package com.ruoyi.lsfx.util;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.ruoyi.lsfx.domain.CallerContext;
import com.ruoyi.lsfx.exception.LsfxApiException;
import com.ruoyi.system.domain.SysApiLog;
import com.ruoyi.system.service.ISysApiLogService;
import jakarta.annotation.Resource;
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.MediaTypeFactory;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestClientResponseException;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;

import java.io.File;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * 业务外部HTTP请求工具，统一保存完整调用日志。
 */
@Component
public class HttpUtil {

    private static final Logger log = LoggerFactory.getLogger(HttpUtil.class);
    private static final String CALL_SUCCESS = "0";
    private static final String CALL_FAILED = "1";

    @Resource
    private RestTemplate restTemplate;

    @Resource
    private ObjectMapper objectMapper;

    @Resource
    private ISysApiLogService apiLogService;

    public static org.springframework.core.io.Resource namedFileResource(File file, String filename) {
        return new NamedFileSystemResource(file, filename);
    }

    private static class NamedFileSystemResource extends FileSystemResource {
        private final String filename;

        NamedFileSystemResource(File file, String filename) {
            super(file);
            this.filename = StringUtils.hasText(filename) ? filename : file.getName();
        }

        @Override
        public String getFilename() {
            return filename;
        }
    }

    public <T> T get(CallerContext caller, String url, Map<String, Object> params,
                     Map<String, String> headers, Class<T> responseType) {
        UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url);
        if (params != null) {
            params.forEach((key, value) -> {
                if (value != null) {
                    builder.queryParam(key, value);
                }
            });
        }
        String fullUrl = builder.toUriString();
        HttpHeaders httpHeaders = createHeaders(headers);
        return execute(caller, fullUrl, HttpMethod.GET, httpHeaders, params,
            new HttpEntity<>(httpHeaders), responseType, "API返回数据为空", "GET请求异常");
    }

    public <T> T get(CallerContext caller, String url, Map<String, String> headers, Class<T> responseType) {
        HttpHeaders httpHeaders = createHeaders(headers);
        return execute(caller, url, HttpMethod.GET, httpHeaders, null,
            new HttpEntity<>(httpHeaders), responseType, "API返回数据为空", "网络请求失败");
    }

    public <T> T postJson(CallerContext caller, String url, Object request,
                          Map<String, String> headers, Class<T> responseType) {
        HttpHeaders httpHeaders = createHeaders(headers);
        httpHeaders.setContentType(MediaType.APPLICATION_JSON);
        return execute(caller, url, HttpMethod.POST, httpHeaders, request,
            new HttpEntity<>(request, httpHeaders), responseType, "API返回数据为空", "网络请求失败");
    }

    public <T> T postFormData(CallerContext caller, String url, Map<String, Object> params,
                              Map<String, String> headers, Class<T> responseType) {
        HttpHeaders httpHeaders = createHeaders(headers);
        httpHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
        if (params != null) {
            params.forEach(body::add);
        }
        return execute(caller, url, HttpMethod.POST, httpHeaders, params,
            new HttpEntity<>(body, httpHeaders), responseType, "API返回数据为空", "网络请求失败");
    }

    public <T> T postUrlEncodedForm(CallerContext caller, String url, Map<String, Object> params,
                                    Map<String, String> headers, Class<T> responseType) {
        HttpHeaders httpHeaders = createHeaders(headers);
        httpHeaders.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        MultiValueMap<String, String> body = toUrlEncodedBody(params);
        return execute(caller, url, HttpMethod.POST, httpHeaders, params,
            new HttpEntity<>(body, httpHeaders), responseType, "API返回数据为空", "网络请求失败");
    }

    public String postUrlEncodedFormForString(CallerContext caller, String url,
                                              Map<String, Object> params, Map<String, String> headers) {
        HttpHeaders httpHeaders = createHeaders(headers);
        httpHeaders.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        MultiValueMap<String, String> body = toUrlEncodedBody(params);
        return execute(caller, url, HttpMethod.POST, httpHeaders, params,
            new HttpEntity<>(body, httpHeaders), String.class, "API返回数据为空", "网络请求失败");
    }

    public <T> T uploadFile(CallerContext caller, String url, Map<String, Object> params,
                            Map<String, String> headers, Class<T> responseType) {
        HttpHeaders httpHeaders = createHeaders(headers);
        httpHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
        if (params != null) {
            params.forEach((key, value) -> {
                if (value instanceof File file) {
                    body.add(key, new FileSystemResource(file));
                } else {
                    body.add(key, value);
                }
            });
        }
        return execute(caller, url, HttpMethod.POST, httpHeaders, params,
            new HttpEntity<>(body, httpHeaders), responseType, "文件上传返回数据为空", "文件上传请求失败");
    }

    private <T> T execute(CallerContext caller, String url, HttpMethod method, HttpHeaders requestHeaders,
                          Object requestParams, HttpEntity<?> requestEntity, Class<T> responseType,
                          String emptyResponseMessage, String requestFailureMessage) {
        if (caller == null) {
            throw new IllegalArgumentException("接口调用用户不能为空");
        }

        long startTime = System.currentTimeMillis();
        SysApiLog apiLog = createBaseApiLog(caller, url, method, startTime);
        try {
            captureRequest(apiLog, requestHeaders, requestParams);
        } catch (Exception e) {
            log.error("接口日志请求快照构建失败: method={}, url={}", method, url, e);
        }
        try {
            ResponseEntity<String> response = restTemplate.exchange(url, method, requestEntity, String.class);
            captureResponse(apiLog, response);
            if (!response.getStatusCode().is2xxSuccessful()) {
                throw new LsfxApiException("API调用失败，HTTP状态码: " + response.getStatusCode().value());
            }
            if (!StringUtils.hasText(response.getBody())) {
                throw new LsfxApiException(emptyResponseMessage);
            }

            T result = parseResponse(response.getBody(), responseType);
            apiLog.setCallStatus(CALL_SUCCESS);
            return result;
        } catch (RestClientResponseException e) {
            apiLog.setResponseStatus(e.getStatusCode().value());
            apiLog.setResponseHeaders(safeSerialize(e.getResponseHeaders()));
            apiLog.setResponseBody(e.getResponseBodyAsString());
            apiLog.setErrorMsg(formatException(e));
            throw new LsfxApiException(requestFailureMessage + ": " + e.getMessage(), e);
        } catch (LsfxApiException e) {
            apiLog.setErrorMsg(formatException(e));
            throw e;
        } catch (RestClientException e) {
            apiLog.setErrorMsg(formatException(e));
            throw new LsfxApiException(requestFailureMessage + ": " + e.getMessage(), e);
        } catch (Exception e) {
            apiLog.setErrorMsg(formatException(e));
            throw new LsfxApiException("响应解析失败: " + e.getMessage(), e);
        } finally {
            apiLog.setCostTime(System.currentTimeMillis() - startTime);
            persistApiLog(apiLog);
        }
    }

    private SysApiLog createBaseApiLog(CallerContext caller, String url, HttpMethod method, long startTime) {
        SysApiLog apiLog = new SysApiLog();
        apiLog.setCallerUserId(caller.userId());
        apiLog.setCallerUsername(caller.username());
        apiLog.setApiUrl(url);
        apiLog.setHttpMethod(method.name());
        apiLog.setCallStatus(CALL_FAILED);
        apiLog.setCallTime(new Date(startTime));
        return apiLog;
    }

    private void captureRequest(SysApiLog apiLog, HttpHeaders headers, Object params) {
        apiLog.setContentType(headers.getContentType() == null ? null : headers.getContentType().toString());
        apiLog.setRequestHeaders(safeSerialize(headers));
        apiLog.setRequestParams(safeSerialize(normalizeValue(params)));
    }

    private void captureResponse(SysApiLog apiLog, ResponseEntity<String> response) {
        apiLog.setResponseStatus(response.getStatusCode().value());
        apiLog.setResponseHeaders(safeSerialize(response.getHeaders()));
        apiLog.setResponseBody(response.getBody());
    }

    @SuppressWarnings("unchecked")
    private <T> T parseResponse(String responseBody, Class<T> responseType) throws Exception {
        if (String.class.equals(responseType)) {
            return (T) responseBody;
        }
        return objectMapper.readValue(responseBody, responseType);
    }

    private MultiValueMap<String, String> toUrlEncodedBody(Map<String, Object> params) {
        MultiValueMap<String, String> body = new LinkedMultiValueMap<>();
        if (params != null) {
            params.forEach((key, value) -> {
                if (value != null) {
                    body.add(key, value.toString());
                }
            });
        }
        return body;
    }

    private HttpHeaders createHeaders(Map<String, String> headers) {
        HttpHeaders httpHeaders = new HttpHeaders();
        if (headers != null) {
            headers.forEach(httpHeaders::set);
        }
        return httpHeaders;
    }

    private Object normalizeValue(Object value) {
        if (value == null) {
            return null;
        }
        if (value instanceof File file) {
            return fileMetadata(file.getName(), file.length());
        }
        if (value instanceof FileSystemResource resource) {
            return fileMetadata(resource.getFilename(), resource.getFile().length());
        }
        if (value instanceof org.springframework.core.io.Resource resource) {
            return fileMetadata(resource.getFilename(), null);
        }
        if (value instanceof Map<?, ?> map) {
            Map<String, Object> normalized = new LinkedHashMap<>();
            map.forEach((key, item) -> normalized.put(String.valueOf(key), normalizeValue(item)));
            return normalized;
        }
        if (value instanceof Iterable<?> iterable) {
            List<Object> normalized = new ArrayList<>();
            iterable.forEach(item -> normalized.add(normalizeValue(item)));
            return normalized;
        }
        if (value.getClass().isArray()) {
            List<Object> normalized = new ArrayList<>();
            for (int i = 0; i < Array.getLength(value); i++) {
                normalized.add(normalizeValue(Array.get(value, i)));
            }
            return normalized;
        }
        return value;
    }

    private Map<String, Object> fileMetadata(String filename, Long size) {
        Map<String, Object> metadata = new LinkedHashMap<>();
        metadata.put("filename", filename);
        metadata.put("size", size);
        metadata.put("contentType", MediaTypeFactory.getMediaType(filename == null ? "" : filename)
            .map(MediaType::toString).orElse(null));
        return metadata;
    }

    private String safeSerialize(Object value) {
        try {
            return objectMapper.writeValueAsString(value);
        } catch (Exception e) {
            log.error("接口日志序列化失败", e);
            return String.valueOf(value);
        }
    }

    private String formatException(Exception exception) {
        StringWriter writer = new StringWriter();
        exception.printStackTrace(new PrintWriter(writer));
        return writer.toString();
    }

    private void persistApiLog(SysApiLog apiLog) {
        try {
            apiLogService.recordApiLog(apiLog);
        } catch (Exception e) {
            log.error("接口日志入库失败: method={}, url={}", apiLog.getHttpMethod(), apiLog.getApiUrl(), e);
        }
    }
}