#!/usr/bin/env bash
# =====================================================================
# WebGIS Database Backup Script
# Location: /opt/webgis-lohne/scripts/backup.sh (on server)
# Purpose:  Creates compressed pg_dump backups with daily/weekly/monthly
#           rotation. Intended to be run via cron.
# =====================================================================

set -euo pipefail

# ---------------------------------------------------------------------
# Configuration
# ---------------------------------------------------------------------
DB_HOST="localhost"
DB_PORT="5432"
DB_NAME="webgis-db"
DB_USER="webgis-db-admin"

BACKUP_ROOT="/var/backups/webgis"
BACKUP_DIR_DAILY="${BACKUP_ROOT}/daily"
BACKUP_DIR_WEEKLY="${BACKUP_ROOT}/weekly"
BACKUP_DIR_MONTHLY="${BACKUP_ROOT}/monthly"

# Retention Periods (in days)
KEEP_DAILY=7
KEEP_WEEKLY=28
KEEP_MONTHLY=365

# Password is read from a protected file (see setup instructions).
# pg_dump honors the PGPASSFILE environment variable.
export PGPASSFILE="/root/.pgpass_webgis"


# ---------------------------------------------------------------------
# Preparation
# ---------------------------------------------------------------------
TIMESTAMP=$(date +"%Y-%m-%d_%H-%M-%S")
DAY_OF_WEEK=$(date +"%u")      # 1=Monday ... 7=Sunday
DAY_OF_MONTH=$(date +"%d")

mkdir -p "${BACKUP_DIR_DAILY}" "${BACKUP_DIR_WEEKLY}" "${BACKUP_DIR_MONTHLY}"


# ---------------------------------------------------------------------
# Create Daily Backup (Custom-Format, compressed)
# ---------------------------------------------------------------------
DAILY_FILE="${BACKUP_DIR_DAILY}/webgis_${TIMESTAMP}.dump"

echo "[$(date)] Starting daily backup -> ${DAILY_FILE}"

pg_dump \
    --host="${DB_HOST}" \
    --port="${DB_PORT}" \
    --username="${DB_USER}" \
    --format=custom \
    --compress=9 \
    --file="${DAILY_FILE}" \
    "${DB_NAME}"

echo "[$(date)] Daily backup complete."


# ---------------------------------------------------------------------
# Promote to Weekly Backup on Sundays
# ---------------------------------------------------------------------
if [[ "${DAY_OF_WEEK}" == "7" ]]; then
    cp "${DAILY_FILE}" "${BACKUP_DIR_WEEKLY}/webgis_${TIMESTAMP}.dump"
    echo "[$(date)] Promoted to weekly backup."
fi


# ---------------------------------------------------------------------
# Promote to Monthly Backup on the First of the Month
# ---------------------------------------------------------------------
if [[ "${DAY_OF_MONTH}" == "01" ]]; then
    cp "${DAILY_FILE}" "${BACKUP_DIR_MONTHLY}/webgis_${TIMESTAMP}.dump"
    echo "[$(date)] Promoted to monthly backup."
fi


# ---------------------------------------------------------------------
# Rotation: Delete Backups Older than Retention Period
# ---------------------------------------------------------------------
find "${BACKUP_DIR_DAILY}"   -name "*.dump" -mtime +${KEEP_DAILY}   -delete
find "${BACKUP_DIR_WEEKLY}"  -name "*.dump" -mtime +${KEEP_WEEKLY}  -delete
find "${BACKUP_DIR_MONTHLY}" -name "*.dump" -mtime +${KEEP_MONTHLY} -delete


echo "[$(date)] Backup rotation complete."