/*
What it does:
1) Requires the currently focused window to belong to the TARGET app (or it exits).
2) Prompts you to choose a destination monitor.
3) On that destination monitor, finds the TOPMOST window that belongs to the TARGET app.
4) Swaps the two windows by moving each to the other's monitor.

Nuances:
- Swaps exactly TWO windows:
  A) The focused TARGET-app window (must be the target app)
  B) The topmost TARGET-app window on the chosen monitor
- Not "all windows" on a monitor.
- No drag detection. Trigger with hotkey or mouse (e.g., XMouseButtonControl).
- If the chosen monitor has no TARGET-app window, nothing happens.
- Uses process-based detection (BFS.Application.GetMainFileByWindow), so titles and skins do not matter.

How to adapt:
- Change TARGET_EXE to the executable you want to swap.
- Optionally adjust TARGET_EXE_MATCH_FALLBACK.
*/

using System;

public static class DisplayFusionFunction
{
    private const string TARGET_EXE = "PotPlayerMini64.exe";
    private const string TARGET_EXE_MATCH_FALLBACK = "PotPlayer";

    public static void Run(IntPtr windowHandle)
    {
        if (windowHandle == IntPtr.Zero)
            return;

        if (!IsTargetAppWindow(windowHandle))
            return;

        uint sourceMonitor = BFS.Monitor.GetMonitorIDByWindow(windowHandle);

        uint destMonitor = BFS.Monitor.ShowMonitorSelector();
        if (destMonitor == 0)
            return;

        if (destMonitor == sourceMonitor)
            return;

        IntPtr destTopmostTarget = GetTopmostTargetAppWindowOnMonitor(destMonitor);
        if (destTopmostTarget == IntPtr.Zero)
            return;

        BFS.Window.MoveToMonitor(destMonitor, windowHandle);
        BFS.Window.MoveToMonitor(sourceMonitor, destTopmostTarget);

        BFS.Window.Focus(windowHandle);
    }

    private static IntPtr GetTopmostTargetAppWindowOnMonitor(uint monitorId)
    {
        IntPtr[] windows = BFS.Window.GetVisibleWindowHandlesByMonitor(monitorId);

        foreach (IntPtr w in windows)
        {
            if (w == IntPtr.Zero)
                continue;

            if (IsTargetAppWindow(w))
                return w;
        }

        return IntPtr.Zero;
    }

    private static bool IsTargetAppWindow(IntPtr window)
    {
        string mainFile = BFS.Application.GetMainFileByWindow(window);
        if (string.IsNullOrEmpty(mainFile))
            return false;

        if (mainFile.IndexOf(TARGET_EXE, StringComparison.OrdinalIgnoreCase) >= 0)
            return true;

        if (!string.IsNullOrEmpty(TARGET_EXE_MATCH_FALLBACK) &&
            mainFile.IndexOf(TARGET_EXE_MATCH_FALLBACK, StringComparison.OrdinalIgnoreCase) >= 0)
            return true;

        return false;
    }
}