package trackertest;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.stream.Collectors;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.DynamicTest;
import org.junit.jupiter.api.TestFactory;

import entity.config;
import tracker.Tracker;

public class TrackerTest {
    private static EntityManagerFactory emf;
    private static EntityManager em;
    private static List<String> userIds;
    private static Map<String, Long> originalUploads;
    private static Tracker tracker;

    @BeforeAll
    static void setup() throws Exception {
        // 强制加载 MySQL 驱动，否则无法建立连接
        Class.forName("com.mysql.cj.jdbc.Driver");
        config cfg = new config();
        Map<String,Object> props = new HashMap<>();
        // 添加时区和 SSL 参数
        String jdbcUrl = String.format(
            "jdbc:mysql://%s/%s?useSSL=false&serverTimezone=UTC",
            cfg.SqlURL, cfg.TestDatabase);
        props.put("javax.persistence.jdbc.url", jdbcUrl);
        props.put("javax.persistence.jdbc.user", cfg.SqlUsername);
        props.put("javax.persistence.jdbc.password", cfg.SqlPassword);
        props.put("javax.persistence.jdbc.driver", "com.mysql.cj.jdbc.Driver");
        emf = Persistence.createEntityManagerFactory("myPersistenceUnit", props);
        em = emf.createEntityManager();
        // 使用简单实体名而非带包名前缀
        userIds = em.createQuery(
            "select u.userid from UserPT u", String.class
        ).getResultList();

        // 保存初始 upload 值
        originalUploads = new HashMap<>();
        for (String uid : userIds) {
            Long up = em.createQuery(
                "select u.upload from UserPT u where u.userid = :uid", Long.class
            ).setParameter("uid", uid)
             .getSingleResult();
            originalUploads.put(uid, up != null ? up : 0L);
        }
        tracker = new Tracker(emf);
    }

    @AfterAll
    static void teardown() {
        if (em != null && em.isOpen()) em.close();
        if (emf != null && emf.isOpen()) emf.close();
    }

    @TestFactory
    Collection<DynamicTest> testAddUpLoad() {
        Random rnd = new Random();
        return userIds.stream()
            .map(uid -> DynamicTest.dynamicTest("AddUpLoad for user " + uid, () -> {
                int delta = rnd.nextInt(1000) + 1; // Ensure non-zero value
                long before = originalUploads.get(uid);
                
                // 操作成功时返回 false
                Assertions.assertFalse(tracker.AddUpLoad(uid, delta), 
                    "AddUpLoad should return false on successful operation");
                
                // Clear the persistence context to ensure fresh data is fetched
                em.clear();
                
                // Fetch updated value
                Long after = em.createQuery(
                    "select u.upload from UserPT u where u.userid = :uid", Long.class
                ).setParameter("uid", uid)
                 .getSingleResult();
                
                Assertions.assertEquals(before + delta, after, 
                    "Upload value should be increased by " + delta);
                
                // 操作成功时返回 false
                Assertions.assertFalse(tracker.ReduceUpLoad(uid, delta),
                    "ReduceUpLoad should return false on successful operation");
            }))
            .collect(Collectors.toList());
    }

    @TestFactory
    Collection<DynamicTest> testReduceUpLoad() {
        Random rnd = new Random();
        return userIds.stream()
            .map(uid -> DynamicTest.dynamicTest("ReduceUpLoad for user " + uid, () -> {
                long before = originalUploads.get(uid);
                int max = (int)Math.min(before, 1000);
                int delta = max > 0 ? rnd.nextInt(max) + 1 : 0;
                if (delta == 0) return;  // 无可减量时跳过
                Assertions.assertFalse(tracker.ReduceUpLoad(uid, delta));
                Long after = em.createQuery(
                    "select u.upload from UserPT u where u.userid = :uid", Long.class
                ).setParameter("uid", uid)
                 .getSingleResult();
                Assertions.assertEquals(before - delta, after);
                // 回滚到初始值
                Assertions.assertFalse(tracker.AddUpLoad(uid, delta));
            }))
            .collect(Collectors.toList());
    }
}