using System.ComponentModel.DataAnnotations;

namespace DramaLing.Api.Models.Entities;

/// <summary>
/// 詞卡複習記錄實體 - 支援間隔重複系統
/// </summary>
public class FlashcardReview
{
    public Guid Id { get; set; }

    /// <summary>
    /// 詞卡ID (外鍵)
    /// </summary>
    [Required]
    public Guid FlashcardId { get; set; }

    /// <summary>
    /// 用戶ID (外鍵)
    /// </summary>
    [Required]
    public Guid UserId { get; set; }

    /// <summary>
    /// 連續成功次數 - 用於間隔重複算法 (2^n 天數計算)
    /// 答對時增加，答錯時重置為0
    /// </summary>
    public int SuccessCount { get; set; } = 0;

    /// <summary>
    /// 下次複習日期 - 基於間隔重複算法計算
    /// 公式: 今天 + 2^SuccessCount 天
    /// </summary>
    public DateTime NextReviewDate { get; set; } = DateTime.UtcNow.AddDays(1);

    /// <summary>
    /// 最後複習日期
    /// </summary>
    public DateTime? LastReviewDate { get; set; }

    /// <summary>
    /// 最後成功複習日期 (答對的日期)
    /// </summary>
    public DateTime? LastSuccessDate { get; set; }

    /// <summary>
    /// 累計跳過次數 (統計用)
    /// </summary>
    public int TotalSkipCount { get; set; } = 0;

    /// <summary>
    /// 累計錯誤次數 (統計用)
    /// </summary>
    public int TotalWrongCount { get; set; } = 0;

    /// <summary>
    /// 累計正確次數 (統計用)
    /// </summary>
    public int TotalCorrectCount { get; set; } = 0;

    /// <summary>
    /// 創建時間
    /// </summary>
    public DateTime CreatedAt { get; set; } = DateTime.UtcNow;

    /// <summary>
    /// 更新時間
    /// </summary>
    public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;

    // Navigation Properties
    public virtual Flashcard Flashcard { get; set; } = null!;
    public virtual User User { get; set; } = null!;
}