#!/bin/zsh
# zed
#
# No other shell could do this.
# Edit small files with the command line editor.
# Use ^X^W to save (or ZZ in vicmd mode), ^C to abort.
# Option -f: edit shell functions.  (Also if called as fned.)
# Option -h: edit shell history.  (Also if called as histed.)

setopt localoptions noksharrays

local var opts zed_file_name
# We do not want timeout while we are editing a file
integer TMOUT=0 okargs=1 fun hist bind
local -a expand

zparseopts -D -A opts f h b x:
fun=$+opts[-f]
hist=$+opts[-h]
bind=$+opts[-b]
if [[ $opts[-x] == <-> ]]; then
  expand=(-x $opts[-x])
elif (( $+opts[-x] )); then
  print -r "Integer expected after -x: $opts[-x]" >&2
  return 1
fi

[[ $0 = fned ]] && fun=1
[[ $0 = histed ]] && hist=1
(( hist && $# <= 2 )) && okargs=$#
(( bind )) && okargs=0

if (( $# != okargs || bind + fun + hist > 1 )); then
    echo 'Usage:
zed filename
zed -f [ -x N ] function
zed -h [ filename [ size ] ]
zed -b' >&2
    return 1
fi

local curcontext=zed:::

() {
    # Matching used in zstyle -m: hide result from caller.
    # Variables not used directly here.
    local -a match mbegin mend
    zstyle -m ":completion:zed:*" insert-tab '*' ||
	zstyle ":completion:zed:*" insert-tab yes
}

zmodload zsh/terminfo 2>/dev/null

__zed_pg_up()
{
    integer count=$(( LINES / 2 - 1 ))
    while (( count -- )); do
        zle up-line
    done
}

__zed_pg_down()
{
    integer count=$(( LINES / 2 - 1 ))
    while (( count -- )); do
        zle down-line
    done
}

if ! zle -la __zed_pg_up __zed_pg_down; then
    zle -N __zed_pg_up
    zle -N __zed_pg_down
fi

if (( bind )) || ! bindkey -M zed >&/dev/null; then
  # Make the zed keymap a copy of the current main.
  bindkey -N zed main
  # Save the current main.  In zle widgets called from
  # zed we may want to set this temporally.
  bindkey -A main zed-normal-keymap

  # Define a widget to use at startup, undo shouldn't clear initial buffer
  __zed_init() {
    UNDO_LIMIT_NO=$UNDO_CHANGE_NO
  }
  zle -N __zed_init

  # Assign some default keys.
  # Depending on your stty's, you may be able to use ^J as accept-line, else:

  # The following isn't useful if we are copying viins, but that's
  # a nicety.
  bindkey -M zed '^x^w' accept-line
  bindkey -M zed '^M' self-insert-unmeta

  [[ ${+terminfo} = 1 ]] && {
    [[  -n "$terminfo[kpp]" ]] && bindkey -M zed "$terminfo[kpp]" __zed_pg_up
    [[ -n "$terminfo[knp]" ]] && bindkey -M zed "$terminfo[knp]" __zed_pg_down
    [[ -n "$terminfo[khome]" ]] && bindkey -M zed "$terminfo[khome]" beginning-of-line
    [[ -n "$terminfo[kend]" ]] && bindkey -M zed "$terminfo[kend]" end-of-line

    # Fallback to well known code as terminfo might be wrong (often) sometimes
    bindkey -M zed "^[[H" beginning-of-line
    bindkey -M zed "^[[F" end-of-line
  }

  # Make zed-set-file-name available.
  # Assume it's in fpath; there's no error at this point if it isn't
  autoload -Uz zed-set-file-name
  zle -N zed-set-file-name
fi
if (( bind )) || ! bindkey -M zed-vicmd >&/dev/null; then
  bindkey -N zed-vicmd vicmd

  bindkey -M zed-vicmd "ZZ" accept-line
  [[ ${+terminfo} = 1 ]] && {
    [[ -n "$terminfo[kpp]" ]] && bindkey -M zed-vicmd "$terminfo[kpp]" __zed_pg_up
    [[ -n "$terminfo[knp]" ]] && bindkey -M zed-vicmd "$terminfo[knp]" __zed_pg_down
    [[ -n "$terminfo[khome]" ]] && bindkey -M zed-vicmd "$terminfo[khome]" vi-beginning-of-line
    [[ -n "$terminfo[kend]" ]] && bindkey -M zed-vicmd "$terminfo[kend]" vi-end-of-line

    # Fallback to well known code as terminfo might be wrong (often) sometimes
    bindkey -M zed-vicmd "^[[H" vi-beginning-of-line
    bindkey -M zed-vicmd "^[[F" vi-end-of-line
  }
fi

(( bind )) && return 0

# don't mangle !'s
setopt localoptions nobanghist

if ((fun)) then
  var="$(functions $expand -- "$1")"
  # If function is undefined but autoloadable, load it
  if [[ $var = *\#\ undefined* ]] then
    var="$(autoload +X "$1"; functions -- "$1")"
  elif [[ -z $var ]] then
    var="${(q-)1} () {
}"
  fi
  vared -M zed -m zed-vicmd -i __zed_init var && eval function "$var"
elif ((hist)) then
  if [[ -n $1 ]]; then
    { fc -p -a "$1" ${2:-$({ wc -l <"$1" } 2>/dev/null)} || return }
    let HISTSIZE++  
    print -s ""		# Work around fc -p limitation
  fi
  # When editing the current shell history, the "zed -h" command is not
  # itself included because the current event is not added to the ring
  # until the next prompt is printed.  This means "zed -h" is prepended
  # to the result of the edit, because of the way "print -s" is defined.
  var=( "${(@Oav)history}" )
  IFS=$'\n' vared -M zed -m zed-vicmd -i __zed_init var
  if (( ? )); then
    [[ -n $1 ]] && unset HISTFILE
  else
    local HISTSIZE=0 savehist=$#var
    fc -R /dev/null	# Remove entries other than those added here
    HISTSIZE=$savehist	# Resets on function exit because local
    [[ -n $1 ]] && SAVEHIST=$savehist	# Resets via foregoing fc -a
    for (( hist=1; hist <= savehist; hist++ ))
    do print -rs -- "$var[hist]"
    done
    if [[ -n $zed_file_name ]]; then
      fc -W "$zed_file_name"
      [[ -n $1 ]] && unset HISTFILE
    fi
    # Note prepend effect when global HISTSIZE greater than $savehist.
    # This does not affect file editing.
  fi
else
  zed_file_name="$1"
  [[ -f $1 ]] && var="$(<"$1")"
  while vared -M zed -m zed-vicmd -i __zed_init var
  do
    {
      print -r -- "$var" >| "$zed_file_name"
    } always {
      (( TRY_BLOCK_ERROR = 0 ))
    } && break
    echo -n -e '\a'
  done
fi

return 0

# End of zed