using System.Text.RegularExpressions;
using Admin.NET.Plugin.AiDOP.MaterialWarehouse;
using Microsoft.Extensions.Logging.Abstractions;
using SqlSugar;
using Xunit;

namespace Admin.NET.Plugin.AiDOP.Tests.S5.MaterialWarehouse;

/// <summary>
/// S5 库存冷链跨实例互斥锁（<see cref="InventoryInboundLockGuard"/>）实库测试。
/// <para>**门禁**：仅当环境变量 AIDOP_IT=1 时执行。</para>
/// <para>
/// 只碰 MySQL 咨询锁（GET_LOCK/RELEASE_LOCK/IS_USED_LOCK），**不读不写任何业务表**；
/// 全部用例使用带 GUID 的一次性锁键，绝不触碰生产键 <c>aidop:s5:inventory-inbound</c>。
/// </para>
/// </summary>
[Trait("Category", "Integration")]
public class InventoryInboundLockGuardTests
{
    private static bool Enabled => Environment.GetEnvironmentVariable("AIDOP_IT") == "1";

    private readonly Xunit.Abstractions.ITestOutputHelper _out;
    public InventoryInboundLockGuardTests(Xunit.Abstractions.ITestOutputHelper output) => _out = output;

    /// <summary>
    /// 一次性测试锁键。**必须 ≤ 64 字符** —— MySQL 8.0 对 GET_LOCK 的 user-level lock name
    /// 有 64 字符硬上限，超长会直接报 "Incorrect user-level lock name" 而不是返回 0，
    /// 表现得像「取不到锁」。故这里只取 GUID 前 8 位，长度约 30 字符，仍足够隔离并发测试。
    /// （生产键 aidop:s5:inventory-inbound 为 26 字符，不受此限影响。）
    /// </summary>
    private static string NewKey(string tag) => $"aidop:t:inv-in:{tag}:{Guid.NewGuid():N}"[..30];

    private static string ReadAidopdevConnectionString()
    {
        const string path = "/home/yy968/work/New9S/AiDOPWarehouse/server/Admin.NET.Application/Configuration/Database.json";
        if (!File.Exists(path)) return null;
        return File.ReadLines(path)
            .Select(l => l.Trim())
            .Where(l => !l.StartsWith("//") && l.Contains("\"ConnectionString\"") && l.Contains("Database=aidopdev") && l.Contains("123.60.180.165"))
            .Select(l => Regex.Match(l, "\"ConnectionString\"\\s*:\\s*\"([^\"]+)\"").Groups[1].Value)
            .FirstOrDefault(v => !string.IsNullOrEmpty(v));
    }

    /// <summary>模拟「业务共享客户端」：与 SqlSugarSetup.cs:128 一致的 IsAutoCloseConnection=true。</summary>
    private static ISqlSugarClient BuildSharedClient(string cs) =>
        new SqlSugarScope(new ConnectionConfig
        {
            ConfigId = "aidopdev-invlock-it", DbType = DbType.MySql, ConnectionString = cs, IsAutoCloseConnection = true,
        });

    /// <summary>模拟「另一个 Web 实例」：独立且不自动关闭的连接，会话全程持有。</summary>
    private static SqlSugarClient BuildDedicatedClient(string cs) =>
        new(new ConnectionConfig
        {
            DbType = DbType.MySql, ConnectionString = cs, IsAutoCloseConnection = false,
        });

    private static async Task<long?> IsUsedLockAsync(ISqlSugarClient probe, string key)
    {
        var dt = await probe.Ado.GetDataTableAsync(
            "SELECT IS_USED_LOCK(@k)", new List<SugarParameter> { new("@k", key) });
        if (dt == null || dt.Rows.Count == 0) return null;
        var v = dt.Rows[0][0];
        return v == DBNull.Value ? (long?)null : Convert.ToInt64(v);
    }

    // ===== Case 1：并发互斥 —— A 进临界区，B 进不来；A 释放后 C 能进 =====

    [Fact]
    public async Task Case1_SecondCallerIsRejectedImmediately_ThirdSucceedsAfterRelease()
    {
        if (!Enabled) return;
        var cs = ReadAidopdevConnectionString();
        Assert.False(string.IsNullOrEmpty(cs));
        var db = BuildSharedClient(cs);
        var key = NewKey("case1");

        var started = DateTime.UtcNow;
        await using (var a = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key))
        {
            Assert.True(a.Acquired, $"acquire failed: {a.BusyReason}");
            Assert.NotNull(a.OwnerConnectionId);

            // B：临界区内的第二个并发请求必须立即被拒，不排队
            var b = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key);
            await using (b)
            {
                Assert.False(b.Acquired);
                Assert.False(string.IsNullOrEmpty(b.BusyReason));
                _out.WriteLine($"B rejected: {b.BusyReason}");
            }
            // 非阻塞语义：整段不得出现 GET_LOCK 的等待
            Assert.True((DateTime.UtcNow - started).TotalSeconds < 20);
        }

        // C：A 释放后必须能进
        await using var c = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key);
        Assert.True(c.Acquired, $"acquire failed: {c.BusyReason}");
    }

    // ===== Case 2：回归断言 —— 任务运行中 IS_USED_LOCK 非 NULL，结束后 NULL =====
    // 这正是原缺陷的判据：旧实现在共享连接上取锁，取完连接回池被 reset，IS_USED_LOCK 恒为 NULL。

    [Fact]
    public async Task Case2_LockIsVisibleToOtherSessions_WhileHeld_AndGoneAfterRelease()
    {
        if (!Enabled) return;
        var cs = ReadAidopdevConnectionString();
        Assert.False(string.IsNullOrEmpty(cs));
        var db = BuildSharedClient(cs);
        var key = NewKey("case2");

        // 用一条独立连接当「观察者」，模拟另一个实例来看锁在不在
        using var probe = BuildDedicatedClient(cs);

        long? ownerWhileHeld;
        long? guardOwner;
        await using (var a = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key))
        {
            Assert.True(a.Acquired, $"acquire failed: {a.BusyReason}");
            guardOwner = a.OwnerConnectionId;

            // 期间在共享 db 上再跑几条普通查询（会不断借还连接），锁必须不受影响
            await db.Ado.GetDataTableAsync("SELECT 1");
            await db.Ado.GetDataTableAsync("SELECT 2");

            ownerWhileHeld = await IsUsedLockAsync(probe, key);
        }

        var ownerAfter = await IsUsedLockAsync(probe, key);

        _out.WriteLine($"guardOwner={guardOwner} whileHeld={ownerWhileHeld} after={ownerAfter}");
        Assert.NotNull(ownerWhileHeld);                 // 修复前这里是 NULL —— 缺陷复现点
        Assert.Equal(guardOwner, ownerWhileHeld);       // 持有者必须就是 guard 的专用连接
        Assert.Null(ownerAfter);                        // 释放后必须干净
    }

    // ===== Case 3：异常路径 —— 临界区内抛异常，finally(await using) 必须释放，后续可继续 =====

    [Fact]
    public async Task Case3_ExceptionInsideCriticalSection_StillReleasesLock()
    {
        if (!Enabled) return;
        var cs = ReadAidopdevConnectionString();
        Assert.False(string.IsNullOrEmpty(cs));
        var db = BuildSharedClient(cs);
        var key = NewKey("case3");
        using var probe = BuildDedicatedClient(cs);

        await Assert.ThrowsAsync<InvalidOperationException>(async () =>
        {
            await using var a = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key);
            Assert.True(a.Acquired, $"acquire failed: {a.BusyReason}");
            throw new InvalidOperationException("boom: 模拟 transform 中途失败");
        });

        // 锁必须已经释放：DB 侧看不到，且下一次能取到
        Assert.Null(await IsUsedLockAsync(probe, key));
        await using var next = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key);
        Assert.True(next.Acquired, $"acquire failed: {next.BusyReason}");
    }

    // ===== Case 4：跨实例互斥 —— 「另一个实例」持锁时，本实例必须被拒（绕过进程内闸门） =====

    [Fact]
    public async Task Case4_WhenAnotherInstanceHoldsLock_AcquireIsRejectedCrossInstance()
    {
        if (!Enabled) return;
        var cs = ReadAidopdevConnectionString();
        Assert.False(string.IsNullOrEmpty(cs));
        var db = BuildSharedClient(cs);
        var key = NewKey("case4");

        // 「实例 2」：独立会话持锁不放
        using var other = BuildDedicatedClient(cs);
        var dt = await other.Ado.GetDataTableAsync(
            "SELECT GET_LOCK(@k, 0)", new List<SugarParameter> { new("@k", key) });
        Assert.Equal(1L, Convert.ToInt64(dt.Rows[0][0]));

        try
        {
            await using var mine = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key);
            Assert.False(mine.Acquired);
            Assert.Equal("cross-instance busy", mine.BusyReason);
        }
        finally
        {
            await other.Ado.ExecuteCommandAsync(
                "SELECT RELEASE_LOCK(@k)", new List<SugarParameter> { new("@k", key) });
        }

        // 对方释放后本实例必须能取到
        await using var after = await InventoryInboundLockGuard.TryAcquireAsync(db, NullLogger.Instance, key);
        Assert.True(after.Acquired, $"acquire failed: {after.BusyReason}");
    }

    // ===== Case 5：缺陷本体的负向留证 —— 旧写法（共享自动关闭连接）取的锁当场蒸发 =====

    [Fact]
    public async Task Case5_LegacyPattern_OnAutoCloseSharedClient_DoesNotHoldLock()
    {
        if (!Enabled) return;
        var cs = ReadAidopdevConnectionString();
        Assert.False(string.IsNullOrEmpty(cs));
        var legacy = BuildSharedClient(cs);           // IsAutoCloseConnection = true —— 旧实现
        var key = NewKey("case5-legacy");
        using var probe = BuildDedicatedClient(cs);

        // 旧实现的取锁语句
        var got = await legacy.Ado.GetIntAsync(
            "SELECT GET_LOCK(@k, 0)", new List<SugarParameter> { new("@k", key) });
        Assert.Equal(1, got);

        // 命令一结束连接即回池并被驱动 reset，MySQL 释放该会话咨询锁 → 其它会话看不到任何持有者
        var owner = await IsUsedLockAsync(probe, key);
        _out.WriteLine("legacy owner after GET_LOCK = " + (owner.HasValue ? owner.Value.ToString() : "NULL"));
        Assert.Null(owner);

        // 因此另一个实例可以毫无阻碍地拿到同一把锁 —— 这就是 P0 缺陷
        await using var second = await InventoryInboundLockGuard.TryAcquireAsync(legacy, NullLogger.Instance, key);
        Assert.True(second.Acquired, $"acquire failed: {second.BusyReason}");
    }
}