using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Domain.Entities.Paper.ValueObject;

namespace Domain.Entities.Paper;

/// <summary>
/// 모의투자 주문 — 접수 시 서버가 FillRule/TargetDate/CancelableUntil 을 확정한다 (d4 §③ 체결 규칙).
/// 실제 기표는 TargetDate 시세가 도착하는 배치(M2)에서 수행 (Pending → Filled/Rejected).
/// </summary>
public class PaperOrder
{
    [ForeignKey(nameof(AccountID))]
    public virtual PaperAccount Account { get; private set; } = null!;

    [Key]
    public int ID { get; private set; }

    public int AccountID { get; private set; }

    /// <summary>단축코드 (char 6)</summary>
    public string StockCode { get; private set; } = default!;

    public PaperOrderSide Side { get; private set; }

    public PaperFillRule FillRule { get; private set; }

    public int Quantity { get; private set; }

    /// <summary>매수 예약금 (매도는 0)</summary>
    public decimal ReservedAmount { get; private set; }

    /// <summary>체결 기준일</summary>
    public DateOnly TargetDate { get; private set; }

    /// <summary>취소 가능 시한 — 이후 취소 불가 (look-ahead 어뷰징 차단)</summary>
    public DateTime CancelableUntil { get; private set; }

    public PaperOrderStatus Status { get; private set; }

    /// <summary>거부 사유 (Rejected 시)</summary>
    public string? RejectReason { get; private set; }

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

    private PaperOrder() { }

    public static PaperOrder Create(
        int accountID,
        string stockCode,
        PaperOrderSide side,
        PaperFillRule fillRule,
        int quantity,
        decimal reservedAmount,
        DateOnly targetDate,
        DateTime cancelableUntil
    ) {
        if (accountID <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(accountID));
        }

        if (stockCode is not { Length: 6 })
        {
            throw new ArgumentException("stockCode must be 6 chars", nameof(stockCode));
        }

        if (quantity <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(quantity));
        }

        if (reservedAmount < 0)
        {
            throw new ArgumentOutOfRangeException(nameof(reservedAmount));
        }

        return new PaperOrder
        {
            AccountID = accountID,
            StockCode = stockCode,
            Side = side,
            FillRule = fillRule,
            Quantity = quantity,
            ReservedAmount = reservedAmount,
            TargetDate = targetDate,
            CancelableUntil = cancelableUntil,
            Status = PaperOrderStatus.Pending
        };
    }

    /// <summary>취소 — Pending 만 취소 가능. 성공 시 true. 시한 검증은 호출자.</summary>
    public bool Cancel()
    {
        if (Status != PaperOrderStatus.Pending)
        {
            return false;
        }

        Status = PaperOrderStatus.Cancelled;
        return true;
    }

    /// <summary>체결 확정 (배치 M2).</summary>
    public void MarkFilled()
    {
        Status = PaperOrderStatus.Filled;
    }

    /// <summary>거부 처리 (배치 M2).</summary>
    public void MarkRejected(string reason)
    {
        Status = PaperOrderStatus.Rejected;
        RejectReason = reason;
    }
}