# config options

default_next_key="n"
tmux_option_next="@copycat_next"

default_prev_key="N"
tmux_option_prev="@copycat_prev"

# keeps track of number of panes in copycat mode
tmux_option_counter="@copycat_counter"

# === awk vs gawk ===
command_exists() {
	command -v "$@" > /dev/null 2>&1
}
AWK_CMD='awk'
if command_exists gawk; then
	AWK_CMD='gawk'
fi

# === general helpers ===

get_tmux_option() {
	local option=$1
	local default_value=$2
	local option_value=$(tmux show-option -gqv "$option")
	if [ -z "$option_value" ]; then
		echo "$default_value"
	else
		echo "$option_value"
	fi
}

set_tmux_option() {
	local option=$1
	local value=$2
	tmux set-option -gq "$option" "$value"
}

tmux_copy_mode() {
	tmux show-option -gwv mode-keys
}

tmux_copy_mode_string() {
	if [ $(tmux_copy_mode) == 'vi' ]; then
		echo copy-mode-vi
	else
		echo copy-mode
	fi
}

# === copycat mode specific helpers ===

set_copycat_mode() {
	set_tmux_option "$(_copycat_mode_var)" "true"
}

unset_copycat_mode() {
	set_tmux_option "$(_copycat_mode_var)" "false"
}

in_copycat_mode() {
	local copycat_mode=$(get_tmux_option "$(_copycat_mode_var)" "false")
	[ "$copycat_mode" == "true" ]
}

not_in_copycat_mode() {
	if in_copycat_mode; then
		return 1
	else
		return 0
	fi
}

# === copycat mode position ===

get_copycat_position() {
	local copycat_position_variable=$(_copycat_position_var)
	echo $(get_tmux_option "$copycat_position_variable" "0")
}

set_copycat_position() {
	local position="$1"
	local copycat_position_variable=$(_copycat_position_var)
	set_tmux_option "$copycat_position_variable" "$position"
}

reset_copycat_position() {
	set_copycat_position "0"
}

# === scrollback and results position ===

get_scrollback_filename() {
	echo "$(_get_tmp_dir)/scrollback-$(_pane_unique_id)"
}

get_copycat_filename() {
	echo "$(_get_tmp_dir)/results-$(_pane_unique_id)"
}

# Ensures a message is displayed for 5 seconds in tmux prompt.
# Does not override the 'display-time' tmux option.
display_message() {
	local message="$1"

	# display_duration defaults to 5 seconds, if not passed as an argument
	if [ "$#" -eq 2 ]; then
		local display_duration="$2"
	else
		local display_duration="5000"
	fi

	# saves user-set 'display-time' option
	local saved_display_time=$(get_tmux_option "display-time" "750")

	# sets message display time to 5 seconds
	tmux set-option -gq display-time "$display_duration"

	# displays message
	tmux display-message "$message"

	# restores original 'display-time' value
	tmux set-option -gq display-time "$saved_display_time"
}

# === counter functions ===

copycat_increase_counter() {
	local count=$(get_tmux_option "$tmux_option_counter" "0")
	local new_count="$((count + 1))"
	set_tmux_option "$tmux_option_counter" "$new_count"
}

copycat_decrease_counter() {
	local count="$(get_tmux_option "$tmux_option_counter" "0")"
	if [ "$count" -gt "0" ]; then
		# decreasing the counter only if it won't go below 0
		local new_count="$((count - 1))"
		set_tmux_option "$tmux_option_counter" "$new_count"
	fi
}

copycat_counter_zero() {
	local count="$(get_tmux_option "$tmux_option_counter" "0")"
	[ "$count" -eq "0" ]
}

# === key binding functions ===

copycat_next_key() {
	echo "$(get_tmux_option "$tmux_option_next" "$default_next_key")"
}

copycat_prev_key() {
	echo "$(get_tmux_option "$tmux_option_prev" "$default_prev_key")"
}

# function expected output: 'C-c Enter q'
copycat_quit_copy_mode_keys() {
	local commands_that_quit_copy_mode="cancel"
	local copy_mode="$(tmux_copy_mode_string)"
	tmux list-keys -T "$copy_mode" |
		\grep "$commands_that_quit_copy_mode" |
		$AWK_CMD '{ print $4 }' |
		sort -u |
		sed 's/C-j//g' |
		xargs echo
}

# === 'private' functions ===

_copycat_mode_var() {
	local pane_id="$(_pane_unique_id)"
	echo "@copycat_mode_$pane_id"
}

_copycat_position_var() {
	local pane_id="$(_pane_unique_id)"
	echo "@copycat_position_$pane_id"
}

_get_tmp_dir() {
	echo "${TMPDIR:-/tmp}/tmux-$EUID-copycat"
}

# returns a string unique to current pane
# sed removes `$` sign because `session_id` contains is
_pane_unique_id() {
	tmux display-message -p "#{session_id}-#{window_index}-#{pane_index}" |
		sed 's/\$//'
}