# 智能填空題系統開發計劃

> 基於 `智能填空題系統設計規格.md` 制定的詳細實施計劃

## 📋 開發階段總覽

### Phase 1: 資料庫結構調整 (預計 0.5 天)
### Phase 2: 後端服務開發 (預計 2 天)
### Phase 3: 前端組件優化 (預計 1 天)
### Phase 4: 測試與優化 (預計 1 天)

---

## Phase 1: 資料庫結構調整

### 🎯 目標
為 Flashcard 實體添加 `FilledQuestionText` 欄位，支援儲存挖空後的題目

### 📝 具體任務

#### 1.1 更新實體模型
**檔案**: `backend/DramaLing.Api/Models/Entities/Flashcard.cs`
```csharp
[MaxLength(1000)]
public string? FilledQuestionText { get; set; }  // 挖空後的題目文字
```

#### 1.2 資料庫 Migration
**命令**: `dotnet ef migrations add AddFilledQuestionText`
**檔案**: `backend/DramaLing.Api/Migrations/[timestamp]_AddFilledQuestionText.cs`

#### 1.3 更新 DbContext 欄位映射
**檔案**: `backend/DramaLing.Api/Data/DramaLingDbContext.cs`
```csharp
private void ConfigureFlashcardEntity(ModelBuilder modelBuilder)
{
    var flashcardEntity = modelBuilder.Entity<Flashcard>();

    // 現有欄位映射...
    flashcardEntity.Property(f => f.UserId).HasColumnName("user_id");
    flashcardEntity.Property(f => f.PartOfSpeech).HasColumnName("part_of_speech");
    flashcardEntity.Property(f => f.ExampleTranslation).HasColumnName("example_translation");

    // 新增欄位映射
    flashcardEntity.Property(f => f.FilledQuestionText).HasColumnName("filled_question_text");
}
```

#### 1.4 執行 Migration
**命令**: `dotnet ef database update`

### ✅ 完成標準
- [ ] Flashcard 實體包含新欄位
- [ ] 資料庫表結構更新完成
- [ ] 現有資料保持完整
- [ ] 後端編譯成功

---

## Phase 2: 後端服務開發

### 🎯 目標
實作智能挖空生成服務，支援程式碼挖空和 AI 輔助

### 📝 具體任務

#### 2.1 建立服務介面
**檔案**: `backend/DramaLing.Api/Services/IBlankGenerationService.cs`
```csharp
public interface IBlankGenerationService
{
    Task<string?> GenerateBlankQuestionAsync(string word, string example);
    string? TryProgrammaticBlank(string word, string example);
    Task<string?> GenerateAIBlankAsync(string word, string example);
    bool HasValidBlank(string blankQuestion);
}
```

#### 2.2 實作挖空服務
**檔案**: `backend/DramaLing.Api/Services/BlankGenerationService.cs`

```csharp
public class BlankGenerationService : IBlankGenerationService
{
    private readonly IWordVariationService _wordVariationService;
    private readonly IAIProviderManager _aiProviderManager;
    private readonly ILogger<BlankGenerationService> _logger;

    public BlankGenerationService(
        IWordVariationService wordVariationService,
        IAIProviderManager aiProviderManager,
        ILogger<BlankGenerationService> logger)
    {
        _wordVariationService = wordVariationService;
        _aiProviderManager = aiProviderManager;
        _logger = logger;
    }

    public async Task<string?> GenerateBlankQuestionAsync(string word, string example)
    {
        if (string.IsNullOrEmpty(word) || string.IsNullOrEmpty(example))
            return null;

        // Step 1: 嘗試程式碼挖空
        var programmaticResult = TryProgrammaticBlank(word, example);
        if (!string.IsNullOrEmpty(programmaticResult))
        {
            _logger.LogInformation("Successfully generated programmatic blank for word: {Word}", word);
            return programmaticResult;
        }

        // Step 2: 程式碼挖空失敗，嘗試 AI 挖空
        _logger.LogInformation("Programmatic blank failed for word: {Word}, trying AI blank", word);
        var aiResult = await GenerateAIBlankAsync(word, example);

        return aiResult;
    }

    public string? TryProgrammaticBlank(string word, string example)
    {
        try
        {
            // 1. 完全匹配
            var exactMatch = Regex.Replace(example, $@"\b{Regex.Escape(word)}\b", "____", RegexOptions.IgnoreCase);
            if (exactMatch != example)
            {
                _logger.LogDebug("Exact match blank successful for word: {Word}", word);
                return exactMatch;
            }

            // 2. 常見變形處理
            var variations = _wordVariationService.GetCommonVariations(word);
            foreach(var variation in variations)
            {
                var variantMatch = Regex.Replace(example, $@"\b{Regex.Escape(variation)}\b", "____", RegexOptions.IgnoreCase);
                if (variantMatch != example)
                {
                    _logger.LogDebug("Variation match blank successful for word: {Word}, variation: {Variation}",
                        word, variation);
                    return variantMatch;
                }
            }

            _logger.LogDebug("Programmatic blank failed for word: {Word}", word);
            return null; // 挖空失敗
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error in programmatic blank for word: {Word}", word);
            return null;
        }
    }

    public bool HasValidBlank(string blankQuestion)
    {
        return !string.IsNullOrEmpty(blankQuestion) && blankQuestion.Contains("____");
    }
}
```

##### AI 挖空邏輯
```csharp
public async Task<string?> GenerateAIBlankAsync(string word, string example)
{
    try
    {
        var prompt = $@"
請將以下例句中與詞彙「{word}」相關的詞挖空，用____替代：

詞彙: {word}
例句: {example}

規則:
1. 只挖空與目標詞彙相關的詞(包含變形、時態、複數等)
2. 用____替代被挖空的詞
3. 保持句子其他部分不變
4. 直接返回挖空後的句子，不要額外說明

挖空後的句子:";

        _logger.LogInformation("Generating AI blank for word: {Word}, example: {Example}",
            word, example);

        var result = await _aiProviderManager.GetDefaultProvider()
            .GenerateTextAsync(prompt);

        // 驗證 AI 回應格式
        if (string.IsNullOrEmpty(result) || !result.Contains("____"))
        {
            _logger.LogWarning("AI generated invalid blank question for word: {Word}", word);
            return null;
        }

        _logger.LogInformation("Successfully generated AI blank for word: {Word}", word);
        return result.Trim();
    }
    catch (Exception ex)
    {
        _logger.LogError(ex, "Error generating AI blank for word: {Word}", word);
        return null;
    }
}
```

#### 2.3 詞彙變形服務
**檔案**: `backend/DramaLing.Api/Services/WordVariationService.cs`
```csharp
public interface IWordVariationService
{
    string[] GetCommonVariations(string word);
    bool IsVariationOf(string baseWord, string variation);
}

public class WordVariationService : IWordVariationService
{
    private readonly ILogger<WordVariationService> _logger;

    private readonly Dictionary<string, string[]> CommonVariations = new()
    {
        ["eat"] = ["eats", "ate", "eaten", "eating"],
        ["go"] = ["goes", "went", "gone", "going"],
        ["have"] = ["has", "had", "having"],
        ["be"] = ["am", "is", "are", "was", "were", "been", "being"],
        ["do"] = ["does", "did", "done", "doing"],
        ["take"] = ["takes", "took", "taken", "taking"],
        ["make"] = ["makes", "made", "making"],
        ["come"] = ["comes", "came", "coming"],
        ["see"] = ["sees", "saw", "seen", "seeing"],
        ["get"] = ["gets", "got", "gotten", "getting"],
        // ... 更多常見變形
    };

    public string[] GetCommonVariations(string word)
    {
        return CommonVariations.TryGetValue(word.ToLower(), out var variations)
            ? variations
            : Array.Empty<string>();
    }

    public bool IsVariationOf(string baseWord, string variation)
    {
        var variations = GetCommonVariations(baseWord);
        return variations.Contains(variation.ToLower());
    }
}
```

#### 2.4 修改 FlashcardsController
**檔案**: `backend/DramaLing.Api/Controllers/FlashcardsController.cs`

##### GetDueFlashcards 方法強化
```csharp
[HttpGet("due")]
public async Task<ActionResult> GetDueFlashcards(
    [FromQuery] string? date = null,
    [FromQuery] int limit = 50)
{
    try
    {
        var userId = GetUserId();
        var queryDate = DateTime.TryParse(date, out var parsed) ? parsed : DateTime.Now.Date;

        var dueCards = await _spacedRepetitionService.GetDueFlashcardsAsync(userId, queryDate, limit);

        // 檢查並生成缺失的挖空題目
        foreach(var flashcard in dueCards)
        {
            if(string.IsNullOrEmpty(flashcard.FilledQuestionText))
            {
                var blankQuestion = await _blankGenerationService.GenerateBlankQuestionAsync(
                    flashcard.Word, flashcard.Example);

                if(!string.IsNullOrEmpty(blankQuestion))
                {
                    flashcard.FilledQuestionText = blankQuestion;
                    _context.Entry(flashcard).Property(f => f.FilledQuestionText).IsModified = true;
                }
            }
        }

        await _context.SaveChangesAsync();

        _logger.LogInformation("Retrieved {Count} due flashcards for user {UserId}",
            dueCards.Count, userId);

        return Ok(new { success = true, data = dueCards, count = dueCards.Count });
    }
    catch (Exception ex)
    {
        _logger.LogError(ex, "Error getting due flashcards");
        return StatusCode(500, new { success = false, error = "Failed to get due flashcards" });
    }
}
```

#### 2.5 新增重新生成端點
```csharp
[HttpPost("{id}/regenerate-blank")]
public async Task<ActionResult> RegenerateBlankQuestion(Guid id)
{
    try
    {
        var userId = GetUserId();
        var flashcard = await _context.Flashcards
            .FirstOrDefaultAsync(f => f.Id == id && f.UserId == userId);

        if (flashcard == null)
        {
            return NotFound(new { success = false, error = "Flashcard not found" });
        }

        var blankQuestion = await _blankGenerationService.GenerateBlankQuestionAsync(
            flashcard.Word, flashcard.Example);

        if (string.IsNullOrEmpty(blankQuestion))
        {
            return StatusCode(500, new { success = false, error = "Failed to generate blank question" });
        }

        flashcard.FilledQuestionText = blankQuestion;
        flashcard.UpdatedAt = DateTime.UtcNow;
        await _context.SaveChangesAsync();

        _logger.LogInformation("Regenerated blank question for flashcard {Id}, word: {Word}",
            id, flashcard.Word);

        return Ok(new { success = true, data = new { filledQuestionText = blankQuestion } });
    }
    catch (Exception ex)
    {
        _logger.LogError(ex, "Error regenerating blank question for flashcard {Id}", id);
        return StatusCode(500, new { success = false, error = "Failed to regenerate blank question" });
    }
}
```

#### 2.6 服務註冊
**檔案**: `backend/DramaLing.Api/Extensions/ServiceCollectionExtensions.cs`
```csharp
// 在 AddBusinessServices 方法中添加
public static IServiceCollection AddBusinessServices(this IServiceCollection services)
{
    // 現有服務...
    services.AddScoped<IBlankGenerationService, BlankGenerationService>();
    services.AddScoped<IWordVariationService, WordVariationService>();

    return services;
}
```

**檔案**: `backend/DramaLing.Api/Program.cs`
```csharp
// 使用擴展方法
builder.Services.AddBusinessServices();
```

### ✅ 完成標準
- [ ] BlankGenerationService 服務實作完成
- [ ] 常見詞彙變形對應表建立
- [ ] AI 挖空整合測試通過
- [ ] API 端點功能驗證
- [ ] 錯誤處理和日誌完善

---

## Phase 3: 前端組件優化

### 🎯 目標
簡化 SentenceFillTest 組件，使用後端提供的挖空題目

### 📝 具體任務

#### 3.1 更新組件 Props 介面
**檔案**: `frontend/components/review/review-tests/SentenceFillTest.tsx`
```typescript
interface SentenceFillTestProps {
  word: string
  definition: string
  example: string                    // 原始例句
  filledQuestionText?: string       // 挖空後的題目 (新增)
  exampleTranslation: string
  pronunciation?: string
  difficultyLevel: string
  exampleImage?: string
  onAnswer: (answer: string) => void
  onReportError: () => void
  onImageClick?: (image: string) => void
  disabled?: boolean
}
```

#### 3.2 簡化渲染邏輯
```typescript
// 替換複雜的 renderSentenceWithInput()
const renderFilledSentence = () => {
  if (!filledQuestionText) {
    // 降級處理：使用當前的程式碼挖空
    return renderSentenceWithInput();
  }

  // 使用後端提供的挖空題目
  const parts = filledQuestionText.split('____');

  return (
    <div className="text-lg text-gray-700 leading-relaxed">
      {parts.map((part, index) => (
        <span key={index}>
          {part}
          {index < parts.length - 1 && (
            <input
              type="text"
              value={fillAnswer}
              onChange={(e) => setFillAnswer(e.target.value)}
              // ... 其他輸入框屬性
            />
          )}
        </span>
      ))}
    </div>
  );
};
```

#### 3.3 更新頁面使用
**檔案**: `frontend/app/review-design/page.tsx`
```typescript
<SentenceFillTest
  word={mockCardData.word}
  definition={mockCardData.definition}
  example={mockCardData.example}
  filledQuestionText={mockCardData.filledQuestionText} // 新增
  exampleTranslation={mockCardData.exampleTranslation}
  // ... 其他屬性
/>
```

### ✅ 完成標準
- [ ] SentenceFillTest 組件支援新欄位
- [ ] 降級處理機制正常運作
- [ ] 前端編譯和類型檢查通過
- [ ] review-design 頁面測試正常

---

## Phase 4: 測試與優化

### 🎯 目標
全面測試智能挖空系統，優化效能和準確性

### 📝 具體任務

#### 4.1 詞彙變形測試
**測試案例**:
```javascript
const testCases = [
  { word: "eat", example: "She ate an apple", expected: "She ____ an apple" },
  { word: "go", example: "He went to school", expected: "He ____ to school" },
  { word: "good", example: "This is better", expected: "This is ____" },
  { word: "child", example: "The children play", expected: "The ____ play" }
];
```

#### 4.2 AI 挖空品質驗證
- 測試 AI 挖空準確性
- 驗證回應格式正確性
- 檢查異常情況處理

#### 4.3 效能優化
- 批次處理挖空生成
- 資料庫查詢優化
- 快取機制考量

#### 4.4 錯誤處理完善
- AI 服務異常處理
- 網路超時處理
- 降級策略驗證

### ✅ 完成標準
- [ ] 所有測試案例通過
- [ ] AI 挖空準確率 > 90%
- [ ] API 回應時間 < 2 秒
- [ ] 錯誤處理覆蓋率 100%

---

## 🚀 部署檢查清單

### 資料庫
- [ ] Migration 執行成功
- [ ] 現有資料完整性確認
- [ ] 新欄位索引建立（如需要）

### 後端服務
- [ ] BlankGenerationService 註冊成功
- [ ] AI 服務整合測試
- [ ] API 端點功能驗證
- [ ] 日誌記錄完善

### 前端組件
- [ ] SentenceFillTest 組件更新
- [ ] TypeScript 類型檢查通過
- [ ] 降級處理機制測試
- [ ] 用戶介面測試

### 整合測試
- [ ] 端到端填空功能測試
- [ ] 各種詞彙變形驗證
- [ ] AI 輔助挖空測試
- [ ] 效能和穩定性測試

---

## 📊 成功指標

### 功能指標
- ✅ 支援 100% 詞彙變形挖空
- ✅ AI 輔助準確率 > 90%
- ✅ 程式碼挖空成功率 > 80%

### 技術指標
- ✅ API 回應時間 < 2 秒
- ✅ 前端組件複雜度降低 50%
- ✅ 挖空生成一次處理，多次使用

### 用戶體驗指標
- ✅ 填空題顯示成功率 100%
- ✅ 智能挖空準確性提升
- ✅ 系統回應速度提升

---

## ⚠️ 風險管控

### 高風險項目
1. **AI 服務依賴**: Gemini API 可能失敗
   - **緩解**: 多層回退機制，程式碼挖空 → AI → 手動標記

2. **資料庫 Migration**: 可能影響現有資料
   - **緩解**: 充分備份，漸進式部署

3. **前端相容性**: 新舊版本相容問題
   - **緩解**: 降級處理邏輯，漸進式替換

### 監控機制
- 挖空生成成功率監控
- AI 調用耗時和失敗率追蹤
- 使用者填空題完成率分析

---

## 📅 時程安排

### Week 1
- **Day 1-2**: Phase 1 (資料庫結構)
- **Day 3-5**: Phase 2 (後端服務開發)

### Week 2
- **Day 1-2**: Phase 3 (前端組件優化)
- **Day 3-4**: Phase 4 (測試與優化)
- **Day 5**: 部署和監控

---

## 🔧 開發工具和資源

### 開發環境
- .NET 8.0 + Entity Framework Core
- Next.js + TypeScript
- SQLite 資料庫

### 外部服務
- Google Gemini AI API
- 現有的音頻和圖片服務

### 測試工具
- 單元測試框架
- 整合測試環境
- 效能監控工具

---

## 📈 後續擴展

### 可能的增強功能
1. **多語言支援**: 支援其他語言的詞彙變形
2. **自訂挖空規則**: 允許手動調整挖空邏輯
3. **挖空難度分級**: 根據學習者程度調整挖空複雜度
4. **統計分析**: 分析挖空成功率和學習效果

### 技術改進
1. **機器學習優化**: 基於歷史資料優化挖空準確性
2. **快取策略**: 實作 Redis 快取提升效能
3. **批次處理**: 大量詞彙的批次挖空處理
4. **監控儀表板**: 即時監控系統狀態和效能指標