using System.Reflection;
using Admin.NET.Plugin.AiDOP.Service.S8.Rules.Health;
using Xunit;

namespace Admin.NET.Plugin.AiDOP.Tests.S8;

/// <summary>
/// S8-AUTHORITY-HEALTH-GATE：恢复放行门禁的判定逻辑。
///
/// <para><b>本文件同时守两种相反的失效，两边都会静默</b>：</para>
/// <list type="number">
///   <item><b>门禁太松</b> —— 中台断供时取数变空，恢复判定会把全部在办异常判成「已恢复」。
///     没有报错、没有通知，异常就消失了。</item>
///   <item><b>门禁太紧</b> —— 若有人把门禁写成「取数为空就拦」，真实恢复将永不发生，
///     异常在列表里堆到天荒地老，而调度器每轮都报成功。
///     <see cref="B_HealthyEmpty_StillAllowsRecovery"/> 就是为这一侧准备的反向守卫。</item>
/// </list>
///
/// <para>判定是纯函数（<see cref="S8AuthorityHealthEvaluator.Evaluate"/>），
/// 不接数据库、不接 DI，因此 A–H 全部可在普通单测里跑。
/// 「怎么把运行日志查出来」是 <c>S8MdpAuthorityHealthResolver</c> 的事，不在此处断言。</para>
/// </summary>
public class S8AuthorityHealthGateTests
{
    private const long TenantA = 838257186181189L;
    private const string Dataset = "ORDER_DELIVERY_RISK";

    /// <summary>固定「现在」，让所有时间边界可逐分钟锁定。</summary>
    private static readonly DateTime Now = new(2026, 9, 8, 12, 0, 0);

    private static readonly TimeSpan Stale = TimeSpan.FromHours(1);

    private static S8AuthorityObservation Obs(
        DateTime? lastSuccessEndAt = null,
        bool specFound = true,
        bool producerTrusted = true,
        bool newerFailure = false,
        string? newerFailureStatus = null,
        DateTime? inFlightStartAt = null,
        string snapshot = S8SnapshotInvariant.NotApplicable,
        string? snapshotDetail = null) => new()
    {
        DatasetCode = Dataset,
        TenantId = TenantA,
        ObservedAt = Now,
        SpecFound = specFound,
        ProducerTrusted = producerTrusted,
        LastSuccessEndAt = lastSuccessEndAt,
        HasNewerTerminalFailure = newerFailure,
        NewerTerminalFailureStatus = newerFailureStatus,
        OldestNewerInFlightStartAt = inFlightStartAt,
        SnapshotInvariant = snapshot,
        SnapshotDetail = snapshotDetail,
        StaleWindow = Stale
    };

    /// <summary>一次完全健康的观测：30 分钟前成功，早于 1 小时的新鲜度窗口。</summary>
    private static S8AuthorityObservation Healthy() => Obs(lastSuccessEndAt: Now.AddMinutes(-30));

    // ══════════════════ CASE A / B：放行侧 ══════════════════

    /// <summary>CASE A：Authority 可信 → 恢复正常放行。</summary>
    [Fact]
    public void A_Healthy_AllowsRecovery()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Healthy());

        Assert.Equal(S8AuthorityHealthState.Healthy, r.State);
        Assert.Equal(S8AuthorityHealthReason.Healthy, r.ReasonCode);
        Assert.Equal(Now.AddMinutes(-30), r.LastSuccessAt);
        Assert.Equal(Now.AddMinutes(-30) + Stale, r.StaleAfter);
        Assert.True(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE B（<b>本文件最重要的一条</b>）：Authority 可信但本轮取数为空 → <b>恢复仍然放行</b>。
    ///
    /// <para>「空集」是恢复的<b>正常输入</b>而非异常信号 —— 全部业务对象都合法退场时，
    /// 本来就该看到 0 行。把门禁写成「空集就拦」，恢复将永不发生且没有任何报错。</para>
    ///
    /// <para>断言分两层：行为上放行；<b>结构上根本拿不到行数</b> ——
    /// 判定的入参类型里不存在任何与行数/命中数相关的字段，
    /// 于是「顺手加个空集判断」在编译期就做不到。这一层比行为断言更耐改。</para>
    /// </summary>
    [Fact]
    public void B_HealthyEmpty_StillAllowsRecovery()
    {
        // 行为层：与 CASE A 走的是同一组判据 —— 判定里根本没有「空/非空」这个分支。
        Assert.True(S8AuthorityHealthEvaluator.Evaluate(Healthy()).AllowsRecovery);

        // 结构层一：判定入参里不得出现任何行数概念。
        var banned = new[] { "hit", "row", "count", "empty", "any", "size", "length" };
        foreach (var p in typeof(S8AuthorityObservation).GetProperties())
        {
            foreach (var b in banned)
            {
                Assert.False(p.Name.Contains(b, StringComparison.OrdinalIgnoreCase),
                    $"S8AuthorityObservation.{p.Name} 疑似把行数引入了健康判定");
            }
        }

        // 结构层二：放行判定是结果对象上的无参属性，没有任何可供传入行数的入口。
        var allows = typeof(S8AuthorityHealthResult).GetProperty(nameof(S8AuthorityHealthResult.AllowsRecovery));
        Assert.NotNull(allows);
        Assert.Empty(allows!.GetMethod!.GetParameters());

        // 结构层三：Evaluate 只有一个入参，就是观测值本身。
        var evaluate = typeof(S8AuthorityHealthEvaluator).GetMethod(
            nameof(S8AuthorityHealthEvaluator.Evaluate), BindingFlags.Public | BindingFlags.Static);
        Assert.NotNull(evaluate);
        Assert.Single(evaluate!.GetParameters());
        Assert.Equal(typeof(S8AuthorityObservation), evaluate.GetParameters()[0].ParameterType);
    }

    // ══════════════════ CASE C–H：拦截侧 ══════════════════

    /// <summary>CASE C：回溯窗口内一次成功都没有 → UNKNOWN。「查不到」不等于「没问题」。</summary>
    [Fact]
    public void C_NoSuccessfulRun_IsUnknownAndBlocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(lastSuccessEndAt: null));

        Assert.Equal(S8AuthorityHealthState.Unknown, r.State);
        Assert.Equal(S8AuthorityHealthReason.NoSuccessfulRun, r.ReasonCode);
        Assert.Null(r.LastSuccessAt);
        Assert.Null(r.StaleAfter);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>CASE C'：数据集压根没声明 AuthoritySpec → UNKNOWN，绝不默认健康。</summary>
    [Fact]
    public void C2_NoAuthoritySpec_IsUnknownAndBlocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(specFound: false, lastSuccessEndAt: Now.AddMinutes(-1)));

        Assert.Equal(S8AuthorityHealthState.Unknown, r.State);
        Assert.Equal(S8AuthorityHealthReason.NoAuthoritySpec, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>CASE D：最近一次成功已超过新鲜度窗口 → DEGRADED / STALE。</summary>
    [Fact]
    public void D_SuccessTooOld_IsStaleAndBlocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(lastSuccessEndAt: Now.AddMinutes(-90)));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.Stale, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>CASE D'：恰好落在窗口边界上仍算健康 —— 阈值是「超过」才降级。</summary>
    [Fact]
    public void D2_ExactlyAtStaleBoundary_IsStillHealthy()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(lastSuccessEndAt: Now - Stale));

        Assert.Equal(S8AuthorityHealthState.Healthy, r.State);
        Assert.True(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE E：成功之后又开了一轮、还没跑完 → IN_FLIGHT。
    /// 此刻 Authority 可能只写了一半，恢复判定不能在这个瞬间做。
    /// </summary>
    [Fact]
    public void E_NewerRunInFlight_Blocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(
            Obs(lastSuccessEndAt: Now.AddMinutes(-40), inFlightStartAt: Now.AddMinutes(-5)));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.InFlight, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE E'：在途运行的年龄已超过新鲜度窗口 → STUCK_RUN，与 IN_FLIGHT 分开报。
    ///
    /// <para>运行日志里的 RUNNING 行没有任何应用侧回收机制（失败路径会吞掉自己的写入异常，
    /// 注释里写的是「遗留 RUNNING 行可由运维手动清理」，而并不存在这样的清理作业）。
    /// 实测该表有 298 条永不终态的 RUNNING 行，S1 占 42 条、最老已 570 小时。
    /// 若与「正在正常跑」混为一谈，运维分不清该等还是该查 —— 两者都拦，但排障动作不同。</para>
    /// </summary>
    [Fact]
    public void E2_StuckRun_IsReportedSeparately()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(
            Obs(lastSuccessEndAt: Now.AddHours(-5), inFlightStartAt: Now.AddHours(-4)));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.StuckRun, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>CASE F：成功之后的那一轮失败了 → LATEST_FAILED。</summary>
    [Fact]
    public void F_NewerRunFailed_Blocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(
            Obs(lastSuccessEndAt: Now.AddMinutes(-40), newerFailure: true, newerFailureStatus: "FAILED"));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.LatestFailed, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE F'：失败发生在最近一次成功<b>之前</b> → 不影响判定。
    /// 历史失败是常态；若一律降级，门禁会永久拦死。
    /// （观测层已按「锚点之后」过滤，此处等价于 newerFailure = false。）
    /// </summary>
    [Fact]
    public void F2_OlderFailure_DoesNotDegrade()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(
            Obs(lastSuccessEndAt: Now.AddMinutes(-20), newerFailure: false));

        Assert.Equal(S8AuthorityHealthState.Healthy, r.State);
        Assert.True(r.AllowsRecovery);
    }

    /// <summary>CASE G：成功之后出现终态 PARTIAL → LATEST_PARTIAL。部分成功的快照不足以支撑恢复判定。</summary>
    [Fact]
    public void G_PartialRun_Blocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(
            Obs(lastSuccessEndAt: Now.AddMinutes(-40), newerFailure: true, newerFailureStatus: "PARTIAL"));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.LatestPartial, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE G'：未知的终态状态一律按失败处置，不得被当成健康放行。
    /// <para>该表的 status 值域实测还包含 <c>SUCCESS_WITH_WARNING</c> 与 <c>CANCELED</c>
    /// （由 S0 维度刷新写出，当前不出现在 S1 上）。采集层用的是
    /// <c>status &lt;&gt; 'SUCCESS'</c> 而非白名单，正是为了让将来新增的终态状态
    /// 默认落到「失败」而不是「健康」这一侧。</para>
    /// </summary>
    [Fact]
    public void G2_UnknownTerminalStatus_IsTreatedAsFailure()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(
            Obs(lastSuccessEndAt: Now.AddMinutes(-40), newerFailure: true, newerFailureStatus: "SUCCESS_WITH_WARNING"));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.LatestFailed, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>CASE G''：快照不变量被破坏 → 即使生产运行成功也降级。</summary>
    [Fact]
    public void G3_SnapshotInvariantViolated_Blocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(
            lastSuccessEndAt: Now.AddMinutes(-10),
            snapshot: S8SnapshotInvariant.Violated,
            snapshotDetail: "同时存在 2 个当前批次"));

        Assert.Equal(S8AuthorityHealthState.Degraded, r.State);
        Assert.Equal(S8AuthorityHealthReason.SnapshotInvariantFailed, r.ReasonCode);
        Assert.Contains("2 个当前批次", r.Reason);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE G'''：快照发布无法确认 → UNKNOWN，<b>不猜</b>。
    ///
    /// <para>这是 Rule03 今天的真实处境：生产侧的发布语句在本轮零行时命中 0 行、
    /// 在库里不留任何批次标记，于是「源侧本轮确实没有数据」与「发布压根没跑成」字面等同。
    /// 猜成健康的代价是把真实缺料预警整体判成已恢复，因此保守拦截。
    /// 消除它需要生产侧补一个发布标记 —— 那是下一批的工作，不在本轮范围。</para>
    /// </summary>
    [Fact]
    public void G4_SnapshotPublicationUnconfirmed_IsUnknownAndBlocks()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(
            lastSuccessEndAt: Now.AddMinutes(-10),
            snapshot: S8SnapshotInvariant.Unconfirmed,
            snapshotDetail: "当前批次数为 0"));

        Assert.Equal(S8AuthorityHealthState.Unknown, r.State);
        Assert.Equal(S8AuthorityHealthReason.SnapshotPublicationUnconfirmed, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    /// <summary>
    /// CASE H：Authority 有多个写入方且部分不留运行日志 → UNKNOWN，
    /// 且必须<b>压过一切健康信号</b>。
    ///
    /// <para>本用例刻意喂进一次「一分钟前刚成功、快照不变量也成立」的完美观测，
    /// 它不得把结论洗白 —— 因为问题不在于生产跑没跑成，
    /// 而在于运行日志根本证明不了表里最终的数据出自谁。</para>
    /// </summary>
    [Fact]
    public void H_MultiWriterAuthority_IsUnknownRegardlessOfRunHealth()
    {
        var r = S8AuthorityHealthEvaluator.Evaluate(Obs(
            producerTrusted: false,
            lastSuccessEndAt: Now.AddMinutes(-1),
            snapshot: S8SnapshotInvariant.Satisfied));

        Assert.Equal(S8AuthorityHealthState.Unknown, r.State);
        Assert.Equal(S8AuthorityHealthReason.Rule01MultiWriterUntrusted, r.ReasonCode);
        Assert.False(r.AllowsRecovery);
    }

    // ══════════════════ 穷尽性与词表封闭 ══════════════════

    public static IEnumerable<object[]> AllNonHealthyReasonCodes() =>
        typeof(S8AuthorityHealthReason)
            .GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy)
            .Where(f => f.IsLiteral && !f.IsInitOnly && f.FieldType == typeof(string))
            .Select(f => (string)f.GetRawConstantValue()!)
            .Where(v => v != S8AuthorityHealthReason.Healthy)
            .Select(v => new object[] { v });

    /// <summary>
    /// 放行只有一个出口：<c>State == HEALTHY</c>。
    /// <para>用反射枚举<b>全部</b>原因码 —— 将来有人新增一个却忘了想清楚放不放行时，
    /// 这条会自动变红。默认必须是拦。</para>
    /// </summary>
    [Theory]
    [MemberData(nameof(AllNonHealthyReasonCodes))]
    public void EveryNonHealthyReason_Blocks(string reasonCode)
    {
        foreach (var state in new[] { S8AuthorityHealthState.Degraded, S8AuthorityHealthState.Unknown })
        {
            var r = new S8AuthorityHealthResult { State = state, ReasonCode = reasonCode };
            Assert.False(r.AllowsRecovery, $"state={state} reason={reasonCode} 不应放行");
        }
    }

    /// <summary>状态是封闭三元集合，不得出现第四种（尤其不得出现 HEALTHY_EMPTY）。</summary>
    [Fact]
    public void StateVocabularyIsClosed_AndHasNoHealthyEmpty()
    {
        var states = typeof(S8AuthorityHealthState)
            .GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy)
            .Where(f => f.IsLiteral && f.FieldType == typeof(string))
            .Select(f => (string)f.GetRawConstantValue()!)
            .OrderBy(v => v, StringComparer.Ordinal)
            .ToArray();

        Assert.Equal(new[] { "DEGRADED", "HEALTHY", "UNKNOWN" }, states);
    }

    /// <summary>端口是接口且实现可被自动注册，调度器才能换实现而不改自身。</summary>
    [Fact]
    public void Resolver_IsASeamInterface()
    {
        Assert.True(typeof(IS8AuthorityHealthResolver).IsInterface);
        Assert.True(typeof(IS8AuthorityHealthResolver)
            .IsAssignableFrom(typeof(S8MdpAuthorityHealthResolver)));
    }
}