#!/usr/bin/env bash
set -euo pipefail

source /etc/restic/restic.env

# Metrics file for node_exporter
METRICS_DIR="/var/lib/node_exporter/textfile_collector"
METRICS_FILE="${METRICS_DIR}/restic_backup.prom"
mkdir -p "${METRICS_DIR}"

# Temporary file for atomic writes
TEMP_FILE=$(mktemp)

# Start backup
START_TIME=$(date +%s)

if restic backup \
{% for path in restic_backup_paths %}
  {{ path }} \
{% endfor %}
{% for pattern in restic_exclude_patterns %}
  --exclude '{{ pattern }}' \
{% endfor %}
  --host {{ ansible_facts["hostname"] }}; then
  
  # Backup succeeded
  STATUS=1
  echo "# HELP restic_backup_success Whether the last backup succeeded (1=success, 0=failure)" > "${TEMP_FILE}"
  echo "# TYPE restic_backup_success gauge" >> "${TEMP_FILE}"
  echo "restic_backup_success ${STATUS}" >> "${TEMP_FILE}"
  
  echo "# HELP restic_backup_timestamp_seconds Timestamp of last backup completion" >> "${TEMP_FILE}"
  echo "# TYPE restic_backup_timestamp_seconds gauge" >> "${TEMP_FILE}"
  echo "restic_backup_timestamp_seconds $(date +%s)" >> "${TEMP_FILE}"
  
  echo "# HELP restic_backup_duration_seconds Duration of last backup in seconds" >> "${TEMP_FILE}"
  echo "# TYPE restic_backup_duration_seconds gauge" >> "${TEMP_FILE}"
  echo "restic_backup_duration_seconds $(($(date +%s) - START_TIME))" >> "${TEMP_FILE}"
  
  # Move temp file to final location atomically
  mv "${TEMP_FILE}" "${METRICS_FILE}"
  
  exit 0
else
  # Backup failed
  STATUS=0
  echo "# HELP restic_backup_success Whether the last backup succeeded (1=success, 0=failure)" > "${TEMP_FILE}"
  echo "# TYPE restic_backup_success gauge" >> "${TEMP_FILE}"
  echo "restic_backup_success ${STATUS}" >> "${TEMP_FILE}"
  
  echo "# HELP restic_backup_timestamp_seconds Timestamp of last backup attempt" >> "${TEMP_FILE}"
  echo "# TYPE restic_backup_timestamp_seconds gauge" >> "${TEMP_FILE}"
  echo "restic_backup_timestamp_seconds $(date +%s)" >> "${TEMP_FILE}"
  
  # Move temp file to final location atomically
  mv "${TEMP_FILE}" "${METRICS_FILE}"
  
  exit 1
fi