#!/usr/bin/env bash
# backup.sh — PostgreSQL backup for Trainingssoftware
#
# Usage:
#   DATABASE_URL=postgres://user:pass@host:5432/dbname \
#   BACKUP_BUCKET=s3://my-bucket/backups \
#   ops/scripts/backup.sh
#
# Environment variables:
#   DATABASE_URL      (required) — full postgres:// connection string
#   BACKUP_BUCKET     (optional) — s3:// prefix to upload the dump; if unset,
#                                  the dump stays in /tmp only
#   BACKUP_RETENTION_DAYS (optional, default 30) — S3 lifecycle handled externally;
#                                                   this value is embedded in the
#                                                   object metadata for auditing
set -euo pipefail

TIMESTAMP="$(date -u +%Y%m%dT%H%M%SZ)"
DUMP_FILE="/tmp/trainingssoftware-${TIMESTAMP}.dump"
RETENTION_DAYS="${BACKUP_RETENTION_DAYS:-30}"

if [[ -z "${DATABASE_URL:-}" ]]; then
  echo "ERROR: DATABASE_URL is not set." >&2
  exit 1
fi

echo "[backup] Starting PostgreSQL dump → ${DUMP_FILE}"
pg_dump \
  --format=custom \
  --compress=9 \
  --no-acl \
  --no-owner \
  "${DATABASE_URL}" \
  --file="${DUMP_FILE}"

DUMP_SIZE="$(du -sh "${DUMP_FILE}" | cut -f1)"
echo "[backup] Dump complete — size: ${DUMP_SIZE}"

if [[ -n "${BACKUP_BUCKET:-}" ]]; then
  S3_KEY="${BACKUP_BUCKET%/}/trainingssoftware-${TIMESTAMP}.dump"
  echo "[backup] Uploading → ${S3_KEY}"
  aws s3 cp "${DUMP_FILE}" "${S3_KEY}" \
    --metadata "retention_days=${RETENTION_DAYS},timestamp=${TIMESTAMP}" \
    --storage-class STANDARD_IA
  echo "[backup] Upload complete."
  rm -f "${DUMP_FILE}"
else
  echo "[backup] BACKUP_BUCKET not set — dump kept at ${DUMP_FILE}"
fi

echo "[backup] Done. timestamp=${TIMESTAMP} size=${DUMP_SIZE}"