package com.ftptool.sync.service;

import com.ftptool.sync.config.ProdApiProperties;
import com.ftptool.sync.config.SyncProperties;
import com.ftptool.sync.model.PackageManifest;
import com.ftptool.sync.model.ProdPullResult;
import com.ftptool.sync.util.FileHashUtils;
import com.ftptool.sync.util.FileTreeUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;

@Service
public class ProdConfigApiService {

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

    private final ProdApiProperties prodApiProperties;
    private final SyncProperties syncProperties;
    private final RestTemplate restTemplate;
    private final WorkDirectoryService workDirectoryService;

    public ProdConfigApiService(
            ProdApiProperties prodApiProperties,
            SyncProperties syncProperties,
            RestTemplate restTemplate,
            WorkDirectoryService workDirectoryService
    ) {
        this.prodApiProperties = prodApiProperties;
        this.syncProperties = syncProperties;
        this.restTemplate = restTemplate;
        this.workDirectoryService = workDirectoryService;
    }

    public void pushPackage(PackageManifest manifest, Path zipFile) {
        String url = buildUrl(prodApiProperties.getPushPath());
        HttpHeaders headers = defaultHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);

        // 当前协议约定 push 使用 multipart/form-data 上传标准同步包。
        MultiValueMap<String, Object> body = new LinkedMultiValueMap<String, Object>();
        body.add("file", new FileSystemResource(zipFile.toFile()));
        body.add("traceId", manifest.getTraceId());
        body.add("direction", manifest.getDirection().name());
        body.add("sourceVersion", manifest.getSourceVersion());
        body.add("contentHash", manifest.getContentHash());

        ResponseEntity<String> response = restTemplate.postForEntity(url, new HttpEntity<MultiValueMap<String, Object>>(body, headers), String.class);
        if (!response.getStatusCode().is2xxSuccessful()) {
            throw new IllegalStateException("Prod push API failed with status " + response.getStatusCodeValue());
        }
        log.info("Prod push API finished. traceId={}, status={}", manifest.getTraceId(), response.getStatusCodeValue());
    }

    public ProdPullResult pullConfigSnapshot() throws IOException {
        String url = buildUrl(prodApiProperties.getPullPath());
        HttpHeaders headers = defaultHeaders();
        // 当前协议约定 pull 直接返回原始配置字节流，由同步工具落成本地文件后再回写 Git。
        ResponseEntity<byte[]> response = restTemplate.exchange(
                url,
                HttpMethod.GET,
                new HttpEntity<Void>(headers),
                byte[].class
        );
        if (!response.getStatusCode().is2xxSuccessful()) {
            throw new IllegalStateException("Prod pull API failed with status " + response.getStatusCodeValue());
        }
        byte[] body = response.getBody();
        if (body == null || body.length == 0) {
            throw new IllegalStateException("Prod pull API returned empty content");
        }

        Path tempDir = Files.createTempDirectory(workDirectoryService.getProdToDevStagingDir(), "pull-");
        FileTreeUtils.ensureDirectory(tempDir);
        Path targetFile = tempDir.resolve(syncProperties.getPullResponseFileName());
        Files.write(targetFile, body);

        String contentHash = FileHashUtils.sha256(body);
        // 优先取服务端显式版本号；如果服务端没给，就退化为内容哈希做幂等判断。
        String sourceVersion = firstNonBlank(
                response.getHeaders().getFirst("X-Config-Version"),
                response.getHeaders().getETag(),
                contentHash
        );
        return new ProdPullResult(tempDir, sourceVersion, contentHash);
    }

    private HttpHeaders defaultHeaders() {
        HttpHeaders headers = new HttpHeaders();
        headers.setAccept(java.util.Collections.singletonList(MediaType.APPLICATION_JSON));
        if (prodApiProperties.getToken() != null && !prodApiProperties.getToken().trim().isEmpty()) {
            headers.setBearerAuth(prodApiProperties.getToken().trim());
        }
        return headers;
    }

    private String buildUrl(String path) {
        String base = prodApiProperties.getBaseUrl();
        if (base.endsWith("/") && path.startsWith("/")) {
            return base.substring(0, base.length() - 1) + path;
        }
        if (!base.endsWith("/") && !path.startsWith("/")) {
            return base + "/" + path;
        }
        return base + path;
    }

    private String firstNonBlank(String... candidates) {
        for (String candidate : candidates) {
            if (candidate != null && !candidate.trim().isEmpty()) {
                return candidate;
            }
        }
        return null;
    }
}