#!/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 create mechanism to specify build effects like %w{-O0 -O4 vanilla-arg-parsing sdk=10.6} etc.

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 nclt?
  $sdkroot != nil
end
def syspath
  if nclt?
    %W{#$sdkroot/usr #$sdkroot/usr/local}
  else
    %W{/usr /usr/local}
  end
end
def exec *args
  path = File.expand_path('~/Library/Logs/Homebrew/cc.log')
  open(path, 'a') do |f|
    f.print '[', $0
    f.print " -%s" % ENV['HOMEBREW_CCCFG'] if ENV['HOMEBREW_CCCFG']
    f.print '] '
    f.puts args.join(' ')
    f.puts
  end
  Kernel.exec *args
end if ENV['HOMEBREW_LOG']


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 ||= case @arg0
    when 'ld' then 'ld'
    when 'cc', 'c99', 'c89'
      # Ideally we would run `cx9`, however these tools are POSIX compliant
      # and don't support many flags. We need -isystem for instance, but also
      # reliability is generally much higher if we just get clang/gcc to do
      # the work since Makefiles are dumb and include a lot of excess flags.
      ENV['HOMEBREW_CC']
    when 'c++'
      if ENV['HOMEBREW_CC'] =~ /gcc/
        'g++'
      else
        'clang++'
      end
    else
      @arg0
    end
  end
  def args
    args = if not cccfg? 'O' or tool == 'ld'
      @args.dup
    else
      refurbished_args
    end
    if tool != 'ld'
      args << "--sysroot=#$sdkroot"
    else
      args << "-syslibroot" << $sdkroot
    end if nclt?
    case mode
    when :cpp
      %w{-E} + args + cppflags
    when :ld
      ldflags + args
    when :cc
      cflags + args + cppflags
    when :ccld
      cflags + args + cppflags + ldflags
    end.compact
  end
  def refurbished_args
    lset = Set.new(libpath + syslibpath)
    iset = Set.new(cpath.flatten)

    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',
           '-pedantic', '-pedantic-errors'
      when '-fopenmp', '-lgomp'
        # clang doesn't support OpenMP
        args << arg if not tool =~ /^clang/
      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(.+)/
        path = $1.chuzzle || whittler.next
        case path.cleanpath
        when %r{^/opt}, %r{^/sw}, %r{/usr/X11}
          # NOOP
        else
          args << "-L#{path}" if lset.add?(path.cleanpath)
        end
      else
        args << arg
      end
    end
    make_fuss(args)
    args
  end
  def cflags
    if cccfg? 'Ob'
      %w{-mtune=generic -Oz}
    elsif cccfg? 'O'
      args = %w{-pipe -w -Os}
      args << '-march=native' if tool =~ /clang/
      args += %w{-arch i386 -arch x86_64} if cccfg? 'u'
      args << "--std=#{@arg0}" if @arg0 =~ /c[89]9/
      args
    else
      []
    end
  end
  def syslibpath
    # We reject brew's lib as we explicitly add this as a -L flag, thus it
    # is given higher priority by cc, so it surpasses the system libpath.
    # NOTE this only counts if Homebrew is installed at /usr/local
    syspath.map{|d| "#{d}/lib" }.reject{ "#$brewfix/lib" }
  end
  def syscpath
    isystem, _ = cpath
    isystem + syspath.map{|d| "#{d}/include" }
  end
  def cpath
    cpath = ENV['CMAKE_PREFIX_PATH'].split(':').map{|d| "#{d}/include" } + ENV['CMAKE_INCLUDE_PATH'].split(':')
    opt = cpath.select{|prefix| prefix =~ %r{^#$brewfix/opt} }
    sys = cpath - opt
    [sys, opt]
  end
  def libpath
    ENV['CMAKE_PREFIX_PATH'].split(':').map{|d| "#{d}/lib" } +
    ENV['CMAKE_LIBRARY_PATH'].split(':') -
    syslibpath
  end
  def ldflags
    libpath.to_flags('-L')
  end
  def cppflags
    sys, opt = cpath
    # we want our keg-only includes to be found before system includes *and*
    # before any other includes the build-system adds
    sys.to_flags('-isystem') + opt.to_flags('-I')
  end
  def make_fuss args
    dels = @args - args
    adds = args - @args
    dups = dels & args

    STDERR.puts "brew: superenv removed: #{dels*' '}" unless dels.empty?
    STDERR.puts "brew: superenv deduped: #{dels}" unless dups.empty?
    STDERR.puts "brew: superenv added: #{adds*' '}" unless adds.empty?
  end
end

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

case ENV['HOMEBREW_CC'].chuzzle when 'cc', nil
  # those values are not allowed
  ENV['HOMEBREW_CC'] = 'clang'
end

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