# This Source Code Form is subject to the terms of the Mozilla Public License,
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at https://mozilla.org/MPL/2.0/. -}
# frozen_string_literal: true

CROSS_GCC = 'build/rootfs/bin/riscv32-unknown-linux-gnu-gcc'
SYSROOT = 'build/sysroot'
QEMU = 'qemu-riscv32'

def assemble_stage(output, compiler, source)
  arguments = [QEMU, '-L', SYSROOT, *compiler]

  puts Term::ANSIColor.green(arguments * ' ')
  puts
  Open3.popen2(*arguments) do |qemu_in, qemu_out|
    qemu_in.write File.read(*source)
    qemu_in.close

    IO.copy_stream qemu_out, output
    qemu_out.close
  end
end

library = []

Dir.glob('boot/*.s').each do |assembly_source|
  source_basename = Pathname.new(assembly_source).basename
  target_object = Pathname.new('build/boot') + source_basename.sub_ext('.o')

  file target_object.to_s => [assembly_source, 'build/boot'] do |t|
    sh CROSS_GCC, '-c', '-o', t.name, assembly_source
  end
  library << assembly_source unless source_basename.to_s.start_with? 'stage'
end

desc 'Initial stage'
file 'build/boot/stage1' => ['build/boot/stage1.o', *library] do |t|
  sh CROSS_GCC, '-nostdlib', '-o', t.name, *t.prerequisites
end

file 'build/boot/stage2a.s' => ['build/boot/stage1', 'boot/stage2.elna'] do |t|
  source, exe = t.prerequisites.partition { |prerequisite| prerequisite.end_with? '.elna' }

  File.open t.name, 'w' do |output|
    assemble_stage output, exe, source
  end
end

['build/boot/stage2a', 'build/boot/stage2b'].each do |exe|
  file exe => [exe.ext('.s'), *library] do |t|
    sh CROSS_GCC, '-nostdlib', '-o', t.name, *t.prerequisites
  end
end

file 'build/boot/stage2b.s' => ['build/boot/stage2a', 'boot/stage2.elna'] do |t|
  source, exe = t.prerequisites.partition { |prerequisite| prerequisite.end_with? '.elna' }

  File.open t.name, 'w' do |output|
    assemble_stage output, exe, source
  end
end