# 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

require 'open3'
require 'rake/clean'
require 'term/ansicolor'

CLOBBER.include 'build'

CROSS_GCC = '../riscv32-ilp32d--glibc/bin/riscv32-linux-gcc'
SYSROOT = '../riscv32-ilp32d--glibc/riscv32-buildroot-linux-gnu/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

desc 'Final stage'
task default: ['build/stage2b', 'build/stage2b.s', 'boot/stage2.elna'] do |t|
  exe, previous_output, source = t.prerequisites

  cat_arguments = ['cat', source]
  compiler_arguments = [QEMU, '-L', SYSROOT, exe]
  diff_arguments = ['diff', '-Nur', '--text', previous_output, '-']
  Open3.pipeline(cat_arguments, compiler_arguments, diff_arguments)
end

directory 'build'

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

  file target_object.to_s => [assembly_source, 'build'] do |t|
    sh CROSS_GCC, '-c', '-o', t.name, assembly_source
  end
end

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

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

file 'build/stage2b.s' => ['build/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