param(
    [Parameter(Mandatory=$true)] [string]$Command,
    [string]$WorkDir = $null
)

# 1. Resolve work directory.
if ([string]::IsNullOrEmpty($WorkDir)) {
    $WorkDir = $PSScriptRoot
} else {
    # Expand variables in WorkDir, such as $env:APPDATA.
    $WorkDir = $ExecutionContext.InvokeCommand.ExpandString($WorkDir)
}

# Make sure the directory exists.
if (-not (Test-Path $WorkDir)) {
    Write-Warning "`n[CMD] WARNING: The work dir does not exist, using ($WorkDir)"
    $WorkDir = $PSScriptRoot
}

# 2. Expand variables in the command.
$ProjectRoot = Split-Path $PSScriptRoot -Parent
# Replace $PSScriptRoot with the project root path.
# Direct string replacement is the safest option for backslashes.
if ($Command.Contains('$PSScriptRoot')) {
    $Command = $Command.Replace('$PSScriptRoot', $ProjectRoot)
}

# This allows commands such as "echo $env:USERNAME".
$Command = $ExecutionContext.InvokeCommand.ExpandString($Command)

Write-Host "`n[CMD] Execute: $Command" -ForegroundColor Gray

# 3. Start cmd.exe.
# /c closes cmd after the command completes.
# /s enables cmd quote handling for complex command strings.
$processOptions = @{
    FilePath = "cmd.exe"
    ArgumentList = "/s", "/c", "`"$Command`""
    WorkingDirectory = $WorkDir
    Wait = $true
    NoNewWindow = $true
    PassThru = $true
}

try {
    $proc = Start-Process @processOptions
    
    # 4. Check exit code.
    if ($proc.ExitCode -ne 0) {
        Write-Error "`n[CMD] Failed to execute, exit code: $($proc.ExitCode)"
    }
} catch {
    Write-Error "`n[CMD] Failed to start process: $_"
}