require "lux/version"
require 'pathname'
require 'shellwords'
require 'thor'
require 'uri'

class Lux::App < Thor

# The Thor subclass containing useful tasks shared between the Lux
# standalone executable and Rake tasks.
#
  desc "check", "Check the integrity of the Git repositories"
  def check
    repobranch = `git symbolic-ref -q HEAD`.chomp.gsub(%r{^.*/},'')
    puts "Repository is on branch #{repobranch}"
    `git fetch --recurse-submodules=on-demand`
    nModuleErr = 0
    nModuleWarn = 0
    # Inspect the submodules currently checked out in turtle
    submodules = Hash[`git submodule status --recursive`.split(/\n/).map do |s|
      die "Bad submodule status #{s}" unless /^(?<flag>[-+U\s])(?<sha>[0-9a-f]{40})\s(?<path>\S+)(\s*\((?<ref>\S+)\))?$/ =~ s
      case flag
      when '-'
        puts "Submodule at #{path} is not initialized!"
        nModuleWarn += 1
      when '+'
        puts "Submodule at #{path} is not at correct commit!"
        nModuleErr += 1
      when 'U'
        puts "Submodule at #{path} is conflicted!"
        nModuleErr += 1
      else
        puts "Submodule at #{path} OK"
      end
      [path, [flag, sha, ref]]
    end ]
    die "There were #{nModuleErr} submodule errors and #{nModuleWarn} warnings" if nModuleErr > 0
    # If the submodule status (above) was good, then we can ignore any submodule issues here
    changes = `git status --porcelain`.split(/\n/).reject do |ch|
      die "Bad status #{ch}" unless /^(?<x>.)(?<y>.)\s(?<path1>\S+)( -> (?<path2>\S+))?$/ =~ ch
      submodules.include? path1
    end
    if changes.size > 0
      die "Repository is not clean (#{changes.size} issues), use 'git status'"
    else
      puts "Repository is clean"
    end
  end

  desc "start", "Run a Docker container with user/home mapping (default is 'base')"
  method_option :image, type: :string, aliases: '-i', default: 'base', desc: 'Docker image'
  method_option :env, type: :string, aliases: '-e', desc: 'Path to environment file'
  method_option :name, type: :string, aliases: '-n', default: '<autogenerated>', desc: 'Docker container name'
  def start
    image = findimage options.image
    puts "Starting #{image} container..."
    me, setup_cmd = user_setup_cmd()
    args = ["-v /home/#{me}:/home/#{me}"]
    args << "--env-file=#{options.env}" if options.env
    args << "--name=#{options.name}" unless options.name == '<autogenerated>'
    cid = `docker run -dit #{args.join(' ')} #{image} /bin/bash`.strip
    die "Container failed to start" unless cid =~ /^[a-z0-9]+$/
    system "docker exec #{cid} bash -c #{setup_cmd.shellescape}"
    puts "Type 'su [-] #{me}' then hit enter to attach to the container as yourself:"
    Kernel.exec "docker attach #{cid}"
  end

  EXCLUDE_VARS = %w{
    _ HOME PWD TMPDIR SSH_AUTH_SOCK SHLVL DISPLAY Apple_PubSub_Socket_Render SECURITYSESSIONID
    XPC_SERVICE_NAME XPC_FLAGS __CF_USER_TEXT_ENCODING TERM_PROGRAM TERM_PROGRAM_VERSION TERM_SESSION_ID
  }

  desc "exec COMMAND", "Run a command inside a Docker container"
  method_option :image, type: :string, aliases: '-i', default: 'base', desc: 'Docker image'
  method_option :env, type: :string, aliases: '-e', desc: 'Path to environment file'
  def exec(*command)
    image = findimage options.image
    me, setup_cmd = user_setup_cmd
    die "You must be within your home directory!" unless relwd = Pathname.pwd.to_s.gsub!(/^#{ENV['HOME']}/,'~')
    command.map!{|m| m.start_with?('/') ? Pathname.new(m).relative_path_from(Pathname.pwd) : m }
    env = ENV.reject{|k,v| EXCLUDE_VARS.include? k or v =~/\s+/}.map{|k,v| "#{k}=#{v.shellescape}"}
    env += IO.readlines(options.env).grep(/^(?!#)/).map(&:rstrip) if options.env
    cmd = setup_cmd + "su - #{me} -c 'cd #{relwd}; env -i #{env.join(' ')} #{command.join(' ')}'"
    args = ["-v /home/#{me}:/home/#{me}"]
    system "docker run --rm #{args.join(' ')} #{image} /bin/bash -c #{cmd.shellescape}"
  end

  desc "clean", "Destroy all exited containers"
  def clean
    exited = `docker ps -q -f status=exited`.gsub! /\n/,' '
    if exited and not exited.empty?
      system "docker rm #{exited}"
    else
      puts "No exited containers"
    end
  end

  desc "tidy", "Remove dangling Docker images"
  def tidy
    images = `docker images -f "dangling=true" -q`
    if images.size > 0
      system 'docker rmi $(docker images -f "dangling=true" -q)'
    else
      puts "No dangling images"
    end
  end

  desc "clobber", "Destroy all containers (even if running!)"
  def clobber
    clean
    running = `docker ps -q -f status=running`.gsub! /\n/,' '
    if running and not running.empty?
      system "docker rm -f #{running}"
    else
      puts "No running containers"
    end
  end

  desc "dockerip", "Show DOCKER_HOST IP address"
  def dockerenv
    docker_url = URI(ENV['DOCKER_HOST'])
    name = docker_url.host
    if z = Socket.gethostbyname(name) rescue nil
        z.shift 3
        z.each do |a|
            name = a.unpack('CCCC').join('.') if a.size == 4
        end
    end
    puts "DOCKER_HOST=#{docker_url.to_s}"
    docker_url.host = name
    puts "export DOCKER_HOST=#{docker_url.to_s}"
  end

  private

  # Get the current list of images and make a guess at which one it is...
  #
  def findimage image
    if image.count('/') == 0
      local_images = `docker images`.strip.split(/\n/)[1..-1].map{|l| l.gsub!(/^(\S+)\s+(\S+).*/,'\1:\2')}.sort
      matching_images = local_images.select{|l| l =~ %r[/#{image}] }
      if matching_images.size > 0
        if image.count(':') == 0
          matching_image = matching_images.select{|l| l =~ /:latest$/ }.first
        end
        unless matching_image
          matching_image = matching_images.first
        end
      else
        matching_image = nil
      end
      image = matching_image ? matching_image : "lightside/"+image
    end
    return image
  end

  # Return two elements:
  # - user name (defaults to current user), and
  # - a bash script setup command
  #
  def user_setup_cmd user = `id -nu`.strip
    [user, <<-COMMAND.gsub(/^\s*/,'').gsub(/\n/,' ; ')]
      uid=$(echo $(stat -c %u:%g /home/#{user}) | cut -d: -f2)
      useradd -M -u $uid -s #{ENV['SHELL']} #{user}
      echo "#{user} ALL=(ALL:ALL) NOPASSWD: ALL" > /etc/sudoers.d/#{user}
    COMMAND
  end

  def die msg, rc = 1
    STDERR.puts msg
    exit(rc)
  end

end

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