class MRuby::Toolchain::Android

DEFAULT_ARCH = 'armeabi' # TODO : Revise if arch should have a default

DEFAULT_TOOLCHAIN = :clang

DEFAULT_NDK_HOMES = %w{
  /usr/local/opt/android-sdk/ndk-bundle
  /usr/local/opt/android-ndk
  ~/Android/Sdk/ndk-bundle
  %LOCALAPPDATA%/Android/android-sdk/ndk-bundle
  %LOCALAPPDATA%/Android/android-ndk
  ~/Library/Android/sdk/ndk-bundle
  ~/Library/Android/ndk
}

TOOLCHAINS = [:clang, :gcc]

ARCHITECTURES = %w{
  armeabi armeabi-v7a arm64-v8a
  x86 x86_64
  mips mips64
}

class AndroidNDKHomeNotFound < StandardError
  def message
      <<-EOM

Couldn't find Android NDK Home. Set ANDROID_NDK_HOME environment variable or set :ndk_home parameter

      EOM
  end
end

class PlatformDirNotFound < StandardError
  def message
      <<-EOM

Couldn't find Android NDK platform directories. Set ANDROID_PLATFORM environment variable or set :platform parameter

      EOM
  end
end

attr_reader :params

def initialize(params)
  @params = params
end

def bin_gcc(command)
  command = command.to_s

  command = case arch
    when /armeabi/    then 'arm-linux-androideabi-'
    when /arm64-v8a/  then 'aarch64-linux-android-'
    when /x86_64/     then 'x86_64-linux-android-'
    when /x86/        then 'i686-linux-android-'
    when /mips64/     then 'mips64el-linux-android-'
    when /mips/       then 'mipsel-linux-android-'
    end + command

  gcc_toolchain_path.join('bin', command).to_s
end

def bin(command)
  command = command.to_s
  toolchain_path.join('bin', command).to_s
end

def home_path
  @home_path ||= Pathname(
    params[:ndk_home] ||
    ENV['ANDROID_NDK_HOME'] ||
    DEFAULT_NDK_HOMES.find { |path|
      path.gsub! '%LOCALAPPDATA%', ENV['LOCALAPPDATA'] || '%LOCALAPPDATA%'
      path.gsub! '\\', '/'
      path.gsub! '~', Dir.home || '~'
      File.directory?(path)
    } || raise(AndroidNDKHomeNotFound)
  )
end

def toolchain
  @toolchain ||= params.fetch(:toolchain){ DEFAULT_TOOLCHAIN }
end

def toolchain_path
  @toolchain_path ||= case toolchain
    when :gcc
      gcc_toolchain_path
    when :clang
      home_path.join('toolchains', 'llvm' , 'prebuilt', host_platform)
    end
end

def gcc_toolchain_path
  if @gcc_toolchain_path === nil then
    prefix = case arch
      when /armeabi/    then 'arm-linux-androideabi-'
      when /arm64-v8a/  then 'aarch64-linux-android-'
      when /x86_64/     then 'x86_64-'
      when /x86/        then 'x86-'
      when /mips64/     then 'mips64el-linux-android-'
      when /mips/       then 'mipsel-linux-android-'
      end

    test = case arch
      when /armeabi/    then 'arm-linux-androideabi-*'
      when /arm64-v8a/  then 'aarch64-linux-android-*'
      when /x86_64/     then 'x86_64-*'
      when /x86/        then 'x86-*'
      when /mips64/     then 'mips64el-linux-android-*'
      when /mips/       then 'mipsel-linux-android-*'
      end

    gcc_toolchain_version = Dir[home_path.join('toolchains', test)].map{|t| t.match(/-(\d+\.\d+)$/); $1.to_f }.max
    @gcc_toolchain_path = home_path.join('toolchains', prefix + gcc_toolchain_version.to_s, 'prebuilt', host_platform)
  end
  @gcc_toolchain_path
end

def host_platform
  @host_platform ||= case RUBY_PLATFORM
    when /cygwin|mswin|mingw|bccwin|wince|emx/i
      path = home_path.join('toolchains', 'llvm' , 'prebuilt', 'windows*')
      Dir.glob(path.to_s){ |item|
        next if File.file?(item)
        path = Pathname(item)
        break
      }
      path.basename
    when /x86_64-darwin/i
      'darwin-x86_64'
    when /darwin/i
      'darwin-x86'
    when /x86_64-linux/i
      'linux-x86_64'
    when /linux/i
      'linux-x86'
    else
      raise NotImplementedError, "Unknown host platform (#{RUBY_PLATFORM})"
    end
end

def arch
  @arch ||= (params[:arch] || ENV['ANDROID_ARCH'] || DEFAULT_ARCH).to_s
end

def sysroot
  @sysroot ||= home_path.join('platforms', platform,
      case arch
      when /armeabi/    then 'arch-arm'
      when /arm64-v8a/  then 'arch-arm64'
      when /x86_64/     then 'arch-x86_64'
      when /x86/        then 'arch-x86'
      when /mips64/     then 'arch-mips64'
      when /mips/       then 'arch-mips'
      end
    ).to_s
end

def platform
  if @platform === nil then
    @platform = params[:platform] || ENV['ANDROID_PLATFORM'] || nil
    if @platform === nil
      Dir.glob(home_path.join('platforms/android-*').to_s){ |item|
        next if File.file?(item)
        if @platform === nil
          @platform = Integer(item.rpartition('-')[2])
        else
          platform = Integer(item.rpartition('-')[2])
          @platform = platform > @platform ? platform : @platform
        end
      }
      if @platform === nil
        raise(PlatformDirNotFound)
      else
        @platform = "android-#{@platform}"
      end
    end
  end
  if Integer(@platform.rpartition('-')[2]) < 21
    case arch
    when /arm64-v8a/, /x86_64/, /mips64/
      raise NotImplementedError, "Platform (#{@platform}) has no implementation for architecture (#{arch})"
    end
  end
  @platform
end

def armeabi_v7a_mfpu
  @armeabi_v7a_mfpu ||= (params[:mfpu] || 'vfpv3-d16').to_s
end

def armeabi_v7a_mfloat_abi
  @armeabi_v7a_mfloat_abi ||= (params[:mfloat_abi] || 'softfp').to_s
end

def no_warn_mismatch
  if %W(soft softfp).include? armeabi_v7a_mfloat_abi
    ''
  else
    ',--no-warn-mismatch'
  end
end

def cc
  case toolchain
  when :gcc then bin_gcc('gcc')
  when :clang then bin('clang')
  end
end

def ar
  case toolchain
  when :gcc   then bin_gcc('ar')
  when :clang then bin_gcc('ar')
  end
end

def ctarget
  flags = []

  case toolchain
  when :gcc
    case arch
    when /armeabi-v7a/  then flags += %W(-march=armv7-a)
    when /armeabi/      then flags += %W(-march=armv5te)
    when /arm64-v8a/    then flags += %W(-march=armv8-a)
    when /x86_64/       then flags += %W(-march=x86-64)
    when /x86/          then flags += %W(-march=i686)
    when /mips64/       then flags += %W(-march=mips64r6)
    when /mips/         then flags += %W(-march=mips32)
    end
  when :clang
    case arch
    when /armeabi-v7a/  then flags += %W(-target armv7-none-linux-androideabi)
    when /armeabi/      then flags += %W(-target armv5te-none-linux-androideabi)
    when /arm64-v8a/    then flags += %W(-target aarch64-none-linux-android)
    when /x86_64/       then flags += %W(-target x86_64-none-linux-android)
    when /x86/          then flags += %W(-target i686-none-linux-android)
    when /mips64/       then flags += %W(-target mips64el-none-linux-android)
    when /mips/         then flags += %W(-target mipsel-none-linux-android)
    end
  end

  case arch
  when /armeabi-v7a/  then flags += %W(-mfpu=#{armeabi_v7a_mfpu} -mfloat-abi=#{armeabi_v7a_mfloat_abi})
  when /armeabi/      then flags += %W(-mtune=xscale -msoft-float)
  when /arm64-v8a/    then flags += %W()
  when /x86_64/       then flags += %W()
  when /x86/          then flags += %W()
  when /mips64/       then flags += %W(-fmessage-length=0)
  when /mips/         then flags += %W(-fmessage-length=0)
  end

  flags
end

def cflags
  flags = []

  flags += %W(-MMD -MP -D__android__ -DANDROID --sysroot="#{sysroot}")
  flags += ctarget
  case toolchain
  when :gcc
  when :clang
    flags += %W(-gcc-toolchain "#{gcc_toolchain_path}" -Wno-invalid-command-line-argument -Wno-unused-command-line-argument)
  end
  flags += %W(-fpic -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes)

  flags
end

def ldflags
  flags = []

  flags += %W(--sysroot="#{sysroot}")

  flags
end

def ldflags_before_libraries
  flags = []

  case toolchain
  when :gcc
    case arch
    when /armeabi-v7a/  then flags += %W(-Wl#{no_warn_mismatch})
    end
  when :clang
    flags += %W(-gcc-toolchain "#{gcc_toolchain_path.to_s}")
    case arch
    when /armeabi-v7a/  then flags += %W(-target armv7-none-linux-androideabi -Wl,--fix-cortex-a8#{no_warn_mismatch})
    when /armeabi/      then flags += %W(-target armv5te-none-linux-androideabi)
    when /arm64-v8a/    then flags += %W(-target aarch64-none-linux-android)
    when /x86_64/       then flags += %W(-target x86_64-none-linux-android)
    when /x86/          then flags += %W(-target i686-none-linux-android)
    when /mips64/       then flags += %W(-target mips64el-none-linux-android)
    when /mips/         then flags += %W(-target mipsel-none-linux-android)
    end
  end
  flags += %W(-no-canonical-prefixes)

  flags
end

end

MRuby::Toolchain.new(:android) do |conf, params|

android = MRuby::Toolchain::Android.new(params)

toolchain android.toolchain

[conf.cc, conf.cxx, conf.objc, conf.asm].each do |cc|
  cc.command = android.cc
  cc.flags = android.cflags
end

conf.archiver.command = android.ar
conf.linker.command = android.cc
conf.linker.flags = android.ldflags
conf.linker.flags_before_libraries = android.ldflags_before_libraries

end