#!/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -W0
#TODO make it work with homebrew/dupes/gcc
#TODO? If we find -mmacosx-version-min=10.8, change sdkroot? warn visibly if no such SDK?
#TODO fix pkg-config files, should point to /usr/local or /usr/local/opt
#TODO for easier to understand code, don't monkey-patch ENV, just set via a hash from a helper class
#TODO create mechanism to specify build effects like %w{-O0 -O4 vanilla-arg-parsing sdk=10.6} etc.
#TODO DSL for lame-env (and rename to typical-env or something better)
#TODO consider always setting CC to cc and instead having HOMEBREW_CC to force cc choice in end toolchain
#     in verbose mode print out things like "gcc called, but redirecting to clang" if that happens
#TODO `brew sh`: https://github.com/mxcl/homebrew/issues/14381#issuecomment-8017538

require "#{File.dirname __FILE__}/../libsuperenv"
require 'set'

def cccfg? flags
  flags.split('').all?{|c| ENV['HOMEBREW_CCCFG'].include? c } if ENV['HOMEBREW_CCCFG']
end
def servile?
  # we are servile when we are called from configure etc.
  # * we give the callee the tools it asks for
  # * we leave ARGV alone
  # when callee is make we optimize and force HOMEBREW_CC
  not cccfg? 'O'
end
def nclt?
  $sdkroot != nil
end
def cmake_prefixes
  @prefixes ||= ENV['CMAKE_PREFIX_PATH'].split(':').reject do |path|
    case path
      when '/usr/local' then !nclt?
      when '/usr', '/', "#$sdkroot/usr" then true
    end
  end
end

class Cmd
  def initialize path, args
    @arg0 = path.basename.freeze
    @args = args.freeze
  end
  def mode
    if @arg0 == 'cpp' or @arg0 == 'ld'
      @arg0.to_sym
    elsif @args.include? '-c'
      :cc
    elsif @args.include? '-E'
      :cpp
    else
      :ccld
    end
  end
  def tool
    @tool ||= if servile? or @arg0 == 'ld'
      @arg0
    elsif @arg0.include? '++'
      if ENV['HOMEBREW_CC'].chuzzle =~ /gcc/
        'g++'
      else
        'clang++'
      end
    else
      ENV['HOMEBREW_CC'].chuzzle or 'clang'
    end
  end
  def args
    args = if servile? or tool == 'ld'
      @args.dup
    else
      refurbished_args
    end
    if tool != 'ld'
      args.unshift("--sysroot=#$sdkroot")
    else
      args.unshift($sdkroot).unshift("-syslibroot")
    end if nclt?
    case mode
    when :cpp
      %w{-E} + cppflags + args
    when :ld
      ldflags + args
    when :cc
      cflags + cppflags + args
    when :ccld
      cflags + cppflags + ldflags + args
    end.compact
  end
  def refurbished_args
    iset = Set.new(cmake_prefixes.map{|prefix| "#{prefix}/include" })
    lset = Set.new
    args = []
    whittler = @args.each
    loop do
      case arg = whittler.next
      when '-arch', /^-Xarch_/
        whittler.next
      when /^-g\d?/, /^-gstabs\d+/, '-gstabs+', /^-ggdb\d?/, '-gdwarf-2',
           /^-march=.+/, /^-mtune=.+/, '-m64', '-m32',
           /^-O[0-9zs]/, '-fast',
           %r{^-[IL]/opt/local}, %r{^-[IL]/sw},    # no macports/fink
           %r{^-[IL]/usr/X11}, %r{^-[IL]/opt/X11}, # we add X11 ourselves
           '-pedantic', '-pedantic-errors'
      when /^-W.*/
        args << arg if arg =~ /^-Wl,/
      when '-macosx_version_min', '-dylib_install_name'
        args << "-Wl,#{arg},#{whittler.next}"
      when '-dylib'
        args << "-Wl,#{arg}"
      when /^-I(.+)/
        # it is okay to add a space after the -I; so let's support it
        path = $1.chuzzle || whittler.next
        args << "-I#{path}" if iset.add?(path.cleanpath)
      when /^-l(.+)/
        lib = $1.chuzzle || whittler.next
        args << "-l#{lib}" if lset.add?(lib)
      else
        args << arg
      end
    end
    make_fuss(args)
    args
  end
  def cflags
    if cccfg? 'Ob'
      %w{-mtune=generic -Oz}
    elsif cccfg? 'O'
      u = '-arch i386 -arch x86_64' if cccfg? 'u'
      c = case tool when 'clang', 'clang++' then '-march=native' end
      %w{-pipe -w -Os} << u << c
    else
      []
    end
  end
  def ldflags
    cmake_prefixes.map{|prefix| "#{prefix}/lib" }.to_flags('-L')
  end
  def cppflags
    all = cmake_prefixes.map{|prefix| "#{prefix}/include" }
    opt = all.select{|prefix| prefix =~ %r{^#$brewfix/opt} }
    sys = all - opt + ENV['CMAKE_INCLUDE_PATH'].split(':')
    # we want our keg-only includes to be found before system includes so that
    # they override the system options.
    sys.to_flags('-isystem') + opt.to_flags('-I')
  end
  def make_fuss args
    dels = @args - args
    if ENV['VERBOSE']
      adds = args - @args
      puts "brew: Superenv removed: #{dels*' '}" unless dels.empty?
      puts "brew: Superenv added: #{adds*' '}" unless adds.empty?
    else
      %w{CPPFLAGS LDFLAGS CXXFLAGS CFLAGS}.each do |flag|
        next unless ENV[flag]
        flags = dels.select{|del| ENV[flag].include? del }.join(' ')
        puts "brew: superenv removed `#{flags}' from #{flag}" unless flags.empty?
      end
    end
  end
end

####################################################################### sanity
abort "The build-tool has reset ENV. --env=std required." unless ENV['HOMEBREW_BREW_FILE']

######################################################################### main
cmd = Cmd.new($0, ARGV)
exec "xcrun", cmd.tool, *cmd.args