#!/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 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
    @cmd = path.basename.freeze
    @args = args.freeze
  end
  def mode
    if @cmd == 'cpp' or @cmd == 'ld'
      @cmd.to_sym
    elsif @args.include? '-c'
      :cc
    elsif @args.include? '-E'
      :cpp
    else
      :ccld
    end
  end
  def tool
    case @cmd
      when /gcc/ then 'gcc'
      when /g\+\+/ then 'g++'
    when 'clang', 'clang++'
      @cmd
    when 'ld', 'cpp', 'cc'
      ENV['HOMEBREW_CC'].chuzzle or 'clang'
    when 'c++'
      case ENV['HOMEBREW_CC']
        when /gcc/ then 'g++'
        else 'clang++'
      end
    else
      abort "Unknown command: #{@cmd}"
    end
  end
  def args
    args = if cccfg? 'O'
      refurbished_args
    else
      @args.dup
    end
    args.unshift("--sysroot=#$sdkroot") 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

    rms = @args - args
    %w{CPPFLAGS LDFLAGS CXXFLAGS CFLAGS}.each do |flag|
      unison = ENV[flag].split(' ') & rms
      puts "Warning! #{unison*' '} removed from #{flag.upcase} by superenv" unless unison.empty?
    end

    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
end

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

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