#!/usr/bin/env bash

# Create timelapse. Stop recording with any key.
# Requires ImageMagick (Linux only) and MPlayer's MEncoder.
#
# @param 1 - interval in seconds (optional, default is 1)
timelapse()
{
	local CAPTURE=

	if type import &>/dev/null
	then
		CAPTURE='import -window root'
	elif type screencapture &>/dev/null
	then
		CAPTURE='screencapture'
	else
		echo 'error: no screen capture tool available' >&2
		return 1
	fi

	if ! type mencoder &>/dev/null
	then
		echo 'error: mencoder not available' >&2
		return 1
	fi

	local CACHE=${CACHE:-`mktemp -d ${BIN}.XXXXXXXXXX`}
	local N=0

	cd "$CACHE" || return $?
	echo 'recording, press any key to stop'

	while ! read -n 1 -s -t ${INTERVAL:-1}
	do
		$CAPTURE $(( ++N )).jpg || return $?
	done

	# don't use ImageMagick's convert to make the video
	# because it's slow and the video will be of bad quality
	mencoder \
		mf://*.jpg \
		-mf fps=${FPS:-25}:type=jpg \
		-ovc lavc  \
		-lavcopts vcodec=mpeg4:mbd=2:trell \
		-oac copy \
		-o ${TIMELAPSE:-../timelapse-`date +%s`.mpg} || return $?

	rm -f *.jpg
	cd .. && rm -rf "$CACHE"
}

if [ "$BASH_SOURCE" == "$0" ]
then
	timelapse "$@"
fi