ANTOOZA-BACKEND/Infrastructure/StockData/MarketCalendar.cs

using Application.Abstractions.Data;
using Microsoft.EntityFrameworkCore;

namespace Infrastructure.StockData;

/// <summary>영업일 판정 — 주말 + MarketHoliday 제외</summary>
internal static class MarketCalendar
{
    /// <summary>fromExclusive 직전 영업일 (주말/휴장일 제외)</summary>
    public static async Task<DateOnly> GetPreviousBusinessDayAsync(IAppDbContext db, DateOnly fromExclusive, CancellationToken ct)
    {
        var date = fromExclusive.AddDays(-1);
        var floor = date.AddDays(-30);
        var holidays = await db.MarketHoliday.AsNoTracking().Where(c => c.Date >= floor && c.Date <= date).Select(c => c.Date).ToListAsync(ct);

        while (date.DayOfWeek is DayOfWeek.Saturday or DayOfWeek.Sunday || holidays.Contains(date))
        {
            date = date.AddDays(-1);
        }

        return date;
    }
}