#!/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="${METRICS_DIR}/restic_prune.prom"
mkdir -p "${METRICS_DIR}"

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

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

if restic forget \
  --keep-daily {{ restic_retention.daily }} \
  --keep-weekly {{ restic_retention.weekly }} \
  --keep-monthly {{ restic_retention.monthly }} \
  --prune; then
  
  # Prune succeeded
  STATUS=1
  echo "# HELP restic_prune_success Whether the last prune succeeded (1=success, 0=failure)" > "${TEMP_FILE}"
  echo "# TYPE restic_prune_success gauge" >> "${TEMP_FILE}"
  echo "restic_prune_success ${STATUS}" >> "${TEMP_FILE}"
  
  echo "# HELP restic_prune_timestamp_seconds Timestamp of last prune completion" >> "${TEMP_FILE}"
  echo "# TYPE restic_prune_timestamp_seconds gauge" >> "${TEMP_FILE}"
  echo "restic_prune_timestamp_seconds $(date +%s)" >> "${TEMP_FILE}"
  
  echo "# HELP restic_prune_duration_seconds Duration of last prune in seconds" >> "${TEMP_FILE}"
  echo "# TYPE restic_prune_duration_seconds gauge" >> "${TEMP_FILE}"
  echo "restic_prune_duration_seconds $(($(date +%s) - START_TIME))" >> "${TEMP_FILE}"
  
  # Move temp file to final location atomically
  mv "${TEMP_FILE}" "${METRICS_FILE}"
  
  exit 0
else
  # Prune failed
  STATUS=0
  echo "# HELP restic_prune_success Whether the last prune succeeded (1=success, 0=failure)" > "${TEMP_FILE}"
  echo "# TYPE restic_prune_success gauge" >> "${TEMP_FILE}"
  echo "restic_prune_success ${STATUS}" >> "${TEMP_FILE}"
  
  echo "# HELP restic_prune_timestamp_seconds Timestamp of last prune attempt" >> "${TEMP_FILE}"
  echo "# TYPE restic_prune_timestamp_seconds gauge" >> "${TEMP_FILE}"
  echo "restic_prune_timestamp_seconds $(date +%s)" >> "${TEMP_FILE}"
  
  # Move temp file to final location atomically
  mv "${TEMP_FILE}" "${METRICS_FILE}"
  
  exit 1
fi