name: Install Clang
description: Install Clang & LLVM

inputs:
  platform:
    description: Target platform
    required: false
    default: x64
  cygwin:
    description: Install Cygwin packages
    required: false
    default: 0
  cc:
    description: Set up cc/c++ executables
    required: false
    default: 1
  hardlinks:
    description: On Cygwin, replace executable symlinks with hardlinks
    required: false
    default: 0

runs:
  using: composite
  steps:
    - 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_host) -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'
            }
        }

        function Install-Package {
            param(
                [Parameter(Mandatory=$true, ValueFromRemainingArguments=$true)]
                [string[]] $Packages
            )

            if ($script:linux_host) {
                sudo apt-get update
                sudo DEBIAN_FRONTEND=noninteractive apt-get install -yq --no-install-recommends $Packages
            } elseif ($script:cygwin_host) {
                $choco = Locate-Choco
                & $choco install $Packages -y --no-progress --source=cygwin
            } elseif ($script:windows_host) {
                $choco = Locate-Choco
                & $choco upgrade $Packages -y --no-progress --allow-downgrade
            } else {
                throw "Sorry, installing packages is unsupported on $script:os"
            }
        }

        if ($linux_host) {
            if ($x64) {
                $pkgs = 'clang','g++','llvm'
            } else {
                $pkgs = 'clang','g++-multilib','llvm'
            }
            Install-Package $pkgs
        } elseif ($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.
        '@
            }

            # IDK why, but without libiconv-devel, even a "Hello, world!"
            # C++ app cannot be compiled as of December 2020. Also, libstdc++
            # is required; it's simpler to install gcc-g++ for all the
            # dependencies.
            Install-Package clang gcc-g++ libiconv-devel llvm
        } elseif ($windows_host) {
            Install-Package llvm

            $bin_dir = Join-Path $env:ProgramFiles LLVM bin
            echo $bin_dir >> $env:GITHUB_PATH
        } else {
            throw "Sorry, installing Clang is unsupported on $os"
        }
      shell: pwsh

    - 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_host) -Option Constant

        New-Variable cc -Value ('${{ inputs.cc }}' -eq '1') -Option Constant

        function Link-Exe {
            param(
                [Parameter(Mandatory=$true)]
                [string] $Exe,
                [Parameter(Mandatory=$true)]
                [string] $LinkName
            )

            $exe_path = (Get-Command $Exe).Path
            $link_dir = if ($script:windows_host) { Split-Path $exe_path } else { '/usr/local/bin' }
            $link_name = if ($script:windows_host) { "$LinkName.exe" } else { $LinkName }
            $link_path = if ($script:cygwin_host) { "$link_dir/$link_name" } else { Join-Path $link_dir $link_name }
            echo "Creating link $link_path -> $exe_path"
            if ($script:linux_host) {
                sudo ln -f -s $exe_path $link_path
            } elseif ($script:cygwin_host) {
                ln.exe -f -s $exe_path $link_path
            } elseif ($script:windows_host) {
                New-Item -ItemType HardLink -Path $link_path -Value $exe_path -Force | Out-Null
            }
        }

        if ($cc) {
            Link-Exe clang cc
            Link-Exe clang++ c++
        }
      shell: pwsh

    - run: |
        New-Variable cygwin_host -Value ('${{ inputs.cygwin }}' -eq '1') -Option Constant
        New-Variable hardlinks -Value ('${{ inputs.hardlinks }}' -eq '1') -Option Constant

        if ($cygwin_host -and $hardlinks) {
            # clang/clang++ are Cygwin symlinks, pointing to clang-X.exe. It's
            # convenient to make proper executables instead so that they can be
            # called from Windows' command prompt.
            echo @'
        while IFS= read -d '' -r link_path; do
            dest_path="$( readlink --canonicalize-existing -- "$link_path" )"
            dest_ext=".${dest_path##*.}"
            [ "$dest_ext" == ".$dest_path" ] && dest_ext=
            link_ext=".${link_path##*.}"
            [ "$link_ext" == ".$link_path" ] && link_ext=
            echo "Removing symlink $link_path" && rm -f -- "$link_path"
            [ "$link_ext" != "$dest_ext" ] && echo "${PATHEXT//\;/
        }" | grep -q --ignore-case --line-regexp -F -- "$dest_ext" && link_path="$link_path$dest_ext"
            echo "Creating hardlink $link_path -> $dest_path" && ln -- "$dest_path" "$link_path"
        done < <( find /usr/local/bin /usr/bin \
                       -type l '-(' \
                       -path '/usr/bin/clang*' -o \
                       -path '/usr/bin/llvm*' -o \
                       -path /usr/local/bin/cc -o \
                       -path /usr/local/bin/c++ \
                       '-)' -print0 )
        '@ | & bash.exe --login -o errexit -o nounset -o pipefail -o igncr
        }
      shell: pwsh

branding:
  icon: star
  color: green