#!/usr/bin/env ruby
require "yaml"

ci_config = File.expand_path('../../.travis.yml', __FILE__)
data = YAML.load(File.read(ci_config))
ruby_versions = data.fetch('rvm')
gemfiles = data.fetch('gemfile')

requirements = {
  'Gemfile.rails3.0'   => Gem::Requirement.new('< 2.4'),
  'Gemfile.rails3.1'   => Gem::Requirement.new('< 2.4'),
  'Gemfile.rails3.2'   => Gem::Requirement.new('< 2.4'),
  'Gemfile.rails4.0'   => Gem::Requirement.new(['< 2.4', '>= 1.9']),
  'Gemfile.rails4.1'   => Gem::Requirement.new(['< 2.4', '>= 1.9']),
  'Gemfile.rails4.2'   => Gem::Requirement.new(['>= 1.9', '< 2.7']),
  'Gemfile.rails5.0'   => Gem::Requirement.new('>= 2.2'),
  'Gemfile.rails5.1'   => Gem::Requirement.new('>= 2.2'),
  'Gemfile.rails5.2'   => Gem::Requirement.new('>= 2.2'),
  'Gemfile'            => Gem::Requirement.new('>= 2.5.0'),
  'Gemfile.rails-edge' => Gem::Requirement.new('>= 2.5.0'),
}

commands = {}

commands['excludes'] = -> {
  excludes = []
  gemfiles.each do |gemfile|
    req = requirements.fetch(gemfile)
    ruby_versions.each do |version|
      unless req.satisfied_by?(Gem::Version.new(version))
        excludes << { 'rvm' => version, 'gemfile' => gemfile }
      end
    end
  end

  data.fetch('matrix')['exclude'] = excludes
  File.open(ci_config, 'w') do |file|
    yaml_str = YAML.dump(data)
      .sub(/^---\n/, '')
      .gsub(/^(\s*-)/, '  \1')
      .gsub(/^(\s+gemfile:)/, '  \1')
    file.write(yaml_str)
  end
}

cmd = commands.fetch(ARGV[0]) do
  $stderr.puts "available commands: #{commands.keys.join(', ')}"
  exit 1
end
cmd.(*ARGV[1..-1])
