Extract BMS archives with appropriate directory structure

bmsext.ps1

function Get-CommonDirectoryPath($paths){
    # original: https://www.rosettacode.org/wiki/Find_common_directory_path#PowerShell
    switch($paths.Count){
        0{return $null}
        1{
            $s=$paths[0].TrimStart('/').Split('/')
            $v=''
            for($r = 0; $r -lt $s.Count-1; $r++) {
                $v+=$s[$r]
            }
            return $v
        }
    }
 
    $p=New-Object System.Collections.ArrayList
    for($i=0; $i -lt $paths.Count; $i++) {
        $dummy=$p.Add(($paths[$i].TrimStart('/').Split('/')))
    }

    $c = -1
    $found = $false
    do {
        $t = $p[0][++$c]
        for($r = 1; $r -lt $p.Count; $r++) {
            if ($t -ne $p[$r][$c]) {$found=$true; break }
        }
    } until ($found)
 
    $s=''
    for($i=0; $i -lt $c; $i++) {$s += "/"+$p[0][$i]}
    return $s.TrimStart("/")
}
function Extract-BmsArchives(){
    $archives=@(Get-ChildItem -Name *.zip,*.rar,*.7z)
    $reg="(?im:^\d{4}-\d{2}-\d{2}\s*\d\d:\d\d:\d\d\s*([A-Z.]{5})\s*\d+\s*\d+\s*(.+)\s*$)"
    $reg_bms="(?i:^.*\.[bp]m([sel]|son)$)"
    $reg_exc_dir="(^|/?)(_MACOSX/)"
    $reg_exc_file="(^|/?)(Thumbs\.db|desktop\.ini|\.DS_Store)$"
    $reg_relpath="^/?(([^/]+/)*)[^/]+$"
    foreach($arc in $archives){
        $dirs=New-Object System.Collections.ArrayList
        $files=New-Object System.Collections.ArrayList
        $bmsfiles=New-Object System.Collections.ArrayList
        [Regex]::Matches(
            [string]::Join("`n",@(7z l $arc)),$reg
        ) | foreach{
            $property=$_.Groups[1].Value
            $path=$_.Groups[2].Value.Replace('\','/')
            if ($property.StartsWith('D')){
                if ($path -notmatch $reg_exc_dir){
                    $dummy=$dirs.Add($path)
                }
            }else{
                if ($path -notmatch $reg_exc_file){
                    $dummy=$files.Add($path)
                }
                if ($path -match $reg_bms){
                    $dummy=$bmsfiles.Add($path)
                }
            }
        }
        $com_pre=Get-CommonDirectoryPath($files)
        $com_pre_bms=Get-CommonDirectoryPath($bmsfiles)
        if($com_pre -ne $com_pre_bms){
            "***Skipped: $arc***"
        }else{
            $dirdict=@{}
            foreach($entry in $files){
                $extpath=[Regex]::Match($entry.Substring($com_pre.Length),$reg_relpath).Groups[1].Value
                if (-not $dirdict.ContainsKey($extpath)){
                    $dirdict[$extpath]=New-Object System.Collections.ArrayList
                }
                $dummy=$dirdict[$extpath].Add($entry)
            }
            $dirname=$null
            if ($args -contains "-DirNameMajored"){
                $dirname=[System.IO.Path]::GetFileNameWithoutExtension($com_pre)
            }
            if (-not $dirname){
                $dirname=[System.IO.Path]::GetFileNameWithoutExtension($arc).TrimEnd(". ")
            }
            foreach($childdir in $dirdict.Keys){
                [String]::Join("`n",$dirdict["$childdir"].ToArray()) | Set-Content -path tmpfilelist.dat -encoding UTF8
                "7z e -aos -o""$dirname/$childdir"" ""$arc"" `@tmpfilelist.dat"
                $dummy=(7z e -aos -o"$dirname/$childdir" "$arc" `@tmpfilelist.dat)
                if ($LASTEXITCOD -gt 0){
                    "7z failed with error code $LASTEXITCODE"
                    exit 1
                }
            }
        }
    }
}

Extract-BmsArchives