using System.ComponentModel.DataAnnotations;
using Microsoft.EntityFrameworkCore;

namespace DramaLing.Api.Models.Entities;

/// <summary>
/// 選項詞彙庫實體 - 用於生成測驗選項的詞彙資料庫
/// </summary>
[Index(nameof(Word), IsUnique = true, Name = "IX_OptionsVocabulary_Word")]
[Index(nameof(CEFRLevel), Name = "IX_OptionsVocabulary_CEFR")]
[Index(nameof(PartOfSpeech), Name = "IX_OptionsVocabulary_PartOfSpeech")]
[Index(nameof(WordLength), Name = "IX_OptionsVocabulary_WordLength")]
[Index(nameof(IsActive), Name = "IX_OptionsVocabulary_Active")]
[Index(nameof(CEFRLevel), nameof(PartOfSpeech), nameof(WordLength), Name = "IX_OptionsVocabulary_Core_Matching")]
public class OptionsVocabulary
{
    /// <summary>
    /// 主鍵
    /// </summary>
    public Guid Id { get; set; }

    /// <summary>
    /// 詞彙內容
    /// </summary>
    [Required]
    [MaxLength(100)]
    public string Word { get; set; } = string.Empty;

    /// <summary>
    /// CEFR 難度等級 (A1, A2, B1, B2, C1, C2)
    /// </summary>
    [Required]
    [MaxLength(2)]
    [RegularExpression("^(A1|A2|B1|B2|C1|C2)$",
                      ErrorMessage = "CEFR等級必須為A1, A2, B1, B2, C1, C2之一")]
    public string CEFRLevel { get; set; } = string.Empty;

    /// <summary>
    /// 詞性 (noun, verb, adjective, adverb, pronoun, preposition, conjunction, interjection, idiom)
    /// </summary>
    [Required]
    [MaxLength(20)]
    [RegularExpression("^(noun|verb|adjective|adverb|pronoun|preposition|conjunction|interjection|idiom)$",
                      ErrorMessage = "詞性必須為有效值")]
    public string PartOfSpeech { get; set; } = string.Empty;

    /// <summary>
    /// 字數（字元長度）- 自動從 Word 計算
    /// </summary>
    public int WordLength { get; set; }

    /// <summary>
    /// 是否啟用
    /// </summary>
    public bool IsActive { get; set; } = true;

    /// <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;

    /// <summary>
    /// 自動計算字數
    /// </summary>
    public void CalculateWordLength()
    {
        WordLength = Word?.Length ?? 0;
    }

    /// <summary>
    /// 更新時間戳
    /// </summary>
    public void UpdateTimestamp()
    {
        UpdatedAt = DateTime.UtcNow;
    }
}