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.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.concurrent.TimeUnit;

/**
 * MinIO STS代理控制器（终极版）
 * 1. 彻底清除客户端鉴权头 + 替换为代理侧STS凭证
 * 2. 强制HTTP通信（绕过SSL连接重置问题）
 * 3. 适配分块上传全流程
 */
@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
    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";

    // 需清除的客户端鉴权头（核心：避免和代理侧凭证冲突）
    private static final String[] AUTH_HEADERS_TO_REMOVE = {
            "Authorization", "X-Amz-Access-Key-Id", "X-Amz-Secret-Access-Key",
            "X-Amz-Security-Token", "AccessKey", "SecretKey", "Token"
    };

    // 配置注入
    @Value("${oss.endpoint}")
    private String minioEndpoint;
    private Integer connectTimeout = 30;
    private Integer readWriteTimeout = 1800;

    @Autowired
    private OssServiceContext ossService;

    // OkHttp客户端（禁用SSL，强制HTTP，最大化兼容性）
    private static OkHttpClient httpClient;

    static {
        // 构建纯HTTP客户端（彻底绕过SSL问题）
        httpClient = new OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .readTimeout(1800, TimeUnit.SECONDS) // 30分钟超时
                .writeTimeout(1800, TimeUnit.SECONDS)
                .connectionPool(new ConnectionPool(30, 10, TimeUnit.MINUTES))
                .retryOnConnectionFailure(true) // 开启重试
                .pingInterval(10, TimeUnit.SECONDS) // TCP保活
                .callTimeout(60, TimeUnit.SECONDS)
                .build();

        log.info("OkHttp客户端初始化完成（纯HTTP模式，禁用SSL）");
    }

    /**
     * 核心代理方法：清除客户端鉴权 + 替换为代理侧STS凭证
     */
    @ApiOperation("MinIO STS代理（清除客户端鉴权+强制HTTP）")
    @RequestMapping("/**")
    public void proxyRequest(HttpServletRequest request, HttpServletResponse response) {
        String method = request.getMethod();
        String requestUri = request.getRequestURI();
        String queryString = request.getQueryString();
        long contentLength = request.getContentLengthLong();

        log.info("STS代理请求开始 | 方法:{} | URI:{} | 参数:{} | 内容长度:{}B",
                method, requestUri, queryString, contentLength);

        // 1. 构造目标地址（强制转换为HTTP，无论配置的是HTTPS）
        String targetUrl = buildTargetUrl(requestUri, queryString);
        if (targetUrl == null) {
            sendError(response, HttpServletResponse.SC_BAD_REQUEST, "请求路径非法");
            return;
        }

        // 2. 获取代理侧STS凭证（核心：替换客户端鉴权）
        CredentialsDTO credentials = getCredentials();
        if (credentials == null) {
            sendError(response, HttpServletResponse.SC_FORBIDDEN, "STS凭证无效");
            return;
        }

        // 3. 构建请求（清除客户端鉴权 + 注入代理侧凭证）
        try {
            Request okRequest = buildRequest(request, method, targetUrl, credentials);
            forwardResponse(okRequest, response);
            log.info("STS代理请求成功 | 目标地址:{}", targetUrl);
        } catch (Exception e) {
            log.error("STS代理请求执行异常", e);
            String errorMsg = e.getMessage().contains("Connection reset") ?
                    "MinIO连接重置（已强制HTTP，需检查MinIO服务是否启动）" : "代理服务异常";
            sendError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, errorMsg);
        }
    }

    /**
     * 构造目标地址：强制转换为HTTP（核心解决SSL问题）
     */
    private String buildTargetUrl(String requestUri, String queryString) {
        try {
            String targetPath = requestUri.substring(PROXY_PREFIX.length());
            // 强制将HTTPS转为HTTP（无论配置的endpoint是啥）
            String httpEndpoint = minioEndpoint.replace("https://", "http://");
            // 修正端口：MinIO HTTPS默认9001 → HTTP默认9000
            if (httpEndpoint.contains(":9001")) {
                httpEndpoint = httpEndpoint.replace(":9001", ":9000");
            }

            StringBuilder urlBuilder = new StringBuilder(httpEndpoint).append(targetPath);
            if (queryString != null && !queryString.isBlank()) {
                urlBuilder.append("?").append(queryString);
            }
            String targetUrl = urlBuilder.toString();
            log.info("构造目标地址（强制HTTP）：{}", targetUrl);
            return targetUrl;
        } catch (Exception e) {
            log.error("构造目标地址失败", e);
            return null;
        }
    }

    /**
     * 获取代理侧STS凭证（确保完整性）
     */
    private CredentialsDTO getCredentials() {
        try {
            CredentialsDTO dto = ossService.getCredentials();
            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）");
                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;
        }
    }

    /**
     * 构建请求：彻底清除客户端鉴权头 + 注入代理侧STS凭证
     */
    private Request buildRequest(HttpServletRequest request, String method, String url, CredentialsDTO credentials) throws IOException {
        Request.Builder builder = new Request.Builder().url(url);

        // ========== 核心步骤1：清除所有客户端鉴权头 ==========
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String name = headerNames.nextElement();
            // 跳过Host头（OkHttp自动处理）
            if (name.equalsIgnoreCase(HOST)) {
                continue;
            }
            // 跳过所有鉴权相关头（避免冲突）
            boolean isAuthHeader = false;
            for (String authHeader : AUTH_HEADERS_TO_REMOVE) {
                if (name.equalsIgnoreCase(authHeader)) {
                    isAuthHeader = true;
                    log.info("清除客户端鉴权头：{}", name);
                    break;
                }
            }
            if (!isAuthHeader) {
                builder.addHeader(name, request.getHeader(name));
            }
        }

        // ========== 核心步骤2：注入代理侧STS凭证 ==========
        // 1. 添加STS临时令牌（MinIO STS必须）
        builder.addHeader(X_AMZ_SECURITY_TOKEN, credentials.getSecurityToken());
        // 2. 添加AK/SK（MinIO签名需要，透传给MinIO）
        builder.addHeader("X-Amz-Access-Key-Id", credentials.getAccessKeyId());
        builder.addHeader("X-Amz-Secret-Access-Key", credentials.getAccessKeySecret());
        // 3. 强制HTTP/1.1（避免协议兼容问题）
        builder.addHeader("Connection", "keep-alive");
        builder.addHeader("Content-Type", request.getContentType() == null ? "application/octet-stream" : request.getContentType());

        // ========== 构建请求体（分大小文件） ==========
        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
            if (contentLength > 0 && contentLength <= MAX_MEMORY_SIZE) {
                log.info("小文件上传：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/octet-stream" : request.getContentType());
                body = RequestBody.create(content, mediaType);
            }
            // 大文件：流式上传
            else {
                log.info("大文件/未知长度上传：使用流式传输");
                body = new RequestBody() {
                    @Override
                    public MediaType contentType() {
                        return MediaType.parse(request.getContentType() == null ? "application/octet-stream" : request.getContentType());
                    }

                    @Override
                    public long contentLength() {
                        return contentLength;
                    }

                    @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;
                                if (totalWritten % (1024 * 1024 * 100) == 0) {
                                    sink.flush();
                                    log.info("已上传：{:.2f}MB", totalWritten / 1024.0 / 1024.0);
                                }
                            }
                            sink.flush();
                        }
                    }
                };
            }
        }

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

    /**
     * 读取InputStream到字节数组
     */
    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
     */
    private void forwardResponse(Request request, HttpServletResponse response) throws IOException {
        try (Response okResponse = httpClient.newCall(request).execute()) {
            // 配置响应头
            response.setStatus(okResponse.code());
            response.setCharacterEncoding("UTF-8");
            String contentType = okResponse.header("Content-Type");
            if (contentType != null) {
                response.setContentType(contentType);
            }

            // 透传响应头（排除Transfer-Encoding）
            Headers headers = okResponse.headers();
            for (String name : headers.names()) {
                if (!name.equalsIgnoreCase(TRANSFER_ENCODING)) {
                    response.setHeader(name, headers.get(name));
                }
            }

            // 透传响应体
            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);
        }
    }
}