# frozen_string_literal: true

require 'formula'
require 'fileutils'

class ThemeCheck < Formula
  module RubyBin
    def ruby_bin
      Formula["ruby"].opt_bin
    end
  end

  class RubyGemsDownloadStrategy < AbstractDownloadStrategy
    include RubyBin

    def fetch(_timeout: nil, **_options)
      ohai("Fetching theme-check from gem source")
      cache.cd do
        ENV['GEM_SPEC_CACHE'] = "#{cache}/gem_spec_cache"
        system("#{ruby_bin}/gem", "fetch", "theme-check", "--version", gem_version)
      end
    end

    def cached_location
      Pathname.new("#{cache}/theme-check-#{gem_version}.gem")
    end

    def cache
      @cache ||= HOMEBREW_CACHE
    end

    def gem_version
      return @version if defined?(@version) && @version
      @version = @resource.version if defined?(@resource)
      raise "Unable to determine version; did Homebrew change?" unless @version
      @version
    end

    def clear_cache
      cached_location.unlink if cached_location.exist?
    end
  end

  include RubyBin

  url "theme-check", using: RubyGemsDownloadStrategy
  version "THEME_CHECK_VERSION"
  sha256 'THEME_CHECK_GEM_CHECKSUM'
  depends_on "ruby"

  def install
    # set GEM_HOME and GEM_PATH to make sure we package all the dependent gems
    # together without accidently picking up other gems on the gem path since
    # they might not be there if, say, we change to a different rvm gemset
    ENV['GEM_HOME'] = prefix.to_s
    ENV['GEM_PATH'] = prefix.to_s

    # Use /usr/local/bin at the front of the path instead of Homebrew shims,
    # which mess with Ruby's own compiler config when building native extensions
    if defined?(HOMEBREW_SHIMS_PATH)
      ENV['PATH'] = ENV['PATH'].sub(HOMEBREW_SHIMS_PATH.to_s, '/usr/local/bin')
    end

    system(
      "#{ruby_bin}/gem",
      "install",
      cached_download,
      "--no-document",
      "--no-wrapper",
      "--no-user-install",
      "--install-dir", prefix,
      "--bindir", bin
    )

    raise "gem install 'theme-check' failed with status #{$CHILD_STATUS.exitstatus}" unless $CHILD_STATUS.success?

    bin.rmtree if bin.exist?
    bin.mkpath

    brew_gem_prefix = "#{prefix}/gems/theme-check-#{version}"

    gemspec = Gem::Specification.load("#{prefix}/specifications/theme-check-#{version}.gemspec")
    ruby_libs = Dir.glob("#{prefix}/gems/*/lib")
    gemspec.executables.each do |exe|
      file = Pathname.new("#{brew_gem_prefix}/#{gemspec.bindir}/#{exe}")
      (bin + file.basename).open('w') do |f|
        f << <<~RUBY
          #!#{ruby_bin}/ruby --disable-gems
          ENV['GEM_HOME']="#{prefix}"
          ENV['GEM_PATH']="#{prefix}"
          require 'rubygems'
          $:.unshift(#{ruby_libs.map(&:inspect).join(',')})
          load "#{file}"
        RUBY
      end
    end
  end
end