using Microsoft.Extensions.Logging;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

namespace RmmAgent.Services;

#pragma warning disable CA1416

public class ScreenshotService
{
    private readonly ILogger<ScreenshotService> _logger;
    private readonly ApiClient _api;

    public ScreenshotService(ILogger<ScreenshotService> logger, ApiClient api)
    {
        _logger = logger;
        _api = api;
    }

    public async Task CaptureAndUploadAsync(CancellationToken ct)
    {
        var (jpegBytes, width, height) = CaptureJpeg();
        if (jpegBytes is null) return;

        try
        {
            await _api.UploadScreenshotAsync(jpegBytes, width, height, ct);
            _logger.LogDebug("Screenshot uploaded: {Size} bytes ({W}x{H})", jpegBytes.Length, width, height);
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "Screenshot upload failed");
            throw;
        }
    }

    [DllImport("user32.dll")]
    private static extern int GetSystemMetrics(int nIndex);

    private const int SM_XVIRTUALSCREEN = 76;
    private const int SM_YVIRTUALSCREEN = 77;
    private const int SM_CXVIRTUALSCREEN = 78;
    private const int SM_CYVIRTUALSCREEN = 79;

    private (byte[]? bytes, int width, int height) CaptureJpeg()
    {
        try
        {
            int x = GetSystemMetrics(SM_XVIRTUALSCREEN);
            int y = GetSystemMetrics(SM_YVIRTUALSCREEN);
            int w = GetSystemMetrics(SM_CXVIRTUALSCREEN);
            int h = GetSystemMetrics(SM_CYVIRTUALSCREEN);
            if (w <= 0 || h <= 0) { w = 1920; h = 1080; }

            using var bmp = new Bitmap(w, h, PixelFormat.Format32bppArgb);
            using (var g = Graphics.FromImage(bmp))
                g.CopyFromScreen(x, y, 0, 0, new Size(w, h), CopyPixelOperation.SourceCopy);

            // Downscale (économise bande passante mutualisé)
            int targetW = Math.Min(1600, w);
            int targetH = h * targetW / w;

            using var resized = new Bitmap(targetW, targetH);
            using (var g = Graphics.FromImage(resized)) {
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.DrawImage(bmp, 0, 0, targetW, targetH);
            }

            using var ms = new MemoryStream();
            var jpegEncoder = ImageCodecInfo.GetImageEncoders().FirstOrDefault(c => c.FormatID == ImageFormat.Jpeg.Guid);
            if (jpegEncoder is null) return (null, 0, 0);

            var encParams = new EncoderParameters(1);
            encParams.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 60L);
            resized.Save(ms, jpegEncoder, encParams);

            return (ms.ToArray(), targetW, targetH);
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "Screen capture failed");
            return (null, 0, 0);
        }
    }
}