require 'mkmf'

using_cached_files = enable_config('cached-files')
if using_cached_files then
  # if --enable-cached-files was specified on the command line, then use cached
  # files
  USING_CACHED_FILES = true
else
  ruby_source_path = arg_config('--ruby-source-path')
  if ruby_source_path.nil? then
    class SetupError < StandardError; end

    # if the user did not specify the source dir, then see if we have one
    # configured
    begin
      require 'ruby_source_dir'
      # if we got here, then we successfuly loaded the configuration
    rescue SetupError
      # otherwise, assume we are using cached files
      USING_CACHED_FILES = true
    end
  else
    # the user did specify the source path
    USING_CACHED_FILES = false
    RUBY_SOURCE_DIR = ruby_source_path
  end
end

def create_ruby_internal_makefile(name)
  rb_files = Dir['*.rb']
  rpp_files = Dir['*.rpp']
  generated_files = rpp_files.map { |f| f.sub(/\.rpp$/, '') }

  # Append the generated C files to the list of source files
  srcs = Dir['*.c']
  generated_files.each do |f|
    if f =~ /\.c$/ then
      srcs << f
    end
  end
  srcs.uniq!
  $objs = srcs.map { |f| f.sub(/\.c$/, ".#{$OBJEXT}") }

  # Turn on warnings and debugging by default on gcc
  if CONFIG['CC'] == 'gcc' then
    $CFLAGS << ' -Wall -g'
  end

  create_makefile(name)

  append_to_makefile = ''

  base_dir = File.dirname(__FILE__)

  if USING_CACHED_FILES then

    subdir = File.expand_path(File.dirname($0))
    subdir = subdir.gsub(File.expand_path(base_dir), '')
    cached_dir = File.join('cached', "ruby-#{RUBY_VERSION}")

    # -- Using cached files --
    rpp_files.each do |rpp_file|
      dest_file = rpp_file.sub(/\.rpp$/, '')
      src_file = File.join(base_dir, cached_dir, subdir, File.basename(dest_file))
      append_to_makefile << <<END
#{dest_file}: #{src_file}
\t@$(RUBY) -e 'begin; require "fileutils"; rescue LoadError; require "ftools"; FileUtils = File end; FileUtils.copy("#{src_file}", ".", :verbose => true)'
END
    end
  else
    # -- Generating files --
    rpp_files.each do |rpp_file|
      dest_file = rpp_file.sub(/\.rpp$/, '')
      append_to_makefile << <<END
#{dest_file}: #{rpp_file} #{rb_files.join(' ')}
\trubypp #{rpp_file} #{dest_file}
END
    end

  end

  # Dependencies
  # TODO: we could be smarter about this
  generated_headers = generated_files.select { |x| x =~ /\.h$/ }
  generated_incs = generated_files.select { |x| x =~ /\.inc$/ }
  append_to_makefile << <<END
$(OBJS): #{generated_headers.join(' ')} #{generated_incs.join(' ')}
clean: clean_generated_files
clean_generated_files:
\t@$(RM) #{generated_files.join(' ')}
generated_files: #{generated_files.join(' ')}
END

  # Append it all to the makefile
  File.open('Makefile', 'a') do |makefile|
    makefile.puts(append_to_makefile)
  end
end

base_dir = File.dirname(__FILE__)
$CPPFLAGS.gsub!(/^/, "-I#{base_dir} ")

ruby_version_code = RUBY_VERSION.gsub(/\./, '').to_i
if ruby_version_code >= 190 then
  if USING_CACHED_FILES then
    $CPPFLAGS.gsub!(/^/, "-I#{base_dir}/internal/yarv-headers ")
  else
    $CPPFLAGS.gsub!(/^/, "-I#{RUBY_SOURCE_DIR} ")
  end
end

module Kernel
  if not method_defined?(:try_const)
    alias_method :try_const, :try_constant
  end

  if not method_defined?(:checking_message)
    def checking_message(checking_for, headers = nil, opt = "")
      return checking_for
    end
  end

  if not method_defined?(:have_const)
    def have_const(const, headers = nil, opt = "", &b)
      checking_for checking_message([*const].compact.join(' '), headers, opt) do
        try_const(const, headers, opt, &b)
      end
    end
  end
end