ANTOOZA-BACKEND/Domain/Entities/Stocks/StockBoardStats.cs

using System.ComponentModel.DataAnnotations;

namespace Domain.Entities.Stocks;

/// <summary>
/// 종목 가상보드 통계 (d2 §③) — StockCode 파티션(가상 보드)별 글/댓글 수 집계.
/// 목록 헤더·trending 랭킹 캐시용. 글/댓글 작성 핸들러에서 lazy upsert(즉시 증가, 별도 배치 불요).
/// Stock FK 는 걸지 않는다(D1 소유). StockCode 자체가 PK.
/// </summary>
public class StockBoardStats
{
    /// <summary>종목 단축코드 (PK, char 6)</summary>
    [Key]
    public string StockCode { get; private set; } = default!;

    /// <summary>게시글 수</summary>
    public int Posts { get; private set; }

    /// <summary>댓글 수</summary>
    public int Comments { get; private set; }

    /// <summary>마지막 글 작성 일시</summary>
    public DateTime? LastPostAt { get; private set; }

    public DateTime UpdatedAt { get; private set; } = DateTime.UtcNow;

    private StockBoardStats() { }

    public static StockBoardStats Create(string stockCode)
    {
        if (stockCode is not { Length: 6 } || stockCode.Any(c => !char.IsAsciiDigit(c)))
        {
            throw new ArgumentException("stockCode must be 6 digits", nameof(stockCode));
        }

        return new StockBoardStats
        {
            StockCode = stockCode
        };
    }

    /// <summary>글 1건 증가 + 최종 작성 일시 갱신.</summary>
    public void IncrementPost(DateTime postAtUtc)
    {
        Posts++;
        LastPostAt = postAtUtc;
        UpdatedAt = DateTime.UtcNow;
    }

    /// <summary>댓글 1건 증가.</summary>
    public void IncrementComment()
    {
        Comments++;
        UpdatedAt = DateTime.UtcNow;
    }
}