using DramaLing.Api.Services.AI.Gemini;
using System.Text.Json;

namespace DramaLing.Api.Tests.Integration.Mocks;

/// <summary>
/// 測試用的 Mock Gemini Client
/// 提供穩定可預測的 AI 服務回應，不依賴外部 API
/// </summary>
public class MockGeminiClient : IGeminiClient
{
    /// <summary>
    /// 模擬 Gemini API 調用
    /// 根據 prompt 內容返回預定義的測試回應
    /// </summary>
    public async Task<string> CallGeminiAPIAsync(string prompt)
    {
        await Task.Delay(50); // 模擬 API 延遲

        // 根據 prompt 類型返回不同的 mock 回應
        if (prompt.Contains("generate distractors") || prompt.Contains("混淆選項"))
        {
            return GenerateDistractorsMockResponse(prompt);
        }

        if (prompt.Contains("analyze sentence") || prompt.Contains("句子分析"))
        {
            return GenerateSentenceAnalysisMockResponse(prompt);
        }

        if (prompt.Contains("synonyms") || prompt.Contains("同義詞"))
        {
            return GenerateSynonymsMockResponse(prompt);
        }

        // 預設回應
        return JsonSerializer.Serialize(new
        {
            response = "Mock response from Gemini API",
            timestamp = DateTime.UtcNow,
            prompt_length = prompt.Length
        });
    }

    /// <summary>
    /// 測試連線 - 在測試環境中永遠回傳成功
    /// </summary>
    public async Task<bool> TestConnectionAsync()
    {
        await Task.Delay(10);
        return true;
    }

    private string GenerateDistractorsMockResponse(string prompt)
    {
        // 從 prompt 中提取目標詞彙 (簡化邏輯)
        var targetWord = ExtractTargetWord(prompt);

        var distractors = targetWord.ToLower() switch
        {
            "hello" => new[] { "goodbye", "welcome", "thanks" },
            "beautiful" => new[] { "ugly", "plain", "ordinary" },
            "sophisticated" => new[] { "simple", "basic", "crude" },
            _ => new[] { "option1", "option2", "option3" }
        };

        return JsonSerializer.Serialize(new
        {
            distractors = distractors,
            target_word = targetWord,
            generated_at = DateTime.UtcNow
        });
    }

    private string GenerateSentenceAnalysisMockResponse(string prompt)
    {
        return JsonSerializer.Serialize(new
        {
            analysis = new
            {
                difficulty = "A2",
                grammar_points = new[] { "present simple", "adjectives" },
                vocabulary = new[] { "basic", "intermediate" },
                suggestions = new[] { "Good sentence structure", "Clear meaning" }
            },
            words = new[]
            {
                new
                {
                    word = "example",
                    translation = "範例",
                    part_of_speech = "noun",
                    difficulty = "A2",
                    synonyms = new[] { "sample", "instance" }
                }
            },
            generated_at = DateTime.UtcNow
        });
    }

    private string GenerateSynonymsMockResponse(string prompt)
    {
        var targetWord = ExtractTargetWord(prompt);

        var synonyms = targetWord.ToLower() switch
        {
            "hello" => new[] { "hi", "greetings", "salutations" },
            "beautiful" => new[] { "gorgeous", "stunning", "lovely" },
            "sophisticated" => new[] { "refined", "elegant", "cultured" },
            _ => new[] { "synonym1", "synonym2", "synonym3" }
        };

        return JsonSerializer.Serialize(synonyms);
    }

    private string ExtractTargetWord(string prompt)
    {
        // 簡化的詞彙提取邏輯
        // 實際實作中可能會更複雜
        var words = prompt.Split(' ');

        // 尋找可能的目標詞彙
        foreach (var word in words)
        {
            var cleanWord = word.Trim('"', '\'', ',', '.', '!', '?').ToLower();
            if (cleanWord.Length > 2 && !IsCommonWord(cleanWord))
            {
                return cleanWord;
            }
        }

        return "unknown";
    }

    private bool IsCommonWord(string word)
    {
        var commonWords = new HashSet<string>
        {
            "the", "and", "or", "but", "for", "with", "from", "to", "of", "in", "on", "at",
            "generate", "create", "make", "find", "get", "give", "word", "words", "options"
        };

        return commonWords.Contains(word);
    }
}