#!/usr/bin/env bash

# This is a pre-allocated string of 30 chars of whitespace
# DO NOT CHANGE THIS without great care - it will break header length
# calculations
LENS=(                              )
export SELF       # Absolute path to the installer script (me!)
export TMP        # Path to tmp install staging directory
export PAYLOAD    # Path to the extracted payload directory
export NOCLEANUP  # Do not clean up deploy resources. Useful for debugging

# Header:    0
# runscript: 1
# payload:   2
extract_chunk_index() {
  local src="${1}"
  local dest="${2}"
  local index="${3}"
  local skip=0  # Byte count to skip into source
  local of      # Output path with 'of=' prefix. Only used if dest is not '-'

  for (( i = 0; i < index; i++ )); do
    skip=$(( skip + LENS[$i] ))
  done

  [ "${dest}" != '-' ] && of="${dest}"
  # Extract the requested chunk index
  dd bs=1 count=${LENS[$index]} iflag=skip_bytes skip=${skip} \
    if=${src} ${of} 2>/dev/null
}

extract_header() {
  extract_chunk_index "${SELF}" "${TMP}/header.sh" 0
}

extract_runscript() {
  extract_chunk_index "${SELF}" '-' 1 | xz -d -c > "${TMP}/run.sh"
}

extract_payload() {
  extract_chunk_index "${SELF}" '-' 2 | xz -d -c | tar -C "${TMP}" -x
  export PAYLOAD="${TMP}/pkg"
}


main() {
  SELF="$(cd $(dirname ${0}) && pwd)/$(basename ${0})"
  TMP="$(mktemp -d /tmp/installer-XXXXXXX)"

  extract_header
  extract_runscript
  #extract_chunks "${self}" "${tmp}"

  cd "${TMP}"
  source run.sh

  # Function 'deploy' is provided by run.sh
  if [ "$(type -t deploy)" == 'function' ]; then
    deploy ${@}
  else
    printf "ERROR: Deploy function not found.\n"
  fi

  # Cleanup
  [ -z "${NOCLEANUP:-}" ] && rm -rf "${TMP}"
}

main ${@}
exit 0