package com.mydreamjob.resume;

import com.mydreamjob.auth.User;
import com.mydreamjob.auth.UserRepository;
import com.mydreamjob.resume.storage.ResumeExportStorageService;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.DefaultTransactionDefinition;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.stream.Collectors;

import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.fail;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

/**
 * 简历版本持久化与并发集成测试：H2 + Flyway V14/V15 真实表结构。
 * 验证：唯一默认约束、version_no 唯一、导出任务 FK ON DELETE SET NULL、
 * 并发设默认/并发创建、导出任务使用创建时的源文件快照。
 */
@SpringBootTest
@ActiveProfiles("integration-test")
class ResumeVersionPersistenceIntegrationTest {

    @Autowired private ResumeVersionRepository versionRepository;
    @Autowired private ResumeExportTaskRepository taskRepository;
    @Autowired private ResumeVersionService resumeVersionService;
    @Autowired private ResumeExportService resumeExportService;
    @Autowired private ResumeExportStorageService resumeExportStorageService;
    @Autowired private UserRepository userRepository;
    @Autowired private PlatformTransactionManager transactionManager;
    @Value("${app.resume.storage-dir:./target/resumes}")
    private String storageDir;

    @MockBean private RedisTemplate<String, Object> redisTemplate;

    private Long userId;

    private static final java.util.concurrent.atomic.AtomicLong PHONE_SEQ =
            new java.util.concurrent.atomic.AtomicLong(200);

    @BeforeEach
    @SuppressWarnings("unchecked")
    void setUp() {
        ValueOperations<String, Object> ops = mock(ValueOperations.class);
        when(redisTemplate.opsForValue()).thenReturn(ops);
        when(redisTemplate.hasKey(any())).thenReturn(false);

        taskRepository.deleteAll();
        versionRepository.deleteAll();

        User student = userRepository.save(User.builder()
                .phone(uniquePhone()).nickname("简历候选人")
                .role(User.Role.STUDENT).active(true).verified(true).build());
        userId = student.getId();
    }

    private String uniquePhone() {
        return "188" + String.format("%08d", PHONE_SEQ.incrementAndGet());
    }

    private ResumeVersion newVersion(int versionNo) {
        return ResumeVersion.builder()
                .userId(userId).name("版本" + versionNo).versionNo(versionNo)
                .fileStoragePath("100_" + versionNo + ".pdf").fileName("r.pdf")
                .contentType("application/pdf").fileSize(7L)
                .defaultKey(null).status(ResumeVersion.STATUS_ACTIVE)
                .build();
    }

    @Test
    void uniqueDefault_databaseConstraint_enforced() {
        ResumeVersion v1 = newVersion(1);
        v1.setDefaultKey(ResumeVersion.DEFAULT_KEY);
        versionRepository.saveAndFlush(v1);
        ResumeVersion v2 = newVersion(2);
        v2.setDefaultKey(ResumeVersion.DEFAULT_KEY);
        assertThrows(DataIntegrityViolationException.class,
                () -> versionRepository.saveAndFlush(v2));
    }

    @Test
    void multipleNonDefault_areAllowed() {
        versionRepository.saveAndFlush(newVersion(1));
        versionRepository.saveAndFlush(newVersion(2));
        versionRepository.saveAndFlush(newVersion(3));
        assertThat(versionRepository.count()).isEqualTo(3);
    }

    @Test
    void versionNo_uniquePerUser() {
        versionRepository.saveAndFlush(newVersion(1));
        assertThrows(DataIntegrityViolationException.class,
                () -> versionRepository.saveAndFlush(newVersion(1)));
    }

    @Test
    void exportTask_fkSetNull_onVersionDelete() {
        ResumeVersion version = versionRepository.saveAndFlush(newVersion(1));
        ResumeExportTask task = taskRepository.saveAndFlush(ResumeExportTask.builder()
                .userId(userId).resumeVersionId(version.getId())
                .resumeVersionName(version.getName()).status(ResumeExportTask.STATUS_SUCCESS).build());

        versionRepository.delete(version);

        ResumeExportTask reloaded = taskRepository.findById(task.getId()).orElseThrow();
        assertNull(reloaded.getResumeVersionId());
        assertThat(reloaded.getStatus()).isEqualTo(ResumeExportTask.STATUS_SUCCESS);
    }

    @Test
    void setDefault_concurrently_shouldLeaveExactlyOneDefault() throws Exception {
        ResumeVersion v1 = versionRepository.saveAndFlush(newVersion(1));
        ResumeVersion v2 = versionRepository.saveAndFlush(newVersion(2));

        ExecutorService pool = Executors.newFixedThreadPool(2);
        CountDownLatch start = new CountDownLatch(1);
        AtomicReference<Throwable> failure = new AtomicReference<>();
        pool.submit(() -> runWithLatch(start, () -> resumeVersionService.setDefault(userId, v1.getId()), failure));
        pool.submit(() -> runWithLatch(start, () -> resumeVersionService.setDefault(userId, v2.getId()), failure));
        start.countDown();
        pool.shutdown();
        assertTrue(pool.awaitTermination(10, TimeUnit.SECONDS));

        // 无论哪个线程获胜/冲突，最终数据库必须恰好一个默认
        long defaults = versionRepository.findAll().stream()
                .filter(ResumeVersion::isDefault).count();
        assertThat(defaults).isEqualTo(1);
    }

    @Test
    void createVersion_concurrently_shouldProduceDistinctVersionNos() throws Exception {
        ExecutorService pool = Executors.newFixedThreadPool(2);
        CountDownLatch start = new CountDownLatch(1);
        AtomicReference<Throwable> failure = new AtomicReference<>();
        MockMultipartFile file = new MockMultipartFile("file", "r.pdf", "application/pdf", pdf("data"));
        pool.submit(() -> runWithLatch(start, () -> resumeVersionService.createVersion(userId, "a", file), failure));
        pool.submit(() -> runWithLatch(start, () -> resumeVersionService.createVersion(userId, "b", file), failure));
        start.countDown();
        pool.shutdown();
        assertTrue(pool.awaitTermination(10, TimeUnit.SECONDS));

        if (failure.get() != null) {
            fail("concurrent create failed: " + failure.get());
        }
        var versions = versionRepository.findByUserIdAndStatusOrderByVersionNoDesc(userId, ResumeVersion.STATUS_ACTIVE);
        assertThat(versions).hasSize(2);
        assertThat(versions.get(0).getVersionNo()).isNotEqualTo(versions.get(1).getVersionNo());
    }

    /**
     * 端到端：创建导出任务（快照文件 A）后修改版本文件为 B，
     * 导出结果仍必须是创建任务时的文件 A。
     */
    @Test
    void export_afterVersionModified_shouldUseOriginalFile() throws Exception {
        byte[] contentA = pdf("AAA");
        byte[] contentB = pdf("BBB");
        MockMultipartFile fileA = new MockMultipartFile("file", "r.pdf", "application/pdf", contentA);
        MockMultipartFile fileB = new MockMultipartFile("file", "r2.pdf", "application/pdf", contentB);

        ResumeVersion v1 = resumeVersionService.createVersion(userId, "v1", fileA);
        ResumeExportTask task = resumeExportService.createExportTask(userId, v1.getId()); // 快照 = A 的路径

        // 创建导出后立刻修改版本（替换文件）→ 旧文件 A 若被进行中的任务引用则保留
        resumeVersionService.updateVersion(userId, v1.getId(), "renamed", fileB);

        ResumeExportTask done = awaitTerminal(task.getId());
        assertEquals(ResumeExportTask.STATUS_SUCCESS, done.getStatus(), "导出应成功: " + done.getErrorMessage());
        assertArrayEquals(contentA, resumeExportStorageService.read(done.getOutputPath()));
        assertEquals("r.pdf", done.getOutputName());
    }

    private ResumeExportTask awaitTerminal(Long taskId) throws InterruptedException {
        for (int i = 0; i < 100; i++) {
            ResumeExportTask t = taskRepository.findById(taskId).orElseThrow();
            if (!ResumeExportTask.STATUS_PENDING.equals(t.getStatus())
                    && !ResumeExportTask.STATUS_RUNNING.equals(t.getStatus())) {
                return t;
            }
            Thread.sleep(50);
        }
        throw new AssertionError("export task did not reach terminal state: " + taskId);
    }

    /**
     * 模拟事务 afterCompletion(STATUS_ROLLED_BACK)：替换版本文件后强制回滚。
     * 断言：新文件被清理、旧文件仍存在、数据库记录未被错误修改。
     */
    @Test
    void updateVersion_outerRollback_shouldCleanNewFileAndKeepOldFileAndDb() throws Exception {
        MockMultipartFile fileA = new MockMultipartFile("file", "r.pdf", "application/pdf", pdf("AAA"));
        MockMultipartFile fileB = new MockMultipartFile("file", "r2.pdf", "application/pdf", pdf("BBB"));
        ResumeVersion v1 = resumeVersionService.createVersion(userId, "v1", fileA);
        String pathA = v1.getFileStoragePath();
        List<String> before = listMyResumeFiles();

        // 事务内更新版本文件，随后强制回滚 → 触发 afterCompletion(STATUS_ROLLED_BACK)
        DefaultTransactionDefinition def = new DefaultTransactionDefinition();
        TransactionStatus tx = transactionManager.getTransaction(def);
        try {
            resumeVersionService.updateVersion(userId, v1.getId(), null, fileB);
            tx.setRollbackOnly();
        } finally {
            transactionManager.rollback(tx);
        }

        // 新文件被清理，旧文件仍在（文件集合不变）
        List<String> after = listMyResumeFiles();
        assertEquals(before, after, "回滚后：新文件应被清理、旧文件仍存在");
        // 数据库记录未被错误修改（仍指向旧文件）
        ResumeVersion reloaded = versionRepository.findById(v1.getId()).orElseThrow();
        assertEquals(pathA, reloaded.getFileStoragePath());
    }

    /** 列出当前测试用户(userId)前缀的简历存储文件 */
    private List<String> listMyResumeFiles() throws IOException {
        Path dir = Paths.get(storageDir).toAbsolutePath().normalize();
        try (var stream = Files.list(dir)) {
            return stream
                    .filter(p -> p.getFileName().toString().startsWith(userId + "_"))
                    .map(p -> p.getFileName().toString())
                    .sorted()
                    .collect(Collectors.toList());
        }
    }

    private void runWithLatch(CountDownLatch start, Runnable action, AtomicReference<Throwable> failure) {
        try {
            start.await();
            action.run();
        } catch (Throwable t) {
            failure.compareAndSet(null, t);
        }
    }

    private byte[] pdf(String content) {
        return ("%PDF-1.7\n" + content + "\n%%EOF\n")
                .getBytes(java.nio.charset.StandardCharsets.US_ASCII);
    }
}