package com.dsh.guns.modular.system.audit;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/** 从 other 服务读取统一账号审计日志，不经公网网关暴露内部接口。 */
@Slf4j
@Component
public class AccountAuditLogReader {
    @Resource private DiscoveryClient discoveryClient;

    public AuditLogPage page(long current, long size, String userAccount, String operationType) {
        try {
            List<ServiceInstance> instances = discoveryClient.getInstances("mb-cloud-other");
            if (instances == null || instances.isEmpty()) return AuditLogPage.empty();
            StringBuilder url = new StringBuilder(instances.get(0).getUri().toString())
                    .append("/internal/audit-logs?current=").append(current)
                    .append("&size=").append(Math.min(size, 200));
            appendQuery(url, "userAccount", userAccount);
            appendQuery(url, "operationType", operationType);
            HttpURLConnection connection = (HttpURLConnection) new URL(url.toString()).openConnection();
            connection.setConnectTimeout(2000);
            connection.setReadTimeout(5000);
            connection.setRequestMethod("GET");
            try (InputStream input = connection.getInputStream()) {
                JSONObject body = JSON.parseObject(new String(readAll(input), StandardCharsets.UTF_8));
                JSONArray records = body.getJSONArray("records");
                return new AuditLogPage(toRecords(records), body.getLongValue("total"));
            } finally {
                connection.disconnect();
            }
        } catch (Exception e) {
            log.warn("读取账号审计日志失败", e);
            return AuditLogPage.empty();
        }
    }

    private static void appendQuery(StringBuilder url, String name, String value) throws Exception {
        if (value != null && !value.trim().isEmpty()) {
            url.append('&').append(name).append('=').append(URLEncoder.encode(value.trim(), "UTF-8"));
        }
    }

    private static byte[] readAll(InputStream input) throws Exception {
        byte[] buffer = new byte[4096];
        int length;
        java.io.ByteArrayOutputStream output = new java.io.ByteArrayOutputStream();
        while ((length = input.read(buffer)) != -1) output.write(buffer, 0, length);
        return output.toByteArray();
    }

    @SuppressWarnings("unchecked")
    private static List<Map<String, Object>> toRecords(JSONArray records) {
        if (records == null || records.isEmpty()) return Collections.emptyList();
        List<Map<String, Object>> result = new ArrayList<Map<String, Object>>(records.size());
        for (Object record : records) {
            if (record instanceof Map) {
                result.add(new LinkedHashMap<String, Object>((Map<String, Object>) record));
            }
        }
        return result;
    }

    public static class AuditLogPage {
        private final List<Map<String, Object>> records;
        private final long total;

        AuditLogPage(List<Map<String, Object>> records, long total) { this.records = records; this.total = total; }
        static AuditLogPage empty() { return new AuditLogPage(Collections.<Map<String, Object>>emptyList(), 0); }
        public List<Map<String, Object>> getRecords() { return records; }
        public long getTotal() { return total; }
    }
}