using System;
using System.Runtime.InteropServices;

namespace BSO
{
    /// <summary>Tasten der Mod (F8-F11): "gerade gedrueckt" erkennen, nur wenn das Spielfenster vorne ist.</summary>
    public static class Input
    {
        [DllImport("user32.dll")] static extern short GetAsyncKeyState(int key);
        [DllImport("user32.dll")] static extern nint GetForegroundWindow();
        [DllImport("user32.dll")] static extern uint GetWindowThreadProcessId(nint window, out uint process);

        public const int F8 = 0x77, F9 = 0x78, F10 = 0x79, F11 = 0x7A;

        static readonly bool[] down = new bool[256], pressed = new bool[256];
        static readonly int[] watched = { F8, F9, F10, F11 };

        /// <summary>Einmal pro Bild vor allen Pressed-Abfragen.</summary>
        public static void Update()
        {
            bool focus = GameHasFocus();
            foreach (int key in watched)
            {
                bool now = focus && GetAsyncKeyState(key) < 0;
                pressed[key] = now && !down[key];
                down[key] = now;
            }
        }

        public static bool Pressed(int key) => pressed[key];

        public static bool GameHasFocus()
        {
            GetWindowThreadProcessId(GetForegroundWindow(), out uint pid);
            return pid == (uint)Environment.ProcessId;
        }
    }
}