#!/bin/bash

# Log file
log_file="/var/log/watchdog.log"

# Configuration file
config_file="/etc/watchdog.conf"

# Function to update watchdog configuration
update_watchdog_config() {
    # Extract watchdog IP addresses
    watchdog=$(sudo cat /var/lib/dhcp/* | grep -a "option watchdog" | tail -1 | \
    awk '{for (i=3; i<=NF; i++) printf "%s ", $i}' | tr -d '";')
    
    IFS=', ' read -r -a ip_array <<< "$watchdog"  # Split IPs by comma or space

    # Backup current configuration
    sudo cp "$config_file" "$config_file.bak"

    # Clean existing configurations
    sudo sed -i '/ping/d' "$config_file"
    sudo sed -i '/^interval/d' "$config_file"

    # Set interval
    echo "interval = 58" | sudo tee -a "$config_file" > /dev/null

    if [ ${#ip_array[@]} -eq 0 ]; then
        echo "No IP addresses found. Watchdog configuration cleared." >> "$log_file"
        return 1  # No IP addresses to configure, return 1 to continue loop
    else
        # Insert IPs into config
        for ip in "${ip_array[@]}"; do
            echo "ping = $ip" | sudo tee -a "$config_file" > /dev/null
        done
        echo "Configured watchdog to ping: ${ip_array[*]}" >> "$log_file"

        # Restart watchdog service
        if sudo systemctl restart watchdog; then
            echo "Watchdog service restarted successfully." >> "$log_file"
            return 0  # Successful restart, exit function with 0 to break main loop
        else
            echo "Failed to restart watchdog service." >> "$log_file"
            return 1  # Failed restart, continue main loop
        fi
    fi
}

# Loop parameters
interval=30  # Interval to wait between checks
start_time=$(date +%s)
end_time=$((start_time + 300))  # 5 minutes in seconds

# Main loop
while true; do
    if ! update_watchdog_config; then
        echo "IP addresses found and watchdog restarted. Exiting loop." >> "$log_file"
        break
    else
        echo "No IP addresses found or restart failed. Waiting for $interval seconds before checking again..." >> "$log_file"
    fi

    # Check if 5 minutes have passed
    if [ "$(date +%s)" -ge "$end_time" ]; then
        echo "5 minutes have passed. Stopping the watchdog service." >> "$log_file"
        sudo systemctl stop watchdog
        break
    fi

    echo "Waiting for $interval seconds before checking for IP addresses again..." >> "$log_file"
    sleep $interval
done

# Version 1.5:
# Created 2024 by Tim Eertmoed @ WiS IT-Solutions GmbH, Germany to work on Raspian as custom PXE init script.