#!/bin/bash -eu

# ---------------------------------------------------------
# Lazy Variables
__save() {
    local name=$1
    shift
    declare -g $name="$*"
}

require() {
    for name in $@; do
        if [ -z "${!name+x}" ]; then
            get_$name "__save $name" "require_for $name"
        fi
    done
}

shopt -s expand_aliases
alias greq='$2 '
alias gsave='$1 '

typeset -gA require_depends=()

invalidate() {
    for name in $@; do
        unset -v $name
        if [ -n "${require_depends[$name]:-""}" ]; then
            local tmp="${require_depends[$name]}"
            unset -v require_depends[$name]
            invalidate $tmp
        fi
    done
}

require_for() {
    local self_name=$1
    shift
    require $@
    for name in $@; do
        require_depends[$name]="${require_depends[$name]-""} $self_name"
    done
}

# ---------------------------------------------------------
# Lazy variables
get_ponymix_prog() {
    gsave $(which ponymix 2>/dev/null)
}

get_pacmd_prog() {
    # May be unavailable if only pulse clients installed
    gsave $(which pacmd 2>/dev/null)
}

get_default_sink() {
    gsave $(pactl info | grep 'Default Sink' | cut -d: -f2)
}

# There doesn't seem to be a better way to get a sink volume right now
get_pacmd_dump() {
    greq pacmd_prog
    [ -n "$pacmd_prog" ] || { echo "ERROR: \$pacmd_dump requires available pacmd which is part of the pulseaudio server package"; exit 44; }
    gsave "$(pacmd dump)"
}

get_pacmd_default_sink_config() {
    greq pacmd_dump default_sink
    gsave "$(echo "$pacmd_dump" | grep "$default_sink")"
}

get_pacmd_default_volume() {
    greq pacmd_default_sink_config
    gsave $[$(echo "$pacmd_default_sink_config" | grep "set-sink-volume" | cut -d' ' -f3)]
}

get_default_volume_percent() {
    greq ponymix_prog
    if [ -n "$ponymix_prog" ]; then
        gsave $($ponymix_prog get-volume)
    else
        greq pacmd_default_volume
        gsave $[(100*$pacmd_default_volume+32768)/65535]
    fi
}

get_default_mute() {
    greq ponymix_prog
    if [ -n "$ponymix_prog" ]; then
        $ponymix_prog is-muted && gsave yes || gsave no
    else
        greq pacmd_default_sink_config
        gsave $(echo "$pacmd_default_sink_config" | grep "set-sink-mute" | cut -d' ' -f3)
    fi
}

# ---------------------------------------------------------
# Operations
do_vol() {
    # Set default sink volume
    require default_sink
    local offset
    case "$1" in
        m|mute)
            pactl set-sink-mute $default_sink true
            ;;
        u|unmute)
            pactl set-sink-mute $default_sink false
            ;;
        t|toggle|toggle-mute)
            pactl set-sink-mute $default_sink toggle
            ;;
        \+) : ${offset:=+5%};&
        \-) : ${offset:=-5%};&
        *)  : ${offset:=$1}
            pactl set-sink-mute $default_sink false
            pactl set-sink-volume $default_sink $offset
            ;;
    esac
    invalidate pacmd_dump default_volume_percent default_mute
}

do_notify() {
    # Notification
    if which dunstify >/dev/null 2>&1 && [ -n "`pgrep --ns $$ -u $(id -u) dunst`" ]; then
        require default_sink default_volume_percent default_mute
        dunst_id=6533319
        if [ $default_mute = yes ]; then
            icon=audio-volume-muted
            text="Volume muted"
        else
            text="Volume $default_volume_percent%"
            if [ $default_volume_percent -lt 35 ]; then
                icon=audio-volume-low
            elif [ $default_volume_percent -lt 75 ]; then
                icon=audio-volume-medium
            else
                icon=audio-volume-high
            fi
        fi
        if echo $default_sink | grep -q bluez; then
            text="Bluetooth $text"
        fi
        bar_size=20
        filled=$[(($bar_size * $default_volume_percent) + (100 / (2 * $bar_size)))/100]
        bar=
        if [ $filled -gt 0 ]; then
            bar="`printf %.s● $(seq $filled)`"
        fi
        if [ $filled -lt $bar_size ]; then
            bar="$bar`printf %.s○ $(seq $[$bar_size-$filled])`"
        fi
        dunstify -a "PA Volume" -u low -i $icon -r $dunst_id "$text" "$bar"
    fi
}

do_print() {
    require default_sink default_volume_percent default_mute
    [ $default_mute = yes ] && muted=muted || muted=unmuted
    echo "$default_sink $default_volume_percent% $muted"
}

# ---------------------------------------------------------
# Main

while [ $# -gt 0 ]; do
    verb=$1; shift

    case $verb in
        v|vol|volume)
            do_vol "$1"; shift
            do_notify
            do_print
            ;;
        set-volume)
            do_vol "$1"; shift
            ;;
        n|notify)
            do_notify
            ;;
        p|print)
            do_print
            ;;
        get-default-sink)
            require default_sink
            echo $default_sink
            ;;
        *)
            echo "Available verbs:"
            echo "  set-volume <[+-]n%|mute|unmute|toggle>  Change default sink volume"
            echo "  notify                                  Display a notification with current default sink volume"
            echo "  print                                   Print the default sink and it's volume"
            echo "  volume <see set-volume>                 Short for \"set-volume <...> notify print\""
            echo "  get-default-sink                        Print default sink name"
            echo
            echo " verbs can be chained by separating them with space. Note that some have additional arguments"
            exit 1
            ;;
    esac
done