boss-key.lua

--[[
  * boss-key.lua v1.0.3
  * (Older versions will lack a version number)
  *
  * AUTHOR: detuur, zaza42
  * License: MIT
  * link: https://github.com/detuur/mpv-scripts
  * 
  * This script minimises and pauses the window when
  * the boss key (default 'b') is pressed.
  * Can be overwriten in input.conf as follows:
  * KEY script-binding boss-key
  * xdotool is required on Xorg(Linux)
--]]

utils = require 'mp.utils'

local platform = nil --set to 'linux', 'windows' or 'macos' to override automatic assign
if not platform then
    local o = {}
    if mp.get_property_native('options/vo-mmcss-profile', o) ~= o then
        platform = 'windows'
    elseif mp.get_property_native('options/macos-force-dedicated-gpu', o) ~= o then
        platform = 'macos'
    else
        platform = 'linux'
    end
end

-- TODO: macOS implementation?
function boss_key()
	mp.set_property_native("pause", true)
	if platform == 'windows' then
	    mp.command([[run cmd /c echo m > \\.\pipe\mpv-boss-key-]]..utils.getpid())
	elseif platform == 'macos' then
	    utils.subprocess({ args = {'osascript', '-e', 'tell application "System Events" to set the visible of the first process whose frontmost is true to false'} })
	elseif platform == 'linux' then
	    utils.subprocess({ args = {'xdotool', 'getactivewindow', 'windowminimize'} })
	end
end

-- The only way to minimize the window in Windows is through a compiled Win32
-- API call. So we open an async powershell session, define the function call,
-- compile it, and then wait for a signal from this script to execute the call.
-- Signaling is done through named pipes, which to my surprise were present on
-- Windows. Not to my surprise, they didn't work reliably. Writing to the pipe
-- from PS or CMD yields different results, for example. In addition, PS's
-- Events and other async were extremely finnicky. Because of these reasons,
-- and after many, many rewrites, I've arrived at the unorthodox mess that is
-- the code below. It's not pretty, but at l(e)ast it works reliably.
if platform == 'windows' then
    mp.command_native_async({
        name = "subprocess",
        playback_only = false,
        detach = true,
        args = {'powershell', '-NoProfile', '-Command', [[&{
$bosspid = ]]..utils.getpid()..[[

# Construct the named pipe's name
$pipename = -join('mpv-boss-key-',$bosspid)
$fullpipename = -join("\\.\pipe\", $pipename)

# This will run in a separate thread
$minimizeloop = {
    param($pipename, $bosspid)
    # Create the named pipe
    $pipe = new-object System.IO.Pipes.NamedPipeServerStream($pipename)

    # Compile the Win32 API function call
    $signature='[DllImport("user32.dll")] public static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);'
    $showWindowAsync = Add-Type -memberDefinition $signature -name "Win32ShowWindowAsync" -namespace Win32Functions -passThru

    # The core loop
    while($true) {
        $pipe.WaitForConnection()
        if ($pipe.ReadByte() -ne 109) {
            break 
        }
        $pipe.Disconnect()
        $showWindowAsync::ShowWindowAsync((Get-Process -id $bosspid).MainWindowHandle, 2)
    }
    $pipe.Dispose()
}

# Exiting this monstrosity (THANKS POWERSHELL FOR BROKEN ASYNC) is surprisingly
# cumbersome. It took literal hours to find something that didn't spontaneously
# combust.
$bossproc = Get-Process -pid $bosspid -ErrorAction SilentlyContinue
$exitsequence = {
    &{echo q > $fullpipename} 2> $null
    [Environment]::Exit(0)
}
if ((-Not $bossproc) -or $bossproc.HasExited) { $exitsequence.Invoke() }

# Begin watching for events until boss closes
Start-Job -ScriptBlock $minimizeloop -Name "mpvminloop" -ArgumentList $pipename,$bosspid
while($true) {
    Start-Sleep 1
    if ($bossproc.HasExited) { $exitsequence.Invoke() }
}
}]]}}, function()end)
end

mp.add_key_binding('b', 'boss-key', boss_key)