354 lines
12 KiB
C#
354 lines
12 KiB
C#
using System.Text.Json;
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using System.Text;
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using DramaLing.Api.Models.Entities;
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namespace DramaLing.Api.Services;
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public interface IGeminiService
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{
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Task<List<GeneratedCard>> GenerateCardsAsync(string inputText, string extractionType, int cardCount);
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Task<ValidationResult> ValidateCardAsync(Flashcard card);
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}
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public class GeminiService : IGeminiService
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{
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private readonly HttpClient _httpClient;
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private readonly IConfiguration _configuration;
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private readonly ILogger<GeminiService> _logger;
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private readonly string _apiKey;
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public GeminiService(HttpClient httpClient, IConfiguration configuration, ILogger<GeminiService> logger)
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{
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_httpClient = httpClient;
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_configuration = configuration;
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_logger = logger;
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_apiKey = Environment.GetEnvironmentVariable("DRAMALING_GEMINI_API_KEY")
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?? _configuration["AI:GeminiApiKey"] ?? "";
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}
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public async Task<List<GeneratedCard>> GenerateCardsAsync(string inputText, string extractionType, int cardCount)
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{
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try
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{
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if (string.IsNullOrEmpty(_apiKey) || _apiKey == "your-gemini-api-key-here")
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{
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throw new InvalidOperationException("Gemini API key not configured");
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}
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var prompt = BuildPrompt(inputText, extractionType, cardCount);
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var response = await CallGeminiApiAsync(prompt);
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return ParseGeneratedCards(response);
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}
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catch (Exception ex)
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{
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_logger.LogError(ex, "Error generating cards with Gemini API");
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throw;
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}
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}
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public async Task<ValidationResult> ValidateCardAsync(Flashcard card)
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{
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try
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{
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if (string.IsNullOrEmpty(_apiKey) || _apiKey == "your-gemini-api-key-here")
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{
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throw new InvalidOperationException("Gemini API key not configured");
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}
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var prompt = BuildValidationPrompt(card);
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var response = await CallGeminiApiAsync(prompt);
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return ParseValidationResult(response);
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}
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catch (Exception ex)
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{
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_logger.LogError(ex, "Error validating card with Gemini API");
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throw;
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}
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}
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private string BuildPrompt(string inputText, string extractionType, int cardCount)
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{
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var template = extractionType == "vocabulary" ? VocabularyExtractionPrompt : SmartExtractionPrompt;
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return template
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.Replace("{cardCount}", cardCount.ToString())
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.Replace("{inputText}", inputText);
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}
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private string BuildValidationPrompt(Flashcard card)
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{
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return CardValidationPrompt
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.Replace("{word}", card.Word)
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.Replace("{translation}", card.Translation)
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.Replace("{definition}", card.Definition)
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.Replace("{partOfSpeech}", card.PartOfSpeech ?? "")
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.Replace("{pronunciation}", card.Pronunciation ?? "")
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.Replace("{example}", card.Example ?? "");
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}
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private async Task<string> CallGeminiApiAsync(string prompt)
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{
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var requestBody = new
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{
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contents = new[]
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{
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new
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{
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parts = new[]
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{
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new { text = prompt }
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}
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}
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}
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};
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var json = JsonSerializer.Serialize(requestBody);
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var content = new StringContent(json, Encoding.UTF8, "application/json");
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var response = await _httpClient.PostAsync(
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$"https://generativelanguage.googleapis.com/v1beta/models/gemini-1.5-flash-latest:generateContent?key={_apiKey}",
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content);
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if (!response.IsSuccessStatusCode)
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{
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var errorContent = await response.Content.ReadAsStringAsync();
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_logger.LogError("Gemini API error: {StatusCode} - {Content}", response.StatusCode, errorContent);
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throw new HttpRequestException($"Gemini API request failed: {response.StatusCode}");
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}
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var responseContent = await response.Content.ReadAsStringAsync();
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var geminiResponse = JsonSerializer.Deserialize<JsonElement>(responseContent);
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if (geminiResponse.TryGetProperty("candidates", out var candidates) &&
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candidates.GetArrayLength() > 0 &&
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candidates[0].TryGetProperty("content", out var contentElement) &&
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contentElement.TryGetProperty("parts", out var parts) &&
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parts.GetArrayLength() > 0 &&
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parts[0].TryGetProperty("text", out var textElement))
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{
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return textElement.GetString() ?? "";
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}
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throw new InvalidOperationException("Invalid response format from Gemini API");
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}
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private List<GeneratedCard> ParseGeneratedCards(string response)
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{
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try
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{
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// 清理回應文本
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var cleanText = response.Trim();
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cleanText = cleanText.Replace("```json", "").Replace("```", "").Trim();
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// 如果不是以 { 開始，嘗試找到 JSON 部分
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if (!cleanText.StartsWith("{"))
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{
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var jsonStart = cleanText.IndexOf("{");
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if (jsonStart >= 0)
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{
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cleanText = cleanText[jsonStart..];
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}
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}
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var jsonResponse = JsonSerializer.Deserialize<JsonElement>(cleanText);
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if (!jsonResponse.TryGetProperty("cards", out var cardsElement) || cardsElement.ValueKind != JsonValueKind.Array)
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{
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throw new InvalidOperationException("Response does not contain cards array");
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}
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var cards = new List<GeneratedCard>();
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foreach (var cardElement in cardsElement.EnumerateArray())
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{
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var card = new GeneratedCard
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{
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Word = GetStringProperty(cardElement, "word"),
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PartOfSpeech = GetStringProperty(cardElement, "part_of_speech"),
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Pronunciation = GetStringProperty(cardElement, "pronunciation"),
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Translation = GetStringProperty(cardElement, "translation"),
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Definition = GetStringProperty(cardElement, "definition"),
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Synonyms = GetArrayProperty(cardElement, "synonyms"),
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Example = GetStringProperty(cardElement, "example"),
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ExampleTranslation = GetStringProperty(cardElement, "example_translation"),
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DifficultyLevel = GetStringProperty(cardElement, "difficulty_level")
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};
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if (!string.IsNullOrEmpty(card.Word) && !string.IsNullOrEmpty(card.Translation))
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{
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cards.Add(card);
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}
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}
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return cards;
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}
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catch (Exception ex)
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{
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_logger.LogError(ex, "Error parsing generated cards response: {Response}", response);
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throw new InvalidOperationException($"Failed to parse AI response: {ex.Message}");
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}
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}
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private ValidationResult ParseValidationResult(string response)
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{
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try
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{
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var cleanText = response.Trim().Replace("```json", "").Replace("```", "").Trim();
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var jsonResponse = JsonSerializer.Deserialize<JsonElement>(cleanText);
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var issues = new List<ValidationIssue>();
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if (jsonResponse.TryGetProperty("issues", out var issuesElement))
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{
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foreach (var issueElement in issuesElement.EnumerateArray())
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{
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issues.Add(new ValidationIssue
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{
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Field = GetStringProperty(issueElement, "field"),
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Original = GetStringProperty(issueElement, "original"),
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Corrected = GetStringProperty(issueElement, "corrected"),
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Reason = GetStringProperty(issueElement, "reason"),
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Severity = GetStringProperty(issueElement, "severity")
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});
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}
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}
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var suggestions = new List<string>();
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if (jsonResponse.TryGetProperty("suggestions", out var suggestionsElement))
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{
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foreach (var suggestion in suggestionsElement.EnumerateArray())
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{
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suggestions.Add(suggestion.GetString() ?? "");
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}
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}
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return new ValidationResult
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{
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Issues = issues,
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Suggestions = suggestions,
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OverallScore = jsonResponse.TryGetProperty("overall_score", out var scoreElement)
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? scoreElement.GetInt32() : 85,
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Confidence = jsonResponse.TryGetProperty("confidence", out var confidenceElement)
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? confidenceElement.GetDouble() : 0.9
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};
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}
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catch (Exception ex)
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{
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_logger.LogError(ex, "Error parsing validation result: {Response}", response);
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throw new InvalidOperationException($"Failed to parse validation response: {ex.Message}");
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}
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}
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private static string GetStringProperty(JsonElement element, string propertyName)
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{
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return element.TryGetProperty(propertyName, out var prop) ? prop.GetString() ?? "" : "";
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}
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private static List<string> GetArrayProperty(JsonElement element, string propertyName)
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{
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var result = new List<string>();
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if (element.TryGetProperty(propertyName, out var arrayElement) && arrayElement.ValueKind == JsonValueKind.Array)
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{
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foreach (var item in arrayElement.EnumerateArray())
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{
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result.Add(item.GetString() ?? "");
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}
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}
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return result;
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}
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// Prompt 模板
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private const string VocabularyExtractionPrompt = @"
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從以下英文文本中萃取 {cardCount} 個最重要的詞彙，為每個詞彙生成詞卡資料。
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輸入文本：
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{inputText}
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請按照以下 JSON 格式回應，不要包含任何其他文字或代碼塊標記：
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{
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""cards"": [
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{
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""word"": ""單字原型"",
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""part_of_speech"": ""詞性(n./v./adj./adv.等)"",
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""pronunciation"": ""IPA音標"",
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""translation"": ""繁體中文翻譯"",
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""definition"": ""英文定義(保持A1-A2程度)"",
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""synonyms"": [""同義詞1"", ""同義詞2""],
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""example"": ""例句(使用原文中的句子或生成新句子)"",
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""example_translation"": ""例句中文翻譯"",
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""difficulty_level"": ""CEFR等級(A1/A2/B1/B2/C1/C2)""
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}
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]
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}
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要求：
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1. 選擇最有學習價值的詞彙
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2. 定義要簡單易懂，適合英語學習者
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3. 例句要實用且符合語境
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4. 確保 JSON 格式正確
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5. 同義詞最多2個，選擇常用的";
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private const string SmartExtractionPrompt = @"
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分析以下英文文本，識別片語、俚語和常用表達，生成 {cardCount} 個學習卡片：
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輸入文本：
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{inputText}
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重點關注：
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1. 片語和俚語
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2. 文化相關表達
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3. 語境特定用法
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4. 慣用語和搭配
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請按照相同的 JSON 格式回應...";
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private const string CardValidationPrompt = @"
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請檢查以下詞卡內容的準確性：
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單字: {word}
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翻譯: {translation}
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定義: {definition}
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詞性: {partOfSpeech}
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發音: {pronunciation}
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例句: {example}
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請按照以下 JSON 格式回應：
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{
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""issues"": [],
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""suggestions"": [],
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""overall_score"": 85,
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""confidence"": 0.9
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}";
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}
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// 支援類型
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public class GeneratedCard
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{
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public string Word { get; set; } = string.Empty;
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public string PartOfSpeech { get; set; } = string.Empty;
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public string Pronunciation { get; set; } = string.Empty;
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public string Translation { get; set; } = string.Empty;
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public string Definition { get; set; } = string.Empty;
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public List<string> Synonyms { get; set; } = new();
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public string Example { get; set; } = string.Empty;
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public string ExampleTranslation { get; set; } = string.Empty;
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public string DifficultyLevel { get; set; } = string.Empty;
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}
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public class ValidationResult
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{
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public List<ValidationIssue> Issues { get; set; } = new();
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public List<string> Suggestions { get; set; } = new();
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public int OverallScore { get; set; }
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public double Confidence { get; set; }
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}
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public class ValidationIssue
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{
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public string Field { get; set; } = string.Empty;
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public string Original { get; set; } = string.Empty;
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public string Corrected { get; set; } = string.Empty;
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public string Reason { get; set; } = string.Empty;
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public string Severity { get; set; } = string.Empty;
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} |