BEGIN {
  RS = "\x0c"
  FS = "\n"
}

/^message}/ {
  mheader = header
  mpart = part
  mparts = parts
  level = 0
  multipart = ""
  header = ""
  part = ""
  parts = ""
}
/^header{/ {
  header = $0
}
/^(part|attachment)}/ {
  level--
}
/^(part|attachment){/ {
  parts = sprintf("%s\n%"(2*level)"s%s", parts, "", substr($1, index($1, "ID")))
  level++
}
# /^part{ ID: [[:digit:]]+, Content-type: multipart\/alternative/ {
#   multipart = "alternative"
# }
# /^part{ ID: [[:digit:]]+, Content-type: multipart\/mixed/ {
#   multipart = "mixed"
# }
/^part{ ID: [[:digit:]]+, Content-type: text\/plain/ {
  part = $0
}

END {
  split(mheader, a, "\n")
  delete a[1]
  # delete a[2]
  for (line in a) {
    print a[line]
  }
  split(mpart, a, "\n")
  delete a[1]
  for (line in a) {
    print a[line]
  }
  print "Parts:"mparts
}