param(
    [Parameter(Mandatory=$true)]
    [string]$Source,

    [Parameter(Mandatory=$true)]
    [string]$Destination
)

try {
    # 1. Expand variables in paths.
    $ResolvedSource = $ExecutionContext.InvokeCommand.ExpandString($Source)
    $ResolvedDest   = $ExecutionContext.InvokeCommand.ExpandString($Destination)

    # 2. Resolve relative source paths from the project root.
    if (-not (Test-Path $ResolvedSource) -and (Test-Path "$PWD\$ResolvedSource")) {
        $ResolvedSource = Join-Path $PWD $ResolvedSource
    }

    # 3. Make sure the source file exists.
    if (-not (Test-Path $ResolvedSource -PathType Leaf)) {
        Write-Warning "`n[FileCopy] [Skip] File not found: $ResolvedSource"
        return
    }

    # 4. Create destination directory when needed.
    $DestDir = Split-Path -Path $ResolvedDest -Parent
    if (-not (Test-Path $DestDir)) {
        Write-Host "`n[FileCopy] Create dir: $DestDir" -ForegroundColor DarkGray
        New-Item -Path $DestDir -ItemType Directory -Force | Out-Null
    }

    # 5. Copy file. Force overwrites existing files.
    Copy-Item -Path $ResolvedSource -Destination $ResolvedDest -Force -ErrorAction Stop
    
    Write-Host "`n[FileCopy] Success: $ResolvedDest" -ForegroundColor Green

} catch {
    Write-Error "`n[FileCopy] Fail: $_"
}