require "tmpdir"

project_name "HOS"
path_prepend "x86_64-elf-gcc/bin"

configure do
  rscons "x86_64-elf-gcc.rb", "-b", "#{build_dir}/x86_64-elf-gcc"
  check_d_compiler "ldc2", use: "ldc2"
  check_c_compiler "x86_64-w64-mingw32-gcc", use: "x86_64-w64-mingw32-gcc"
  check_c_compiler "x86_64-elf-gcc", use: "x86_64-elf-gcc"
  check_c_compiler
  check_program "mformat", on_fail: "Install the mtools package"
  check_cfg package: "freetype2", on_fail: "Install libfreetype-dev", use: "freetype"
  sh %w[git submodule update --init]
end

# Kernel default font size.
KFONT_SIZE = 18

class HulkBinObj < Builder
  def run(options)
    FileUtils.mkdir_p(File.dirname(@target))
    File.write(@target, <<EOF)
.section ".rodata"
.balign 4096
.global hulk_bin_start
hulk_bin_start:
.incbin "#{@sources.first}"
.balign 4096
.global hulk_bin_end
hulk_bin_end:
EOF
    unless @cache.up_to_date?(@target, nil, @sources, @env)
      print_run_message("Creating HULK binary object <target>#{@target}<reset>", nil)
      @cache.register_build(@target, nil, @sources, @env)
    end
    true
  end
end

class Image < Builder
  def run(options)
    unless @cache.up_to_date?(@target, nil, @sources, @env)
      print_run_message("Creating disk image <target>#{@target}<reset>", nil)
      File.binwrite(@target, "\0" * (1440 * 1024))
      system(*%W[mformat -i #{@target} -f 1440 ::])
      system(*%W[mmd -i #{@target} ::/EFI])
      system(*%W[mmd -i #{@target} ::/EFI/BOOT])
      system(*%W[mcopy -i #{@target} #{@sources.first} ::/EFI/BOOT])
      @cache.register_build(@target, nil, @sources, @env)
    end
    true
  end
end

class FontGen < Builder
  def run(options)
    if @command
      finalize_command
    else
      fontgen = @vars["fontgen"]
      @sources += [fontgen]
      command = %W[#{fontgen} #{@sources.first} #{KFONT_SIZE} #{@target}]
      standard_command("FontGen <target>#{@target}<reset>", command, {})
    end
  end
end

fontgen_env = env "fontgen", use: "freetype" do |env|
  env.Program("^/fontgen", glob("src/fontgen/**/*.c"))
end

hulk_env = env "hulk", use: %w[ldc2 x86_64-elf-gcc] do |env|
  env.add_builder(FontGen)
  env.FontGen("^/src/hulk/kfont.d", "font/Hack-Regular.ttf",
              "fontgen" => fontgen_env.expand("^/fontgen"))
  env["sources"] = glob("src/hulk/**/*.d")
  env["sources"] << "^/src/hulk/kfont.d"
  env["DFLAGS"] += %w[-mtriple=x86_64-unknown-elf --betterC -release -O3 --wi --enable-cross-module-inlining -code-model=large]
  env["D_IMPORT_PATH"] += %w[src]
  env["D_IMPORT_PATH"] << env.expand("^/src")
  env["LD"] = "x86_64-elf-gcc"
  env["LDFLAGS"] += %w[-nostdlib -Tsrc/hulk/hulk.ld -Wl,-Map,${_TARGET}.map]
  env["LDCMD"] = %w[${LD} -o ${_TARGET} ${LDFLAGS} ${_SOURCES} ${LIBDIRPREFIX}${LIBPATH} ${LIBLINKPREFIX}${LIBS}]
  env["OBJDUMP"] = "x86_64-elf-objdump"
  env["OBJCOPY"] = "x86_64-elf-objcopy"
  env.Program("^/hulk.elf", "${sources}")
  env.depends("^/hulk.elf", "src/hulk/hulk.ld")
  env["SIZE"] = "x86_64-elf-size"
  env.Size("^/hulk.size", "^/hulk.elf")
  env.Disassemble("^/hulk.txt", "^/hulk.elf")
  env.Command("^/hulk.bin", "^/hulk.elf",
              "CMD" => %W[${OBJCOPY} -O binary ${_SOURCES} ${_TARGET}],
              "CMD_DESC" => "Convert ELF to binary:")
  env.add_build_hook do |builder|
    if builder.target.end_with?(".o")
      env.Disassemble("#{builder.target}.txt", builder.target)
    end
  end
end

hello_env = env "hello", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
  env.add_builder(Image)
  env.add_builder(HulkBinObj)
  env["sources"] = glob("src/hello/**/*.d")
  env["sources"] += glob("uefi-d/source/**/*.d")
  env.HulkBinObj("^/hulk_bin.S", hulk_env.expand("^/hulk.bin"))
  env.Object("^/hulk_bin.o", "^/hulk_bin.S")
  env.depends("^/hulk_bin.o", hulk_env.expand("^/hulk.bin"))
  env["sources"] << "^/hulk_bin.o"
  env["DFLAGS"] += %w[-mtriple=x86_64-unknown-windows-coff --betterC -release -O3 --wi --enable-cross-module-inlining]
  env["D_IMPORT_PATH"] += %w[src uefi-d/source]
  env["LD"] = "x86_64-w64-mingw32-gcc"
  env["LDFLAGS"] += %w[-nostdlib -Wl,-dll -shared -Wl,--subsystem,10 -e efi_main -Wl,-Map,${_TARGET}.map]
  env["LDCMD"] = %w[${LD} -o ${_TARGET} ${LDFLAGS} ${_SOURCES} ${LIBDIRPREFIX}${LIBPATH} ${LIBLINKPREFIX}${LIBS}]
  env["OBJDUMP"] = "x86_64-w64-mingw32-objdump"
  env.Program("^/BOOTX64.EFI", "${sources}")
  env["SIZE"] = "x86_64-w64-mingw32-size"
  env.Size("^/BOOTX64.size", "^/BOOTX64.EFI")
  env.Disassemble("^/BOOTX64.txt", "^/BOOTX64.EFI")
  env.Image("^/hos.img", "^/BOOTX64.EFI")
end

task "run", desc: "Run HOS in QEMU" do
  Dir.mktmpdir do |tmpdir|
    img = hello_env.expand("^/hos.img")
    FileUtils.cp(img, tmpdir)
    sh %W[qemu-system-x86_64 -bios OVMF.fd -drive file=#{tmpdir}/hos.img,format=raw]
  end
end