require "mkmf"

if RUBY_VERSION < '1.9'
  raise NotImplementedError, "Sorry, you need at least Ruby 1.9!"
end

# Function derived from NArray's extconf.rb.
def create_conf_h(file) #:nodoc:
  print "creating #{file}\n"
  File.open(file, 'w') do |hfile|
    header_guard = file.upcase.sub(/\s|\./, '_')

    hfile.puts "#ifndef #{header_guard}"
    hfile.puts "#define #{header_guard}"
    hfile.puts

    # FIXME: Find a better way to do this:
    hfile.puts "#define RUBY_2 1" if RUBY_VERSION >= '2.0'

    for line in $defs
      line =~ /^-D(.*)/
      hfile.printf "#define %s 1\n", $1
    end

    hfile.puts
    hfile.puts "#endif"
  end
end

def find_newer_gplusplus #:nodoc:
  print "checking for apparent GNU g++ binary with C++0x/C++11 support... "
  [9,8,7,6,5,4,3].each do |minor|
    ver = "4.#{minor}"
    gpp = "g++-#{ver}"
    result = `which #{gpp}`
    next if result.empty?
    CONFIG['CXX'] = gpp
    puts ver
    return CONFIG['CXX']
  end
  false
end

def gplusplus_version
  cxxvar = proc { |n| `#{CONFIG['CXX']} -E -dM - <#{File::NULL} | grep #{n}`.chomp.split(' ')[2] }
  major = cxxvar.call('__GNUC__')
  minor = cxxvar.call('__GNUC_MINOR__')
  patch = cxxvar.call('__GNUC_PATCHLEVEL__')

  raise("unable to determine g++ version (match to get version was nil)") if major.nil? || minor.nil? || patch.nil?

  "#{major}.#{minor}.#{patch}"
end


if /cygwin|mingw/ =~ RUBY_PLATFORM
  CONFIG["DLDFLAGS"] << " --output-lib libnmatrix.a"
end

# Fix compiler pairing
if CONFIG['CC'] == 'clang' && CONFIG['CXX'] != 'clang++'
  puts "WARNING: CONFIG['CXX'] is not 'clang++' even though CONFIG['CC'] is 'clang'.",
       "WARNING: Force to use clang++ together with clang."

  CONFIG['CXX'] = 'clang++'
end

if CONFIG['CXX'] == 'clang++'
  $CXX_STANDARD = 'c++11'
else
  version = gplusplus_version
  if version < '4.3.0' && CONFIG['CXX'] == 'g++'  # see if we can find a newer G++, unless it's been overridden by user
    if !find_newer_gplusplus
      raise("You need a version of g++ which supports -std=c++0x or -std=c++11. If you're on a Mac and using Homebrew, we recommend using mac-brew-gcc.sh to install a more recent g++.")
    end
    version = gplusplus_version
  end

  if version < '4.7.0'
    $CXX_STANDARD = 'c++0x'
  else
    $CXX_STANDARD = 'c++11'
  end
  puts "using C++ standard... #{$CXX_STANDARD}"
  puts "g++ reports version... " + `#{CONFIG['CXX']} --version|head -n 1|cut -f 3 -d " "`
end

# For release, these next two should both be changed to -O3.
$CFLAGS += " -O3 "
#$CFLAGS += " -static -O0 -g "
$CXXFLAGS += " -O3 -std=#{$CXX_STANDARD} " #-fmax-errors=10 -save-temps
#$CXXFLAGS += " -static -O0 -g -std=#{$CXX_STANDARD} "

if CONFIG.has_key?('warnflags')
  CONFIG['warnflags'].gsub!('-Wshorten-64-to-32', '') # doesn't work except in Mac-patched gcc (4.2)
  CONFIG['warnflags'].gsub!('-Wdeclaration-after-statement', '')
  CONFIG['warnflags'].gsub!('-Wimplicit-function-declaration', '')
end
  
have_func("rb_array_const_ptr", "ruby.h")