;
            }
            log.info("STS凭证获取成功 | AK前缀:{}", dto.getAccessKeyId().substring(0, 4) + "***");
            return dto;
        } catch (Exception e) {
            log.error("获取STS凭证异常", e);
            return null;
        }
    }

    /**
     * 构建OkHttp请求（适配分块上传的请求体/头透传）
     */
    private Request buildRequest(HttpServletRequest request, String method, String url, CredentialsDTO credentials) throws IOException {
        Request.Builder builder = new Request.Builder().url(url);

        // 1. 透传所有请求头（排除Host，OkHttp自动处理）
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String name = headerNames.nextElement();
            if (!name.equalsIgnoreCase(HOST)) {
                builder.addHeader(name, request.getHeader(name));
            }
        }

        // 2. 添加STS鉴权头（MinIO分块上传必须）
        builder.addHeader(X_AMZ_SECURITY_TOKEN, credentials.getSecurityToken());
        // 补充MinIO鉴权必要的头（防止签名失败）
        builder.addHeader("X-Amz-Date", String.valueOf(System.currentTimeMillis()));

        // 3. 构建请求体（区分小文件/大文件/分块合并XML）
        RequestBody body = null;
        if (!"GET".equalsIgnoreCase(method) && !"HEAD".equalsIgnoreCase(method)) {
            InputStream inputStream = request.getInputStream();
            long contentLength = request.getContentLengthLong();

            // 小文件：预读取到内存（稳定，适配分块上传的小文件块）
            if (contentLength > 0 && contentLength <= MAX_MEMORY_SIZE) {
                log.info("小文件/分块上传：预读取到内存，大小:{:.2f}MB", contentLength / 1024.0 / 1024.0);
                byte[] content = readInputStreamToBytes(inputStream);
                MediaType mediaType = MediaType.parse(request.getContentType() == null ? "application/xml" : request.getContentType());
                body = RequestBody.create(content, mediaType);
            }
            // 大文件/未知长度：流式上传（省内存，适配大文件分块）
            else {
                log.info("大文件/未知长度上传：使用流式传输（适配分块上传）");
                body = new RequestBody() {
                    @Override
                    public MediaType contentType() {
                        return MediaType.parse(request.getContentType() == null ? "application/xml" : request.getContentType());
                    }

                    @Override
                    public long contentLength() {
                        return contentLength; // 避免chunked编码，适配MinIO分块
                    }

                    @Override
                    public void writeTo(BufferedSink sink) throws IOException {
                        byte[] buffer = new byte[BUFFER_SIZE];
                        int len;
                        long totalWritten = 0;
                        try (InputStream in = inputStream) {
                            while ((len = in.read(buffer)) != -1) {
                                sink.write(buffer, 0, len);
                                totalWritten += len;
                                // 每100MB刷新一次（防止缓冲区溢出）
                                if (totalWritten % (1024 * 1024 * 100) == 0) {
                                    sink.flush();
                                    log.info("分块上传进度：已写入{:.2f}MB", totalWritten / 1024.0 / 1024.0);
                                }
                            }
                            sink.flush();
                            log.info("流式上传完成，总写入：{:.2f}MB", totalWritten / 1024.0 / 1024.0);
                        }
                    }
                };
            }
        }

        return builder.method(method, body).build();
    }

    /**
     * 读取InputStream到字节数组（小文件/分块专用）
     */
    private byte[] readInputStreamToBytes(InputStream inputStream) throws IOException {
        try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
            byte[] buffer = new byte[BUFFER_SIZE];
            int len;
            while ((len = inputStream.read(buffer)) != -1) {
                bos.write(buffer, 0, len);
            }
            bos.flush();
            return bos.toByteArray();
        }
    }

    /**
     * 转发MinIO响应到客户端（关键：透传ETag/UploadId等分块参数）
     */
    private void forwardResponse(Request request, HttpServletResponse response) throws IOException {
        try (Response okResponse = httpClient.newCall(request).execute()) {
            // 1. 基础响应配置（确保分块合并的XML响应正常透传）
            response.setStatus(okResponse.code());
            response.setCharacterEncoding("UTF-8");
            String contentType = okResponse.header("Content-Type");
            if (contentType != null) {
                response.setContentType(contentType); // 透传XML/JSON类型
            }

            // 2. 透传所有响应头（重点：ETag/UploadId等分块核心参数）
            Headers headers = okResponse.headers();
            for (String name : headers.names()) {
                // 排除Transfer-Encoding（防止Tomcat重复编码）
                if (!name.equalsIgnoreCase(TRANSFER_ENCODING)) {
                    response.setHeader(name, headers.get(name));
                }
            }

            // 3. 透传响应体（分块初始化的UploadId、合并的成功响应等）
            ResponseBody responseBody = okResponse.body();
            if (responseBody != null) {
                try (InputStream in = responseBody.byteStream()) {
                    byte[] buffer = new byte[BUFFER_SIZE];
                    int len;
                    while ((len = in.read(buffer)) != -1) {
                        response.getOutputStream().write(buffer, 0, len);
                    }
                    response.getOutputStream().flush();
                }
            }
        }
    }

    /**
     * 统一返回错误响应
     */
    private void sendError(HttpServletResponse response, int code, String msg) {
        try {
            response.sendError(code, msg);
        } catch (IOException e) {
            log.error("发送错误响应失败", e);
        }
    }
}