namespace Admin.NET.Plugin.AiDOP.SmartOps;

/// <summary>
/// 九宫格卡片同时保留最后可用值和最新一次计算。展示状态只看行主键，不看日期是否相同。
/// </summary>
public static class HomeGridDisplayPolicy
{
    public sealed class Row
    {
        public long Id { get; init; }
        public decimal? MetricValue { get; init; }
        public decimal? TargetValue { get; init; }
        public string? ResultStatus { get; init; }
        public string? ResultReason { get; init; }
        public DateTime BizDate { get; init; }
    }

    public sealed class Card
    {
        public decimal? CurrentValue { get; init; }
        public decimal? TargetValue { get; init; }
        public string? ResultStatus { get; init; }
        public string? ResultReason { get; init; }
        public DateTime? BizDate { get; init; }
        public string? LatestResultStatus { get; init; }
        public string? LatestResultReason { get; init; }
        public DateTime? LatestBizDate { get; init; }
        public string DisplayState { get; init; } = "NO_DATA";
        public string FreshnessState { get; init; } = "NO_VALUE";
        public int? ValueAgeDays { get; init; }
        public int? FreshnessSlaDays { get; init; }
        public bool FutureBizDate { get; init; }
    }

    public static Card Decide(Row? usable, Row? latest, int? slaDays, DateTime today)
    {
        string displayState;
        if (usable == null)
        {
            displayState = string.Equals(latest?.ResultStatus, "SOURCE_UNSUPPORTED", StringComparison.OrdinalIgnoreCase)
                ? "SOURCE_UNSUPPORTED"
                : "NO_DATA";
        }
        else if (latest != null && usable.Id == latest.Id)
        {
            displayState = "CURRENT_VALUE";
        }
        else
        {
            displayState = "LAST_KNOWN_VALUE";
        }

        var freshness = "NO_VALUE";
        int? age = null;
        var future = false;
        if (usable != null)
        {
            if (slaDays is null or <= 0)
            {
                freshness = "POLICY_MISSING";
            }
            else
            {
                var rawAge = (today.Date - usable.BizDate.Date).Days;
                if (rawAge < 0)
                {
                    future = true;
                    age = 0;
                }
                else
                {
                    age = rawAge;
                }
                freshness = age > slaDays ? "STALE" : "FRESH";
            }
        }

        return new Card
        {
            CurrentValue = usable?.MetricValue,
            TargetValue = usable?.TargetValue,
            ResultStatus = usable == null ? latest?.ResultStatus : NormalizeUsableStatus(usable.ResultStatus),
            ResultReason = usable?.ResultReason,
            BizDate = usable?.BizDate,
            LatestResultStatus = latest?.ResultStatus,
            LatestResultReason = latest?.ResultReason,
            LatestBizDate = latest?.BizDate,
            DisplayState = displayState,
            FreshnessState = freshness,
            ValueAgeDays = age,
            FreshnessSlaDays = slaDays,
            FutureBizDate = future,
        };
    }

    private static string NormalizeUsableStatus(string? status) =>
        string.IsNullOrWhiteSpace(status) ? "OK" : status;
}