#!/usr/bin/env bash

. "${HOME}/.cache/wal/colors.sh"

quote() {
    local q="$(printf '%q ' "$@")"
    printf '%s' "${q% }"
}

hc_quoted="$(quote "${herbstclient_command[@]:-herbstclient}")"
hc() { "${herbstclient_command[@]:-herbstclient}" "$@"; }
monitor=${1:-0}
geometry=($(hc monitor_rect "$monitor"))
if [ -z "$geometry" ]; then
    echo "Invalid monitor $monitor"
    exit 1
fi
# geometry has the format W H X Y
x=$((${geometry[0]} + 12))
y=$((${geometry[1]} + 12))
panel_width=$((${geometry[2]} - 24))
panel_height=29
font="*mono*"

####
# Try to find textwidth binary.
# In e.g. Ubuntu, this is named dzen2-textwidth.
if which textwidth &>/dev/null; then
    textwidth="textwidth"
elif which dzen2-textwidth &>/dev/null; then
    textwidth="dzen2-textwidth"
elif which xftwidth &>/dev/null; then # For guix
    textwidth="xtfwidth"
else
    echo "This script requires the textwidth tool of the dzen2 project."
    exit 1
fi
####
# true if we are using the svn version of dzen2
# depending on version/distribution, this seems to have version strings like
# "dzen-" or "dzen-x.x.x-svn"
if dzen2 -v 2>&1 | head -n 1 | grep -q '^dzen-\([^,]*-svn\|\),'; then
    dzen2_svn="true"
else
    dzen2_svn=""
fi

if awk -Wv 2>/dev/null | head -1 | grep -q '^mawk'; then
    mawk needs "-W interactive" to line-buffer stdout correctly
    # http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=593504
    uniq_linebuffered() {
        awk -W interactive '$0 != l { print ; l=$0 ; fflush(); }' "$@"
    }
else
    # other awk versions (e.g. gawk) issue a warning with "-W interactive", so
    # we don't want to use it there.
    uniq_linebuffered() {
        awk '$0 != l { print ; l=$0 ; fflush(); }' "$@"
    }
fi

# get the current pulseaudio volume, or state incase muted
pulsegetvol() {
    if [ $(pulsemixer --get-mute) == 1 ]; then
        echo -ne "^fg($foreground)muted\n"
    else
        volume=$(pulsemixer --get-volume | awk '{print $1; exit}')
        echo -n "^fg($foreground)$volume"
    fi
}

# using pactl we can subscribe to pulseaudio and check for changes
pulsesub() {
    pactl subscribe | grep --line-buffered "change.*sink" | while read -r line; do
        echo -ne "pulseaudio\t$(pulsegetvol)\n"
    done
}

# used when reloading / quitting, kills all event generators as they no longer have a use
list_descendants() {
    local children=$(ps -o pid= --ppid "$1")
    for pid in $children; do
        list_descendants "$pid"
    done
    echo "$children"
}

hc pad $monitor $(($panel_height + 12))

{
    ### Event generator ###
    # based on different input data (mpc, date, hlwm hooks, ...) this generates events, formed like this:
    #   <eventname>\t<data> [...]
    # e.g.
    #   date    ^fg(#efefef)18:33^fg(#909090), 2013-10-^fg(#efefef)29

    #mpc idleloop player &
    pulsesub &
    while true; do
        # "date" output is checked once a second, but an event is only
        # generated if the output changed compared to the previous run.
        date +$"date	^fg($foreground)%a %b %d %H:%M"
        sleep 1 || break
    done > >(uniq_linebuffered) &
    hc --idle
} 2>/dev/null | {
    IFS=$'\t' read -ra tags <<<"$(hc tag_status $monitor)"
    visible=true
    date=""
    windowtitle=""
    volume="$(pulsegetvol)"
    while true; do

        ### Output ###
        # This part prints dzen data based on the _previous_ data handling run,
        # and then waits for the next event to happen.

        separator="^bg()^fg($color8)|"
        # draw tags
        for i in "${tags[@]}"; do
            case ${i:0:1} in
            '#')
                # tag is focused
                echo -n "^bg($color2)^fg()"
                ;;
            ':')
                # tag is not empty
                echo -n "^bg()^fg($foreground)"
                ;;
            '!')
                # tag containts an urgent window
                echo -n "^bg($color6)^fg()"
                ;;
            '-')
                # tag is viewed on a non-focused monitor
                echo -n "^bg($color1)^fg()"
                ;;
            *)
                # tag is empty
                echo -n "^bg()^fg($color8)"
                ;;
            esac
            if [ ! -z "$dzen2_svn" ]; then
                # clickable tags if using SVN dzen
                echo -n "^ca(1,$hc_quoted focus_monitor \"$monitor\" && "
                echo -n "$hc_quoted use \"${i:1}\") ${i:1} ^ca()"
            else
                # non-clickable tags if using older dzen
                echo -n " ${i:1} "
            fi
        done
        echo -n "$separator"
        echo -n "^bg()^fg() ${windowtitle//^/^^}"
        # small adjustments
        right="$volume $separator $date"
        right_text_only=$(echo -n "$right" | sed 's.\^[^(]*([^)]*)..g')
        # get width of right aligned text.. and add some space..
        width=$($textwidth "$font" "$right_text_only    ")
        echo -n "^pa($(($panel_width - $width)))$right"
        echo

        ### Data handling ###
        # This part handles the events generated in the event loop, and sets
        # internal variables based on them. The event and its arguments are
        # read into the array cmd, then action is taken depending on the event
        # name.
        # "Special" events (quit_panel/togglehidepanel/reload) are also handled
        # here.

        # wait for next event
        IFS=$'\t' read -ra cmd || break
        # find out event origin
        case "${cmd[0]}" in
        tag*)
            #echo "resetting tags" >&2
            IFS=$'\t' read -ra tags <<<"$(hc tag_status $monitor)"
            ;;
        date)
            #echo "resetting date" >&2
            date="${cmd[@]:1}"
            ;;
        quit_panel)
            kill $(list_descendants $$)
            exit
            ;;
        togglehidepanel)
            currentmonidx=$(hc list_monitors | sed -n '/\[FOCUS\]$/s/:.*//p')
            if [ "${cmd[1]}" -ne "$monitor" ]; then
                continue
            fi
            if [ "${cmd[1]}" = "current" ] && [ "$currentmonidx" -ne "$monitor" ]; then
                continue
            fi
            echo "^togglehide()"
            if $visible; then
                visible=false
                hc pad $monitor 0
            else
                visible=true
                hc pad $monitor $(($panel_height + 12))
            fi
            ;;
        reload)
            kill $(list_descendants $$)
            exit
            ;;
        focus_changed | window_title_changed)
            windowtitle="${cmd[@]:2}"
            ;;
        pulseaudio)
            volume="${cmd[@]:1}"
            ;;
        esac
    done

    ### dzen2 ###
    # After the data is gathered and processed, the output of the previous block
    # gets piped to dzen2.

} 2>/dev/null | dzen2 -w $panel_width -x $x -y $y -fn mononoki-15 -h $panel_height \
    -e "button3=;button4=exec:$hc_quoted use_index -1;button5=exec:$hc_quoted use_index +1" \
    -ta l -bg "$background" -fg "$foreground"