# 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'

STAGES = Dir.glob('boot/stage*')
  .collect { |stage| File.basename stage }
  .sort { |a, b| a.delete_prefix('stage').to_i <=> b.delete_prefix('stage').to_i }
  .drop(1) # First assembly stage does not count.

CLOBBER.include 'build'

def run(exe)
  ENV.fetch('QEMU', '').split << exe
end

directory 'build'

task :default do
  Rake::Task["build/valid/#{STAGES.last}/cl"].invoke
  Rake::Task["boot"].invoke
end

desc 'Final stage'
task boot: "build/valid/#{STAGES.last}/cl"
task boot: "boot/#{STAGES.last}/cl.elna" do |t|
  groupped = t.prerequisites.group_by { |stage| File.extname stage }.transform_values(&:first)
  exe = groupped['']
  expected = groupped[''] + '.s'
  source = groupped['.elna']

  cat_arguments = ['cat', source]
  diff_arguments = ['diff', '-Nur', '--text', expected, '-']
  Open3.pipeline(cat_arguments, run(exe), diff_arguments)
end

namespace :stage do
  stage_number = STAGES.last.delete_prefix('stage').to_i

  desc 'Create a new stabe by duplicating the last one'
  task :new do
    new_stage = "stage#{stage_number.succ}"
    cp_r "boot/stage#{stage_number}", "boot/#{new_stage}"
    STAGES << new_stage
    Rake::Task['ninja'].invoke
  end

  desc 'Delete the last stage'
  task :drop do
    rm_r "boot/stage#{stage_number}"
    STAGES.pop
    Rake::Task['ninja'].invoke
  end

  desc 'Convert previous stage language into the current stage language'
  task :convert do
    from = "boot/stage#{stage_number.pred}/cl.elna"
    to = "boot/stage#{stage_number}/cl.elna"
    puts "Converting #{from} to #{to}."

    File.open(to, 'w') do |current_stage|
      File.readlines(from).each do |line|
        current_stage << line
      end
    end
  end
end