#!/bin/sh
#
# https://www.romanzolotarev.com/bin/screencapture
# Copyright 2018 Roman Zolotarev <hi@romanzolotarev.com>
#
# pkg_add slop ffmpeg mpv
# rcctl set sndiod flags -s default -m play,mon -s mon
# rcctl restart sndiod
#

set -e
log='/tmp/screencast.log'
trap 'clean_up' EXIT
trap exit HUP INT TERM

clean_up() {
	logger 'screencast: clean up'

	[ -f "$log" ] && {
		logger \
		"ffmpeg: $(tr '
' ' '<"$log"|sed -E 's/ {1,}/ /g')"
		rm "$log"
	}
	[ -f "$output" ] && {
		stat -f '%z bytes' "$output"
		mpv --loop=inf --really-quiet "$output"
	}
}

case $1 in

start)
	area=$(slop -o -f '%x,%y+%wx%h')

	origin=$(echo "$area"|cut -d'+' -f1)
	input=":0.0+$origin"

	# width and height should be divisible by two
	odd_size=$(echo "$area"|cut -d'+' -f2)
	w=$(( $(echo "$odd_size"|cut -d'x' -f1) / 2 * 2))
	h=$(( $(echo "$odd_size"|cut -d'x' -f2) / 2 * 2))
	size="${w}x${h}"

	dir="$HOME/downloads"
	mkdir -p "$dir"
	date="$(date +%Y%m%d-%H%M%S)"
	output="$dir/${date}-$size.mp4"

	logger "screencast: capture $size from $input to $output"

	ffmpeg \
	-f x11grab -r 30 -s "$size" -i "$input" \
	-hide_banner \
	-movflags +faststart \
	-pix_fmt yuv420p \
	-preset veryslow \
	-tune animation \
	-vcodec h264 \
	"$output" 2> "$log"
	# -acodec mp3 -ab 192 -ar 44100 -t 20\
	# -f sndio -i snd/0.mon \

	;;

stop)
	if ! pgrep -q ffmpeg; then
		logger 'screencast: nothing to stop'
		exit 1
	fi
	if pkill ffmpeg; then
		logger 'screencast: stopped'
	else
		logger 'screencast: failed to stop'
	fi
	;;

*)
	echo 'usage: screencapture start'
	echo '                   | stop'
	exit 1
	;;

esac