#!/bin/bash

set -eu

QUEUE_DIR="$1"
shift

mkdir -p "$QUEUE_DIR"
cd "$QUEUE_DIR"

mkdir -p candidates in-progress

while true; do
    CANDIDATE="$(ls -1 candidates | rl -c 1 2>/dev/null)"

    if [[ "$CANDIDATE" == "" ]]; then
        break
    fi

    if mv -n candidates/"$CANDIDATE" in-progress/"$CANDIDATE" 2>/dev/null; then
        cat in-progress/"$CANDIDATE"
        printf "export TASK_ID=%q\n" "$CANDIDATE"
        break
    fi
done