AiDOPWarehouse/server/Plugins/Admin.NET.Plugin.AiDOP/Infrastructure/S8/S8PeriodHelper.cs

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

/// <summary>
/// 首版按服务器自然周期对齐大屏统计口径；显式日期范围优先于 period。
/// </summary>
public static class S8PeriodHelper
{
    /// <summary>
    /// 将 period 字符串解析为半开区间 [from, to)。
    /// 支持 today / this_week / this_month / this_quarter（大小写容错）。
    /// 非法或空值返回 (null, null)，调用方保持全量行为。
    /// </summary>
    public static (DateTime? from, DateTime? to) Resolve(string? period)
    {
        if (string.IsNullOrWhiteSpace(period)) return (null, null);

        var today = DateTime.Today;
        return period.Trim().ToLowerInvariant() switch
        {
            "today"        => (today, today.AddDays(1)),
            "this_week"    => ResolveThisWeek(today),
            "this_month"   => (new DateTime(today.Year, today.Month, 1), new DateTime(today.Year, today.Month, 1).AddMonths(1)),
            "this_quarter" => ResolveThisQuarter(today),
            "last_24h"     => (DateTime.Now.AddHours(-24), DateTime.Now),
            "last_7d"      => (today.AddDays(-6), today.AddDays(1)),
            "last_30d"     => (today.AddDays(-29), today.AddDays(1)),
            _              => (null, null),
        };
    }

    private static (DateTime? from, DateTime? to) ResolveThisWeek(DateTime today)
    {
        // 周一作为周起始（DayOfWeek.Monday = 1）
        var offset = ((int)today.DayOfWeek - (int)DayOfWeek.Monday + 7) % 7;
        var monday = today.AddDays(-offset);
        return (monday, monday.AddDays(7));
    }

    private static (DateTime? from, DateTime? to) ResolveThisQuarter(DateTime today)
    {
        // 季度起始月：1 / 4 / 7 / 10
        var quarterStartMonth = ((today.Month - 1) / 3) * 3 + 1;
        var start = new DateTime(today.Year, quarterStartMonth, 1);
        return (start, start.AddMonths(3));
    }
}