#define SHOW_ON_ONE_SCREEN

using Svg;
using System.Runtime.InteropServices;
using System.Text;
using System.Text.Json;

namespace McsrGraphImageDownloader;

internal class Program {
#if SHOW_ON_ONE_SCREEN
    private const int screenToShowItOn = 0; // must be >= 0 and < amount_of_screens, will be clamped if necessary

    [ComImport]
    [Guid("B92B56A9-8B55-4E14-9A89-0199BBB6F93B")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    private interface IDesktopWallpaper {
        void SetWallpaper([MarshalAs(UnmanagedType.LPWStr)] string monitorID, [MarshalAs(UnmanagedType.LPWStr)] string wallpaper);

        [return: MarshalAs(UnmanagedType.LPWStr)]
        string GetWallpaper([MarshalAs(UnmanagedType.LPWStr)] string monitorID);

        void GetMonitorDevicePathAt(uint monitorIndex, [MarshalAs(UnmanagedType.LPWStr)] out string monitorID);

        uint GetMonitorDevicePathCount();

        // Remaining methods omitted since not needed
    }
#endif

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern int SystemParametersInfo(int uAction, int uParam, string lpvParam, int fuWinIni);
    public const int SPI_SETDESKWALLPAPER = 0x14;
    public const int SPIF_UPDATEINIFILE = 1;
    public const int SPIF_SENDCHANGE = 2;

    private const string outputFilename = "mcsrChart.png";

    private static async Task Main(string[] args) {
        using var hc = new HttpClient();
        while (true) {
            var svgJson = await hc.GetStringAsync("https://mcsr.ghxx.dev/api/chart");
            var svgText = JsonDocument.Parse(svgJson).RootElement.GetProperty("data").GetString();
            var svg = SvgDocument.Open<SvgDocument>(new MemoryStream(Encoding.UTF8.GetBytes(svgText!)));
            using (var bitmap = svg.Draw(1920, 1080)) {
                bitmap.Save(outputFilename);
            }

#if SHOW_ON_ONE_SCREEN
            Type type = Type.GetTypeFromCLSID(new Guid("C2CF3110-460E-4FC1-B9D0-8A1C0C9CC4BD"))!;

            var wallpaper = (IDesktopWallpaper)Activator.CreateInstance(type)!;

            uint monitorCount = wallpaper.GetMonitorDevicePathCount();

            Console.WriteLine($"Monitor count: {monitorCount}");
            var monitorIndex = Math.Clamp(screenToShowItOn, 0, monitorCount - 1);

            wallpaper.GetMonitorDevicePathAt(monitorIndex, out string? monitorId);

            wallpaper.SetWallpaper(monitorId, Path.GetFullPath(outputFilename));

            Console.WriteLine($"Wallpaper set for monitor {monitorIndex} only.");
#else
            SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, Path.GetFullPath(outputFilename), SPIF_UPDATEINIFILE | SPIF_SENDCHANGE);
#endif
            await Task.Delay(TimeSpan.FromMinutes(15));
        }
    }
}