# Fish-like autosuggestions for zsh. Some of the code was based on the code
# for 'predict-on' 
#
# ```zsh
# zle-line-init() {
#		autosuggest-start
# }
# zle -N zle-line-init
# ```

ZLE_AUTOSUGGEST_PAUSE_WIDGETS=(
vi-cmd-mode vi-backward-char backward-char backward-word beginning-of-line
history-search-forward history-search-backward up-line-or-history
down-line-or-history
)

ZLE_AUTOSUGGEST_COMPLETION_WIDGETS=(
complete-word expand-or-complete expand-or-complete-prefix list-choices
menu-complete reverse-menu-complete menu-expand-or-complete menu-select
accept-and-menu-complete
)

autosuggest-pause() {
	[[ -z $ZLE_AUTOSUGGESTING ]] && return
	unset ZLE_AUTOSUGGESTING
	local widget
	# When autosuggestions are disabled, kill the unmaterialized part
	RBUFFER=''
	zle -A self-insert autosuggest-paused-self-insert
	zle -A .magic-space magic-space
	zle -A .backward-delete-char backward-delete-char
	zle -A .accept-line accept-line
	for widget in $ZLE_AUTOSUGGEST_PAUSE_WIDGETS; do
		eval "zle -A autosuggest-${widget}-orig ${widget}"
	done
	for widget in $ZLE_AUTOSUGGEST_COMPLETION_WIDGETS; do
		eval "zle -A autosuggest-${widget}-orig $widget"
	done
	autosuggest-highlight-suggested-text
}

autosuggest-resume() {
	[[ -n $ZLE_AUTOSUGGESTING ]] && return
	ZLE_AUTOSUGGESTING=1
	local widget
	# Replace prediction widgets by versions that will also highlight RBUFFER
	zle -N self-insert autosuggest-insert-or-space
	zle -N magic-space autosuggest-insert-or-space
	zle -N backward-delete-char autosuggest-backward-delete-char
	zle -N accept-line autosuggest-accept-line
	# Hook into some default widgets that should pause autosuggestion
	# automatically 
	for widget in $ZLE_AUTOSUGGEST_PAUSE_WIDGETS; do
		eval "zle -A $widget autosuggest-${widget}-orig; \
			zle -A autosuggest-suspend $widget"
	done
	# Hook into completion widgets to handle suggestions after completions
	for widget in $ZLE_AUTOSUGGEST_COMPLETION_WIDGETS; do
		eval "zle -A $widget autosuggest-${widget}-orig; \
			zle -A autosuggest-tab $widget"
	done
	if [[ $BUFFER != '' ]]; then
		autosuggest-request-suggestion
	fi
}

autosuggest-start() {
	autosuggest-resume
}

autosuggest-highlight-suggested-text() {
	if [[ -n $ZLE_AUTOSUGGESTING ]]; then
		local color='fg=8'
		[[ -n $AUTOSUGGESTION_HIGHLIGHT_COLOR ]] &&\
			color=$AUTOSUGGESTION_HIGHLIGHT_COLOR
		region_highlight=("$(( $CURSOR + 1 )) $(( $CURSOR + $#RBUFFER )) $color")
	else
		region_highlight=()
	fi
}

autosuggest-insert-or-space() {
	if [[ $LBUFFER == *$'\012'* ]] || (( PENDING )); then
		# Editing a multiline buffer or pasting in a chunk of text, dont
		# autosuggest
		zle .$WIDGET "$@"
	elif [[ ${RBUFFER[1]} == ${KEYS[-1]} ]]; then
    # Same as what's typed, just move on
		((++CURSOR))
		autosuggest-highlight-suggested-text
	else
    LBUFFER="$LBUFFER$KEYS"
		autosuggest-request-suggestion
	fi
}

autosuggest-backward-delete-char() {
	if ! (( CURSOR )); then
	 	zle .kill-whole-line
		return
	fi

	if [[ $LBUFFER == *$'\012'* || $LASTWIDGET != (self-insert|magic-space|backward-delete-char) ]]; then
		# When editing a multiline buffer or if the last widget was e.g. a motion,
		# then probably the intent is to actually edit the line, not change the
		# search prefix.
		LBUFFER="$LBUFFER[1,-2]"
	else
		((--CURSOR))
		zle .history-beginning-search-forward || RBUFFER=''
	fi
}

# When autosuggesting, ignore RBUFFER which corresponds to the 'unmaterialized'
# section when the user accepts the line
autosuggest-accept-line() {
	RBUFFER=''
	region_highlight=()
	zle .accept-line
}

autosuggest-paused-self-insert() {
	if [[ $RBUFFER == '' ]]; then
		# Resume autosuggestions when inserting at the end of the line
		autosuggest-resume
		zle autosuggest-modify
	else
		zle .self-insert
	fi
}

autosuggest-request-suggestion() {
	if (( $CURSOR == 0 )) || [[ ${LBUFFER[-1]} == ' ' ]]; then
	 	RBUFFER=''
		return
	fi

	[[ -n $ZLE_DISABLE_AUTOSUGGEST || $LBUFFER == '' ]] && return
	zle .history-beginning-search-backward || RBUFFER=''
	autosuggest-highlight-suggested-text
}

autosuggest-suspend() {
	autosuggest-pause
	zle autosuggest-${WIDGET}-orig "$@"
}

autosuggest-tab() {
	RBUFFER=''
	zle autosuggest-${WIDGET}-orig "$@"
	autosuggest-highlight-suggested-text
}

autosuggest-accept-suggested-small-word() {
	zle .vi-forward-word
	autosuggest-highlight-suggested-text
}

autosuggest-accept-suggested-word() {
	zle .forward-word
	autosuggest-highlight-suggested-text
}

zle -N autosuggest-start
zle -N autosuggest-accept-suggested-small-word
zle -N autosuggest-accept-suggested-word
zle -N autosuggest-suspend
zle -N autosuggest-tab