#!/bin/bash

# ==============================================================================
# Script: paperless_backup.sh
# Description: This script securely backs up Paperless-ngx to a designated 
#              mounted drive using rsync. It includes pre-run checks to ensure 
#              the source files and destination are valid, and sends ntfy 
#              notifications for each task.
# Usage:       sudo ./hass_backup.sh
# Notes:       This script may require sudo/root privileges to access files.
# ==============================================================================

# ==============================================================================
# Define Variables for Source and Destination
# ==============================================================================
# This makes the script easier to read and modify.
BACKUP_MOUNT_POINT="/mnt/5TB-Disk1"
BACKUP_DESTINATION="$BACKUP_MOUNT_POINT/backup"

# Paperless backup directories
PAPERLESS_SOURCE="/srv/doc-archive/export"
PAPERLESS_DESTINATION="$BACKUP_MOUNT_POINT/backup/services/paperless-ngx"

# ntfy Notification Configuration
# To use this feature, you must have the 'curl' command installed.
# NTFY_TOPIC is the topic you wish to send notifications to.
# NTFY_SERVER is the URL of your ntfy server.
# NTFY_TOKEN is the authorization token for your ntfy server.
NTFY_TOPIC="Server"
NTFY_SERVER="https://ntfy.speerfam.net"
NTFY_TOKEN="tk_3xo9mejjtgemyowzckqw2souo3mux"

# ==============================================================================
# Pre-flight Checks (for the destination drive)
# ==============================================================================

# Check if the mount point directory exists and is a mounted filesystem.
# This is a critical check to ensure we are writing to the intended air-gapped
# drive and not to a local directory if the mount failed.
if ! mountpoint -q "$BACKUP_MOUNT_POINT"; then
    echo "Error: '$BACKUP_MOUNT_POINT' is not a mount point. Please ensure the drive is mounted." >&2
    # Send a failure notification
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: Script failed. Destination '$BACKUP_MOUNT_POINT' is not mounted." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    exit 1
fi

# ==============================================================================
# Task 9: Sync Paperless-ngx backup
# ==============================================================================
echo "Starting Paperless-ngx backup process..."

# Step 1: Execute the Docker command to create the backup.
echo "Running Paperless-ngx document exporter via Docker..."
sudo docker compose -f /srv/docker/dockhand/data/stacks/Local/paperless-ngx/compose.yaml exec -T webserver document_exporter ../export -z
if [ $? -ne 0 ]; then
    echo "Error: Docker command failed to create Paperless-ngx backup." >&2
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: Docker command failed to create Paperless-ngx backup." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    exit 1
fi
echo "Paperless-ngx backup script completed successfully."
curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Paperless-ngx backup created. Starting rsync." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1

# Step 2: Rsync the Paperless-ngx backup directory to the destination.
echo "Starting rsync of '$PAPERLESS_SOURCE' to '$PAPERLESS_DESTINATION'..."

# Check if the Paperless-ngx backup source directory exists.
if [ ! -d "$PAPERLESS_SOURCE" ]; then
    echo "Error: Paperless-ngx backup source directory '$PAPERLESS_SOURCE' not found." >&2
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: Script failed. Paperless-ngx backup source not found." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    exit 1
fi

rsync -av --progress "$PAPERLESS_SOURCE" "$PAPERLESS_DESTINATION"

# Post-rsync status check for the Paperless-ngx backup directory.
if [ $? -eq 0 ]; then
    echo "Success: Paperless-ngx backup directory has been successfully copied to '$PAPERLESS_DESTINATION'."
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Success: Paperless-ngx backup copied to $PAPERLESS_DESTINATION" "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
else
    echo "Error: rsync failed to copy the Paperless-ngx backup directory. Please check permissions." >&2
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: rsync failed to copy Paperless-ngx backup directory." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    exit 1
fi