#!/bin/bash

## Sequencer script is doing nothing on its own. It is included by a squence script
## which uses the sequencer.sh to provide sequencial operations with or without
## user interaction (see generated template which can be generated by calling this
## script directly)

## Version information

VERSION_REV=11
VERSION_MAJOR=0
VERSION_MINOR=2

## Start of generic script part

QUIET=0
DRY=0
VERBOSE=0
SINGLE=0
ERNO=0
STEP_ARGS=
STEP_RETURN=255
MAX_STEP=512
ALIAS=
SEQ_CONFIG_NAME=".seqs"
SEQ_CONFIG_HOME="$HOME/$SEQ_CONFIG_NAME"
SEQ_CONFIG_FILE=
TEMPLATE_NAME=seqTemplateExample.sh
MISSING_CONF=missingConf.log
VERSION_STRING="${VERSION_REV}.${VERSION_MAJOR}.${VERSION_MINOR}"

helpSequencer() {
  echo "Usage: ${0##*/} [OPTIONS] [STEP NUMBER(s) or ALIAS] [STEP ARGUMENTS]" 
  echo
  echo " [OPTIONS]"
  echo "  --dry-run, -d  : Only print to console what would be done"
  echo "                   ! Attention - Sequence must support this"
  echo "  --help, -h     : Display help"
  echo "  --helpapi, -ha : Display help about build-in supporting functions"
  echo "                   (e.g. exe,addconf,echerr,...)"
  echo "  --quiet, -q    : Don't ask for permission to execute steps"
  echo "                   If called without starting step number, only this help is shown"
  echo "           -qq   : Same as --quiet but suppresses regular sequencer.sh output"
  echo "  --single, -s   : Execute only one step"
  echo "                   If more than one step is requested, only the first will be executed"
  echo "  --verbose, -v  : Verbose output (use exe() function to call shell commands in seqs)"
  echo "                   ( e.g.: exe apt update )"
  echo "  --version      : Display version of sequencer and revision of sequence"
  echo 
  echo " [STEP NUMBER\"(s)\" 1-${MAX_STEP} or ALIAS]"
  echo "        No STEP  or ALIAS : assume 1 as starting point"
  echo "    Single STEP  or ALIAS : starting point of sequential process"
  echo "  Multiple STEPS or ALIAS : execute only given steps"
  echo "                            (e.g. $0 \"2 4 12\")"
  echo "                            multiple steps need to be given as string"
  echo " [STEP ARGUMENTS]"
  echo "                        * : Arguments will be passed to selected steps and step infos as:"
  echo "                            \$2 ..."
  echo "                            \$1 is always the step number" 
}

helpApi() {
  echo "sequencer.sh API"
  echo
  echo "The sequencer.sh build-in functions are available in all sequence functions:"
  echo "- step_config"
  echo "  If optional step_config is defined in the sequence, it will be called once before any step."
  echo "- step_[1-${MAX_STEP}]_info"
  echo "- step_[1-${MAX_STEP}]_alias"
  echo "- step_[1-${MAX_STEP}]"
  echo
  echo "sequencer.sh global variables:"
  echo
  echo " \$QUIET"
  echo "    0       : default"
  echo "    1  (-q) : No user interaction (e.g. question to start a step)"
  echo "    2 (-qq) : 1 and no regular output of sequencer.sh"
  echo " \$DRY"
  echo "    0      : default"
  echo "    1 (-d) : Commands shall only be printed but not executed"
  echo " \$SEQ_CONFIG_HOME"
  echo "    Path to user specific seq configuration directory"
  echo " \$SEQ_CONFIG_FILE"
  echo "    Path to user specific seq configuration file"
  echo "    Will be empty if unused"
  echo
  echo "sequencer.sh build-in functions:"
  echo
  echo " exe [COMMANDLINE]"
  echo "    Execute command line without pipes or redirects (>,<,|)."
  echo "    Supporting: dry-run (-d): only print command without execution" 
  echo "                verbose (-v): print command before execution"
  echo
  echo " exep \"[COMMANDLINE]\""
  echo "    See exe, but support for pipes or redirects."
  echo "    Important:"
  echo "      - Shell commands cd, read, ... won't work because COMMANDLINE is started in a new shell."
  echo "      - All apostrophes need to be esacped since the command line is given as string."
  echo
  echo " initSeqConfig [OPTION] <NAME> [TEMPLATE]"
  echo "    Create a configuration file in $SEQ_CONFIG_HOME/ and source it if already existent."
  echo "      [OPTION]"
  echo "        -t  : Source config also if created from template"
  echo "        -e  : Create empty configuration if no template is found"
  echo "      Returns"
  echo "         0       : sourced configuration or"
  echo "            (-t) : created and sourced configuration from template"
  echo "         1       : created configuration from template but not sourced"
  echo "         2       : created empty configuration"
  echo "         3       : No configuration created"
  echo
  echo " addConf <OPTIONS> [SOURCE TYPE] <SOURCE> <DESTINATION FILE>"
  echo "    Trying to write or append text or a file (<SOURCE>) to a destination file."
  echo "    If the CONFIGFILE exists, a backup (name_%Y%m%d-%H%M%S.bck) is saved at the same location."
  echo "    If -s fails or -m, \"$(realpath "$MISSING_CONF")\" is created with the conflicts"
  echo "    to be resolved by the user."
  echo "      <OPTIONS>"
  echo "        -c : create a new file"
  echo "        -a : append to existing file"
  echo "        -s : skip if CONFIGFILE exists (no backup and entry in missing conf)"
  echo "        -m : only add content to missing conf and warn user"
  echo "      [SOURCE TYPE]"
  echo "        -f : <SOURCE> is a file"
  echo "      <SOURCE>"
  echo "        Text or file (-f) to create or added to <DESTINATION FILE>"
  echo "      <DESTINATION FILE>"
  echo "        Target file to be created or modified."
  echo
  echo " step <STEP NUMBER OR ALIAS>"
  echo "    Executes a single step also by alias. Useful if step numbers get reorganized."
  echo "    dry-run is not applied in this function! The executed step is responsible."
  echo
  echo " echoerr [...]"
  echo "    echo to stderr"
  echo "      [...] : all parameter are forwarded to echo"
  echo
  echo " echoinfo [...]"
  echo "    echo additional correctly indented line to step info"
  echo "      [...] : all parrameter are forwared to echo"
  echo
  echo " endCheckEmpty <VARIABLENAME> [DESCRIPTION]"
  echo "    exit 666 if variable is empty"
  echo "      <VARIABLENAME> : Name used within eval"
  echo "      [DESCRIPTION]  : Additional text for error output"
  echo
  echo " saveReturn [ERRORCODE]"
  echo "    Save ERRORCODE if it is != 0 for later use with endReturn"
  echo
  echo " getReturn"
  echo "    Return last saved error code"
  echo
  echo " endReturn [OPTIONS] [MESSAGE]"
  echo "    Notifys user that there was an error (previously saved by saveReturn,"
  echo "    or -o [ERRORCODE]) and asks to continue or end the sequence."
  echo "    Always exits with evaluated error code."
  echo "      [OPTIONS]"
  echo "        -f           : force exit without user input, if error code is not 0"
  echo "        -o ERRORCODE : override stored error code and check ERRORCODE"
  echo "      [MESSAGE]"
  echo "        String which is displayed in the error output"
  echo
}

# Echo to stderr
echoerr() { >&2 echo "$@"; }

# Echo additional line to info correctly indented
CONTEXT_HELP=0
INDENT_HELP='              : '
INDENTAPPEND_HELP='                '
INDENTAPPEND_INFO='          '
echoinfo() { 
  if [ $CONTEXT_HELP -ne 0 ] ; then
    printf '%s' "$INDENTAPPEND_HELP"; echo "$@"
  else
    printf '%s' "$INDENTAPPEND_INFO"; echo "$@"
  fi
}

# endCheckEmpty <VariableName> [DESCRIPTION]
#    DESCRIPTION : Optional text for error
endCheckEmpty() {
  eval 'local ref=$'$1

  if [ -z $ref ] ; then
    if [ ! -z "$2" ] ; then
      echoerr -e " [E] $2\n     Sequence stopped."
    else 
      echoerr -e " [E] $1 must not be empty.\n     Sequence stopped."
    fi
    exit 666
  fi 
}

existsFunction() {
  local NOTFOUND=0
  declare -F $1 &>>/dev/null || NOTFOUND=1
  return $NOTFOUND
}

# saveReturn <ERRNO>
# Function returns with <ERRNO> in case step wants additional evaluation
saveReturn() {
  if [ $1 -ne 0 ] ; then
    ERNO=$1
  fi
  return $ERNO
}

# getReturn
# Returns latest saved $ERNO
getReturn() {
  return $ERNO
}

# endReturn [-f] [-o ERRORCODE] [MESSAGE]
#      -f : force exit with $ERNO without user input
#      -o : override and check given error code
# MESSAGE : Custom error message
#
endReturn() {
  local arg
  local forceExit=0
  local errorCode=$ERNO
  local endMessage=""

  for arg in "$@" ; do
    case "$1" in
      -f)
        forceExit=1
        shift
        ;;
      -o)
        shift
        local rex='^[-]*[0-9]+$'
        # Check if string is a number or alias 
        if [[ "$1" =~ $rex ]] ; then
          errorCode=$1
        else
          echoerr " [W] Ignoring invalid error code: $1"
        fi
        shift
        ;;
      "")
        break
        ;;
      *)
        endMessage="$@"
        break
        ;;
    esac
  done

  if [[ ( $errorCode -ne 0 && $QUIET -ne 0 ) || ( $errorCode -ne 0 && $forceExit -ne 0 ) ]] ; then
    echo
    if [ "$endMessage" != "" ]; then
      echoerr -e " [E] $endMessage\n     Sequence stopped"
    else
      echoerr -e " [E] Return value $errorCode detected.\n     Sequence stopped"
    fi
    exit $errorCode
  fi
  if [ $errorCode -ne 0 ] ; then
    echo
    if [ "$endMessage" != "" ]; then
      echoerr -e " [W] $endMessage"
    else
      echoerr " [W] Return value $errorCode detected."
    fi
    read -p "End sequence: [y]/n? " answer
    case $answer in
      [nN])
        # reset saved error code if user chooses to continue
        ERNO=0
        echo
        echo " [I] Continuing sequence..."
        ;;
      *)
        echo
        echoerr " [E] Sequence stopped"
        exit $errorCode; 
        ;;
    esac
  fi
}

# initSeqConfig [OPTION] <NAME> [TEMPLATE]
# Create a configuration file in the users' home.
# Source it if already existent
#  [OPTION]
#     -t  : Source config also if created from template
#     -e  : Create empty configuration if no template is found
#  Return
#      0       : Sourced configuration or
#         (-t) : created and sourced configuration from template
#      1       : Created configuration from template but not sourced
#      2       : Created empty configuration
#      3       : No configuration created
initSeqConfig() {
  local arg
  local sourceAlways=0
  local createEmpty=0
  for arg in "$@" ; do
    case "$1" in
      -t)
        sourceAlways=1
        shift
        ;;
      -e)
        createEmpty=1
        shift
        ;;
    esac
  done

  local configLoc="$SEQ_CONFIG_HOME/$1"
  local configTemplate="$2"

  # Create config subdir in users home
  if [ ! -e "$SEQ_CONFIG_HOME/" ] ; then
    echo -n " [I] Creating $(realpath $SEQ_CONFIG_HOME)..."
    exe mkdir -p "$SEQ_CONFIG_HOME" && echo "Ok" || echo "Nok"
  fi

  if [ -s "$configLoc" ] ; then
    echo " [I] Using configuration file: $configLoc"
    SEQ_CONFIG_FILE="$configLoc"
    . "$configLoc"
    return 0
  fi

  # Config does not exist, check for template
  if [ -s "$configTemplate" ] ; then
    
    # Check first if there is an existing configuration at the templates position
    local configExists="$(dirname $configTemplate)/$1"
    if [ -s "$configExists" ] ; then
      exe mv "$configExists" "$configLoc"
      endReturn -o $? "Unable to use existing configuration: $configExists"

      echoerr " [I] Using existing configuration: $configExists"
      echoerr "     (Moved to $SEQ_CONFIG_HOME)"
      . "$configLoc"
      return 0
    fi

    exe cp -ar "$configTemplate" "$configLoc"
    endReturn -o $? "Failed to create configuration"

    if [ $sourceAlways -eq 0 ] ; then
      echoerr " [W] Seq configuration created from template but not used"
      echoerr "     Please modify "$configLoc" first and restart sequence"
      return 1 
    else
      echo " [W] Using seq configuration from template $configTemplate"
      echo "     (Copied to $SEQ_CONFIG_HOME)"
      SEQ_CONFIG_FILE="$configLoc"
      . "$configLoc"
      return 0
    fi
  else
    echo " [W] Seq configuration template not found"
  fi

  if [ $createEmpty -ne 0 ] ; then
    # Create empty config file
    echo " [W] Created empty configuration file $configLoc"
    exe touch "$configLoc"
    return 2
  fi

  echoerr " [E] No seq configuration created"
  return 3
}

# addConf <CONF_MODE> [FILE_MODE] <SOURCE> <DESTINATION_FILE>
# trying to write a file
# if exists, one attempt is made to create bck file of it
# if all fails, a log file is created with the conflicts to be resolved by the user
addConf() {
  local arg
  local confMode=""
  local transferCmd="echo"

  for arg in $@ ; do
    case "$1" in
      -c) # create a new file 
        confMode="-c"
        shift
        ;;
      -a) # append to existing file
        confMode="-a"
        shift
        ;;
      -s) # skip if CONFIGFILE exists
        confMode="-s"
        shift
        ;;
      -m) # only add content to missing conf and warn user
        confMode="-m"
        shift
        ;;
      -f) # choose if source is a file or text
        transferCmd="cat"
        shift
        ;;
      *) # default
        if [ "$confMode" == "" ] ; then 
          echoerr " [E] Parameter 1 (-a|-c|-m|-s) missing for addConf()"
          exit 0;
        fi
        ;;
    esac
  done
  
  local source="$1"
  local dest="$2"

  if [ "$transferCmd" == "cat" ] && [ ! -f "$source" ] ; then
    echoerr " [E] Source: \"$source\" does not exist"
    return 1;
  fi
  if [ "$dest" == "" ] ; then
    echoerr " [E] Destination empty"
    return 1;
  fi

  if [ "$DRY" -ne 0 ] ; then
    echo " [I] Writing $dest ...dry-run"
    return 0;
  fi
  echo -n " [I] Writing $dest ..."

  if [ $confMode != "-m" ] ; then 
    # try writing config directly if it doesn't exist
    if [ ! -f "$dest" ] ; then
      $transferCmd "$source" > "$dest"
      echo "ok"
      return 0
    fi

    if [ $confMode == "-s" ] ; then
      # if skip is selected, don't try to backup but add confilict entry
      echo "skipping (exists)"
    else 
      # try backup existing config
      local addConfBackup="${dest}_`date +%Y%m%d-%H%M%S`.bck"
      if [ ! -f "$addConfBackup" ] ; then
        cp -ar "$dest" "$addConfBackup"
        if [ $confMode == "-c" ] ; then
          $transferCmd "$source" > "$dest"
        else
          $transferCmd "$source" >> "$dest"
        fi
        echo -e "ok \n [I] Existing config saved to ${addConfBackup}"
        return 0
      else
        echo "nok"
        echoerr " [W] backup exists"
      fi
    fi
  else
    echo -e "ok \n [I] no change requested"
  fi

  # add configuration to missingConf file
  if [ "$missingDate" = "" ] ; then
    missingDate=set
    echo -n "###  " >> "$MISSING_CONF"
    date >> "$MISSING_CONF"
  fi
  
  local helpText="needs to be added manually"
  if [ "$confMode" == "-s" ] ; then
    helpText="not overwritten"
  fi

  echo "#--- \"$dest\" $helpText (Option: $confMode) ---" >> "$MISSING_CONF"
  $transferCmd "$source" >> "$MISSING_CONF"
  echo >> "$MISSING_CONF"

  echoerr " [W] Check $(realpath "$MISSING_CONF") for configuration conflicts ($dest)"
  return 1
}

# execute [-q] <Step Number>
#    -q: don't stop and don't report step functions which cannot be found 
# execute given step_<Step Number> function
execute() {
  local NOTFOUND=0
  local NOREPORT=0

  if [ $1 == "-q" ] ; then
    NOREPORT=1
    shift
  fi

  # check if step function exists
  declare -F step_$1 &>>/dev/null || NOTFOUND=1
  if [ $NOTFOUND -eq 1 ] && [ $NOREPORT -ne 1 ] ; then
    echoerr " [E] Step $1 not found" 
    exit 1;
  fi

  # don't execute step functions which are not available
  if [ $NOTFOUND -ne 0 ] ; then
    return $NOTFOUND
  fi 

  if [ $QUIET -ne 2 ] ; then
    echo -en "\n [STEP $1] "
    existsFunction step_${1}_info
    if [ $? -eq 0 ] ; then
      step_${1}_info $1 "${STEP_ARGS[@]}"
    else
      # Add newline if no info is given
      echo
    fi
  fi

  if [ $QUIET -eq 0 ] ; then
    read -p "Start: (y)es/[n]o/(s)kip? " answer
    case $answer in
      [yY])
        step_$1 $1 "${STEP_ARGS[@]}"
        STEP_RETURN=$?
        ;;
      [sS]) # skip step
        STEP_RETURN=0
        return 0 
        ;;
      *)
        local stepId="$1"
        # Display alias if exists
        existsFunction step_${1}_alias
        if [ $? -eq 0 ] ; then
          step_${i}_alias 
          stepId="$ALIAS" 
        fi
        echoerr " [I] Stopping sequence at step: $stepId"
        exit 1; 
        ;;
    esac
  else
    step_$1 $1 "${STEP_ARGS[@]}"
    STEP_RETURN=$?
  fi
}

# checkStep <Step Number or Alias>
#  return 0 - for invalid step
#  return Step Number
# Check sanitiy of step number or
# Check if alias exists
checkStep() {
  local rex='^[0-9]+$'
  local ref=""

  # Check if string is a number or alias 
  if ! [[ "$1" =~ $rex ]] ; then
    eval 'ref=$alias_'"$1"
    # Catch special character after eval
    if ! [[ "$ref" =~ $rex ]] ; then
      ref=0
    fi
  else
    ref=$1 
  fi

  if (( $ref < 1 || $ref > $MAX_STEP )) ; then
    echoerr " [E] Invalid step: $ref"
    return 0 
  else
    existsFunction step_$ref
    if [ $? -eq 0 ] ; then
      return $ref
    else
      # step doesn't exist
      echoerr " [E] Invalid step: $ref"
      return 0
    fi
  fi
}

# step <Step Number of Alias>
# execute given step
step() {
  local stepNo=0
  local stepArgs=("$@")

  checkStep "$1"
  stepNo=$?
  if [ "$stepNo" == "0" ] ; then
    return 1
  else
    step_$stepNo "${stepArgs[@]}"
  fi
}

# continous <Starting Step Number>
# (max $MAX_STEP)
# execute sequence continously from given starting step
continous() {
  local i
  local step=0

  checkStep "$1"
  step=$?
  if [[ $step == 0 ]] ; then
    return 1
  fi

  if [ $QUIET -ne 2 ]; then echo " [I] Starting sequence $(realpath $0) ..."; fi

  for ((i=$step; i<=${MAX_STEP}; i++)); do
    execute -q $i
    local res=$?
    if [ $res -ne 0 ] ; then
      break 
    fi
    if [ $STEP_RETURN -ne 0 ] ; then
      break
    fi
  done
  return $STEP_RETURN
}

# selection <STEP ARRAY>
# execute given step list
# e.g.: selection -q (1, 4, 12)
selection() {
  local i
  local step=0
  local array=("$@")

  if [ ${#array[@]} -eq 0 ] ; then
    return 1
  fi
  
  if [ $QUIET -ne 2 ]; then echo " [I] Starting sequence $(realpath $0) ..."; fi

  for i in ${array[@]} ; do
    checkStep "$i"
    step=$?
    if [ $step -eq 0 ] ; then
      return 1
    else 
      execute $step
    fi
  done
  return $STEP_RETURN
}

# Creating a minimal seq (step definition) template
createTemplate() {
  if [ -f $TEMPLATE_NAME ] ; then
    return 1
  fi
  echo "#!/bin/bash" > $TEMPLATE_NAME
  echo >> $TEMPLATE_NAME
  echo "toolName=mytool" >> $TEMPLATE_NAME
  echo >> $TEMPLATE_NAME
  echo "# Get script working directory" >> $TEMPLATE_NAME
  echo "# (when called from a different directory)" >> $TEMPLATE_NAME
  echo "WDIR=\"\$( cd \"\$( dirname \"\${BASH_SOURCE[0]}\" )\" >>/dev/null 2>&1 && pwd )\"" >> $TEMPLATE_NAME
  echo "CONFIG=0" >> $TEMPLATE_NAME
  echo "CONFIG_FILE_NAME=\"\${toolName}.cfg\"" >> $TEMPLATE_NAME
  echo "CONFIG_FILE_TEMPLATE=\"\$WDIR/\${CONFIG_FILE_NAME}.example\"" >> $TEMPLATE_NAME
  echo >> $TEMPLATE_NAME
  echo "step_config() {" >> $TEMPLATE_NAME
  echo "  echo \"Called once before executing steps.\"" >> $TEMPLATE_NAME
  echo "  ## e.g. to source a config file manually:" >> $TEMPLATE_NAME
  echo "  #. \"\$CONFIG_FILE\"" >> $TEMPLATE_NAME
  echo "  ## or to use sequencer api:" >> $TEMPLATE_NAME
  echo "  #initSeqConfig \"\$CONFIG_FILE_NAME\" \"\$CONFIG_FILE_TEMPLATE\"" >> $TEMPLATE_NAME 
  echo "  #if [ \$? -eq 0 ] ; then" >> $TEMPLATE_NAME
  echo "  #  CONFIG=1" >> $TEMPLATE_NAME
  echo "  #fi" >> $TEMPLATE_NAME
  echo "}" >> $TEMPLATE_NAME
  echo >> $TEMPLATE_NAME
  echo "step_1_info() { echo \"My custom step\"; }" >> $TEMPLATE_NAME
  echo "step_1_alias() { ALIAS=\"begin\"; }" >> $TEMPLATE_NAME
  echo "step_1() {" >> $TEMPLATE_NAME
  echo "  echo \"Doing something for step \$1 ...\"" >> $TEMPLATE_NAME
  echo "  echo \"Command line arguments starting with argument 2: \$@\"" >> $TEMPLATE_NAME
  echo "  # Use exe for regular command" >> $TEMPLATE_NAME
  echo "  # Use exep \"command\" for commands containing pipes or redirects" >> $TEMPLATE_NAME
  echo "  exe ls" >> $TEMPLATE_NAME
  echo "  exep \"dmesg | grep usb\"" >> $TEMPLATE_NAME
  echo "}" >> $TEMPLATE_NAME
  echo >> $TEMPLATE_NAME
  echo "VERSION_SEQREV=${VERSION_REV}" >> $TEMPLATE_NAME
  echo ". $0" >> $TEMPLATE_NAME

  chmod +x $TEMPLATE_NAME
  return 0
}

# Parse alias functions "step_[STEP NUBER]_alias" to create 
# back reference variable of schema: 
# alias_[ALIAS]=[STEP NUMBER]
parseAlias() {
  local i
  for ((i=1; i<=${MAX_STEP}; i++)); do
    # Check for alias definition
    existsFunction step_${i}_alias
    if [ $? -ne 0 ] ; then
      continue
    fi

    # Function writes global ALIAS variable
    step_${i}_alias

    eval 'alias_'$ALIAS'='$i
  done
}

# displayHelp [NO TEMPLATE]
#    [NO TEMPLATE] 
#       0 (default)  : Ask for template creation
#       1            : Do not ask for template creation
# Always display sequencer help and, if available, sequence help
displayHelp() {
  local i
  local createTemplate=1
  local stepsFound=0
  CONTEXT_HELP=1
  helpSequencer

  if [ ! -z $1 ] && [ $1 -eq 1 ] ; then
    createTemplate=0
  fi

  # check if step definition exists by looking for a step_*() function
  for ((i=1; i<=${MAX_STEP}; i++)); do
    existsFunction step_${i}
    if [ $? -ne 0 ] ; then
      continue
    fi
    stepsFound=1
  done

  if [ $stepsFound -eq 0 ] ; then
    echo -e "\n  It seems ${0##*/} was called directly."
    echo -e "  Please create a sequence script first.\n"
    if [ $createTemplate -ne 0 ] ; then
      read -p "  Create a template now? y/[n]? " answer
      case $answer in
        [yY])
          createTemplate
          if [ $? -eq 0 ] ; then
            echo -e "\n  $TEMPLATE_NAME created."
          else
            echo -e "\n  $TEMPLATE_NAME exists...Nothing to do!"
          fi
          ;;
        *)
          echo -e "\n  Nothing to do!" 
          ;;
      esac
    fi
    exit 1;
  else
    echo -e "\n  Step (= alias) documentation:"
    for ((i=1; i<=${MAX_STEP}; i++)); do

      # Display step reference in help if step function exists 
      existsFunction step_${i}
      if [ $? -ne 0 ] ; then
        continue
      fi
      printf '    Step %3s ' $i

      # Display alias if exists
      existsFunction step_${i}_alias
      if [ $? -eq 0 ] ; then
        step_${i}_alias 
        echo " = $ALIAS" 
        printf '%s' "$INDENT_HELP"
      else
        echo -n " : "
      fi

      # Display step help only if info function exists
      existsFunction step_${i}_info
      if [ $? -eq 0 ] ; then
        step_${i}_info $i 
      else
        echo " - step_${i}_info() missing"
      fi
    done
    echo
  fi
  CONTEXT_HELP=0
}

# showVersion
showVersion() {
  echo    "Sequencer    ${VERSION_STRING}"
  echo -n "Seq Revision "
  if [ ! -z "${VERSION_SEQREV}" ] ; then
    echo "${VERSION_SEQREV}"
  else
    echo "-"
  fi
}

exe() {
  local arr=("$@")
  if [ $DRY -ne 0 ] ; then
    echo -n "--"
  fi
  if [ $DRY -ne 0 ] || [ $VERBOSE -eq 1 ]  ; then
    (set -x; : "${arr[@]}")
  fi 
  
  if [ $DRY -eq 0 ] ; then 
    "${arr[@]}"
  fi
}

# Handle dry run and verbose output for commands containing pipe and/or redirects
# exep <COMMAND TO RUN AS STRING>
exep() {
  if [ $DRY -ne 0 ]  ; then
    echo "--++ : $1"
  elif [ $VERBOSE -eq 1 ] ; then
    echo "++ : $1"
  fi

  if [ $DRY -eq 0 ] ; then 
    bash -c "$1"
  fi
}

main() {
  local arg
  local START=0
  local EMPTYCALL=1

  # options check
  for arg in "$@" ; do
    case "$1" in
      --dry-run|-d) # shows what would be done
        DRY=1
        shift
        ;;
      --help|-h) # show only help
        displayHelp 1
        exit 0;
        ;;
      --helpapi|-ha) #show build-in functions
        helpApi
        exit 0;
        ;;
      --quiet|-q|-qq) # detect if option quiet is available
        if [ "$1" == "-qq" ] ; then
          QUIET=2
        else
          QUIET=1
        fi
        shift
        ;;
      --single|-s) # execute only one step and stop
        SINGLE=1
        shift
        ;;
      --verbose|-v) # set verbose flag
        VERBOSE=1
        shift
        ;;
      --version) # version request
        showVersion
        exit 0;
        ;;
    esac
  done

  if [ -z "$1" ] || [ "$1" == "" ] ; then
    # Empty -> show help
    displayHelp
    # Assume starting at one for interactive mode
    START=1
  else
    EMPTYCALL=0
    read -r -a START <<< "$1" 
    shift
    STEP_ARGS=( "$@" )
  fi

  # compatibility check of sequence
  if [ ! -z $VERSION_SEQREV ] && [ $VERSION_SEQREV -gt $VERSION_REV ] ; then
    echoerr " [E] Unsupported sequence revision"
    showVersion
    exit 1
  fi
  # exclude older versions if needed
  if [ ! -z $VERSION_SEQREV ] && [ $VERSION_SEQREV -lt 3 ] ; then
    echoerr " [E] Unsupported sequence revision (addConf)"
    showVersion
    exit 1
  fi
  if [ -z $VERSION_SEQREV ] ; then
    echoerr -e " [W] No sequence revision found. Trying anyway...\n";
  fi

  # End here on quiet mode and no step was given
  if [ $EMPTYCALL -ne 0 ] && [ $QUIET -ne 0 ] ; then
      exit 1;
  fi

  if [ $DRY -ne 0 ] && [ $QUIET -eq 0 ] ; then
    echo
    echo " [W] Dry run active."
    echo "     - Printed commands may not be accurate (e.g. quotation incorrect)"
    echo "     - Sequence may ignore dry run"
    read -p "Press enter to continue or Ctrl + C to abort"
  fi

  parseAlias

  # run configuration for seq only if available and if first step is valid
  existsFunction step_config
  if [ $? -eq 0 ] ; then
    checkStep "${START[0]}"
    if [ $? -ne 0 ] ; then
      echo " [I] Configuring sequence (step_config) ..."
      step_config
    else
      return 1
    fi
  fi

  # check if more than one step is given and select execution mode
  if [ $SINGLE -ne 0 ] ; then
    selection "${START[0]}" 
  elif [ "${#START[@]}" -gt "1" ]; then
    selection "${START[@]}"
  else
    continous $START
  fi
}

main "$@"
MAINRETURN=$?

if [ $QUIET -ne 2 ] ; then 
  echo
  echo "${0##*/} finished"
fi

exit $MAINRETURN;