#!/usr/bin/env bash

if ! command -v inotifywait >/dev/null 2>&1; then
  echo "Please install inotify_utils"
  exit 1
fi

if ! command -v v4l2-ctl >/dev/null 2>&1; then
  echo "Please install v4l-utils"
  exit 1
fi

declare -A STREAMS

sigint() {
  for pid in "${STREAMS[@]}"; do
    wait "$pid"
  done
}

trap sigint INT

failed() {
  file=$1
  echo "Streaming $file failed"
  tail -n 5 "/tmp/${file}_log"

  unset "STREAMS[$file]"
}

streaming() {
  echo "Streaming $1"
  echo "Logfile: /tmp/$1_log"

  (set -o xtrace; ffmpeg \
    -f v4l2 \
    -framerate 30 \
    -i "/dev/$1" \
    -pix_fmt uyvy422 \
    -f libndi_newtek \
    -y "$1" \
    > "/tmp/$1_log" \
    2>&1
  ) || failed "$1"

  unset "STREAMS[$file]"
}

check() {
  file=$1
  echo "Found $file"

  if v4l2-ctl -n -d "/dev/$file" | grep -q 'Input'; then
    (streaming "$file") &
    STREAMS[$file]=$!
    echo "$file PID ${STREAMS[$file]}"
  fi
}

check_initial_devices() {
  for file in /dev/video*; do
    file="${file##*/}"
    check "$file"
  done
}

listen_for_new_devices() {
  inotifywait -m /dev --format "%f" -e create |
    while read -r file; do
      if [[ "$file" =~ video[0-9]+$ ]]; then

        if ! ps -p "${STREAMS[$file]}"> /dev/null; then
          unset "STREAMS[$file]"
        fi

        if [[ ! -v "STREAMS[$file]" ]]; then
          check "$file"
        fi
      fi
    done
}

check_initial_devices
listen_for_new_devices