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

    [Parameter(Mandatory = $false)]
    [string]$Output = "artifacts"
)

$ErrorActionPreference = "Stop"

if (-not (Test-Path $Executable)) {
    throw "Executable does not exist: $Executable"
}

New-Item -ItemType Directory -Force -Path $Output | Out-Null

$windowsDirectories = @(
    $env:WINDIR,
    (Join-Path $env:WINDIR "System32"),
    (Join-Path $env:WINDIR "SysWOW64")
)

$processed = @{}

function Test-IsWindowsSystemDll {
    param(
        [string]$Name
    )

    foreach ($directory in $windowsDirectories) {
        $path = Join-Path $directory $Name

        if (Test-Path $path) {
            return $true
        }
    }

    return $false
}

function Find-Dependency {
    param(
        [string]$Name,
        [string]$BinaryDirectory
    )

    $localPath = Join-Path $BinaryDirectory $Name

    if (Test-Path $localPath) {
        return $localPath
    }

    $command = Get-Command $Name -ErrorAction SilentlyContinue

    if ($command) {
        return $command.Source
    }

    return $null
}

function Copy-Dependencies {
    param(
        [string]$Binary
    )

    $binaryDirectory = Split-Path -Parent $Binary

    $dependencies = dumpbin /DEPENDENTS $Binary |
        Select-String '^\s+.*\.dll$' |
        ForEach-Object { $_.Line.Trim() } |
        Sort-Object -Unique

    foreach ($dll in $dependencies) {

        $key = $dll.ToLowerInvariant()

        if ($processed.ContainsKey($key)) {
            continue
        }

        $processed[$key] = $true

        if (Test-IsWindowsSystemDll $dll) {
            Write-Host "Skipping Windows system dependency: $dll"
            continue
        }

        $source = Find-Dependency `
            -Name $dll `
            -BinaryDirectory $binaryDirectory

        if (-not $source) {
            Write-Warning "Could not locate dependency: $dll"
            continue
        }

        $destination = Join-Path $Output (Split-Path -Leaf $source)

        if (-not (Test-Path $destination)) {
            Write-Host "Copying dependency: $source"
            Copy-Item $source $destination -Force
        }

        Copy-Dependencies -Binary $source
    }
}

Copy-Dependencies -Binary $Executable