require 'mkmf'
require 'erb'
require 'rubygems'
require 'sane'

# re-build google's lib locally...

dir = Dir.pwd
Dir.chdir 'sparsehash-1.8.1' do
  dir = dir + '/local_installed'
  # only if haven't already built it...except who installing a gem would ever have it already there? reinstallers?
  unless File.directory?(dir)
    puts 'building local copy/version of google sparse/dense hash library'
    configure = "sh configure --prefix=#{dir}"
    puts configure
    system configure
    system "make"
    system "make install"
  end
end

$CFLAGS += " -I./local_installed/include "
$CPPFLAGS += " -I./local_installed/include "

if RUBY_VERSION < '1.9'
  # appears to link using gcc on 1.8 [mingw at least]
  $LDFLAGS += " -lstdc++ "
end

# create our files...

if OS.bits == 32
  unreachable_int = 31
  unreachable_long = 31
else
  unreachable_int = 31
  unreachable_long = 63
end

ruby_key =  {:convert_keys_from_ruby => "", :convert_keys_to_ruby => "", :key_type => "VALUE", :english_key_type => "ruby",
  :extra_hash_params => ", hashrb, eqrb", :unreachable_key => "current_instance"}
  
int_key = {:assert_key_type => 'T_FIXNUM', :convert_keys_from_ruby => "FIX2INT",
  :convert_keys_to_ruby => "INT2FIX", :key_type => "int", :unreachable_key => "1<<#{unreachable_int}"}
  
# "long" is useful on 64 bit...since it can handle a wider range of incoming int's

long_key = {:assert_key_type => 'T_FIXNUM', :convert_keys_from_ruby => "FIX2LONG",
  :convert_keys_to_ruby => "LONG2FIX", :key_type => "long", :unreachable_key => "1<<#{unreachable_long}"}

# currently "big numbers" we handle by storing them as a double
# TODO floats [does ruby do real doubles underneath?] too
bignum_as_double_key = {:assert_key_type => ['T_BIGNUM', 'T_FIXNUM'], :convert_keys_from_ruby => "rb_big2dbl",
  :convert_keys_to_ruby => "rb_dbl2big", :key_type => "double", :unreachable_key => "1<<#{unreachable_long}",  # LODO is this a bignum value though? LODO TEST this key on 64 bit!
  #:extra_hash_params => ", hashdouble, eqdouble", # these methods provided natively these days?
  :extra_set_code => "if(TYPE(set_this) == T_FIXNUM)\nset_this = rb_int2big(FIX2INT(set_this));",
  :extra_get_code => "if(TYPE(get_this) == T_FIXNUM) \n get_this = rb_int2big(FIX2INT(get_this));"
}

ruby_value = {:value_type => "VALUE", :english_value_type => "ruby"}
int_value = {:assert_value_type => 'T_FIXNUM', :convert_values_from_ruby => "FIX2INT",
  :convert_values_to_ruby => "INT2FIX", :value_type => "int"}
long_value = {:assert_value_type => 'T_FIXNUM', :convert_values_from_ruby => "FIX2LONG",
  :convert_values_to_ruby => "LONG2FIX", :value_type => "long"}
  
bignum_as_double_value = {:assert_value_type => ['T_BIGNUM', 'T_FIXNUM'], :convert_values_from_ruby => "rb_big2dbl",
  :convert_values_to_ruby => "rb_dbl2big", :value_type => "double",
  :extra_set_code2 => "if(TYPE(to_this) == T_FIXNUM)\nto_this = rb_int2big(FIX2INT(to_this));"
}

init_funcs = []

for key in [ruby_key, int_key, bignum_as_double_key, long_key] do
  for value in [ruby_value, int_value, long_value, bignum_as_double_value] do
    options = key.merge(value)
    for type in ['sparse', 'dense'] do

      # create local variables so that the template can look cleaner
      unreachable_key = options[:unreachable_key]
      convert_keys_from_ruby = options[:convert_keys_from_ruby]
      convert_keys_to_ruby = options[:convert_keys_to_ruby]
      key_type = options[:key_type]
      value_type = options[:value_type]
      english_key_type = options[:english_key_type] || options[:key_type]
      english_value_type = options[:english_value_type] || options[:value_type]

      
      assert_key_type = [options[:assert_key_type]].flatten[0]
      assert_key_type2 = [options[:assert_key_type]].flatten[1]
      convert_values_from_ruby = options[:convert_values_from_ruby]
      convert_values_to_ruby = options[:convert_values_to_ruby]
      assert_value_type = [options[:assert_value_type]].flatten[0]
      assert_value_type2 = [options[:assert_value_type]].flatten[1]

      extra_hash_params = options[:extra_hash_params]
      
      template = ERB.new(File.read('template/google_hash.cpp.erb'))
      descriptor = type + '_' + english_key_type + '_to_' + english_value_type;
      File.write(descriptor + '.cpp', template.result(binding))
      init_funcs << "init_" + descriptor
    end
  end
end

# write our Init method

template = ERB.new(File.read('template/main.cpp.erb'))
File.write 'main.cpp', template.result(binding)

Config::CONFIG['CPP'] = "g++ -E" # else cannot check for c++ headers? huh wuh?
have_header('tr1/functional')

if have_header('functional') && OS.x?
  $CPPFLAGS += " -std=c++11 -stdlib=libc++ " # LLVM, no idea what I'm doing here...
end

create_makefile('google_hash')