#autoload

#emulate -L zsh
setopt localoptions nullglob

# This is still needlessly mutt-biased and should be fixed.

local -U dirboxes
local i j expl muttrc="${muttrc:-~/.muttrc}" files nm="$compstate[nmatches]"
local pinedirectory="${pinedirectory:-~/mail}"
local maildirectory="${maildirectory:-~/Mail}"

if (( ! $+_mailbox_cache )) then

  typeset -U -g _mailbox_cache
  typeset -U -g _maildir_cache _mbox_cache _mh_cache _mutt_cache _pine_cache

  _mailbox_cache=()
  _mbox_cache=()
  _maildir_cache=()
  _mh_cache=()
  _mutt_cache=()
  _pine_cache=()

  [[ -f ${~muttrc:-.} ]] &&
    _mutt_cache=( ${$(grep mailboxes ${~muttrc})[2,-1]} )

  _mbox_cache=( ${~maildirectory}/*(^/) )
  _pine_cache=( ${~pinedirectory}/**/*(.) )

  dirboxes=( ${~maildirectory}/*(/) )

  while (( $#dirboxes )); do
    i=${dirboxes[1]}
    shift dirboxes
    if [[ -d "$i/cur" ]]; then
      _maildir_cache=( "${_maildir_cache[@]}" "$i" )
    elif j=( $i/<1-> ) && [[ -n "$j" ]]; then
      _mh_cache=( "${_mh_cache[@]}" "$i" )
    else
      _mbox_cache=( "${_mbox_cache[@]}" "$i"/*(.) )
      dirboxes=( $dirboxes $i/*(/) )
    fi
  done

  [[ -n "$_mutt_cache" || -d ~/.elm || -d ~/.mutt ]] &&
      _mailbox_cache=( \! \< \> )
  [[ -n "$mailpath" ]] &&
      _mailbox_cache=( "${_mailbox_cache[@]}" "${(@)mailpath%%\?*}" )

  [[ -n "$MAIL" ]] && _mailbox_cache=( "${_mailbox_cache[@]}" $MAIL )
fi

# Files for pine must be absolute paths.

if [[ "$PREFIX" != (|-f)+* &&
      ( "${curcontext}" = *:(mail|zmail|zmlite):* ||
        ( "${curcontext}" = *:pine:* && "$PREFIX" = (|-f)[/\~]* ) ) ]]; then
  _tags mailboxes files
else
  _tags mailboxes
fi

while _tags; do
  if _requested mailboxes expl 'mailbox specification'; then
    local mbox_short
    local -U mbox_names

    mbox_short=()
    mbox_names=()

    case "${curcontext}" in
    (*:elm:*) # I've probably got this wrong, or at least incomplete
      mbox_names=( "${_mbox_cache[@]}" "${_mailbox_cache[@]}" )
      mbox_short=( \! \< \> )
      ;;
    (*:mail:*)
      if compset -P '+|-f+'; then
        mbox_names=( "${(@)_mbox_cache#$~maildirectory/}" )
      else
        mbox_names=( +"${(@)^_mbox_cache#$~maildirectory/}" "${_mailbox_cache[@]}" )
      fi
      ;;
    (*:mh:*) # I've probably got this wrong, or at least incomplete
      (( $#_mh_cache )) && _multi_parts "${expl[@]}" / _mh_cache
      ;;
    (*:mutt:*)
      mbox_names=( "${_mutt_cache[@]}" "${_mailbox_cache[@]}" "${_maildir_cache[@]}" )
      mbox_short=( \! \< \> );;
    (*:pine:*)
      # Pine is like mail but with no leading `+' to disambiguate;
      # any files not in $pinedirectory must be absolute paths.
      mbox_names=( "${(@)_pine_cache#$~pinedirectory/}" "${_mbox_cache[@]}" )
      ;;
    (*:(zmail|zmlite):*)
      if compset -P '+|-f+'; then
        mbox_names=( "${(@)_mbox_cache#$~maildirectory/}" )
      else
        mbox_names=( +"${(@)^_mbox_cache#$~maildirectory/}"
		     "${_mailbox_cache[@]}" "${_mh_cache[@]}" )
        mbox_short=( % \& )
      fi
      ;;
    (*) # Some other program wants mailbox names?  Use them all?
       mbox_names=( "${_mailbox_cache[@]}" "${_mbox_cache[@]}"
		    "${_mh_cache[@]}" "${_mutt_cache[@]}" "${_pine_cache[@]}" )
       ;;
    esac

    (( $#mbox_names )) && _multi_parts "${expl[@]}" / mbox_names
    (( $#mbox_short )) && compadd "$expl[@]" - "$mbox_short[@]"
  fi
  if _requested files expl 'mailbox file'; then
    compset -P -f
    _path_files "$expl[@]"
  fi
  [[ nm -ne $compstate[nmatches] ]] && return 0
done

return 1