exit(0) if ENV["USE_SYSTEM_LIBYAJL2"]

require 'rbconfig'
require 'fileutils'
require 'mkmf'

module Libyajl2Build
  class BuildError < StandardError; end

  LIBYAJL2_VENDOR_DIR = File.expand_path("../vendor/yajl", __FILE__).freeze

  PREFIX = File.expand_path("../../../lib/libyajl2/vendored-libyajl2", __FILE__).freeze

  def self.windows?
    !!(RUBY_PLATFORM =~ /mswin|mingw|windows/)
  end

  def self.libyajl2_vendor_dir
    LIBYAJL2_VENDOR_DIR
  end

  def self.prefix
    PREFIX
  end

  def self.setup_env
    RbConfig::MAKEFILE_CONFIG['CC'] = ENV['CC'] if ENV['CC']

    # set some sane defaults
    if RbConfig::MAKEFILE_CONFIG['CC'] =~ /gcc|clang/
      # magic flags copied from upstream yajl build system (-std=c99 is necessary for older gcc)
      $CFLAGS << " -std=c99 -pedantic -Wpointer-arith -Wno-format-y2k -Wstrict-prototypes -Wmissing-declarations -Wnested-externs -Wextra  -Wundef -Wwrite-strings -Wold-style-definition -Wredundant-decls -Wno-unused-parameter -Wno-sign-compare -Wmissing-prototypes"
      $CFLAGS << " -O2"  # match what the upstream uses for optimization

      # create the implib on windows
      if windows?
        $LDFLAGS << " -Wl,--export-all-symbols -Wl,--enable-auto-import -Wl,--out-implib=libyajl.dll.a"
      end
    end

    $CFLAGS << " -DNDEBUG"


    # ENV vars can override everything
    $CFLAGS = ENV['CFLAGS'] if ENV['CFLAGS']
    $LDFLAGS = ENV['LDFLAGS'] if ENV['LDFLAGS']

    if windows?
      # on windows this will try to spit out a *.def that exports Init_libyajl which is wrong, we aren't a ruby lib, so we
      # will never export that.
      RbConfig::MAKEFILE_CONFIG['DLDFLAGS'].gsub!(/\$\(DEFFILE\)/, '')
    end
  end

  def self.makemakefiles
    setup_env
    dir_config("libyajl")
    create_makefile("libyajl")

    # we cheat and build it right away...
    system("make V=1")
    # ...so we can hack up what install does later and copy over the include files

    File.open("Makefile", "w+") do |f|
      f.write <<EOF
TARGET = libyajl
DLLIB = $(TARGET).#{RbConfig::MAKEFILE_CONFIG['DLEXT']}
all:

install:
\tmkdir -p #{prefix}/lib
\tcp $(DLLIB) #{prefix}/lib
\tmkdir -p #{prefix}/include/yajl
\tcp yajl/*.h #{prefix}/include/yajl
EOF
    end
  end
end

Libyajl2Build.makemakefiles