#!/bin/sh
set -eu

makefile_pre() {
	cat <<'EOF'
.POSIX:
FFMFLAGS = -y -hide_banner -loglevel warning



.SUFFIXES:
.SUFFIXES: .mpd .webmx .txt

.mpd.webmx:
	cd $(?D) && ffmpeg $(FFMFLAGS) -i $(<F) $(*F).webm
	touch $@

.txt.webmx:
	ffmpeg $(FFMFLAGS) -f concat -i $< -c copy $*.webm
	mkdir -p processed/"`basename $(*D)`"
	ln -f $*.webm processed/"`basename $(*D)`"/
	touch $@


all:
EOF
}

makefile_post() {
	cat <<'EOF'

sources.webmx  = $(sources.mpd:.mpd=.webmx)
combined.webmx = $(combined.txt:.txt=.webmx)

all: $(sources.webmx) $(combined.txt) $(combined.webmx)

$(combined.txt):
	cd $(@D) && find */live.webm | LANG=POSIX.UTF-8 sort | \
		sed 's|^|file |' > $(@F)
EOF
}

mpds() {
	find data/*/*/live.mpd | LANG=POSIX.UTF-8 sort
}

mkdeps() {
	mpds | varlist 'sources.mpd'
	mpds | cut -d/ -f1-2 | sed 's,$,/combined.txt,' | uniq |
		varlist 'combined.txt'
	printf '\n'

	mpds | sed 's/^\(.*\)\.mpd$/\1.webmx:\t\1.mpd/'
	mpds | sed 's/^\(.*\)\.mpd$/\1.webm:\t\1.webmx/'
	printf '\n'

	mpds | sed 's/\.mpd$/.webm/' | awk -F/ '{
		printf "data/%s/combined.txt:\t%s\n", $2, $0
	}'

	mpds | xargs dirname | xargs dirname | uniq |
		sed 's|^\(.*\)$|\1/combined.webm:\t\1combined.txt|'
}


{
	makefile_pre
	mkdeps
	makefile_post
} | make -f-