#!/bin/bash
set -euo pipefail

CRON_FILE="${1:-/etc/cron.d/tenbackward}"

if [ ! -f "${CRON_FILE}" ]; then
    echo "install-cron: cron file ${CRON_FILE} does not exist" >&2
    exit 1
fi

if grep -q '__RUN_AT__' "${CRON_FILE}"; then
    echo "install-cron: refusing to install cron file with unresolved __RUN_AT__ placeholder" >&2
    exit 1
fi

chmod 0644 "${CRON_FILE}"

if ! head -n 1 "${CRON_FILE}" | grep -qE '^[A-Z_]+='; then
    echo "install-cron: ${CRON_FILE} must start with a cron env line (e.g. SHELL=/bin/bash)" >&2
    exit 1
fi

if ! grep -q '/usr/local/bin/run-bot.sh' "${CRON_FILE}"; then
    echo "install-cron: ${CRON_FILE} must invoke /usr/local/bin/run-bot.sh" >&2
    exit 1
fi

if ! grep -qE '/proc/1/fd/1' "${CRON_FILE}"; then
    echo "install-cron: ${CRON_FILE} must redirect output to /proc/1/fd/1" >&2
    exit 1
fi

echo "install-cron: ${CRON_FILE} installed (mode 0644)"