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

namespace Admin.NET.Plugin.AiDOP.Controllers;

/// <summary>
/// 智慧诊断选根与指标树：只沿 ParentId 下钻，无下级时自然截止，不跨树补位。
/// </summary>
internal static class SmartDiagnosisTree
{
    public const string SelectionSpecified = "specified";
    public const string SelectionGlobalWorst = "global_worst";

    internal readonly record struct ValueSnap(decimal? MetricValue, decimal? TargetValue);

    internal readonly record struct RootResolveResult(
        AdoSmartOpsKpiMaster? Root,
        string SelectionMode,
        string? Error);

    public static RootResolveResult ResolveRoot(
        List<AdoSmartOpsKpiMaster> l1Metrics,
        IReadOnlyDictionary<string, ValueSnap> values,
        string? metricCode)
    {
        if (!string.IsNullOrWhiteSpace(metricCode))
        {
            var specified = l1Metrics.FirstOrDefault(x =>
                string.Equals(x.MetricCode, metricCode.Trim(), StringComparison.OrdinalIgnoreCase));
            if (specified == null)
                return new RootResolveResult(null, SelectionSpecified, "metricCode 不是当前模块已启用的 L1 指标。");
            return new RootResolveResult(specified, SelectionSpecified, null);
        }

        var worst = l1Metrics
            .OrderByDescending(x => DiagnosisSeverity(ComputeStatus(x, values)))
            .ThenByDescending(x => DiagnosisDeviation(x, values))
            .ThenBy(x => x.SortNo)
            .FirstOrDefault();
        return new RootResolveResult(worst, SelectionGlobalWorst, null);
    }

    public static List<AdoSmartOpsKpiMaster> DirectChildren(
        IEnumerable<AdoSmartOpsKpiMaster> kpis,
        long parentId,
        int level) =>
        kpis
            .Where(x => x.MetricLevel == level && x.ParentId == parentId)
            .OrderBy(x => x.SortNo)
            .ToList();

    public static string ComputeStatus(AdoSmartOpsKpiMaster kpi, IReadOnlyDictionary<string, ValueSnap> values)
    {
        values.TryGetValue(kpi.MetricCode, out var value);
        return AidopS4KpiMerge.AchievementLevel(
            value.MetricValue,
            value.TargetValue,
            kpi.Direction ?? "higher_is_better",
            kpi.YellowThreshold,
            kpi.RedThreshold);
    }

    public static decimal DiagnosisDeviation(AdoSmartOpsKpiMaster kpi, IReadOnlyDictionary<string, ValueSnap> values)
    {
        if (!values.TryGetValue(kpi.MetricCode, out var value) || value.MetricValue == null || value.TargetValue == null || value.TargetValue == 0)
            return 0m;
        var current = value.MetricValue.Value;
        var target = value.TargetValue.Value;
        return string.Equals(kpi.Direction, "lower_is_better", StringComparison.OrdinalIgnoreCase)
            ? Math.Max(0m, (current - target) / Math.Abs(target))
            : Math.Max(0m, (target - current) / Math.Abs(target));
    }

    public static int DiagnosisSeverity(string? status) => (status ?? "").ToLowerInvariant() switch
    {
        "red" => 3,
        "yellow" => 2,
        "green" => 1,
        _ => 0
    };

    public static string BuildDiagnosisRate(decimal? current, decimal? target, string? direction)
    {
        if (current == null || target == null || target == 0) return "-";
        var ratio = string.Equals(direction, "lower_is_better", StringComparison.OrdinalIgnoreCase)
            ? target.Value / current.Value * 100m
            : current.Value / target.Value * 100m;
        return $"{decimal.Round(ratio, 0):0}%";
    }
}