_powerline_tmux_setenv() {
	emulate -L zsh
	if [[ -n "$TMUX" ]]; then
		tmux setenv TMUX_"$1"_$(tmux display -p "#D" | tr -d %) "$2"
	fi
}

_powerline_tmux_set_pwd() {
	_powerline_tmux_setenv PWD "$PWD"
}

_powerline_tmux_set_columns() {
	_powerline_tmux_setenv COLUMNS "$COLUMNS"
}

_powerline_install_precmd() {
	emulate zsh
	for f in "${precmd_functions[@]}"; do
		if [[ "$f" = "_powerline_precmd" ]]; then
			return
		fi
	done
	chpwd_functions+=( _powerline_tmux_set_pwd )
	setopt promptpercent
	setopt promptsubst
	if zmodload zsh/zpython &>/dev/null ; then
		zpython 'from powerline.bindings.zsh import setup as powerline_setup'
		zpython 'powerline_setup()'
		zpython 'del powerline_setup'
	else
		PS1='$(powerline shell left -r zsh_prompt --last_exit_code=$? --last_pipe_status="$pipestatus")'
		RPS1='$(powerline shell right -r zsh_prompt --last_exit_code=$? --last_pipe_status="$pipestatus")'
	fi
}

trap "_powerline_tmux_set_columns" SIGWINCH
_powerline_tmux_set_columns

_powerline_install_precmd