#!/usr/bin/env zsh
#
# This is a clean-room implementation of the Fish[1] shell's history search
# feature, where you can type in any part of any previously entered command
# and press the UP and DOWN arrow keys to cycle through the matching commands.
#
#-----------------------------------------------------------------------------
# Usage
#-----------------------------------------------------------------------------
#
# 1. Load this script into your interactive ZSH session:
#
#       % source history-substring-search.zsh
#
#    If you want to use the zsh-syntax-highlighting[6] script along with this
#    script, then make sure that you load it *before* you load this script:
#
#       % source zsh-syntax-highlighting.zsh
#       % source history-substring-search.zsh
#
# 2. Type any part of any previous command and then:
#
#     * Press the UP arrow key to select the nearest command that (1) contains
#       your query and (2) is older than the current command in the command
#       history.
#
#     * Press the DOWN arrow key to select the nearest command that (1)
#       contains your query and (2) is newer than the current command in the
#       command history.
#
#     * Press ^U (the Control and U keys simultaneously) to abort the search.
#
# 3. If a matching command spans more than one line of text, press the LEFT
#    arrow key to move the cursor away from the end of the command, and then:
#
#     * Press the UP arrow key to move the cursor to the line above.  When the
#       cursor reaches the first line of the command, pressing the UP arrow
#       key again will cause this script to perform another search.
#
#     * Press the DOWN arrow key to move the cursor to the line below.  When
#       the cursor reaches the last line of the command, pressing the DOWN
#       arrow key again will cause this script to perform another search.
#
#-----------------------------------------------------------------------------
# Configuration
#-----------------------------------------------------------------------------
#
# This script defines the following global variables. You may override their
# default values only after having loaded this script into your ZSH session.
#
# * HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND is a global variable that defines
#   how the query should be highlighted inside a matching command. Its default
#   value causes this script to highlight using bold, white text on a magenta
#   background. See the "Character Highlighting" section in the zshzle(1) man
#   page to learn about the kinds of values you may assign to this variable.
#
# * HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND is a global variable that
#   defines how the query should be highlighted when no commands in the
#   history match it. Its default value causes this script to highlight using
#   bold, white text on a red background. See the "Character Highlighting"
#   section in the zshzle(1) man page to learn about the kinds of values you
#   may assign to this variable.
#
# * HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS is a global variable that defines
#   how the command history will be searched for your query. Its default value
#   causes this script to perform a case-insensitive search. See the "Globbing
#   Flags" section in the zshexpn(1) man page to learn about the kinds of
#   values you may assign to this variable.
#
#-----------------------------------------------------------------------------
# History
#-----------------------------------------------------------------------------
#
# This script was originally written by Peter Stephenson[2], who published it
# to the ZSH users mailing list (thereby making it public domain) in September
# 2009. It was later revised by Guido van Steen and released under the BSD
# license (see below) as part of the fizsh[3] project in January 2011.
#
# It was later extracted from fizsh[3] release 1.0.1, refactored heavily, and
# repackaged as both an oh-my-zsh plugin[4] and as an independently loadable
# ZSH script[5] by Suraj N. Kurapati in 2011.
#
# It was further developed[4] by Guido van Steen, Suraj N. Kurapati, Sorin
# Ionescu, and Vincent Guerci in 2011.
#
# [1]: http://fishshell.com
# [2]: http://www.zsh.org/mla/users/2009/msg00818.html
# [3]: http://sourceforge.net/projects/fizsh/
# [4]: https://github.com/robbyrussell/oh-my-zsh/pull/215
# [5]: https://github.com/sunaku/zsh-history-substring-search
# [6]: https://github.com/nicoulaj/zsh-syntax-highlighting
#
##############################################################################
#
# Copyright (c) 2009 Peter Stephenson
# Copyright (c) 2011 Guido van Steen
# Copyright (c) 2011 Suraj N. Kurapati
# Copyright (c) 2011 Sorin Ionescu
# Copyright (c) 2011 Vincent Guerci
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#  * Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  * Redistributions in binary form must reproduce the above
#    copyright notice, this list of conditions and the following
#    disclaimer in the documentation and/or other materials provided
#    with the distribution.
#
#  * Neither the name of the FIZSH nor the names of its contributors
#    may be used to endorse or promote products derived from this
#    software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
##############################################################################
 
#-----------------------------------------------------------------------------
# configuration variables
#-----------------------------------------------------------------------------
 
HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND='bg=magenta,fg=white,bold'
HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND='bg=red,fg=white,bold'
HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS='i'
 
#-----------------------------------------------------------------------------
# the main ZLE widgets
#-----------------------------------------------------------------------------
 
function history-substring-search-up() {
  _history-substring-search-begin
 
  _history-substring-search-up-history ||
  _history-substring-search-up-buffer ||
  _history-substring-search-up-search
 
  _history-substring-search-end
}
 
function history-substring-search-down() {
  _history-substring-search-begin
 
  _history-substring-search-down-history ||
  _history-substring-search-down-buffer ||
  _history-substring-search-down-search
 
  _history-substring-search-end
}
 
zle -N history-substring-search-up
zle -N history-substring-search-down
 
bindkey '\e[A' history-substring-search-up
bindkey '\e[B' history-substring-search-down
 
#-----------------------------------------------------------------------------
# implementation details
#-----------------------------------------------------------------------------
 
setopt extendedglob
zmodload -F zsh/parameter
 
#
# We have to "override" some keys and widgets if the
# zsh-syntax-highlighting plugin has not been loaded:
#
# https://github.com/nicoulaj/zsh-syntax-highlighting
#
if [[ $+functions[_zsh_highlight] -eq 0 ]]; then
  #
  # Dummy implementation of _zsh_highlight()
  # that simply removes existing highlights
  #
  function _zsh_highlight() {
    region_highlight=()
  }
 
  #
  # Remove existing highlights when the user
  # inserts printable characters into $BUFFER
  #
  function ordinary-key-press() {
    if [[ $KEYS == [[:print:]] ]]; then
      region_highlight=()
    fi
    zle .self-insert
  }
  zle -N self-insert ordinary-key-press
 
  #
  # Override ZLE widgets to invoke _zsh_highlight()
  #
  # https://github.com/nicoulaj/zsh-syntax-highlighting/blob/
  # bb7fcb79fad797a40077bebaf6f4e4a93c9d8163/zsh-syntax-highlighting.zsh#L121
  #
  #--------------8<-------------------8<-------------------8<-----------------
  #
  # Copyright (c) 2010-2011 zsh-syntax-highlighting contributors
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  #
  #  * Redistributions in binary form must reproduce the above copyright
  #    notice, this list of conditions and the following disclaimer in the
  #    documentation and/or other materials provided with the distribution.
  #
  #  * Neither the name of the zsh-syntax-highlighting contributors nor the
  #    names of its contributors may be used to endorse or promote products
  #    derived from this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  # IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
  # Load ZSH module zsh/zleparameter, needed to override user defined widgets.
  zmodload zsh/zleparameter 2>/dev/null || {
    echo 'zsh-syntax-highlighting: failed loading zsh/zleparameter, exiting.' >&2
    return -1
  }
 
  # Override ZLE widgets to make them invoke _zsh_highlight.
  for event in ${${(f)"$(zle -la)"}:#(_*|orig-*|.run-help|.which-command)}; do
    if [[ "$widgets[$event]" == completion:* ]]; then
      eval "zle -C orig-$event ${${${widgets[$event]}#*:}/:/ } ; $event() { builtin zle orig-$event && _zsh_highlight } ; zle -N $event"
    else
      case $event in
        accept-and-menu-complete)
          eval "$event() { builtin zle .$event && _zsh_highlight } ; zle -N $event"
          ;;
 
        # The following widgets should NOT remove any previously
        # applied highlighting. Therefore we do not remap them.
        .forward-char|.backward-char|.up-line-or-history|.down-line-or-history)
          ;;
 
        .*)
          clean_event=$event[2,${#event}] # Remove the leading dot in the event name
          case ${widgets[$clean_event]-} in
            (completion|user):*)
              ;;
            *)
              eval "$clean_event() { builtin zle $event && _zsh_highlight } ; zle -N $clean_event"
              ;;
          esac
          ;;
        *)
          ;;
      esac
    fi
  done
  unset event clean_event
  #-------------->8------------------->8------------------->8-----------------
fi
 
function _history-substring-search-begin() {
  _history_substring_search_move_cursor_eol=false
  _history_substring_search_query_highlight=
 
  #
  # Continue using the previous $_history_substring_search_result by default,
  # unless the current query was cleared or a new/different query was entered.
  #
  if [[ -z $BUFFER || $BUFFER != $_history_substring_search_result ]]; then
    #
    # For the purpose of highlighting we will also keep
    # a version without doubly-escaped meta characters.
    #
    _history_substring_search_query=$BUFFER
 
    #