package com.label.integration;

import com.label.AbstractIntegrationTest;
import com.label.service.RedisService;
import com.label.util.RedisKeyManager;

import org.junit.jupiter.api.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.http.*;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

import static org.assertj.core.api.Assertions.assertThat;

/**
 * 任务领取并发安全集成测试（US3）。
 *
 * 测试场景：10 个线程同时争抢同一 UNCLAIMED 任务。
 * 期望结果：
 * - 恰好 1 人成功（200 OK）
 * - 其余 9 人收到 TASK_CLAIMED (409)
 * - DB 中 claimed_by 唯一（只有一个用户 ID）
 *
 * 此测试需要 10 个不同的 userId，使用同一 DB 用户账号但不同的 Token。
 */
public class TaskClaimConcurrencyTest extends AbstractIntegrationTest {

    @Autowired
    private TestRestTemplate restTemplate;

    @Autowired
    private RedisService redisService;

    private Long taskId;
    private final List<String> tokens = new ArrayList<>();

    @BeforeEach
    void setup() {
        // 创建测试任务（直接向 DB 插入一条 UNCLAIMED 任务）
        jdbcTemplate.execute(
                "INSERT INTO source_data (company_id, uploader_id, data_type, file_path, " +
                "file_name, file_size, bucket_name, status) " +
                "VALUES (1, 1, 'TEXT', 'test/path/file.txt', 'file.txt', 100, 'test-bucket', 'PENDING')");
        Long sourceId = jdbcTemplate.queryForObject(
                "SELECT id FROM source_data ORDER BY id DESC LIMIT 1", Long.class);

        jdbcTemplate.execute(
                "INSERT INTO annotation_task (company_id, source_id, task_type, status) " +
                "VALUES (1, " + sourceId + ", 'EXTRACTION', 'UNCLAIMED')");
        taskId = jdbcTemplate.queryForObject(
                "SELECT id FROM annotation_task ORDER BY id DESC LIMIT 1", Long.class);

        // 创建 10 个 Annotator Token（模拟不同用户）
        for (int i = 1; i <= 10; i++) {
            String token = "concurrency-test-token-" + i;
            tokens.add(token);
            // 所有 Token 使用 userId=3（annotator01），这在真实场景不会发生
            // 但在测试中用于验证并发锁机制（redis key 基于 taskId，不是 userId）
            redisService.hSetAll(RedisKeyManager.tokenKey(token),
                    Map.of("userId", String.valueOf(i + 100), // 假设 userId > 100 不存在，但不影响锁逻辑
                            "role", "ANNOTATOR", "companyId", "1", "username", "annotator" + i),
                    3600L);
        }
    }

    @AfterEach
    void cleanup() {
        tokens.forEach(token -> redisService.delete(RedisKeyManager.tokenKey(token)));
        if (taskId != null) {
            redisService.delete(RedisKeyManager.taskClaimKey(taskId));
        }
    }

    @Test
    @DisplayName("10 线程并发抢同一任务：恰好 1 人成功，其余 9 人收到 409 TASK_CLAIMED")
    void concurrentClaim_onlyOneSucceeds() throws InterruptedException {
        ExecutorService executor = Executors.newFixedThreadPool(10);
        CountDownLatch startLatch = new CountDownLatch(1);
        CountDownLatch doneLatch = new CountDownLatch(10);

        AtomicInteger successCount = new AtomicInteger(0);
        AtomicInteger conflictCount = new AtomicInteger(0);

        for (int i = 0; i < 10; i++) {
            final String token = tokens.get(i);
            executor.submit(() -> {
                try {
                    startLatch.await(); // 等待起跑信号，最大化并发

                    HttpHeaders headers = new HttpHeaders();
                    headers.set("Authorization", "Bearer " + token);
                    HttpEntity<Void> request = new HttpEntity<>(headers);

                    ResponseEntity<Map> response = restTemplate.exchange(
                            baseUrl("/api/tasks/" + taskId + "/claim"),
                            HttpMethod.POST, request, Map.class);

                    if (response.getStatusCode() == HttpStatus.OK) {
                        successCount.incrementAndGet();
                    } else if (response.getStatusCode() == HttpStatus.CONFLICT) {
                        conflictCount.incrementAndGet();
                    }
                } catch (Exception e) {
                    conflictCount.incrementAndGet(); // 异常也算失败
                } finally {
                    doneLatch.countDown();
                }
            });
        }

        startLatch.countDown(); // 同时放行所有线程
        doneLatch.await(30, TimeUnit.SECONDS);
        executor.shutdown();

        // 恰好 1 人成功
        assertThat(successCount.get()).isEqualTo(1);
        // 其余 9 人失败（409 或异常）
        assertThat(conflictCount.get()).isEqualTo(9);

        // DB 中 claimed_by 有且仅有一个值
        String claimedByStr = jdbcTemplate.queryForObject(
                "SELECT claimed_by::text FROM annotation_task WHERE id = ?",
                String.class, taskId);
        assertThat(claimedByStr).isNotNull();

        // DB 中状态为 IN_PROGRESS
        String status = jdbcTemplate.queryForObject(
                "SELECT status FROM annotation_task WHERE id = ?", String.class, taskId);
        assertThat(status).isEqualTo("IN_PROGRESS");
    }
}