helpers.sh

#!/usr/bin/env bash

##
# Varialbes
##
LAST_FILE="/tmp/tmux_net_speed.last"
_last=()
_current=()

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"
}

get_velocity()
{
    local new_value=$1
    local old_value=$2
    local interval=${3:-$(get_tmux_option 'status-interval' 5)}

    # Consts
    local THOUSAND=1024
    local MILLION=1048576

    local vel=$(( ( new_value - old_value ) / interval ))
    local vel_kb=$(( vel / THOUSAND ))
    local vel_mb=$(( vel / MILLION ))

    if [[ $vel_mb != 0 ]] ; then
        echo -n "$vel_mb MB/s"
    elif [[ $vel_kb != 0 ]] ; then
        echo -n "$vel_kb KB/s";
    else
        echo -n "$vel B/s";
    fi
}

# Reads from value from file. If file does not exist,
# is empty, or not readable, starts back at 0
read_file()
{
    local path="$1"
    local fallback_val=0

    # File exists and is readdable?
    if [[ ! -f "$path" ]] ; then
        echo $fallback_val
        return 1
    elif [[ ! -r "$path" ]]; then
        echo $fallback_val
        return 1
    fi


    # Does the file have content?
    tmp=$(< "$path")
    if [[ "x${tmp}" == "x" ]] ; then
        echo $fallback_val
        return 1
    fi

    # Now return known value
    echo $tmp
}

# Update values in file
write_file()
{
    local path="$1"
    local val="$2"

    # TODO Add error checking
    echo "$val" > "$path"
}

get_interfaces()
{
    local os=${1:-$(os_type)}
    local interfaces=$(get_tmux_option @net_speed_interfaces "")

    if [[ -z "$interfaces" ]] ; then
        case $os in
	    freebsd|osx)
		for interface in $(ifconfig -l); do
		    interfaces+="$interface "
		done
		;;
	    linux)
        	for interface in /sys/class/net/*; do
            	    interfaces+=$(echo $(basename $interface) " ");
        	done
		;;
	esac
    fi

    # Do not quote the variable. This way will handle trailing whitespace
    echo -n $interfaces
}

sum_speed()
{
    local os=$(os_type)
    local down_total=0
    local up_total=0

    declare -a interfaces=$(get_interfaces $os)

    for intf in ${interfaces[@]} ; do
	case $os in
	    freebsd|osx)
		line=( $(netstat -I "$intf" -ibn | grep 'Link#' | awk '{ print $(NF-4), $(NF-1) }') )
		;;
	    linux)
		line=( $(cat /proc/net/dev | grep "$intf" | cut -d':' -f 2 | awk '{ print $1, $9 }') )
		;;
	    esac
	let down_total+=${line[0]}
	let up_total+=${line[1]}
    done

    echo $down_total $up_total
}

# 1 - download, 2 - upload
get_speed()
{
    local column=$1
    local subprocess=${2:-0}
    local interval=$(get_tmux_option 'status-interval' 5)
    local now=$(date +%s)

    # timestamp download_cumulative upload_cumulative
    local last=( "${_last[@]}" )
    if [ ${#last[@]} -eq 0 ]; then
	last=( $(read_file "$LAST_FILE" "$now 0 0") )
	_last=( "${last[@]}" )
    fi
    # protect against division by 0
    if [[ $last -eq $now ]]; then sleep 1; now=$(date +%s); fi
    local current=( "${_current[@]}" )
    if [ ${#current[@]} -eq 0 ]; then
	current=( $now $(sum_speed) )
	_current=( "${current[@]}" )
    fi
    local delta_t=$(( $current - $last ))
    local speed=$(get_velocity ${current[$column]} ${last[$column]} $delta_t)

    if [[ $subprocess -eq 0 ]] && [[ $((${last[0]}+$interval)) -le $now ]]; then
	function update_last()
	{
	    write_file "$LAST_FILE" "${_current[*]}"
	}
	trap update_last EXIT
    fi

    echo $speed
}

is_osx() {
    [ $(uname) == "Darwin" ]
}

is_cygwin() {
    command -v WMIC > /dev/null
}

command_exists() {
    local command="$1"
    type "$command" >/dev/null 2>&1
}

os_type() {
    local os_name="unknown"

    case $(uname | tr '[:upper:]' '[:lower:]') in
      linux*)
        os_name="linux"
        ;;
      darwin*)
        os_name="osx"
        ;;
      msys*)
        os_name="windows"
        ;;
      freebsd*)
        os_name="freebsd"
        ;;
    esac
  
    echo -n $os_name
}