using System;
using System.Runtime.InteropServices;

namespace SweetLib.Utils.TaskBar
{
    public static class TaskBarProgress
    {
        public enum TaskbarStates
        {
            NoProgress = 0,
            Indeterminate = 0x1,
            Normal = 0x2,
            Error = 0x4,
            Paused = 0x8
        }

        [ComImport]
        [Guid("26C41017-74B8-4C70-88AA-61B11D8C0D5A")]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface ITaskbarList3
        {
            // ITaskbarList
            [PreserveSig]
            void HrInit();
            [PreserveSig]
            void AddTab(IntPtr hwnd);
            [PreserveSig]
            void DeleteTab(IntPtr hwnd);
            [PreserveSig]
            void ActivateTab(IntPtr hwnd);
            [PreserveSig]
            void SetActiveAlt(IntPtr hwnd);

            // ITaskbarList2
            [PreserveSig]
            void MarkFullscreenWindow(IntPtr hwnd, [MarshalAs(UnmanagedType.Bool)] bool fFullscreen);

            // ITaskbarList3
            [PreserveSig]
            void SetProgressValue(IntPtr hwnd, UInt64 ullCompleted, UInt64 ullTotal);
            [PreserveSig]
            void SetProgressState(IntPtr hwnd, TaskbarStates state);
        }

        [Guid("D6031210-4108-4E8A-B740-A627052FDAC2")]
        [ClassInterface(ClassInterfaceType.None)]
        [ComImport]
        private class TaskbarInstance
        {
        }

        private static ITaskbarList3 taskbarInstance = (ITaskbarList3)new TaskbarInstance();
        private static bool taskbarSupported = Environment.OSVersion.Version >= new Version(6, 1);

        public static void SetState(IntPtr windowHandle, TaskbarStates taskbarState)
        {
            if (taskbarSupported) taskbarInstance.SetProgressState(windowHandle, taskbarState);
        }

        public static void SetValue(IntPtr windowHandle, double progressValue, double progressMax)
        {
            if (taskbarSupported) taskbarInstance.SetProgressValue(windowHandle, (ulong)progressValue, (ulong)progressMax);
        }
    }
}