using DramaLing.Api.Data;
using DramaLing.Api.Models.Entities;
using DramaLing.Api.Services.Storage;
using DramaLing.Api.Services;

namespace DramaLing.Api.Services.AI.Generation;

public class ImageSaveManager : IImageSaveManager
{
    private readonly ILogger<ImageSaveManager> _logger;

    public ImageSaveManager(ILogger<ImageSaveManager> logger)
    {
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
    }

    public async Task<ExampleImage> SaveGeneratedImageAsync(
        DramaLingDbContext dbContext,
        IImageStorageService storageService,
        IImageProcessingService imageProcessingService,
        ImageGenerationRequest request,
        string optimizedPrompt,
        ReplicateImageResult imageResult)
    {
        // 下載原圖 (1024x1024)
        using var httpClient = new HttpClient();
        var originalBytes = await httpClient.GetByteArrayAsync(imageResult.ImageUrl);

        _logger.LogInformation("Downloaded original image: {OriginalSize}KB", originalBytes.Length / 1024);

        // 壓縮為 512x512
        var resizedBytes = await imageProcessingService.ResizeImageAsync(originalBytes, 512, 512);
        var imageStream = new MemoryStream(resizedBytes);

        // 生成檔案名稱
        var fileName = $"{request.FlashcardId}_{Guid.NewGuid()}.png";

        // 儲存到本地/雲端
        var relativePath = await storageService.SaveImageAsync(imageStream, fileName);

        // 建立 ExampleImage 記錄
        var exampleImage = new ExampleImage
        {
            Id = Guid.NewGuid(),
            RelativePath = relativePath,
            AltText = $"Example image for {request.Flashcard?.Word}",
            GeminiPrompt = request.GeminiPrompt,
            GeminiDescription = request.GeneratedDescription,
            ReplicatePrompt = optimizedPrompt,
            ReplicateModel = "ideogram-v2a-turbo",
            GeminiCost = request.GeminiCost ?? 0.002m,
            ReplicateCost = imageResult.Cost,
            TotalGenerationCost = (request.GeminiCost ?? 0.002m) + imageResult.Cost,
            FileSize = resizedBytes.Length,
            ImageWidth = 512,
            ImageHeight = 512,
            ContentHash = ComputeHash(resizedBytes),
            ModerationStatus = "pending",
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow
        };

        dbContext.ExampleImages.Add(exampleImage);

        // 建立詞卡圖片關聯
        var flashcardImage = new FlashcardExampleImage
        {
            FlashcardId = request.FlashcardId,
            ExampleImageId = exampleImage.Id,
            DisplayOrder = 1,
            IsPrimary = true,
            ContextRelevance = 1.0m,
            CreatedAt = DateTime.UtcNow
        };

        dbContext.FlashcardExampleImages.Add(flashcardImage);
        await dbContext.SaveChangesAsync();

        return exampleImage;
    }

    private static string ComputeHash(byte[] bytes)
    {
        using var sha256 = System.Security.Cryptography.SHA256.Create();
        var hashBytes = sha256.ComputeHash(bytes);
        return Convert.ToHexString(hashBytes);
    }
}