require 'os/mac'
require 'extend/ENV/shared'

### Why `superenv`?
# 1) Only specify the environment we need (NO LDFLAGS for cmake)
# 2) Only apply compiler specific options when we are calling that compiler
# 3) Force all incpaths and libpaths into the cc instantiation (less bugs)
# 4) Cater toolchain usage to specific Xcode versions
# 5) Remove flags that we don't want or that will break builds
# 6) Simpler code
# 7) Simpler formula that *just work*
# 8) Build-system agnostic configuration of the tool-chain

module Superenv
  include SharedEnvExtension

  attr_accessor :keg_only_deps, :deps, :x11
  alias_method :x11?, :x11

  def self.extended(base)
    base.keg_only_deps = []
    base.deps = []

    # Many formula assume that CFLAGS etc. will not be nil. This should be
    # a safe hack to prevent that exception cropping up. Main consequence of
    # this is that self['CFLAGS'] is never nil even when it is which can break
    # if checks, but we don't do such a check in our code. Redefinition must be
    # done on the singleton class, because in MRI all ENV methods are defined
    # on its singleton class, precluding the use of extend.
    class << base
      alias_method :"old_[]", :[]
      def [] key
        if has_key? key
          fetch(key)
        elsif %w{CPPFLAGS CFLAGS LDFLAGS}.include? key
          self[key] = ""
        end
      end
    end
  end

  def self.bin
    @bin ||= (HOMEBREW_REPOSITORY/"Library/ENV").children.reject{|d| d.basename.to_s > MacOS::Xcode.version }.max
  end

  def reset
    %w{CC CXX OBJC OBJCXX CPP MAKE LD LDSHARED
      CFLAGS CXXFLAGS OBJCFLAGS OBJCXXFLAGS LDFLAGS CPPFLAGS
      MACOS_DEPLOYMENT_TARGET SDKROOT
      CMAKE_PREFIX_PATH CMAKE_INCLUDE_PATH CMAKE_FRAMEWORK_PATH
      CPATH C_INCLUDE_PATH CPLUS_INCLUDE_PATH OBJC_INCLUDE_PATH}.
      each{ |x| delete(x) }
    delete('CDPATH') # avoid make issues that depend on changing directories
    delete('GREP_OPTIONS') # can break CMake
    delete('CLICOLOR_FORCE') # autotools doesn't like this

    # Configure scripts generated by autoconf 2.61 or later export as_nl, which
    # we use as a heuristic for running under configure
    delete('as_nl')
  end

  def setup_build_environment(formula=nil)
    reset

    self.cc  = self['HOMEBREW_CC']  = determine_cc
    self.cxx = self['HOMEBREW_CXX'] = determine_cxx
    validate_cc!(formula) unless formula.nil?
    self['DEVELOPER_DIR'] = determine_developer_dir
    self['MAKEFLAGS'] ||= "-j#{determine_make_jobs}"
    self['PATH'] = determine_path
    self['PKG_CONFIG_PATH'] = determine_pkg_config_path
    self['PKG_CONFIG_LIBDIR'] = determine_pkg_config_libdir
    self['HOMEBREW_CCCFG'] = determine_cccfg
    self['HOMEBREW_OPTIMIZATION_LEVEL'] = 'Os'
    self['HOMEBREW_BREW_FILE'] = HOMEBREW_BREW_FILE
    self['HOMEBREW_PREFIX'] = HOMEBREW_PREFIX
    self['HOMEBREW_SDKROOT'] = "#{MacOS.sdk_path}" if MacOS::Xcode.without_clt?
    self['HOMEBREW_DEVELOPER_DIR'] = determine_developer_dir # used by our xcrun shim
    self['HOMEBREW_VERBOSE'] = "1" if ARGV.verbose?
    self['HOMEBREW_OPTFLAGS'] = determine_optflags
    self['CMAKE_PREFIX_PATH'] = determine_cmake_prefix_path
    self['CMAKE_FRAMEWORK_PATH'] = determine_cmake_frameworks_path
    self['CMAKE_INCLUDE_PATH'] = determine_cmake_include_path
    self['CMAKE_LIBRARY_PATH'] = determine_cmake_library_path
    self['ACLOCAL_PATH'] = determine_aclocal_path
    self['M4'] = MacOS.locate("m4") if deps.include? "autoconf"

    # The HOMEBREW_CCCFG ENV variable is used by the ENV/cc tool to control
    # compiler flag stripping. It consists of a string of characters which act
    # as flags. Some of these flags are mutually exclusive.
    #
    # u - A universal build was requested
    # 3 - A 32-bit build was requested
    # O - Enables argument refurbishing. Only active under the
    #     make/bsdmake wrappers currently.
    # x - Enable C++11 mode.
    # g - Enable "-stdlib=libc++" for clang.
    # h - Enable "-stdlib=libstdc++" for clang.
    #
    # On 10.8 and newer, these flags will also be present:
    # s - apply fix for sed's Unicode support
    # a - apply fix for apr-1-config path

    warn_about_non_apple_gcc($1) if ENV['HOMEBREW_CC'] =~ GNU_GCC_REGEXP
  end

  private

  def determine_cc
    cc = compiler
    COMPILER_SYMBOL_MAP.invert.fetch(cc, cc)
  end

  def determine_cxx
    determine_cc.to_s.gsub('gcc', 'g++').gsub('clang', 'clang++')
  end

  def determine_path
    paths = [Superenv.bin]
    if MacOS::Xcode.without_clt?
      paths << "#{MacOS::Xcode.prefix}/usr/bin"
      paths << "#{MacOS::Xcode.prefix}/Toolchains/XcodeDefault.xctoolchain/usr/bin"
    end
    paths += deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/bin" }
    paths << MacOS::X11.bin if x11?
    paths += %w{/usr/bin /bin /usr/sbin /sbin}

    # Homebrew's apple-gcc42 will be outside the PATH in superenv,
    # so xcrun may not be able to find it
    if self['HOMEBREW_CC'] == 'gcc-4.2'
      apple_gcc42 = begin
        Formulary.factory('apple-gcc42')
      rescue Exception # in --debug, catch bare exceptions too
        nil
      end
      paths << apple_gcc42.opt_prefix/'bin' if apple_gcc42
    end

    if self['HOMEBREW_CC'] =~ GNU_GCC_REGEXP
      gcc_name = 'gcc' + $1.delete('.')
      gcc = Formulary.factory(gcc_name)
      paths << gcc.opt_prefix/'bin'
    end

    paths.to_path_s
  end

  def determine_pkg_config_path
    paths  = deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/lib/pkgconfig" }
    paths += deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/share/pkgconfig" }
    paths.to_path_s
  end

  def determine_pkg_config_libdir
    paths = %W{/usr/lib/pkgconfig #{HOMEBREW_LIBRARY}/ENV/pkgconfig/#{MacOS.version}}
    paths << "#{MacOS::X11.lib}/pkgconfig" << "#{MacOS::X11.share}/pkgconfig" if x11?
    paths.to_path_s
  end

  def determine_cmake_prefix_path
    paths = keg_only_deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}" }
    paths << HOMEBREW_PREFIX.to_s # put ourselves ahead of everything else
    paths << "#{MacOS.sdk_path}/usr" if MacOS::Xcode.without_clt?
    paths.to_path_s
  end

  def determine_cmake_frameworks_path
    paths = deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/Frameworks" }
    paths << "#{MacOS.sdk_path}/System/Library/Frameworks" if MacOS::Xcode.without_clt?
    paths.to_path_s
  end

  def determine_cmake_include_path
    sdk = MacOS.sdk_path if MacOS::Xcode.without_clt?
    paths = []
    paths << "#{sdk}/usr/include/libxml2" unless deps.include? 'libxml2'
    paths << "#{sdk}/usr/include/apache2" if MacOS::Xcode.without_clt?
    paths << "#{sdk}/System/Library/Frameworks/OpenGL.framework/Versions/Current/Headers" unless x11?
    paths << MacOS::X11.include << "#{MacOS::X11.include}/freetype2" if x11?
    paths.to_path_s
  end

  def determine_cmake_library_path
    sdk = MacOS.sdk_path if MacOS::Xcode.without_clt?
    paths = []
    # things expect to find GL headers since X11 used to be a default, so we add them
    paths << "#{sdk}/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries" unless x11?
    paths << MacOS::X11.lib if x11?
    paths.to_path_s
  end

  def determine_aclocal_path
    paths = keg_only_deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/share/aclocal" }
    paths << "#{HOMEBREW_PREFIX}/share/aclocal"
    paths << "#{MacOS::X11.share}/aclocal" if x11?
    paths.to_path_s
  end

  def determine_make_jobs
    if (j = self['HOMEBREW_MAKE_JOBS'].to_i) < 1
      Hardware::CPU.cores
    else
      j
    end
  end

  def determine_optflags
    if ARGV.build_bottle?
      arch = ARGV.bottle_arch || Hardware.oldest_cpu
      Hardware::CPU.optimization_flags.fetch(arch)
    elsif Hardware::CPU.intel? && !Hardware::CPU.sse4?
      Hardware::CPU.optimization_flags.fetch(Hardware.oldest_cpu)
    else
      "-march=native" if compiler == :clang
    end
  end

  def determine_cccfg
    s = ""
    # Fix issue with sed barfing on unicode characters on Mountain Lion
    s << 's' if MacOS.version >= :mountain_lion
    # Fix issue with >= 10.8 apr-1-config having broken paths
    s << 'a' if MacOS.version >= :mountain_lion
    s
  end

  def determine_developer_dir
    # If Xcode path is fucked then this is basically a fix. In the case where
    # nothing is valid, it still fixes most usage to supply a valid path that
    # is not "/".
    MacOS::Xcode.prefix || self['DEVELOPER_DIR']
  end

  public

  def deparallelize
    delete('MAKEFLAGS')
  end
  alias_method :j1, :deparallelize

  COMPILER_SYMBOL_MAP.values.each do |compiler|
    define_method compiler do
      @compiler = compiler
      self.cc  = self['HOMEBREW_CC']  = determine_cc
      self.cxx = self['HOMEBREW_CXX'] = determine_cxx
    end
  end

  GNU_GCC_VERSIONS.each do |n|
    define_method(:"gcc-4.#{n}") do
      @compiler = "gcc-4.#{n}"
      self.cc  = self['HOMEBREW_CC']  = determine_cc
      self.cxx = self['HOMEBREW_CXX'] = determine_cxx
    end
  end

  def make_jobs
    self['MAKEFLAGS'] =~ /-\w*j(\d)+/
    [$1.to_i, 1].max
  end

  def universal_binary
    self['HOMEBREW_ARCHFLAGS'] = Hardware::CPU.universal_archs.as_arch_flags
    append 'HOMEBREW_CCCFG', "u", ''
  end

  def cxx11
    if self['HOMEBREW_CC'] == 'clang'
      append 'HOMEBREW_CCCFG', "x", ''
      append 'HOMEBREW_CCCFG', "g", ''
    elsif self['HOMEBREW_CC'] =~ /gcc-4\.(8|9)/
      append 'HOMEBREW_CCCFG', "x", ''
    else
      raise "The selected compiler doesn't support C++11: #{self['HOMEBREW_CC']}"
    end
  end

  def libcxx
    if self['HOMEBREW_CC'] == 'clang'
      append 'HOMEBREW_CCCFG', "g", ''
    end
  end

  def libstdcxx
    if self['HOMEBREW_CC'] == 'clang'
      append 'HOMEBREW_CCCFG', "h", ''
    end
  end

  # m32 on superenv does not add any CC flags. It prevents "-m32" from being erased.
  def m32
    append 'HOMEBREW_CCCFG', "3", ''
  end

  %w{O4 O3 O2 O1 O0 Os}.each do |opt|
    define_method opt do
      self['HOMEBREW_OPTIMIZATION_LEVEL'] = opt
    end
  end

  def noop(*args); end
  noops = []

  # These methods are no longer necessary under superenv, but are needed to
  # maintain an interface compatible with stdenv.
  noops.concat %w{fast Og libxml2 x11 set_cpu_flags macosxsdk remove_macosxsdk}

  # These methods provide functionality that has not yet been ported to
  # superenv.
  noops.concat %w{m64 gcc_4_0_1 minimal_optimization no_optimization enable_warnings}

  noops.each { |m| alias_method m, :noop }
end


class Array
  def to_path_s
    map(&:to_s).uniq.select{|s| File.directory? s }.join(File::PATH_SEPARATOR).chuzzle
  end
end
