require "concourse/version"

class Concourse
  include Rake::DSL

  # these numbers/names align with public docker image names
  RUBIES = {
    mri:   %w[2.1 2.2 2.3 2.4], # docker repository: "ruby"
    jruby: %w[1.7 9.1],         # docker repository: "jruby"
    rbx:   %w[latest],          # docker repository: "rubinius/docker"
  }

  DIRECTORY = "concourse"

  attr_reader :project_name, :pipeline_filename, :pipeline_erb_filename

  def self.validate_fly_target task, task_args
    unless task_args[:fly_target]
      raise "ERROR: must specify a fly target, like `rake #{task.name}[targetname]`"
    end
    return task_args[:fly_target]
  end

  def initialize project_name
    @project_name = project_name
    @pipeline_filename = File.join(DIRECTORY, "#{project_name}.yml")
    @pipeline_erb_filename = "#{pipeline_filename}.erb"
  end

  def create_tasks!
    unless Dir.exist? DIRECTORY
      mkdir_p DIRECTORY
    end

    unless File.exist? pipeline_erb_filename
      raise "ERROR: concourse pipeline template #{pipeline_erb_filename.inspect} does not exist"
    end

    CLOBBER.include pipeline_filename if defined?(CLOBBER)

    namespace :concourse do
      #
      #  pipeline commands
      #
      desc "generate and validate the pipeline file for #{project_name}"
      task "generate" do |t|
        File.open pipeline_filename, "w" do |f|
          f.write ERB.new(File.read(pipeline_erb_filename)).result(binding)
        end
        sh "fly validate-pipeline -c #{pipeline_filename}"
      end

      desc "upload the pipeline file for #{project_name}"
      task "set", [:fly_target] => ["generate"] do |t, args|
        fly_target = Concourse.validate_fly_target t, args
        sh "fly -t #{fly_target} set-pipeline -p #{project_name} -c #{pipeline_filename}"
      end

      %w[expose hide pause unpause].each do |command|
        desc "#{command} the #{project_name} pipeline"
        task "#{command}", [:fly_target] do |t, args|
          fly_target = Concourse.validate_fly_target t, args
          sh "fly -t #{fly_target} #{command}-pipeline -p #{project_name}"
        end
      end

      desc "remove generate pipeline file"
      task "clean" do |t|
        rm_f pipeline_filename
      end

      #
      #  task commands
      #
      desc "list all the available tasks from the #{project_name} pipeline"
      task "tasks" => "generate" do
        tasks = []

        each_task do |job, task|
          tasks << "#{job["name"]}/#{task["task"]}"
        end

        puts "Available Concourse tasks for #{project_name} are:"
        tasks.each { |task| puts " * #{task}" }
      end

      desc "fly execute the specified task"
      task "task", [:fly_target, :task_name, :fly_execute_args] => "generate" do |t, args|
        fly_target = Concourse.validate_fly_target t, args
        task_name        = args[:task_name]
        fly_execute_args = args[:fly_execute_args] || "--input=#{project_name}=."

        unless task_name
          raise "ERROR: must specify a task name, like `rake #{t.name}[target,taskname]`"
        end

        concourse_task = find_task task_name
        raise "ERROR: could not find task `#{task_name}`" unless concourse_task

        puts concourse_task.to_yaml
        Tempfile.create do |f|
          f.write concourse_task["config"].to_yaml
          f.close
          sh "fly -t #{fly_target} execute #{fly_execute_args} -c #{f.path} -x"
        end
      end
    end
  end

  def each_task
    pipeline = YAML.load_file(pipeline_filename)

    pipeline["jobs"].each do |job|
      job["plan"].each do |task|
        yield job, task if task["task"]
      end
    end
  end

  def find_task task_name
    job_name, task_name = *task_name.split("/")
    each_task do |job, task|
      return task if task["task"] == task_name && job["name"] == job_name
    end
    nil
  end
end