require "formula"

module Homebrew extend self
  def diy
    %w[name version].each do |opt|
      if ARGV.include? "--set-#{opt}"
        opoo "--set-#{opt} is deprecated, please use --#{opt}=<#{opt}> instead"
      end
    end

    path = Pathname.getwd

    version = ARGV.value "version"
    version ||= if ARGV.include? "--set-version"
      ARGV.next
    elsif path.version.to_s.empty?
      raise "Couldn't determine version, set it with --version=<version>"
    else
      path.version
    end

    name = ARGV.value "name"
    name ||= ARGV.next if ARGV.include? "--set-name"
    name ||= detected_name(path, version)

    prefix = HOMEBREW_CELLAR/name/version

    if File.file? "CMakeLists.txt"
      puts "-DCMAKE_INSTALL_PREFIX=#{prefix}"
    elsif File.file? "Makefile.am"
      puts "--prefix=#{prefix}"
    else
      raise "Couldn't determine build system"
    end
  end

  def detected_name(path, version)
    basename = path.basename.to_s
    detected_name = basename[/(.*?)-?#{Regexp.escape(version)}/, 1] || basename
    canonical_name = Formula.canonical_name(detected_name)

    odie <<-EOS.undent if detected_name != canonical_name
      The detected name #{detected_name.inspect} exists in Homebrew as an alias
      of #{canonical_name.inspect}. Consider using the canonical name instead:
        brew diy --name=#{canonical_name}

      To continue using the detected name, pass it explicitly:
        brew diy --name=#{detected_name}
      EOS

    detected_name
  end
end