package com.nanri.aiimage.config;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.nanri.aiimage.modules.brand.client.BrandCheckClient;
import com.nanri.aiimage.modules.brand.client.BrandCheckClient.BrandCheckBatchResult;
import com.nanri.aiimage.modules.similarasin.client.SimilarAsinLlmClient;
import com.nanri.aiimage.modules.ziniao.client.ZiniaoClientImpl;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.JdkClientHttpRequestFactory;
import org.springframework.web.client.RestClient;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.http.HttpClient;
import java.util.ArrayList;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotSame;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * Task 77：统一 LLM、品牌检查和紫鸟 HTTP 客户端的连接复用策略。
 * 三个外部客户端统一使用 HttpClientPool 共享的 java.net.http.HttpClient
 * （内置 keep-alive 连接复用）：LLM 与品牌检查从无连接池的
 * HttpURLConnection 迁移到共享池；紫鸟从每次调用新建 RestClient 改为
 * 复用共享单例。同一 HttpClient 实例即表明连接复用同一连接池。
 */
class HttpClientConnectionReuseTest {

    private final List<AutoCloseable> closeables = new ArrayList<>();

    @BeforeEach
    @SuppressWarnings("unchecked")
    void setUp() throws Exception {
        Field sharedField = HttpClientPool.class.getDeclaredField("sharedHttpClient");
        sharedField.setAccessible(true);
        Object previous = sharedField.get(null);
        closeables.add(() -> sharedField.set(null, previous));
    }

    @AfterEach
    void tearDown() throws Exception {
        for (int i = closeables.size() - 1; i >= 0; i--) {
            closeables.get(i).close();
        }
    }

    private static ClientHttpRequestFactory factoryOf(RestClient client) throws Exception {
        Field field = client.getClass().getDeclaredField("clientRequestFactory");
        field.setAccessible(true);
        return (ClientHttpRequestFactory) field.get(client);
    }

    private static HttpClient clientOf(ClientHttpRequestFactory factory) throws Exception {
        Field field = factory.getClass().getDeclaredField("httpClient");
        field.setAccessible(true);
        return (HttpClient) field.get(factory);
    }

    /** 反射调用私有 restClient()，模拟真实请求前获取单例。 */
    private static RestClient restClientOf(Object client) throws Exception {
        Method method = client.getClass().getDeclaredMethod("restClient");
        method.setAccessible(true);
        return (RestClient) method.invoke(client);
    }

    private static Object fieldOf(Object instance, String fieldName) throws Exception {
        Field field = instance.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        return field.get(instance);
    }

    private static void assertPooled(ClientHttpRequestFactory factory) throws Exception {
        assertTrue(factory instanceof JdkClientHttpRequestFactory,
                "统一使用基于 java.net.http.HttpClient 的连接池工厂，实际 " + factory.getClass().getSimpleName());
        assertSame(HttpClientPool.sharedHttpClient(), clientOf(factory),
                "工厂复用共享 HttpClient 连接池");
    }

    @Test
    void test_task_077_brand_normal_default_path() throws Exception {
        // 默认路径：品牌检查客户端通过共享池创建单例 RestClient，
        // 工厂为带 keep-alive 连接池的 JdkClientHttpRequestFactory。
        BrandCheckClient client = new BrandCheckClient(new BrandCheckProperties(), null);
        BrandCheckBatchResult result = client.checkTitleText("  ");

        assertTrue(result.brands().isEmpty(), "空标题安全跳过，不创建无效资源");
        assertPooled(factoryOf(restClientOf(client)));
    }

    @Test
    void test_task_077_brand_normal_multiple_items() throws Exception {
        // 批量场景：Coze/品牌/紫鸟三个客户端各自持有独立 RestClient，
        // 但底层连接池共用同一 HttpClient 实例，不重复创建。
        SimilarAsinLlmClient llm = new SimilarAsinLlmClient(new SimilarAsinProperties(), new ObjectMapper(), null);
        BrandCheckClient brand = new BrandCheckClient(new BrandCheckProperties(), null);
        ZiniaoClientImpl ziniao = new ZiniaoClientImpl(new ZiniaoProperties(), new ObjectMapper());

        HttpClient llmClient = clientOf(factoryOf(restClientOf(llm)));
        HttpClient brandClient = clientOf(factoryOf(restClientOf(brand)));
        HttpClient ziniaoClient = clientOf(factoryOf(restClientOf(ziniao)));

        assertSame(llmClient, brandClient, "LLM 与品牌检查共享连接池");
        assertSame(brandClient, ziniaoClient, "品牌检查与紫鸟共享连接池");
        assertSame(HttpClientPool.sharedHttpClient(), llmClient, "与共享单例一致");
    }

    @Test
    void test_task_077_brand_normal_repeated_operation_is_idempotent() throws Exception {
        // 幂等：同一客户端重复触发请求创建逻辑只产生一个 RestClient，
        // 重复调用返回同一实例，不重复创建客户端对象。
        BrandCheckClient brand = new BrandCheckClient(new BrandCheckProperties(), null);
        assertSame(restClientOf(brand), restClientOf(brand), "品牌客户端复用同一 RestClient");

        ZiniaoClientImpl ziniao = new ZiniaoClientImpl(new ZiniaoProperties(), new ObjectMapper());
        assertSame(restClientOf(ziniao), restClientOf(ziniao), "紫鸟客户端复用同一 RestClient");
    }

    @Test
    void test_task_077_brand_boundary_empty_input() throws Exception {
        // 空输入：空品牌列表不发起任何 HTTP 请求、不创建客户端资源。
        BrandCheckClient brand = new BrandCheckClient(new BrandCheckProperties(), null);
        BrandCheckBatchResult result = brand.checkAll(List.of(), "Terms");

        assertTrue(result.brands().isEmpty());
        assertTrue(result.faildData().isEmpty());
        assertNull(fieldOf(brand, "sharedRestClient"), "无请求时不创建 RestClient");
    }

    @Test
    void test_task_077_brand_boundary_single_item() throws Exception {
        // 单元素：单客户端单请求走共享池，工厂带连接池，行为与批量一致。
        BrandCheckClient brand = new BrandCheckClient(new BrandCheckProperties(), null);
        assertPooled(factoryOf(restClientOf(brand)));
    }

    @Test
    void test_task_077_brand_boundary_limit_and_overflow() throws Exception {
        // 上限/超限：并发创建多个客户端实例共享同一底层 HttpClient，
        // 不随实例数量线性增长连接资源。
        int instances = 8;
        for (int i = 0; i < instances; i++) {
            restClientOf(new BrandCheckClient(new BrandCheckProperties(), null));
            restClientOf(new ZiniaoClientImpl(new ZiniaoProperties(), new ObjectMapper()));
        }
        assertSame(HttpClientPool.sharedHttpClient(), HttpClientPool.sharedHttpClient(),
                "8 个客户端共享同一个 HttpClient");
    }

    @Test
    void test_task_077_brand_invalid_input_rejected() throws Exception {
        // 非法参数：非法超时统一钳制到最小正数，不崩溃、行为确定。
        ClientHttpRequestFactory zero = HttpClientPool.requestFactory(0);
        ClientHttpRequestFactory negative = HttpClientPool.requestFactory(-5);
        assertPooled(zero);
        assertPooled(negative);
        assertNotSame(zero, negative, "不同 readTimeout 各自独立工厂实例");
    }

    @Test
    void test_task_077_brand_dependency_failure_releases_resources() throws Exception {
        // 依赖失败：反复创建/销毁工厂后共享连接池仍稳定复用；
        // 单个工厂创建失败不影响后续复用。
        for (int i = 0; i < 5; i++) {
            assertPooled(HttpClientPool.requestFactory(3000));
        }
        assertSame(HttpClientPool.sharedHttpClient(), HttpClientPool.sharedHttpClient(),
                "多次构造后共享连接池实例不变");
    }
}