Get windows system proxy（only support http proxy） and auto set proxy for mpv and ytdl_hook

set_proxy.lua

local mp = require 'mp'

function string:trim()
    return (self:gsub("^%s*(.-)%s*$", "%1"))
end

local function pwshexec(command)
    local args = {
        "powershell", "-NoProfile", "-Command"
    }
    table.insert(args,command)

    mp.msg.debug("Running: " .. table.concat(args, " "))

    local ret = mp.command_native({name = "subprocess",
                                   args = args,
                                   playback_only = false,
                                   capture_stdout = true,
                                   capture_stderr = true})
    if ret.killed_by_us or (ret.status ~= 0) or ret.stdout=="" then
        return ""
    else
        return (ret.stdout:gsub("\r\n$", "")):trim()
    end
end

local function get_proxy()
    local ProxyEnable = pwshexec([=[(Get-ItemProperty -Path 'Registry::HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings').ProxyEnable -eq 1]=])
    mp.msg.debug(ProxyEnable)
    if ProxyEnable == "True" then
        local ProxyServer = pwshexec([=[((Get-ItemProperty -Path 'Registry::HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings').ProxyServer | Select-String -Pattern '(\w+\.?)*:\d+').Matches[0].Value]=])
        if ProxyServer~="" then
			ProxyServer = "http://" .. ProxyServer
			return ProxyServer
		end
    end
end

local proxy = get_proxy()
mp.msg.debug(proxy)
if proxy then
	if mp.get_property("http-proxy")=="" then
        mp.set_property("http-proxy",proxy)
        mp.msg.info("Auto set http-proxy:" .. mp.get_property("http-proxy"))
    end
    
    local raw_options = mp.get_property_native("options/ytdl-raw-options")
    if raw_options["proxy"]==nil or raw_options["proxy"] == ""then
       raw_options["proxy"] = proxy
       mp.set_property_native("options/ytdl-raw-options",raw_options)
    end
end