require 'rake'

module ParallelTests
  module Tasks
    class << self
      def rails_env
        ENV['RAILS_ENV'] || 'test'
      end

      def run_in_parallel(cmd, options={})
        count = " -n #{options[:count]}" if options[:count]
        executable = File.expand_path("../../../bin/parallel_test", __FILE__)
        command = "#{executable} --exec '#{cmd}'#{count}#{' --non-parallel' if options[:non_parallel]}"
        abort unless system(command)
      end

      # this is a crazy-complex solution for a very simple problem:
      # removing certain lines from the output without chaning the exit-status
      # normally I'd not do this, but it has been lots of fun and a great learning experience :)
      #
      # - sed does not support | without -r
      # - grep changes 0 exitstatus to 1 if nothing matches
      # - sed changes 1 exitstatus to 0
      # - pipefail makes pipe fail with exitstatus of first failed command
      # - pipefail is not supported in (zsh)
      # - defining a new rake task like silence_schema would force users to load parallel_tests in test env
      # - do not use ' since run_in_parallel uses them to quote stuff
      # - simple system "set -o pipefail" returns nil even though set -o pipefail exists with 0
      def suppress_output(command, ignore_regex)
        activate_pipefail = "set -o pipefail"
        remove_ignored_lines = %Q{(grep -v "#{ignore_regex}" || test 1)}

        if system("#{activate_pipefail} && test 1")
          "#{activate_pipefail} && (#{command}) | #{remove_ignored_lines}"
        else
          command
        end
      end

      def check_for_pending_migrations
        abort_migrations = "db:abort_if_pending_migrations"
        if Rake::Task.task_defined?(abort_migrations)
          Rake::Task[abort_migrations].invoke
        end
      end

      # parallel:spec[:count, :pattern, :options]
      def parse_args(args)
        # order as given by user
        args = [args[:count], args[:pattern], args[:options]]

        # count given or empty ?
        # parallel:spec[2,models,options]
        # parallel:spec[,models,options]
        count = args.shift if args.first.to_s =~ /^\d*$/
        num_processes = count.to_i unless count.to_s.empty?
        pattern = args.shift
        options = args.shift

        [num_processes, pattern.to_s, options.to_s]
      end
    end
  end
end

namespace :parallel do
  desc "create test databases via db:create --> parallel:create[num_cpus]"
  task :create, :count do |t,args|
    ParallelTests::Tasks.run_in_parallel("rake db:create RAILS_ENV=#{ParallelTests::Tasks.rails_env}", args)
  end

  desc "drop test databases via db:drop --> parallel:drop[num_cpus]"
  task :drop, :count do |t,args|
    ParallelTests::Tasks.run_in_parallel("rake db:drop RAILS_ENV=#{ParallelTests::Tasks.rails_env}", args)
  end

  desc "update test databases by dumping and loading --> parallel:prepare[num_cpus]"
  task(:prepare, [:count]) do |t,args|
    ParallelTests::Tasks.check_for_pending_migrations
    if defined?(ActiveRecord) && ActiveRecord::Base.schema_format == :ruby
      # dump then load in parallel
      Rake::Task['db:schema:dump'].invoke
      Rake::Task['parallel:load_schema'].invoke(args[:count])
    else
      # there is no separate dump / load for schema_format :sql -> do it safe and slow
      args = args.to_hash.merge(:non_parallel => true) # normal merge returns nil
      ParallelTests::Tasks.run_in_parallel('rake db:test:prepare --trace', args)
    end
  end

  # when dumping/resetting takes too long
  desc "update test databases via db:migrate --> parallel:migrate[num_cpus]"
  task :migrate, :count do |t,args|
    ParallelTests::Tasks.run_in_parallel("rake db:migrate RAILS_ENV=#{ParallelTests::Tasks.rails_env}", args)
  end

  # just load the schema (good for integration server <-> no development db)
  desc "load dumped schema for test databases via db:schema:load --> parallel:load_schema[num_cpus]"
  task :load_schema, :count do |t,args|
    command = "rake db:schema:load RAILS_ENV=#{ParallelTests::Tasks.rails_env}"
    ParallelTests::Tasks.run_in_parallel(ParallelTests::Tasks.suppress_output(command, "^   ->\\|^-- "), args)
  end

  desc "load the seed data from db/seeds.rb via db:seed --> parallel:seed[num_cpus]"
  task :seed, :count do |t,args|
    ParallelTests::Tasks.run_in_parallel("rake db:seed RAILS_ENV=#{ParallelTests::Tasks.rails_env}", args)
  end

  desc "launch given rake command in parallel"
  task :rake, :command do |t, args|
    ParallelTests::Tasks.run_in_parallel("RAILS_ENV=#{ParallelTests::Tasks.rails_env} rake #{args.command}")
  end

  ['test', 'spec', 'features'].each do |type|
    desc "run #{type} in parallel with parallel:#{type}[num_cpus]"
    task type, [:count, :pattern, :options] do |t, args|
      ParallelTests::Tasks.check_for_pending_migrations

      $LOAD_PATH << File.expand_path(File.join(File.dirname(__FILE__), '..'))
      require "parallel_tests"

      count, pattern, options = ParallelTests::Tasks.parse_args(args)
      test_framework = {
        'spec' => 'rspec',
        'test' => 'test',
        'features' => 'cucumber'
      }[type]

      executable = File.join(File.dirname(__FILE__), '..', '..', 'bin', 'parallel_test')
      command = "#{executable} #{type} --type #{test_framework} " \
        "-n #{count} "                     \
        "--pattern '#{pattern}' "          \
        "--test-options '#{options}'"

      abort unless system(command) # allow to chain tasks e.g. rake parallel:spec parallel:features
    end
  end
end