#!/bin/bash

set -x

monitor="HDMI1"
xrandr_out="$(xrandr)"
output="/tmp/vid.mkv"

find_device_info() {
        pactl list sources \
                | grep "Name: ${1}" -A3
}

parse_device_name() {
        echo "${1}" \
                | grep Name \
                | awk '{print $2}'
}

parse_channels() {
        echo "${1}" \
                | grep 'Sample Specification' \
                | awk '{print $4}' \
                | sed 's/ch//'
}

parse_rate() {
        echo "${1}" \
                | grep 'Sample Specification' \
                | awk '{print $5}' \
                | sed 's/Hz//'
}

find_monitor_info() {
        dev="${2}"
        echo "${1}" \
                | awk "BEGIN {found = \"false\"}
                        /^${dev}/ {found = \"true\"; print \$0; next}
                        /^[[:space:]]/ {if (found == \"true\") {print \$0} }
                        /^\w/ {if (found == \"true\") {exit 0}}"
}

get_monitor_size() {
        dev="${2}"
        echo "${1}" \
                | awk "/^${dev}.*primary/ {print \$4; exit}
                        /^${dev}/ {print \$3; exit}" \
                | sed 's/^\([[:digit:]]*x[[:digit:]]*\).*/\1/'
}

get_monitor_pos() {
        dev="${2}"
        echo "${1}" \
                | awk "/^${dev}.*primary/ {print \$4; exit}
                        /^${dev}/ {print \$3; exit}" \
                | sed 's/.*\([[:digit:]]+[[:digit:]]*\)/\1/' \
                | sed 's/+/,/'
}

get_monitor_rate() {
        echo "${1}" \
                | awk '/*/ {print $2}' \
                | sed 's/\([[:digit:]]\+\).*/\1/'
}

get_screen_number() {
        echo "${1}" \
                | awk '/Screen / {print $2; exit 0}' \
                | sed 's/://'
}

get_minimum() {
        echo "${*}" \
                sed 's/ /\n/g' \
                | awk "BEGIN {min = 1000000000}
                        {if (\$1 < min) {min = \$1}}
                        END {print min}"
}

odev_info=$(find_device_info "alsa_output")
odev=$(parse_device_name "${odev_info}")
odev_c=$(parse_channels "${odev_info}")
odev_r=$(parse_rate "${odev_info}")

idev_info=$(find_device_info "alsa_input")
idev=$(parse_device_name "${idev_info}")
idev_c=$(parse_channels "${idev_info}")
idev_r=$(parse_rate "${idev_info}")

min_sound_r=$(get_minimum "${odev_r}" "${idev_r}")

mon_info=$(find_monitor_info "${xrandr_out}" "${monitor}")
mon_s=$(get_monitor_size "${mon_info}" "${monitor}")
mon_p=$(get_monitor_pos "${mon_info}" "${monitor}")
mon_r=$(get_monitor_rate "${mon_info}")

screen=$(get_screen_number "${xrandr_out}")

ffmpeg -f pulse -ac "${odev_c}" -ar "${odev_r}" -i "${odev}" \
        -f pulse -ac "${idev_c}" -ar "${idev_r}" -i "${idev}" \
        -filter_complex amix=inputs=2 \
        -f x11grab -s "${mon_s}" -r "${mon_r}" -probesize 100M -i "${DISPLAY}.${screen}+${mon_p}" \
        -vcodec libx264 -preset veryfast -crf 18 \
        -acodec libmp3lame -ar "${min_sound_r}" \
        "${output}"