name: Install Clang
description: Install Clang & LLVM

inputs:
  platform:
    description: Target platform
    required: false
    default: x64
  cygwin:
    description: Install inside Cygwin
    required: false
    default: 0

outputs:
  clang:
    description: clang executable name or path
    value: '${{ steps.setup.outputs.clang }}'
  clangxx:
    description: clang++ executable name or path
    value: '${{ steps.setup.outputs.clangxx }}'

runs:
  using: composite
  steps:
    - id: setup
      run: |
        New-Variable os -Value '${{ runner.os }}' -Option Constant

        New-Variable linux_host -Value ($os -eq 'Linux') -Option Constant
        New-Variable cygwin_host -Value ('${{ inputs.cygwin }}' -eq '1') -Option Constant
        New-Variable windows_host -Value ($os -eq 'Windows' -and !$cygwin) -Option Constant

        New-Variable x64 -Value ('${{ inputs.platform }}' -eq 'x64') -Option Constant

        function Locate-Choco {
            $path = Get-Command 'choco' -ErrorAction SilentlyContinue
            if ($path) {
                $path.Path
            } else {
                Join-Path ${env:ProgramData} 'chocolatey' 'bin' 'choco'
            }
        }

        if ($linux_host) {
            sudo apt update
            if ($x64) {
                sudo apt install -y clang g++
            } else {
                sudo apt install -y clang g++-multilib
            }

            echo "::set-output name=clang::clang"
            echo "::set-output name=clangxx::clang++"
        } elseif ($cygwin_host) {
            if (!$x64) {
                echo @'
        ::warning ::
        32-bit-targeting Clang is unavailable on 64-bit Cygwin.
        Please use 32-bit Cygwin instead.
        If you _are_ using 32-bit Cygwin, please ignore this message.
        '@
            }
            $choco = Locate-Choco

            # IDK why, but without libiconv-devel, even a "Hello, world!"
            # C++ app cannot be compiled as of December 2020.
            # Also, libstdc++ is required, and for simplicity's sake, gcc-g++
            # is installed.
            & $choco install -y --no-progress --source=cygwin clang libiconv-devel gcc-g++

            # clang/clang++ are symlinks on Cygwin, pointing to clang-VERSION.exe.
            $clang = cygpath.exe -wa (readlink.exe --canonicalize-existing /usr/bin/clang)
            $clangxx = cygpath.exe -wa (readlink.exe --canonicalize-existing /usr/bin/clang++)

            echo "::set-output name=clang::$clang"
            echo "::set-output name=clangxx::$clangxx"
        } elseif ($windows_host) {
            $choco = Locate-Choco

            & $choco install -y --no-progress llvm
            echo (Join-Path $env:ProgramFiles LLVM bin) >> $env:GITHUB_PATH

            echo "::set-output name=clang::clang"
            echo "::set-output name=clangxx::clang++"
        } else {
            throw "Sorry, installing Clang is unsupported on $os"
        }
      shell: pwsh

branding:
  icon: star
  color: green