class AllImages::App

def env
  vars = @config.fetch('env', [])
  vars << 'TERM' if ENV.key?('TERM')
  vars.each_with_object({}) { |v, h|
    name, value = v.split(?=, 2)
    if value
      h[name] = value
    else
      h[name] = ENV[name]
    end
  }
end

def initialize(args)
  @args     = args.dup
  @command  = pick_command
  @commands = %w[ ls help run debug run_all ].sort
  @suffix   = Tins::Token.new(alphabet: Tins::Token::BASE32_ALPHABET, bits: 32)
end

def load_config
  config_filename = '.all_images.yml'
  if @args.empty?
    unless File.exist?(config_filename)
      AllImages::Config.init(config_filename)
      puts bold("Config file #{config_filename} not found!\n\n")  +
        "The following example was created, adapt to your own needs:\n\n",
        AllImages::Config.example, ""
      return
    end
  else
    config_filename = @args.shift
  end
  AllImages::Config.load(config_filename)
end

def name
  [ 'all_images', @suffix ] * ?-
end

def pick_command
  case command = @args.shift
  when 'run_all', nil
    'run_all'
  when 'ls'
    'ls'
  when 'run'
    @selected = @args.shift or fail "Usage: #{File.basename($0)} #{command} IMAGE"
    'run_selected'
  when 'debug'
    @selected = @args.shift or fail "Usage: #{File.basename($0)} #{command} IMAGE"
    'debug_selected'
  else
    'help'
  end
end

def provide_image(image, dockerfile, script)
  prefix = @config.fetch('prefix', File.basename(Dir.pwd))
  tag    = "#{prefix}/all_images/#{image}"
  sh "docker pull '#{image}'"
  build_dir = File.join(Dir.tmpdir, 'build')
  mkdir_p build_dir
  cd build_dir do
    File.open('script', ?w) do |s|
      s.print script
    end
    File.open('Dockerfile', ?w) do |t|
      t.puts <<~end
      FROM #{image}
      WORKDIR /work
      #{dockerfile}
      COPY --chmod=755 script /script
    end
    end
    sh "docker build --pull -t '#{tag}' ."
  end
  tag
ensure
  rm_rf File.join(Dir.tmpdir, 'build')
end

def run
  @config   = load_config or return 23
  result = 0
  case @command
  when 'ls'
    puts Array(@config['images']).map(&:first)
  when 'help'
    puts "Usage: #{File.basename($0)} #{@commands * ?|} [IMAGE]"
  else
    Array(@config['images']).each do |image, script|
      case @command
      when 'run_all'
        result |= run_image(image, script)
      when 'run_selected'
        image == @selected and result |= run_image(image, script)
      when 'debug_selected'
        image == @selected and result |= run_image(image, script, interactive: true)
      end
      if @config['fail_fast'] && result != 0
        return 1
      end
    end
  end
  result
end

def run_image(image, script, interactive: false)
  dockerfile = @config.fetch('dockerfile').to_s
  tag  = provide_image image, dockerfile, script
  envs = env.full? { |e| +' ' << e.map { |n, v| '-e %s=%s' % [ n, v.inspect ] } * ' ' }
  if interactive
    puts "You can run /script interactively now."
    sh "docker run --name #{name} -it#{envs} -v `pwd`:/work '#{tag}' sh"
    return 0
  else
    if sh "docker run --name #{name} -it#{envs} -v `pwd`:/work '#{tag}' sh -c /script"
      puts green('SUCCESS')
      return 0
    else
      puts red('FAILURE')
      return 1
    end
  end
ensure
  sh "docker rm -f #{name} >/dev/null"
end

def sh(*a)
  if $DEBUG
    STDERR.puts "Executing #{a.inspect}."
  end
  system(*a)
  if $?.success?
    true
  else
    raise "Command #{Shellwords.join(a).inspect} failed with: #{$?.exitstatus}"
  end
end