#!/bin/bash

usage () {
  echo "Usage: launcher COMMAND CONFIG [--skip-prereqs] [--docker-args STRING]"
  echo "Commands:"
  echo "    start:      Start/initialize a container"
  echo "    stop:       Stop a running container"
  echo "    restart:    Restart a container"
  echo "    destroy:    Stop and remove a container"
  echo "    enter:      Open a shell to run commands inside the container"
  echo "    logs:       View the Docker logs for a container"
  echo "    bootstrap:  Bootstrap a container for the config based on a template"
  echo "    rebuild:    Rebuild a container (destroy old, bootstrap, start new)"
  echo "    cleanup:    Remove all containers that have stopped for > 24 hours"
  echo
  echo "Options:"
  echo "    --skip-prereqs             Don't check launcher prerequisites"
  echo "    --docker-args              Extra arguments to pass when running docker"
  echo "    --skip-mac-address         Don't assign a mac address"
  exit 1
}

command=$1
config=$2
user_args=""

while [ ${#} -gt 0 ]; do
  case "${1}" in
  --debug)
    DEBUG="1"
    ;;
  --skip-prereqs)
    SKIP_PREREQS="1"
    ;;
  --skip-mac-address)
    SKIP_MAC_ADDRESS="1"
    ;;
  --docker-args)
    user_args="$2"
    shift
    ;;
  esac

  shift 1
done

# Docker doesn't like uppercase characters, spaces or special characters, catch it now before we build everything out and then find out
re='[A-Z/ !@#$%^&*()+~`=]'
if [[ $config =~ $re ]];
  then
    echo
    echo "ERROR: Config name must not contain upper case characters, spaces or special characters. Correct config name and rerun $0."
    echo
    exit 1
fi

cd "$(dirname "$0")"

docker_min_version='1.8.0'
docker_rec_version='1.8.0'
git_min_version='1.8.0'
git_rec_version='1.8.0'

config_file=containers/"$config".yml
cidbootstrap=cids/"$config"_bootstrap.cid
local_discourse=local_discourse
image=discourse/base:2.0.20170728
docker_path=`which docker.io || which docker`
git_path=`which git`

if [ "${SUPERVISED}" = "true" ]; then
  restart_policy="--restart=no"
  attach_on_start="-a"
  attach_on_run="-a stdout -a stderr"
else
  attach_on_run="-d"
fi

if [ -n "$DOCKER_HOST" ]; then
  docker_ip=`sed -e 's/^tcp:\/\/\(.*\):.*$/\1/' <<< "$DOCKER_HOST"`
elif [ -x "$(which ip 2>/dev/null)" ]; then
  docker_ip=`ip addr show docker0 | \
                  grep 'inet ' | \
                  awk '{ split($2,a,"/"); print a[1] }';`
else
  docker_ip=`ifconfig | \
                  grep -B1 "inet addr" | \
                  awk '{ if ( $1 == "inet" ) { print $2 } else if ( $2 == "Link" ) { printf "%s:" ,$1 } }' | \
                  grep docker0 | \
                  awk -F: '{ print $3 }';`
fi

compare_version() {
    declare -a ver_a
    declare -a ver_b
    IFS=. read -a ver_a <<< "$1"
    IFS=. read -a ver_b <<< "$2"

    while [[ -n $ver_a ]]; do
        if (( ver_a > ver_b )); then
            return 0
        elif (( ver_b > ver_a )); then
            return 1
        else
            unset ver_a[0]
            ver_a=("${ver_a[@]}")
            unset ver_b[0]
            ver_b=("${ver_b[@]}")
        fi
    done
    return 1  # They are equal
}


install_docker() {
  echo "Docker is not installed, you will need to install Docker in order to run Launcher"
  echo "See https://docs.docker.com/installation/"
  exit 1
}

check_prereqs() {

  if [ -z $docker_path ]; then
    install_docker
  fi

  # 1. docker daemon running?
  # we send stderr to /dev/null cause we don't care about warnings,
  # it usually complains about swap which does not matter
  test=`$docker_path info 2> /dev/null`
  if [[ $? -ne 0 ]] ; then
    echo "Cannot connect to the docker daemon - verify it is running and you have access"
    exit 1
  fi

  # 2. running an approved storage driver?
  if ! $docker_path info 2> /dev/null | egrep -q '^Storage Driver: (aufs|btrfs|zfs|overlay|overlay2)$'; then
    echo "Your Docker installation is not using a supported storage driver.  If we were to proceed you may have a broken install."
    echo "aufs is the recommended storage driver, although zfs/btrfs/overlay and overlay2 may work as well."
    echo "Other storage drivers are known to be problematic."
    echo "You can tell what filesystem you are using by running \"docker info\" and looking at the 'Storage Driver' line."
    echo
    echo "If you wish to continue anyway using your existing unsupported storage driver,"
    echo "read the source code of launcher and figure out how to bypass this check."
    exit 1
  fi

  # 3. running recommended docker version
  test=($($docker_path --version))  # Get docker version string
  test=${test[2]//,/}  # Get version alone and strip comma if exists

  # At least minimum docker version
  if compare_version "${docker_min_version}" "${test}"; then
    echo "ERROR: Docker version ${test} not supported, please upgrade to at least ${docker_min_version}, or recommended ${docker_rec_version}"
    exit 1
  fi

  # Recommend newer docker version
  if compare_version "${docker_rec_version}" "${test}"; then
    echo "WARNING: Docker version ${test} deprecated, recommend upgrade to ${docker_rec_version} or newer."
  fi

  # 4. discourse docker image is downloaded
  test=`$docker_path images | awk '{print $1 ":" $2 }' | grep "$image"`

  if [ -z "$test" ]; then
    echo
    echo "WARNING: We are about to start downloading the Discourse base image"
    echo "This process may take anywhere between a few minutes to an hour, depending on your network speed"
    echo
    echo "Please be patient"
    echo
  fi

  # 5. running recommended git version
  test=($($git_path --version))  # Get git version string
  test=${test[2]//,/}  # Get version alone and strip comma if exists

  # At least minimum version
  if compare_version "${git_min_version}" "${test}"; then
    echo "ERROR: Git version ${test} not supported, please upgrade to at least ${git_min_version}, or recommended ${git_rec_version}"
    exit 1
  fi

  # Recommend best version
  if compare_version "${git_rec_version}" "${test}"; then
    echo "WARNING: Git version ${test} deprecated, recommend upgrade to ${git_rec_version} or newer."
  fi

  # 6. able to attach stderr / out / tty
  test=`$docker_path run $user_args -i --rm -a stdout -a stderr $image echo working`
  if [[ "$test" =~ "working" ]] ; then : ; else
    echo "Your Docker installation is not working correctly"
    echo
    echo "See: https://meta.discourse.org/t/docker-error-on-bootstrap/13657/18?u=sam"
    exit 1
  fi

  # 7. enough space for the bootstrap on docker folder
  folder=`$docker_path info --format '{{.DockerRootDir}}'`
  safe_folder=${folder:-/var/lib/docker}
  test=$(($(stat -f --format="%a*%S" $safe_folder)/1024**3 < 5))
  if [[ $test -ne 0 ]] ; then
    echo "You have less than 5GB of free space on the disk. You will need more space to continue"
    echo
    read -p "Would you like to attempt to recover space by cleaning docker images and containers in the system?(y/N)" -n 1 -r
    echo
    if [[ $REPLY =~ ^[Yy]$ ]]
    then
      docker system prune
      echo "If the cleanup was successful, you may try again now"
    fi
    exit 1
  fi
}


if [ -z "$SKIP_PREREQS" ] && [ "$command" != "cleanup" ]; then
  check_prereqs
fi

host_run() {
  read -r -d '' env_ruby << 'RUBY'
  require 'yaml'

  input = STDIN.readlines.join
  yaml = YAML.load(input)

  if host_run = yaml['host_run']
    params = yaml['params'] || {}
    host_run.each do |run|
      params.each do |k,v|
        run = run.gsub("$#{k}", v)
      end
      STDOUT.write "#{run}--SEP--"
    end
  end
RUBY

  host_run=`cat $config_file | $docker_path run $user_args --rm -i -a stdout -a stdin $image ruby -e "$env_ruby"`

  while [ "$host_run" ] ; do
    iter=${host_run%%--SEP--*}
    echo
    echo "Host run: $iter"
    $iter || exit 1
    echo
    host_run="${host_run#*--SEP--}"
  done
}


set_volumes() {
  volumes=`cat $config_file | $docker_path run $user_args --rm -i -a stdout -a stdin $image ruby -e \
        "require 'yaml'; puts YAML.load(STDIN.readlines.join)['volumes'].map{|v| '-v ' << v['volume']['host'] << ':' << v['volume']['guest'] << ' '}.join"`
}

set_links() {
    links=`cat $config_file | $docker_path run $user_args --rm -i -a stdout -a stdin $image ruby -e \
        "require 'yaml'; puts YAML.load(STDIN.readlines.join)['links'].map{|l| '--link ' << l['link']['name'] << ':' << l['link']['alias'] << ' '}.join"`
}

find_templates() {
    local templates=`cat $1 | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
      "require 'yaml'; puts YAML.load(STDIN.readlines.join)['templates']"`

    local arrTemplates=${templates// / }

    if [ ! -z "$templates" ]; then
      for template in "${arrTemplates[@]}"
      do
        local nested_templates=$(find_templates $template)

        if [ ! -z "$nested_templates" ]; then
          templates="$templates $nested_templates"
        fi
      done

      echo $templates
    else
      echo ""
    fi
}

set_template_info() {
    templates=$(find_templates $config_file)

    arrTemplates=(${templates// / })
    config_data=$(cat $config_file)

    input="hack: true"

    for template in "${arrTemplates[@]}"
    do
      [ ! -z $template ] && {
        input="$input _FILE_SEPERATOR_ $(cat $template)"
      }
    done

    # we always want our config file last so it takes priority
    input="$input _FILE_SEPERATOR_ $config_data"

    read -r -d '' env_ruby << 'RUBY'
    require 'yaml'

    input=STDIN.readlines.join
    # default to UTF-8 for the dbs sake
    env = {'LANG' => 'en_US.UTF-8'}
    input.split('_FILE_SEPERATOR_').each do |yml|
       yml.strip!
       begin
         env.merge!(YAML.load(yml)['env'] || {})
       rescue Psych::SyntaxError => e
        puts e
        puts "*ERROR."
       rescue => e
        puts yml
        p e
       end
    end
    puts env.map{|k,v| "-e\n#{k}=#{v}" }.join("\n")
RUBY

    raw=`exec echo "$input" | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e "$env_ruby"`

    env=()
    ok=1
    while read i; do
      if [ "$i" == "*ERROR." ]; then
        ok=0
      elif [ -n "$i" ]; then
        env[${#env[@]}]=$i
      fi
    done <<< "$raw"

    if [ "$ok" -ne 1 ]; then
      echo "${env[@]}"
      echo "YAML syntax error. Please check your containers/*.yml config files."
      exit 1
    fi

    read -r -d '' labels_ruby << 'RUBY'
    require 'yaml'

    input=STDIN.readlines.join
    # default to UTF-8 for the dbs sake
    labels = {}
    input.split('_FILE_SEPERATOR_').each do |yml|
       yml.strip!
       begin
         labels.merge!(YAML.load(yml)['labels'] || {})
       rescue Psych::SyntaxError => e
        puts e
        puts "*ERROR."
       rescue => e
        puts yml
        p e
       end
    end
    puts labels.map{|k,v| "-l\n#{k}=#{v}" }.join("\n")
RUBY

    raw=`exec echo "$input" | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e "$labels_ruby"`

    labels=()
    ok=1
    while read i; do
      if [ "$i" == "*ERROR." ]; then
        ok=0
      elif [ -n "$i" ]; then
        labels[${#labels[@]}]=$i
      fi
    done <<< "$raw"

    if [ "$ok" -ne 1 ]; then
      echo "${labels[@]}"
      echo "YAML syntax error. Please check your containers/*.yml config files."
      exit 1
    fi
}

if [ -z $docker_path ]; then
  install_docker
fi

[ "$command" == "cleanup" ] && {
  echo
  echo "The following command will"
  echo "- Delete all docker images for old containers"
  echo "- Delete all stopped and orphan containers"
  echo
  read -p "Are you sure (Y/n): " -n 1 -r && echo
  if [[ $REPLY =~ ^[Yy]$ || ! $REPLY ]]
    then
      space=$(df /var/lib/docker | awk '{ print $4 }' | grep -v Available)
      echo "Starting Cleanup (bytes free $space)"

      STATE_DIR=./.gc-state scripts/docker-gc

      space=$(df /var/lib/docker | awk '{ print $4 }' | grep -v Available)
      echo "Finished Cleanup (bytes free $space)"

    else
      exit 1
  fi
  exit 0
}

if [ -z "$command" -a -z "$config" ]; then
  usage
fi

if [ ! "$command" == "setup" ]; then
  if [[ ! -e $config_file ]]; then
    echo "Config file was not found, ensure $config_file exists"
    echo
    echo "Available configs ( `cd containers && ls -dm *.yml | tr -s '\n' ' ' | awk '{ gsub(/\.yml/, ""); print }'`)"
    exit 1
  fi
fi

docker_version=($($docker_path --version))
docker_version=${test[2]//,/}
restart_policy=${restart_policy:---restart=always}

set_existing_container(){
  existing=`$docker_path ps -a | awk '{ print $1, $(NF) }' | grep " $config$" | awk '{ print $1 }'`
}

run_stop() {

  set_existing_container

  if [ ! -z $existing ]
     then
       (
        set -x
        $docker_path stop -t 10 $config
       )
     else
       echo "$config was not started !"
       exit 1
  fi
}

set_run_image() {
  run_image=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
    "require 'yaml'; puts YAML.load(STDIN.readlines.join)['run_image']"`

  if [ -z "$run_image" ]; then
    run_image="$local_discourse/$config"
  fi
}

set_boot_command() {
  boot_command=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
    "require 'yaml'; puts YAML.load(STDIN.readlines.join)['boot_command']"`

  if [ -z "$boot_command" ]; then

    no_boot_command=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
      "require 'yaml'; puts YAML.load(STDIN.readlines.join)['no_boot_command']"`

    if [ -z "$no_boot_command" ]; then
      boot_command="/sbin/boot"
    fi
  fi
}

run_start() {

   existing=`$docker_path ps | awk '{ print $1, $(NF) }' | grep " $config$" | awk '{ print $1 }'`
   echo $existing
   if [ ! -z $existing ]
   then
     echo "Nothing to do, your container has already started!"
     exit 0
   fi

   existing=`$docker_path ps -a | awk '{ print $1, $(NF) }' | grep " $config$" | awk '{ print $1 }'`
   if [ ! -z $existing ]
   then
     echo "starting up existing container"
     (
       set -x
       $docker_path start $config
     )
     exit 0
   fi

   host_run

   ports=`cat $config_file | $docker_path run $user_args --rm -i -a stdout -a stdin $image ruby -e \
         "require 'yaml'; puts YAML.load(STDIN.readlines.join)['expose'].map{|p| \"-p #{p}\"}.join(' ')"`

   docker_args=`cat $config_file | $docker_path run $user_args --rm -i -a stdout -a stdin $image ruby -e \
          "require 'yaml'; puts YAML.load(STDIN.readlines.join)['docker_args']"`

   set_template_info
   set_volumes
   set_links
   set_run_image
   set_boot_command

   # get hostname and settings from container configuration
   for envar in "${env[@]}"
   do
     if [[ $envar == DOCKER_USE_HOSTNAME* ]] || [[ $envar == DISCOURSE_HOSTNAME* ]]
     then
       # use as environment variable
       eval $envar
     fi
   done

   (
     hostname=`hostname -s`
     # overwrite hostname
     if [ "$DOCKER_USE_HOSTNAME" = "true" ]
     then
       hostname=$DISCOURSE_HOSTNAME
     else
       hostname=$hostname-$config
     fi

     # we got to normalize so we only have allowed strings, this is more comprehensive but lets see how bash does first
     # hostname=`$docker_path run $user_args --rm $image ruby -e 'print ARGV[0].gsub(/[^a-zA-Z-]/, "-")' $hostname`
     # docker added more hostname rules
     hostname=${hostname//_/-}


     if [ -z "$SKIP_MAC_ADDRESS" ] ; then
      mac_address="--mac-address $($docker_path run $user_args -i --rm -a stdout -a stderr $image /bin/sh -c "echo $hostname | md5sum | sed 's/^\(..\)\(..\)\(..\)\(..\)\(..\).*$/02:\1:\2:\3:\4:\5/'")"
     fi

     set -x
     $docker_path run $links $attach_on_run $restart_policy "${env[@]}" "${labels[@]}" -h "$hostname" \
        -e DOCKER_HOST_IP="$docker_ip" --name $config -t $ports $volumes $mac_address $docker_args $user_args \
        $run_image $boot_command

   )
   exit 0

}


run_bootstrap() {

  # I got no frigging clue what this does, ask Sam Saffron. It RUNS STUFF ON THE HOST I GUESS?
  host_run

  # Is the image available?
  # If not, pull it here so the user is aware what's happening.
  $docker_path history $image >/dev/null 2>&1 || $docker_path pull $image

  set_template_info

  base_image=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
    "require 'yaml'; puts YAML.load(STDIN.readlines.join)['base_image']"`

  update_pups=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
    "require 'yaml'; puts YAML.load(STDIN.readlines.join)['update_pups']"`

  if [[ ! X"" = X"$base_image" ]]; then
    image=$base_image
  fi

  set_volumes
  set_links

  rm -f $cidbootstrap

  run_command="cd /pups &&"
  if [[ ! "false" =  $update_pups ]]; then
    run_command="$run_command git pull &&"
  fi
  run_command="$run_command /pups/bin/pups --stdin"

  echo $run_command

  unset ERR
  (exec echo "$input" | $docker_path run $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" --cidfile $cidbootstrap -i -a stdin -a stdout -a stderr $volumes $image \
    /bin/bash -c "$run_command") || ERR=$?

  unset FAILED
  # magic exit code that indicates a retry
  if [[ "$ERR" == 77 ]]; then
    $docker_path rm `cat $cidbootstrap`
    rm $cidbootstrap
    exit 77
  elif [[ "$ERR" > 0 ]]; then
    FAILED=TRUE
  fi

  if [[ $FAILED = "TRUE" ]]; then
    if [[ ! -z "$DEBUG" ]]; then
      $docker_path commit `cat $cidbootstrap` $local_discourse/$config-debug || echo 'FAILED TO COMMIT'
      echo "** DEBUG ** Maintaining image for diagnostics $local_discourse/$config-debug"
    fi

    $docker_path rm `cat $cidbootstrap`
    rm $cidbootstrap
    echo "** FAILED TO BOOTSTRAP ** please scroll up and look for earlier error messages, there may be more than one"
    exit 1
  fi

  sleep 5

  $docker_path commit `cat $cidbootstrap` $local_discourse/$config || echo 'FAILED TO COMMIT'
  $docker_path rm `cat $cidbootstrap` && rm $cidbootstrap
}



case "$command" in
  bootstrap)
      run_bootstrap
      echo "Successfully bootstrapped, to startup use ./launcher start $config"
      exit 0
      ;;

  enter)
      exec $docker_path exec -it $config /bin/bash --login
      ;;

  stop)
      run_stop
      exit 0
      ;;

  logs)

      $docker_path logs $config
      exit 0
      ;;

  restart)
      run_stop
      run_start
      exit 0
      ;;

  start)
      run_start
      exit 0
      ;;

  rebuild)
      if [ "$(git symbolic-ref --short HEAD)" == "master" ]; then
        echo "Ensuring launcher is up to date"

        git remote update

        LOCAL=$(git rev-parse @)
        REMOTE=$(git rev-parse @{u})
        BASE=$(git merge-base @ @{u})

        if [ $LOCAL = $REMOTE ]; then
          echo "Launcher is up-to-date"

        elif [ $LOCAL = $BASE ]; then
          echo "Updating Launcher"
          git pull || (echo 'failed to update' && exit 1)

          for (( i=${#BASH_ARGV[@]}-1,j=0; i>=0,j<${#BASH_ARGV[@]}; i--,j++ ))
          do
            args[$j]=${BASH_ARGV[$i]}
          done
          exec /bin/bash $0 "${args[@]}" # $@ is empty, because of shift at the beginning. Use BASH_ARGV instead.

        elif [ $REMOTE = $BASE ]; then
          echo "Your version of Launcher is ahead of origin"

        else
          echo "Launcher has diverged source, this is only expected in Dev mode"
        fi

      fi

      set_existing_container

      if [ ! -z $existing ]
        then
          echo "Stopping old container"
          (
            set -x
            $docker_path stop -t 10 $config
          )
      fi

      run_bootstrap

      if [ ! -z $existing ]
        then
          echo "Removing old container"
          (
            set -x
            $docker_path rm $config
          )
      fi

      run_start
      exit 0
      ;;


  destroy)
      (set -x; $docker_path stop -t 10 $config && $docker_path rm $config) || (echo "$config was not found" && exit 0)
      exit 0
      ;;
esac

usage