# Fish-like fast/unobtrusive autosuggestions for zsh.
# https://github.com/zsh-users/zsh-autosuggestions
# v0.3.1
# Copyright (c) 2013 Thiago de Arruda
# Copyright (c) 2016 Eric Freese
# 
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
# 
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.

#--------------------------------------------------------------------#
# Global Configuration Variables                                     #
#--------------------------------------------------------------------#

# Color to use when highlighting suggestion
# Uses format of `region_highlight`
# More info: http://zsh.sourceforge.net/Doc/Release/Zsh-Line-Editor.html#Zle-Widgets
ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE='fg=8'

# Prefix to use when saving original versions of bound widgets
ZSH_AUTOSUGGEST_ORIGINAL_WIDGET_PREFIX=autosuggest-orig-

ZSH_AUTOSUGGEST_STRATEGY=default

# Widgets that clear the suggestion
ZSH_AUTOSUGGEST_CLEAR_WIDGETS=(
	history-search-forward
	history-search-backward
	history-beginning-search-forward
	history-beginning-search-backward
	history-substring-search-up
	history-substring-search-down
	up-line-or-history
	down-line-or-history
	accept-line
)

# Widgets that accept the entire suggestion
ZSH_AUTOSUGGEST_ACCEPT_WIDGETS=(
	forward-char
	end-of-line
	vi-forward-char
	vi-end-of-line
)

# Widgets that accept the entire suggestion and execute it
ZSH_AUTOSUGGEST_EXECUTE_WIDGETS=(
)

# Widgets that accept the suggestion as far as the cursor moves
ZSH_AUTOSUGGEST_PARTIAL_ACCEPT_WIDGETS=(
	forward-word
	vi-forward-word
	vi-forward-word-end
	vi-forward-blank-word
	vi-forward-blank-word-end
)

#--------------------------------------------------------------------#
# Handle Deprecated Variables/Widgets                                #
#--------------------------------------------------------------------#

_zsh_autosuggest_deprecated_warning() {
	>&2 echo "zsh-autosuggestions: $@"
}

_zsh_autosuggest_check_deprecated_config() {
	if [ -n "$AUTOSUGGESTION_HIGHLIGHT_COLOR" ]; then
		_zsh_autosuggest_deprecated_warning "AUTOSUGGESTION_HIGHLIGHT_COLOR is deprecated. Use ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE instead."
		[ -z "$ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE" ] && ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE=$AUTOSUGGESTION_HIGHLIGHT_STYLE
		unset AUTOSUGGESTION_HIGHLIGHT_STYLE
	fi

	if [ -n "$AUTOSUGGESTION_HIGHLIGHT_CURSOR" ]; then
		_zsh_autosuggest_deprecated_warning "AUTOSUGGESTION_HIGHLIGHT_CURSOR is deprecated."
		unset AUTOSUGGESTION_HIGHLIGHT_CURSOR
	fi

	if [ -n "$AUTOSUGGESTION_ACCEPT_RIGHT_ARROW" ]; then
		_zsh_autosuggest_deprecated_warning "AUTOSUGGESTION_ACCEPT_RIGHT_ARROW is deprecated. The right arrow now accepts the suggestion by default."
		unset AUTOSUGGESTION_ACCEPT_RIGHT_ARROW
	fi
}

_zsh_autosuggest_deprecated_start_widget() {
	_zsh_autosuggest_deprecated_warning "The autosuggest-start widget is deprecated. For more info, see the README at https://github.com/zsh-users/zsh-autosuggestions."
	zle -D autosuggest-start
	eval "zle-line-init() {
		$(echo $functions[${widgets[zle-line-init]#*:}] | sed -e 's/zle autosuggest-start//g')
	}"
}

zle -N autosuggest-start _zsh_autosuggest_deprecated_start_widget

#--------------------------------------------------------------------#
# Widget Helpers                                                     #
#--------------------------------------------------------------------#

# Bind a single widget to an autosuggest widget, saving a reference to the original widget
_zsh_autosuggest_bind_widget() {
	local widget=$1
	local autosuggest_action=$2
	local prefix=$ZSH_AUTOSUGGEST_ORIGINAL_WIDGET_PREFIX

	# Save a reference to the original widget
	case $widgets[$widget] in
		# Already bound
		user:_zsh_autosuggest_(bound|orig)_*);;

		# User-defined widget
		user:*)
			zle -N $prefix$widget ${widgets[$widget]#*:}
			;;

		# Built-in widget
		builtin)
			eval "_zsh_autosuggest_orig_$widget() { zle .$widget }"
			zle -N $prefix$widget _zsh_autosuggest_orig_$widget
			;;

		# Completion widget
		completion:*)
			eval "zle -C $prefix$widget ${${widgets[$widget]#*:}/:/ }"
			;;
	esac

	# Pass the original widget's name explicitly into the autosuggest
	# function. Use this passed in widget name to call the original
	# widget instead of relying on the $WIDGET variable being set
	# correctly. $WIDGET cannot be trusted because other plugins call
	# zle without the `-w` flag (e.g. `zle self-insert` instead of
	# `zle self-insert -w`).
	eval "_zsh_autosuggest_bound_$widget() {
		_zsh_autosuggest_widget_$autosuggest_action $prefix$widget \$@
	}"

	# Create the bound widget
	zle -N $widget _zsh_autosuggest_bound_$widget
}

# Map all configured widgets to the right autosuggest widgets
_zsh_autosuggest_bind_widgets() {
	local widget;

	# Find every widget we might want to bind and bind it appropriately
	for widget in ${${(f)"$(builtin zle -la)"}:#(.*|_*|orig-*|autosuggest-*|$ZSH_AUTOSUGGEST_ORIGINAL_WIDGET_PREFIX*|zle-line-*|run-help|which-command|beep|set-local-history|yank)}; do
		if [ ${ZSH_AUTOSUGGEST_CLEAR_WIDGETS[(r)$widget]} ]; then
			_zsh_autosuggest_bind_widget $widget clear
		elif [ ${ZSH_AUTOSUGGEST_ACCEPT_WIDGETS[(r)$widget]} ]; then
			_zsh_autosuggest_bind_widget $widget accept
		elif [ ${ZSH_AUTOSUGGEST_EXECUTE_WIDGETS[(r)$widget]} ]; then
			_zsh_autosuggest_bind_widget $widget execute
		elif [ ${ZSH_AUTOSUGGEST_PARTIAL_ACCEPT_WIDGETS[(r)$widget]} ]; then
			_zsh_autosuggest_bind_widget $widget partial_accept
		else
			# Assume any unspecified widget might modify the buffer
			_zsh_autosuggest_bind_widget $widget modify
		fi
	done
}

# Given the name of an original widget and args, invoke it, if it exists
_zsh_autosuggest_invoke_original_widget() {
	# Do nothing unless called with at least one arg
	[ $# -gt 0 ] || return

	local original_widget_name="$1"

	shift

	if [ $widgets[$original_widget_name] ]; then
		zle $original_widget_name -- $@
	fi
}

#--------------------------------------------------------------------#
# Highlighting                                                       #
#--------------------------------------------------------------------#

# If there was a highlight, remove it
_zsh_autosuggest_highlight_reset() {
	typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT

	if [ -n "$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT" ]; then
		region_highlight=("${(@)region_highlight:#$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT}")
		unset _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
	fi
}

# If there's a suggestion, highlight it
_zsh_autosuggest_highlight_apply() {
	typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT

	if [ $#POSTDISPLAY -gt 0 ]; then
		_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT="$#BUFFER $(($#BUFFER + $#POSTDISPLAY)) $ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE"
		region_highlight+=("$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT")
	else
		unset _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
	fi
}

#--------------------------------------------------------------------#
# Autosuggest Widget Implementations                                 #
#--------------------------------------------------------------------#

# Clear the suggestion
_zsh_autosuggest_clear() {
	# Remove the suggestion
	unset POSTDISPLAY

	_zsh_autosuggest_invoke_original_widget $@
}

# Modify the buffer and get a new suggestion
_zsh_autosuggest_modify() {
	# Original widget modifies the buffer
	_zsh_autosuggest_invoke_original_widget $@

	# Get a new suggestion if the buffer is not empty after modification
	local suggestion
	if [ $#BUFFER -gt 0 ]; then
		suggestion="$(_zsh_autosuggest_suggestion "$BUFFER")"
	fi

	# Add the suggestion to the POSTDISPLAY
	if [ -n "$suggestion" ]; then
		POSTDISPLAY="${suggestion#$BUFFER}"
	else
		unset POSTDISPLAY
	fi
}

# Accept the entire suggestion
_zsh_autosuggest_accept() {
	local -i max_cursor_pos=$#BUFFER

	# When vicmd keymap is active, the cursor can't move all the way
	# to the end of the buffer
	if [ "$KEYMAP" = "vicmd" ]; then
		max_cursor_pos=$((max_cursor_pos - 1))
	fi

	# Only accept if the cursor is at the end of the buffer
	if [ $CURSOR -eq $max_cursor_pos ]; then
		# Add the suggestion to the buffer
		BUFFER="$BUFFER$POSTDISPLAY"

		# Remove the suggestion
		unset POSTDISPLAY

		# Move the cursor to the end of the buffer
		CURSOR=${#BUFFER}
	fi

	_zsh_autosuggest_invoke_original_widget $@
}

# Accept the entire suggestion and execute it
_zsh_autosuggest_execute() {
	# Add the suggestion to the buffer
	BUFFER="$BUFFER$POSTDISPLAY"

	# Remove the suggestion
	unset POSTDISPLAY

	# Call the original `accept-line` to handle syntax highlighting or
	# other potential custom behavior
	_zsh_autosuggest_invoke_original_widget "accept-line"
}

# Partially accept the suggestion
_zsh_autosuggest_partial_accept() {
	# Save the contents of the buffer so we can restore later if needed
	local original_buffer="$BUFFER"

	# Temporarily accept the suggestion.
	BUFFER="$BUFFER$POSTDISPLAY"

	# Original widget moves the cursor
	_zsh_autosuggest_invoke_original_widget $@

	# If we've moved past the end of the original buffer
	if [ $CURSOR -gt $#original_buffer ]; then
		# Set POSTDISPLAY to text right of the cursor
		POSTDISPLAY="$RBUFFER"

		# Clip the buffer at the cursor
		BUFFER="$LBUFFER"
	else
		# Restore the original buffer
		BUFFER="$original_buffer"
	fi
}

for action in clear modify accept partial_accept execute; do
	eval "_zsh_autosuggest_widget_$action() {
		_zsh_autosuggest_highlight_reset
		_zsh_autosuggest_$action \$@
		_zsh_autosuggest_highlight_apply
	}"
done

zle -N autosuggest-accept _zsh_autosuggest_widget_accept
zle -N autosuggest-clear _zsh_autosuggest_widget_clear
zle -N autosuggest-execute _zsh_autosuggest_widget_execute

#--------------------------------------------------------------------#
# Suggestion                                                         #
#--------------------------------------------------------------------#

# Delegate to the selected strategy to determine a suggestion
_zsh_autosuggest_suggestion() {
	local prefix="$1"
	local strategy_function="_zsh_autosuggest_strategy_$ZSH_AUTOSUGGEST_STRATEGY"

	if [ -n "$functions[$strategy_function]" ]; then
		echo -E "$($strategy_function "$prefix")"
	fi
}

_zsh_autosuggest_escape_command() {
	setopt localoptions EXTENDED_GLOB

	# Escape special chars in the string (requires EXTENDED_GLOB)
	echo -E "${1//(#m)[\\()\[\]|*?]/\\$MATCH}"
}

# Get the previously executed command
_zsh_autosuggest_prev_command() {
	echo -E "${history[$((HISTCMD-1))]}"
}

#--------------------------------------------------------------------#
# Default Suggestion Strategy                                        #
#--------------------------------------------------------------------#
# Suggests the most recent history item that matches the given
# prefix.
#

_zsh_autosuggest_strategy_default() {
	local prefix="$(_zsh_autosuggest_escape_command "$1")"

	# Get the keys of the history items that match
	local -a histkeys
	histkeys=(${(k)history[(r)$prefix*]})

	# Echo the value of the first key
	echo -E "${history[$histkeys[1]]}"
}

#--------------------------------------------------------------------#
# Match Previous Command Suggestion Strategy                         #
#--------------------------------------------------------------------#
# Suggests the most recent history item that matches the given
# prefix and whose preceding history item also matches the most
# recently executed command.
#
# For example, suppose your history has the following entries:
#   - pwd
#   - ls foo
#   - ls bar
#   - pwd
#
# Given the history list above, when you type 'ls', the suggestion
# will be 'ls foo' rather than 'ls bar' because your most recently
# executed command (pwd) was previously followed by 'ls foo'.
#

_zsh_autosuggest_strategy_match_prev_cmd() {
	local prefix="$(_zsh_autosuggest_escape_command "$1")"

	# Get all history event numbers that correspond to history
	# entries that match pattern $prefix*
	local history_match_keys
	history_match_keys=(${(k)history[(R)$prefix*]})

	# By default we use the first history number (most recent history entry)
	local histkey="${history_match_keys[1]}"

	# Get the previously executed command
	local prev_cmd="$(_zsh_autosuggest_prev_command)"
	prev_cmd="$(_zsh_autosuggest_escape_command "$prev_cmd")"

	# Iterate up to the first 200 history event numbers that match $prefix
	for key in "${(@)history_match_keys[1,200]}"; do
		# Stop if we ran out of history
		[[ $key -gt 1 ]] || break

		# See if the history entry preceding the suggestion matches the
		# previous command, and use it if it does
		if [[ "${history[$((key - 1))]}" == "$prev_cmd" ]]; then
			histkey="$key"
			break
		fi
	done

	# Echo the matched history entry
	echo -E "$history[$histkey]"
}

#--------------------------------------------------------------------#
# Start                                                              #
#--------------------------------------------------------------------#

# Start the autosuggestion widgets
_zsh_autosuggest_start() {
	_zsh_autosuggest_check_deprecated_config
	_zsh_autosuggest_bind_widgets
}

autoload -Uz add-zsh-hook
add-zsh-hook precmd _zsh_autosuggest_start