#!/bin/bash
# Sway WM screen + audio recorder
# original author: Aaron D. Fields
# blog post: https://blog.spirotot.com/2017/08/21/a-dirty-hack-to-enable-acceptable-sway-wm-screen-recording/
# currently error 503 :-(
#
# Updated version: ernierasta
# Repo: https://gist.github.com/ernierasta
# 
# Changelog:
#       - switched to wf-recorder (https://github.com/ammen99/wf-recorder), swaygrab do not work anymore
#       - switched to pulseaudio sound recording, this will allow us to record specific streams to separate
#         files and to capture sounds from apps and microphone
#       - added option to run set output without -o parameter
#       - script will keep temporary files, they can be useful for manual merge (volume adjustments, cuts, ...)
#         in something like openshot
#       - more documentation
#       - added -n option to disable post-processing (video resizing + audio,video merging)
#
# Usage: sway-record -d [display] -a [app audio sink] -m [mic audio sink]  -o [project_output_name] -n
#       or alternatively:
#       sway-record project_output_name
#
# When you finish recording, pres CTRL+C and it will stop all processes.
#
# -n option allows to disable post-processing entirely
#
#
# INSTALL & SETTINGS:
#
# Copy this file as /usr/local/bin/sway-recorder or to any other dir in your $PATH.
#
# Displays can be listed with:
#
#   swaymsg -t get_outputs
#
# PulseAudio sinks can be listed by: parecord -d <TAB> or:
#
#   pacmd list-source-outputs | grep "source" | grep -oP "<\K[^ >]+"
# 
# Dependencies: ffmpeg, pulseaudio, wf-recorder
#
# WARNING: you probably need to compile wf-recorder, follow instructions on project page(https://github.com/ammen99/wf-recorder).
#
# Example: sway-record -d DP-1 -a alsa_output.pci-0000_21_00.3.analog-stereo.monitor -m alsa_input.usb-audio-technica____AT2020_USB-00.analog-stereo my_recording
#
# Note: If this file is sorely out of date, it's either no longer relevant,
# and/or I decided to push changes here: https://github.com/Spirotot/dotFiles
# Note 2: Maybe I am blind ... do not see this in repo. ;-) ErnieRasta
# Note 3: This in no more outdated! Works with sway 1.0 RC5

# You can define some defaults, which is very convinient...
DISP="eDP-1"
AUDIO_APP="alsa_output.pci-0000_00_1f.3.analog-stereo.monitor"
AUDIO_MIC="alsa_input.usb-audio-technica____AT2020_USB-00.analog-stereo"
OUTPUT="record"

# change to true if you want to disable post-processing entirely
NO_PROCESSING=false

# You probably want to leave vars below empty
SCREEN_CMD=""
AUDIO_APP_CMD=""
AUDIO_MIC_CMD=""

# These for sure should be empty!
SCREEN_PID=""
AUDIO_APP_PID=""
AUDIO_MIC_PID=""
START=""

# Set a trap for Ctrl+C (SIGINT) so that we can forward the
# Ctrl+C to the `swaygrab` and `arecord` subprocesses.
# Inspired by: https://stackoverflow.com/questions/8993655/can-a-bash-script-run-simultaneous-commands-then-wait-for-them-to-complete
trap killandconvert SIGINT

# `killandconvert()` kills the `swaygrab` and `arecord` subprocesses
# when Ctrl+C is pressed, and then proceeds to fix up the length
# discrepencies, and create the final output MKV.
killandconvert() {
        # Forward the SIGINT to `swagrab` and `arecord` so they can shut
        # themselves down properly. 
        kill -2 $SCREEN_PID
        kill -2 $AUDIO_APP_PID
        kill -2 $AUDIO_MIC_PID

        # Wait for them to exit...
        wait $AUDIO_APP_PID
        wait $AUDIO_MIC_PID
        wait $SCREEN_PID

        if [ "$NO_PROCESSING" = true ]; then
                return
        fi

        # Get the lengths:
        #         * https://forum.videolan.org/viewtopic.php?t=56438
        #         * https://stackoverflow.com/questions/20323640/ffmpeg-deocde-without-producing-output-file
        # Convert the lengths with awk: https://askubuntu.com/questions/407743/convert-time-stamp-to-seconds-in-bash
        SCREEN_LENGTH=`ffmpeg -i ${OUTPUT}_orig.mkv -f null /dev/null 2>&1 | \
                                   grep Duration | awk '{print $2}' | tr -d "," | \
                                   awk -F: '{print ($1 * 3600) + ($2 * 60) + $3}'`

        if [ "$START" = "" ]; then
                AUDIO_LENGTH=`ffmpeg -i ${OUTPUT}_app_orig.wav -f null /dev/null 2>&1 | \
                                          grep Duration | awk '{print $2}' | tr -d "," | \
                                          awk -F: '{print ($1 * 3600) + ($2 * 60) + $3}'`
        else
                # https://unix.stackexchange.com/questions/53841/how-to-use-a-timer-in-bash
                AUDIO_LENGTH=$((SECONDS - START))
        fi

        # Calculate the multiplier used to sync the video to the audio.
        # https://stackoverflow.com/questions/12722095/how-do-i-use-floating-point-division-in-bash
        MULTIPLIER=`bc -l <<< "scale=8; $AUDIO_LENGTH/$SCREEN_LENGTH"`

        # "Sync" the video to the audio by stretching it.
        # https://trac.ffmpeg.org/wiki/How%20to%20speed%20up%20/%20slow%20down%20a%20video
        `ffmpeg -i ${OUTPUT}_orig.mkv -filter:v "setpts=${MULTIPLIER}*PTS" \
        -preset ultrafast ${OUTPUT}_tmp.mkv`

        if [ "$START" = "" ]; then
                # Combine the video and audio streams into one output file.
        # mixing: https://stackoverflow.com/questions/50168993/merging-2-audios-files-with-a-video-in-ffmpeg
                `ffmpeg -i ${OUTPUT}_tmp.mkv -i ${OUTPUT}_app_orig.wav -i ${OUTPUT}_mic_orig.wav \
                -filter_complex "[1][2]amix=inputs=2[a]" \
                -map 0:v -map "[a]" \
                -c:v copy -c:a aac ${OUTPUT}.mkv`
        else
                # If there is no audio stream, then just rename the video stream
                # as the final outout file.
                mv ${OUTPUT}_tmp.mkv ${OUTPUT}.mkv
        fi

        # Cleanup
        #rm -f ${OUTPUT}_orig.mkv
        #rm -f ${OUTPUT}_tmp.mkv
        #rm -f ${OUTPUT}_orig.wav
}

# mandatory trick to enable non-option parameter
# https://stackoverflow.com/questions/21753340/script-with-non-option-and-option-arguments
mandatory=()
# Parse the command line options...
# http://abhipandey.com/2016/03/getopt-vs-getopts/
while [ $# -gt 0 ] && [ "$1" != "--" ]; do
        while getopts d:a:m:o:n FLAG; do
                case $FLAG in
                        d)
                                DISP=$OPTARG
                                ;;
                        a)
                                AUDIO_APP=$OPTARG
                                ;;
                        m)
                                AUDIO_MIC=$OPTARG
                                ;;
                        o)
                                OUTPUT=$OPTARG
                                ;;
                        n)
                                NO_PROCESSING=true
                                echo "NO PROCESSING!"
                                ;;
                esac
        done
        shift $((OPTIND-1))

        while [ $# -gt 0 ] && ! [[ "$1" =~ ^- ]]; do
                mandatory=("${mandatory[@]}" "$1") 
                shift                                                                                                       
        done
done

if [ "$1" == "--" ]; then
        shift
        mandatory=("${mandatory[@]}" "$@")
fi

if [ "${mandatory[0]}" != "" ]; then
        echo ${mandatory[0]}
        OUTPUT=${mandatory[0]}
fi

# Check the user's options to make sure they're somewhat sane.
if [ "$OUTPUT" = "" ]; then
        echo "No output specified."
        exit 1
fi

if [ "$DISP" = "" ]; then
        echo "No display specified."
        exit 1
else
        # Build the command used for screen recording.
        SCREEN_CMD="wf-recorder -o $DISP -f ${OUTPUT}_orig.mkv"
fi

# Build the command used for app audio recording.
AUDIO_APP_CMD="parecord -d ${AUDIO_APP} ${OUTPUT}_app_orig.wav"
AUDIO_MIC_CMD="parecord -d ${AUDIO_MIC} ${OUTPUT}_mic_orig.wav"
# Start the screen recorder...
$SCREEN_CMD &
# ... and save the PID so we can kill it gracefully later.
SCREEN_PID=$!

if [ ! "$AUDIO_APP_CMD" = "" ]; then
        # Start the audio recorder...
        $AUDIO_APP_CMD &
        # ... and save the PID so we can kill it gracefully later.
        AUDIO_APP_PID=$!
else
        # Unless we're not going to record audio, in which case we'll
        # simply use a timer to figure out how much we need to stretch
        # the video...
        # https://unix.stackexchange.com/questions/53841/how-to-use-a-timer-in-bash
        START=$SECONDS
fi

if [ ! "$AUDIO_MIC_CMD" = "" ]; then
        # Start the audio recorder...
        $AUDIO_MIC_CMD &
        # ... and save the PID so we can kill it gracefully later.
        AUDIO_MIC_PID=$!
else
        # Unless we're not going to record audio, in which case we'll
        # simply use a timer to figure out how much we need to stretch
        # the video...
        # https://unix.stackexchange.com/questions/53841/how-to-use-a-timer-in-bash
        START=$SECONDS
fi



# Just hang out until the user presses Ctrl+C
wait