require 'morpher'
require 'anima'
require 'mutant'

# Namespace module for corpus testing
module Corpus
  # Project under corpus test
  # rubocop:disable ClassLength
  ROOT = Pathname.new(__FILE__).parent.parent.parent
  TMP = ROOT.join('tmp').freeze

  class Project
    MUTEX = Mutex.new
    include Adamantium, Anima.new(
      :name,
      :repo_uri,
      :exclude,
      :mutation_coverage,
      :mutation_generation,
      :namespace,
      :expect_coverage
    )

    # Verify mutation coverage
    #
    # @return [self]
    #   if successful
    #
    # @raise [Exception]
    #
    def verify_mutation_coverage
      checkout
      Dir.chdir(repo_path) do
        Bundler.with_clean_env do
          install_mutant
          system(%W[bundle exec mutant --use rspec -I lib -r #{name} --score #{expect_coverage} #{namespace}*])
        end
      end
    end

    # Verify mutation generation
    #
    # @return [self]
    #   if successful
    #
    # @raise [Exception]
    #   otherwise
    #
    # rubocop:disable MethodLength
    # rubocop:disable AbcSize
    #
    def verify_mutation_generation
      checkout
      start = Time.now
      paths = Pathname.glob(repo_path.join('**/*.rb')).sort_by(&:size).reverse
      options = {
        finish:       method(:finish),
        start:        method(:start),
        in_processes: parallel_processes
      }
      total = Parallel.map(paths, options) do |path|
        count = 0
        node =
          begin
            Parser::CurrentRuby.parse(path.read)
          rescue EncodingError, ArgumentError
            nil # Make rubocop happy
          end
        if node
          Mutant::Mutator::Node.each(node) do
            count += 1
          end
        end
        count
      end.inject(0, :+)
      took = Time.now - start
      puts format(
        'Total Mutations/Time/Parse-Errors: %s/%0.2fs - %0.2f/s',
        total,
        took,
        total / took
      )
      self
    end

    # Checkout repository
    #
    # @return [self]
    #
    # @api private
    #
    def checkout
      return self if noinstall?
      TMP.mkdir unless TMP.directory?
      if repo_path.exist?
        Dir.chdir(repo_path) do
          system(%w[git fetch origin])
          system(%w[git reset --hard])
          system(%w[git clean -f -d -x])
          system(%w[git checkout origin/master])
          system(%w[git reset --hard])
          system(%w[git clean -f -d -x])
        end
      else
        system(%W[git clone #{repo_uri} #{repo_path}])
      end
      self
    end
    memoize :checkout

  private

    # Install mutant
    #
    # @return [undefined]
    #
    # @api private
    #
    def install_mutant
      return if noinstall?
      relative = ROOT.relative_path_from(repo_path)
      repo_path.join('Gemfile').open('a') do |file|
        file << "gem 'mutant', path: '#{relative}'\n"
        file << "gem 'mutant-rspec', path: '#{relative}'\n"
      end
      lockfile = repo_path.join('Gemfile.lock')
      lockfile.delete if lockfile.exist?
      system('bundle install')
    end

    # Not in the docs. Number from chatting with their support.
    CIRCLE_CI_CONTAINER_PROCESSES = 2

    # Return number of parallel processes to use
    #
    # @return [Fixnum]
    #
    # @api private
    #
    def parallel_processes
      if ENV['CI']
        Mutant::Config::DEFAULT.jobs
      else
        Parallel.processor_count
      end
    end

    # Return repository path
    #
    # @return [Pathname]
    #
    # @api private
    #
    def repo_path
      TMP.join(name)
    end

    # Test if installation should be skipped
    #
    # @return [Boolean]
    #
    # @api private
    #
    def noinstall?
      ENV.key?('NOINSTALL')
    end

    # Print start progress
    #
    # @param [Pathname] path
    # @param [Fixnum] _index
    #
    # @return [undefined]
    #
    def start(path, _index)
      MUTEX.synchronize do
        puts format('Starting - %s', path)
      end
    end

    # Print finish progress
    #
    # @param [Pathname] path
    # @param [Fixnum] _index
    # @param [Fixnum] count
    #
    # @return [undefined]
    #
    def finish(path, _index, count)
      MUTEX.synchronize do
        puts format('Mutations - %4i - %s', count, path)
      end
    end

    # Helper method to execute system commands
    #
    # @param [Array<String>] arguments
    #
    # @api private
    #
    def system(arguments)
      return if Kernel.system(*arguments)
      if block_given?
        yield
      else
        fail 'System command failed!'
      end
    end

    LOADER = Morpher.build do
      s(:block,
        s(:guard, s(:primitive, Array)),
        s(:map,
          s(:block,
            s(:guard, s(:primitive, Hash)),
            s(:hash_transform,
              s(:key_symbolize, :repo_uri,            s(:guard, s(:primitive, String))),
              s(:key_symbolize, :name,                s(:guard, s(:primitive, String))),
              s(:key_symbolize, :namespace,           s(:guard, s(:primitive, String))),
              s(:key_symbolize, :expect_coverage,     s(:guard, s(:primitive, Float))),
              s(:key_symbolize, :mutation_coverage,
                s(:guard, s(:or, s(:primitive, TrueClass), s(:primitive, FalseClass)))),
              s(:key_symbolize, :mutation_generation,
                s(:guard, s(:or, s(:primitive, TrueClass), s(:primitive, FalseClass)))),
              s(:key_symbolize, :exclude,             s(:map, s(:guard, s(:primitive, String))))
            ),
            s(:load_attribute_hash,
              # NOTE: The domain param has no DSL currently!
              Morpher::Evaluator::Transformer::Domain::Param.new(
                Project,
                [:repo_uri, :name, :exclude, :mutation_coverage, :mutation_generation]
              )
            )
          )
        )
      )
    end

    ALL = LOADER.call(YAML.load_file(ROOT.join('spec', 'integrations.yml')))
  end # Project
end # Corpus