#!/bin/bash

# ==============================================================================
# Script: host_backup.sh
# Description: This script securely backs up important host files 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"

# Host backup directories
FSTAB_SOURCE="/etc/fstab"
DDCLIENT_CONF_SOURCE="/etc/ddclient.conf"
DDCLIENT_DEFAULT_SOURCE="/etc/default/ddclient"
FSTAB_DESTINATION="$BACKUP_MOUNT_POINT/backup/server/os"
DDCLIENT_DESTINATION="$BACKUP_MOUNT_POINT/backup/services/ddclient"

# 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

# Check if the destination directories exist and create them if they don't.
# This prevents rsync from failing on the first run.
# mkdir -p "$BACKUP_DESTINATION"
# mkdir -p "$PHOTOS_DESTINATION"

# ==============================================================================
# Task 1: Sync /etc/fstab
# ==============================================================================
echo "Starting rsync of '$FSTAB_SOURCE' to '$FSTAB_DESTINATION'..."

# Check if the source file for fstab exists.
if [ ! -f "$FSTAB_SOURCE" ]; then
    echo "Error: Source file '$FSTAB_SOURCE' not found." >&2
    # Send a failure notification
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: Script failed. Source file '$FSTAB_SOURCE' not found." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    exit 1
fi

rsync -av --progress "$FSTAB_SOURCE" "$FSTAB_DESTINATION"

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

# ==============================================================================
# Task 2: Sync ddclient configuration
# ==============================================================================
echo "Starting rsync of ddclient configuration files to '$DDCLIENT_DESTINATION'..."

# Check if ddclient.conf exists.
if [ ! -f "$DDCLIENT_CONF_SOURCE" ]; then
    echo "Error: Source file '$DDCLIENT_CONF_SOURCE' not found." >&2
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: Script failed. ddclient.conf source not found." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
else
    rsync -av --progress "$DDCLIENT_CONF_SOURCE" "$DDCLIENT_DESTINATION"
    if [ $? -eq 0 ]; then
        echo "Success: ddclient.conf copied to '$DDCLIENT_DESTINATION'."
        curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Success: ddclient.conf copied to $DDCLIENT_DESTINATION" "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    else
        echo "Error: rsync failed to copy ddclient.conf. Please check permissions." >&2
        curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: rsync failed to copy ddclient.conf." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    fi
fi

# Check if ddclient default configuration exists.
if [ ! -f "$DDCLIENT_DEFAULT_SOURCE" ]; then
    echo "Error: Source file '$DDCLIENT_DEFAULT_SOURCE' not found." >&2
    curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: Script failed. ddclient default source not found." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
else
    rsync -av --progress "$DDCLIENT_DEFAULT_SOURCE" "$DDCLIENT_DESTINATION"
    if [ $? -eq 0 ]; then
        echo "Success: ddclient default configuration copied to '$DDCLIENT_DESTINATION'."
        curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Success: ddclient default copied to $DDCLIENT_DESTINATION" "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    else
        echo "Error: rsync failed to copy ddclient default configuration. Please check permissions." >&2
        curl -H "Authorization: Bearer $NTFY_TOKEN" -d "Error: rsync failed to copy ddclient default." "$NTFY_SERVER/$NTFY_TOPIC" > /dev/null 2>&1
    fi
fi