#!/bin/bash
# I, Ian Kelling, follow the GNU license recommendations at
# https://www.gnu.org/licenses/license-recommendations.en.html. They
# recommend that small programs, < 300 lines, be licensed under the
# Apache License 2.0. This file contains or is part of one or more small
# programs. If a small program grows beyond 300 lines, I plan to change
# to a recommended GPL license.

# Copyright 2024 Ian Kelling

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# ffs = ffmpeg stream

# todo: learn to start working in one corner of the screen.

# todo: get an icecast on li.b8.nz for when i'm away from home.

# potential improvement: it might be nice that we could have a tall terminal bug only use
# the top half for a 1080p stream, this is how:
# https://superuser.com/questions/1106674/how-to-add-blank-lines-above-the-bottom-in-terminal
#
# potential improvement: sometimes I probably want to stream full height
# window. I could add an option for that.

# potential improvement: setup a function which automatically mutes after some time, or
# after some time of no audio input.


### begin background/development docs ###

# zmq vs stdin commands:
#
# * zmq allows targeting a specific filter when there are duplicates.
#
# * if you type stdin command too slow, ffmpeg will die because it stops
#   doing normal work while it is waiting.
#
# * zmq returns a result to the calling process, rather than printing to
#   stdout.
#
# * the only simple zmq tool I found, zmqsend, requires compiling. I
#   used the latest ffmpeg 7.0.1. Build like so:
#
# p build-dep ffmpeg/aramo
# ./configure --enable-libzmq # i already had libzmq3-dev installed
# make alltools
# cp tools/zmqsend /a/opt/bin
#
# * ffmpeg debug output was useful in testing zmq commands.
#
# * Important documentation for stdin commands is only found by typing
#   "c" into the stdin of ffmpeg and reading the output.
#
#
#
# stdin command docs, before I abandoned it for zmq:
#  mkfifo -m 0600 /tmp/iank-ffmpeg
# # ffmpeg sits and waits until we do this. dunno why.
#  echo >/tmp/iank-ffmpeg &
#  ffmpeg ... </tmp/iank-ffmpeg |& while read -r line; do : check results; done
#  # example of working commands:
#  echo "cdrawbox -1 t 0" >/tmp/iank-ffmpeg
#  echo "cdrawbox -1 t fill" >/tmp/iank-ffmpeg
#  echo "cdrawtext -1 reinit text=''" >/tmp/iank-ffmpeg
#  echo "cvolume -1 volume=1" >/tmp/iank-ffmpeg


# For testing: to show the number of audio channels in a resulting file
# https://stackoverflow.com/questions/47905083/how-to-check-number-of-channels-in-my-audio-wav-file-using-ffmpeg-command
#
# ffprobe -i /tmp/out.wav -show_entries stream=channels -select_streams a:0 -of compact=p=0:nk=1 -v 0

# for a right/left speaker test:
# https://askubuntu.com/questions/148363/which-linux-command-can-i-use-to-test-my-speakers-for-current-talk-radio-output
# p install alsa-utils
# speaker-test -t wav -c 2 -l 1

# There are 2 other options for audio, so I wanted to do a little
# performance measurement of this method.
# 1 is to combine the 2 audio sources in pulse,
# https://unix.stackexchange.com/questions/351764/create-combined-source-in-pulseaudio .
# 1 is to record mumble and combine in post processing.

### benchmark / perf tests: these are pretty inaccurate.
# 29 seconds cpu use. video bitrate 1500k, 8 fps, 2x keyframe interval.
# * 64k vorbis: 69.7%
# * 128k vorbis: 70.1% (used in subsequent tests)
# * 1 audio input: 64.3%
# * 0 audio inputs: 59.2%

# how I did perf testing: add -to 00:00:30 to ffmpeg opts to
# conveniently exit after measurement. Then run:
#
# ffmpeg "${opts[@]}" &
# pid=$!
# sleep 29
# ps -p $pid -o %cpu
# kill %%

# filter for only 1 audio input:
#-filter_complex "[0]azmq,volume=precision=fixed;[1]zmq='b=tcp\://127.0.0.1\:5557',drawbox=color=0x262626,drawtext=fontsize=90: fontcolor=beige: x=40: y=40: text=''"
# filter with 0 audio input:
# -filter_complex "[0]zmq='b=tcp\://127.0.0.1\:5557',drawbox=color=0x262626,drawtext=fontsize=90: fontcolor=beige: x=40: y=40: text=''"


# When things weren't working, I did some checking on newer ffmpeg to
# see if that helped. It never did. I compiled the latest ffmpeg release
# tarball, 7.0.1, and tried the version in debian bullseye by schrooting
# before running ffmpeg. Building was just configure; make, but then I
# found some flags that were needed. gpl flags r just because I noticed them.
# ./configure --enable-libzmq --enable-libpulse --enable-libvorbis --enable-gpl --enable-version3
#

### end background/development docs ###


if ! test "$BASH_VERSION"; then echo "error: shell is not bash" >&2; exit 1; fi
shopt -s inherit_errexit 2>/dev/null ||: # ignore fail in bash < 4.4
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" exit status: $?, PIPESTATUS: ${PIPESTATUS[*]}" >&2' ERR


debug=false
loglevel=fatal

# 3 mountpoints: fsf-sysops (default, public), fsf (all staff), fsf-tech (tech team)
# # note: duplicated in ffp
mount_suffix=-sysops
while [[ $1 ]]; do
  case $1 in
    sysops|tech)
      mount_suffix=-$1
      ;;
    staff)
      mount_suffix=
      ;;
    -d)
      debug=true
      loglevel=debug
      ;;
  esac
  shift
done

host=live.iankelling.org:8000
if [[ $(dig +short @10.2.0.1 -x 10.2.0.2 2>&1 ||:) == kd.b8.nz. ]] \
     && ip n show 10.2.0.1 | grep . &>/dev/null; then
  host=127.0.0.1:8000
fi

pass=$(sed -n 's/ *<source-password>\([^<]*\).*/\1/p' /p/c/icecast.xml)


tmpf=$(mktemp)
xrandr >$tmpf

# example xrandr output: 1280x800+0+0
primary_res=$(awk '$2 == "connected" && $3 == "primary" { print $4 }' $tmpf | sed 's/+.*//')
secondary_res=$(awk '$2 == "connected" && $3 != "primary" { print $3 }' $tmpf | sed 's/+.*//')

if [[ $secondary_res ]]; then
  # assumes secondary is on the right
  x_offset=${primary_res%%x*}
  secondary_x=${secondary_res%%x*}
  secondary_y=${secondary_res##*x}
  stream_res=$(( secondary_x / 2 ))x$(( secondary_y / 2))
else
  x_offset=0
  stream_res=$primary_res
fi

framerate=8
keyframe_interval=$((framerate * 2))

# Monitor of default sink.
# eg: alsa_output.usb-Audio-gd_Audio-gd-00.analog-stereo
pa_sink=$(pacmd list-sinks | awk '/\*/ {getline; print $2}' | sed 's/^<//;s/>$//').monitor

opts=(
  # global options
  # be relatively quiet. switch to debug when testing.
  -v $loglevel
  -hide_banner
  -nostats

  # note: ordering of inputs also affects zmqsend commands.

  ## audio input options

  -f pulse
  -name ffs
  # note: duplicated above
  -thread_queue_size 160
  -fragment_size 512
  -i default

  -f pulse
  # this is for ffmpeg warnings. doesnt seem to affect latency.
  -thread_queue_size 160
  # pulse knows this name somewhere
  -name ffsdesktop
  # This fixes latency. i haven't tried tuning it, but going too low creates
  # choppy output.
  -fragment_size 512
  -i "$pa_sink"


  ## video input options
  -video_size $stream_res
  -f x11grab
  -framerate $framerate
  -i :0.0+$x_offset.0

  # Video + audio filter. Note: this has only the things we actually need in it.
  #
  # volume=precision=fixed fixes this error:
  # The following filters could not choose their formats: Parsed_amerge_4.
  #
  # Default volume precision is float. Our input is fixed. maybe ffmpeg
  # thinks the input could change and so can't commit to an output.
  # The error suggests using aformat, which seems like it would probably
  # also fix the error.
  #
  # man page say zmq url default includes "localhost", but specifying a
  # localhost url caused an error for me.
  -filter_complex "[0]azmq,volume=precision=fixed: volume=0 [vol0];
[1]azmq='b=tcp\://127.0.0.1\:5556',volume=precision=fixed: volume=0 [vol1];
[vol0][vol1] amerge=inputs=2 [out];
[2]zmq='b=tcp\://127.0.0.1\:5557',drawbox=color=0x262626,drawtext=fontsize=90: fontcolor=beige: x=40: y=40: text=''"

  # Based on error message and poking around, it seems ffmpeg is not
  # smart enough to see that [vol0] and [vol1] are inputs to the amerge
  # filter, and thus we would not want them as final outputs. So, we
  # have to identify the amerge output and pass it to -out. This
  # identifier is called an "output pad" in man ffmpeg-filters, and a
  # "link label" in man ffmpeg.
  -map '[out]'

  # video output options
  -vcodec libvpx
  -g $keyframe_interval
  -quality realtime
  # for 1080p, default 256k is poor quality. 500 is ok. 1500 is a bit better.
  -b:v 1500k
  -threads 2
  -buffer_duration 10
  -error-resilient 1

  ## audio output options
  -c:a libvorbis
  -b:a 128k
  # afaik, this ensures that the amerge doesn't make 4 channel output if
  # our output format supported it.
  -ac 2

  -content_type video/webm
  -f webm
  icecast://source:$pass@$host/fsf$mount_suffix.webm
)

rm -f /tmp/iank-ffmpeg-interlude-toggle

# start muted
pactl set-source-mute @DEFAULT_SOURCE@ true

#echo executing: ffmpeg ${opts[@]}

#{ sleep 1; ffp &>/dev/null & }

if $debug; then
  ffmpeg "${opts[@]}"
  exit 0
fi

# For now, we want to watch the stream and end the stream when we stop watching.
ffmpeg "${opts[@]}" &
sleep 2
ffp ||:
kill %%