# Edit the command line using your usual editor.
# Binding this to '!' in the vi command mode map,
#   autoload -Uz edit-command-line
#   zle -N edit-command-line
#   bindkey -M vicmd '!' edit-command-line
# will give ksh-like behaviour for that key,
# except that it will handle multi-line buffers properly.

emulate -L zsh
local left right prebuffer buffer=$BUFFER lbuffer=$LBUFFER
local TMPSUFFIX=.zsh
# set up parameters depending on which context we are called from,
# see below comment for more details
if (( REGION_ACTIVE == 1 )); then
  if (( CURSOR < MARK )); then
    left=$CURSOR right=$MARK
  else
    left=$MARK right=$CURSOR
  fi
  lbuffer=$lbuffer[++left,-1]
  buffer=$BUFFER[left,++right]
elif (( REGION_ACTIVE == 2 )); then
  local nl=$'\n'
  if (( CURSOR < MARK )); then
    left=${${BUFFER[1,CURSOR]}[(I)$nl]}
    right=${${BUFFER[MARK+1,-1]}[(i)$nl]}
    (( right += MARK ))
  else
    left=${${BUFFER[1,MARK]}[(I)$nl]}
    right=${${BUFFER[CURSOR+1,-1]}[(i)$nl]}
    (( right += CURSOR ))
  fi
  lbuffer=$lbuffer[++left,-1]
  if [[ $BUFFER[right] = $nl ]]; then
    # Keep the newline because "$(<$1)" below trims it
    (( --right ))
  fi
  buffer=$BUFFER[left,right]
elif (( ! ZLE_RECURSIVE )); then
  prebuffer=$PREBUFFER
fi

() {
  exec </dev/tty

  # Compute the cursor's position in bytes, not characters.
  setopt localoptions nomultibyte noksharrays

  (( $+zle_bracketed_paste )) && print -r -n - $zle_bracketed_paste[2]

  # Open the editor, placing the cursor at the right place if we know how.
  local -a editor
  zstyle -a :zle:$WIDGET editor editor
  if (( ! $#editor )); then
    editor=( "${(@Q)${(z)${VISUAL:-${EDITOR:-vi}}}}" )
  fi
  case $editor in
    (*vim*)
      integer byteoffset=$(( $#prebuffer + $#lbuffer + 1 ))
      "${(@)editor}" -c "normal! ${byteoffset}go" -- $1;;
    (*emacs*)
      local lines=( "${(@f):-"$prebuffer$lbuffer"}" )
      "${(@)editor}" +${#lines}:$((${#lines[-1]} + 1)) $1;;
    (*) "${(@)editor}" $1;;
  esac

  (( $+zle_bracketed_paste )) && print -r -n - $zle_bracketed_paste[1]

  # Replace the buffer with the editor output.
  # avoid drawing a new prompt when we can:
  # - in recursive-edit, the send-break will just cancel the recursive-edit
  #   rather than reload the line from print -z so in that case we want to
  #   just set $BUFFER (unfortunately, recursive-edit doesn't reset CONTEXT
  #   or PREBUFFER so we have to explicitly handle this case, which overrides
  #   the following point)
  # - when we are at PS2 (CONTEXT == cont && ! ZLE_RECURSIVE) we do want the
  #   break or otherwise the text from PREBUFFER will be inserted twice
  # - when the region is active, we only want to change the parts of BUFFER
  #   covered by the region, and any PREBUFFER stays as PREBUFFER
  # - in all other cases (that I can think of) we also just want to set
  #   $BUFFER directly.
  if (( REGION_ACTIVE )); then
    # adjust the length of the region to the length of the edited text
    local prelen=$#BUFFER
    BUFFER[left,right]="$(<$1)"
    if (( MARK > CURSOR )); then
      (( MARK += $#BUFFER - prelen ))
    else
      (( CURSOR += $#BUFFER - prelen ))
    fi
  elif [[ $CONTEXT != cont ]] || (( ZLE_RECURSIVE )); then
    BUFFER="$(<$1)" 
  else
    print -Rz - "$(<$1)"
    zle send-break
  fi

} =(<<<"$prebuffer$buffer")