#!/usr/bin/bash

# There are several situations in which we may find the jobs:
# - There are no jobs queued or running
# - There is at least one job running
# - There is one job queued
# - There was a job running but ended and is now ending

set -x
set -e

path="$1"
allocated=

# First determine if we already have jobs already
n=$(squeue --me -lh | wc -l)

if [ "$n" -gt 1 ]; then
  echo "Too many jobs queued already" >&2
  exit 1
fi

if [ "$n" == 0 ]; then
  # No running jobs, so allocate a new job
  salloc -N 1 --constraint=dmaqdma --no-shell -t 1-00
  allocated=1

  # Wait until the job is running
  while [ "$n" != 1 ]; do
    sleep 2
    n=$(squeue --me -lh | grep RUNNING | wc -l)
  done
else
  # There is one job, ensure it is running
  n=$(squeue --me -lh | grep RUNNING | wc -l)

  if [ "$n" != 1 ]; then
    echo "The job is not running, stopping" >&2
    exit 1
  fi
fi

# If this point is reached there is one job running

host=$(squeue -h -o %N)
echo "Switching to $host"

# Continue the execution there
ssh "$host" "$path/run-node.sh" "$path"

# Cancel our job if it was successful
if [ "$allocated" ]; then
  scancel --me
fi