using Admin.NET.Plugin.AiDOP.Entity.S8;
using Admin.NET.Plugin.AiDOP.Infrastructure.S8;

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

/// <summary>
/// S8-DEMO-IMPACT-SORT-NOTICE-1：异常影响统计服务。
/// 滚动 30 天窗口；归类键 = (tenant_id, factory_id, exception_type_code)；
/// 累计损失只统计已关闭异常（closed_at - created_at）；未关闭不计入；
/// 算法/阈值见 Compute 方法内常量；运行期计算，不落库。
/// </summary>
public class S8ImpactMetricsService : ITransient
{
    private readonly SqlSugarRepository<AdoS8Exception> _rep;

    // 影响分权重上限（保护 score 不超过设计区间 0-140）
    private const int RepeatCap = 5;
    private const decimal LossHoursCap = 72m;
    private const decimal LossWeightCap = 30m;
    private const decimal SeverityWeightSerious = 40m;
    private const decimal SeverityWeightFollow = 10m;
    private const decimal TimeoutWeight = 20m;
    private const decimal RepeatUnitWeight = 10m;

    // 关注级别阈值
    private const int HighRepeatThreshold = 3;
    private const decimal HighLossThreshold = 24m;
    private const int MediumRepeatThreshold = 2;
    private const decimal MediumLossThreshold = 8m;

    public S8ImpactMetricsService(SqlSugarRepository<AdoS8Exception> rep)
    {
        _rep = rep;
    }

    /// <summary>
    /// 批量计算：传入候选异常子集（同一 tenant/factory），一次性按 exception_type_code 聚合 30 天窗口数据，
    /// 内存填充各行 6 个影响字段。无 N+1。candidates 为空或 typeCode 全空时不查库。
    /// </summary>
    public async Task FillBatchAsync(
        long tenantId,
        long factoryId,
        IReadOnlyList<ExceptionImpactRow> candidates)
    {
        if (candidates == null || candidates.Count == 0) return;

        var since = DateTime.Now.AddDays(-30);

        var typeCodes = candidates
            .Select(c => c.ExceptionTypeCode)
            .Where(c => !string.IsNullOrWhiteSpace(c))
            .Distinct()
            .ToList();

        var repeatMap = new Dictionary<string, int>(StringComparer.Ordinal);
        var lossMap = new Dictionary<string, decimal>(StringComparer.Ordinal);

        if (typeCodes.Count > 0)
        {
            // repeatCount30d：按 exception_type_code GROUP BY 计数全部行（含未关闭）。
            var repeatRows = await _rep.Context.Queryable<AdoS8Exception>()
                .Where(x => x.TenantId == tenantId
                            && x.FactoryId == factoryId
                            && !x.IsDeleted
                            && x.ExceptionTypeCode != null
                            && typeCodes.Contains(x.ExceptionTypeCode)
                            && x.CreatedAt >= since)
                .GroupBy(x => x.ExceptionTypeCode!)
                .Select(x => new
                {
                    ExceptionTypeCode = x.ExceptionTypeCode!,
                    RepeatCount = SqlFunc.AggregateCount(x.Id),
                })
                .ToListAsync();

            foreach (var r in repeatRows)
            {
                repeatMap[r.ExceptionTypeCode] = r.RepeatCount;
            }

            // cumulativeLossHours30d：仅已关闭异常 (closed_at - created_at) 分钟差累计。
            var lossRows = await _rep.Context.Queryable<AdoS8Exception>()
                .Where(x => x.TenantId == tenantId
                            && x.FactoryId == factoryId
                            && !x.IsDeleted
                            && x.ExceptionTypeCode != null
                            && typeCodes.Contains(x.ExceptionTypeCode)
                            && x.CreatedAt >= since
                            && x.ClosedAt != null)
                .GroupBy(x => x.ExceptionTypeCode!)
                .Select(x => new
                {
                    ExceptionTypeCode = x.ExceptionTypeCode!,
                    LossMinutes = SqlFunc.AggregateSum(
                        SqlFunc.DateDiff(DateType.Minute, x.CreatedAt, x.ClosedAt!.Value)),
                })
                .ToListAsync();

            foreach (var r in lossRows)
            {
                lossMap[r.ExceptionTypeCode] = Math.Round((decimal)r.LossMinutes / 60m, 1);
            }
        }

        foreach (var c in candidates)
        {
            int repeatCount;
            decimal lossHours;
            if (string.IsNullOrWhiteSpace(c.ExceptionTypeCode))
            {
                // exception_type_code 为空 → 视为孤例：自身计 1 次；若自身已关闭则累计自身损失
                repeatCount = 1;
                lossHours = (c.ClosedAt != null)
                    ? Math.Round((decimal)(c.ClosedAt.Value - c.CreatedAt).TotalHours, 1)
                    : 0m;
            }
            else
            {
                repeatCount = repeatMap.TryGetValue(c.ExceptionTypeCode, out var rc) ? rc : 1;
                lossHours = lossMap.TryGetValue(c.ExceptionTypeCode, out var lh) ? lh : 0m;
            }

            var (impactScore, level, label, reason) = Compute(c.Severity, repeatCount, lossHours, c.TimeoutFlag);

            c.RepeatCount30d = repeatCount;
            c.CumulativeLossHours30d = lossHours;
            c.ImpactScore = impactScore;
            c.SuggestedAttentionLevel = level;
            c.SuggestedAttentionLabel = label;
            c.ImpactReason = reason;
        }
    }

    /// <summary>
    /// 单异常计算：通知派发路径调用；exception_type_code / created_at / closed_at / severity / sla_deadline 从实体读取。
    /// 同样的 30 天窗口聚合，但只查询当前 typeCode 一条。
    /// </summary>
    public async Task<ExceptionImpactSnapshot> ComputeOneAsync(AdoS8Exception entity)
    {
        if (entity == null) throw new ArgumentNullException(nameof(entity));

        var since = DateTime.Now.AddDays(-30);
        var now = DateTime.Now;
        var timeoutFlag = entity.SlaDeadline != null
            && entity.SlaDeadline < now
            && entity.Status != "CLOSED"
            && entity.Status != "RECOVERED";

        int repeatCount;
        decimal lossHours;

        if (string.IsNullOrWhiteSpace(entity.ExceptionTypeCode))
        {
            repeatCount = 1;
            lossHours = (entity.ClosedAt != null)
                ? Math.Round((decimal)(entity.ClosedAt.Value - entity.CreatedAt).TotalHours, 1)
                : 0m;
        }
        else
        {
            var typeCode = entity.ExceptionTypeCode;
            // repeatCount30d：30 天窗口内同 typeCode 全量计数（含未关闭）。
            repeatCount = await _rep.Context.Queryable<AdoS8Exception>()
                .Where(x => x.TenantId == entity.TenantId
                            && x.FactoryId == entity.FactoryId
                            && !x.IsDeleted
                            && x.ExceptionTypeCode == typeCode
                            && x.CreatedAt >= since)
                .CountAsync();
            if (repeatCount == 0) repeatCount = 1; // 自身刚建尚未可见时回退 1。

            // cumulativeLossHours30d：仅已关闭异常 (closed_at - created_at)。
            var lossMinutesNullable = await _rep.Context.Queryable<AdoS8Exception>()
                .Where(x => x.TenantId == entity.TenantId
                            && x.FactoryId == entity.FactoryId
                            && !x.IsDeleted
                            && x.ExceptionTypeCode == typeCode
                            && x.CreatedAt >= since
                            && x.ClosedAt != null)
                .SumAsync(x => (int?)SqlFunc.DateDiff(DateType.Minute, x.CreatedAt, x.ClosedAt!.Value));
            var lossMinutes = lossMinutesNullable ?? 0;
            lossHours = Math.Round((decimal)lossMinutes / 60m, 1);
        }

        var (impactScore, level, label, reason) = Compute(entity.Severity, repeatCount, lossHours, timeoutFlag);

        return new ExceptionImpactSnapshot
        {
            RepeatCount30d = repeatCount,
            CumulativeLossHours30d = lossHours,
            ImpactScore = impactScore,
            SuggestedAttentionLevel = level,
            SuggestedAttentionLabel = label,
            ImpactReason = reason,
        };
    }

    /// <summary>
    /// 算法实现。Severity 已通过 S8SeverityCode.Normalize 统一为 FOLLOW / SERIOUS。
    /// score = severityWeight + min(repeat,5)*10 + min(loss,72)/72*30 + (timeout?20:0)，理论范围 0-140。
    /// 关注级别按重复 / 损失 / 严重度 / 超时四因子判定。
    /// </summary>
    private static (decimal score, string level, string label, string reason) Compute(
        string? severity, int repeatCount, decimal lossHours, bool timeoutFlag)
    {
        var normalizedSeverity = S8SeverityCode.Normalize(severity);
        var severityWeight = normalizedSeverity switch
        {
            "SERIOUS" => SeverityWeightSerious,
            "FOLLOW" => SeverityWeightFollow,
            _ => 0m,
        };

        var cappedRepeat = Math.Min(repeatCount, RepeatCap);
        var repeatWeight = cappedRepeat * RepeatUnitWeight;

        var cappedLoss = Math.Min(lossHours, LossHoursCap);
        var lossWeight = cappedLoss / LossHoursCap * LossWeightCap;

        var timeoutWeight = timeoutFlag ? TimeoutWeight : 0m;

        var impactScore = Math.Round(severityWeight + repeatWeight + lossWeight + timeoutWeight, 1);

        string level;
        if (normalizedSeverity == "SERIOUS"
            || repeatCount >= HighRepeatThreshold
            || lossHours >= HighLossThreshold)
        {
            level = "HIGH";
        }
        else if (repeatCount >= MediumRepeatThreshold
            || lossHours >= MediumLossThreshold
            || timeoutFlag)
        {
            level = "MEDIUM";
        }
        else
        {
            level = "LOW";
        }

        var label = level switch
        {
            "HIGH" => "高",
            "MEDIUM" => "中",
            "LOW" => "低",
            _ => "—",
        };

        var reasonParts = new List<string>(4);
        if (repeatCount > 1) reasonParts.Add($"重复 {repeatCount} 次");
        if (lossHours > 0) reasonParts.Add($"累计损失 {lossHours.ToString("0.#")} 小时");
        if (normalizedSeverity == "SERIOUS") reasonParts.Add("严重");
        if (timeoutFlag) reasonParts.Add("当前超时");
        var reason = reasonParts.Count == 0 ? "无显著影响" : string.Join("/", reasonParts);

        return (impactScore, level, label, reason);
    }

}

/// <summary>
/// S8-DEMO-IMPACT-SORT-NOTICE-1：批量影响计算的最小行契约。
/// S8ExceptionService 投影时构造，FillBatchAsync 在内存回填 6 个 30d 字段后，再赋给 DTO。
/// </summary>
public sealed class ExceptionImpactRow
{
    public long Id { get; set; }
    public string? ExceptionTypeCode { get; set; }
    public string? Severity { get; set; }
    public DateTime CreatedAt { get; set; }
    public DateTime? ClosedAt { get; set; }
    public bool TimeoutFlag { get; set; }

    public int RepeatCount30d { get; set; }
    public decimal CumulativeLossHours30d { get; set; }
    public decimal ImpactScore { get; set; }
    public string? SuggestedAttentionLevel { get; set; }
    public string? SuggestedAttentionLabel { get; set; }
    public string? ImpactReason { get; set; }
}

/// <summary>
/// 单异常计算结果快照；通知派发路径使用。
/// </summary>
public sealed class ExceptionImpactSnapshot
{
    public int RepeatCount30d { get; set; }
    public decimal CumulativeLossHours30d { get; set; }
    public decimal ImpactScore { get; set; }
    public string? SuggestedAttentionLevel { get; set; }
    public string? SuggestedAttentionLabel { get; set; }
    public string? ImpactReason { get; set; }
}