require 'pathname'
require 'rake/clean'
require 'open3'

M2C = 'gm2' # Modula-2 compiler.
BOOT_OBJECTS = FileList['boot/*.mod']
  .map do |file|
    File.join('build', Pathname.new(file).sub_ext('.o'))
  end

directory 'build/boot'

CLEAN.include 'build'

rule(/build\/boot\/.+\.o$/ => ->(file) { test_for_out(file) }) do |t|
  sources = t.prerequisites.filter { |f| f.end_with? '.mod' }

  sh M2C, '-c', '-I', 'boot', '-o', t.name, *sources
end

file 'build/boot/Compiler.o' => ['build/boot', 'boot/Compiler.mod'] do |t|
  sources = t.prerequisites.filter { |f| f.end_with? '.mod' }

  sh M2C, '-fscaffold-main', '-c', '-I', 'boot', '-o', t.name, *sources
end

file 'build/boot/Compiler' => BOOT_OBJECTS do |t|
  sh M2C, '-o', t.name, *t.prerequisites
end

task default: 'build/boot/Compiler'
task :default do |t|
  sh t.prerequisites.first
end

def test_for_out(out_file)
  path = Pathname.new(out_file).relative_path_from('build')
  implementation = path.sub_ext('.mod').to_path
  definition = path.sub_ext('.def').to_path

  ['build/boot', implementation, definition]
end

DFLAGS = ['--warn-no-deprecated', '-L/usr/lib64/gcc-12']
BINARY = 'build/bin/elna'
TESTS = FileList['tests/*.eln'].flat_map do |test|
  build = Pathname.new 'build'
  test_basename = Pathname.new(test).basename('')

  [build + 'riscv' + test_basename].map { |path| path.sub_ext('').to_path }
end

SOURCES = FileList['source/**/*.d']

rule(/build\/riscv\/.+\.o$/ => ->(file) { test_for_object(file, '.eln') }) do |t|
  Pathname.new(t.name).dirname.mkpath
  sh BINARY, '-o', t.name, t.source
end

file BINARY => SOURCES do |t|
  sh({ 'DFLAGS' => (DFLAGS * ' ') }, 'dub', 'build', '--compiler=gdc')
end

desc 'Run all tests and check the results'
task test: TESTS
task test: BINARY do
  TESTS.each do |test|
    expected = Pathname
      .new(test)
      .sub_ext('.txt')
      .sub(/^build\/[[:alpha:]]+\//, 'tests/expectations/')
      .to_path

    puts "Running #{test}"
    if test.include? '/riscv/'
      spike = [
        '/opt/riscv/bin/spike',
        '--isa=RV32IMAC',
        '/opt/riscv/riscv32-unknown-elf/bin/pk',
        test
      ]
      diff = ['diff', '-Nur', '--color', expected, '-']
      tail = ['tail', '-n', '1']

      last_stdout, wait_threads = Open3.pipeline_r spike, tail, diff
    else
      raise 'Unsupported test platform'
    end
    print last_stdout.read
    last_stdout.close

    fail unless wait_threads.last.value.exitstatus.zero?
  end
end

def test_for_object(out_file, extension)
  test_source = Pathname
    .new(out_file)
    .sub_ext(extension)
    .sub(/^build\/[[:alpha:]]+\//, 'tests/')
    .to_path
  [test_source, BINARY]
end