#!/bin/bash

# Mullvad_VPN_Check
# A script that checks for a Mullvad VPN connection, logs the status,
# and sends alerts if the VPN status changes.

# Set Discord webhook
WEBHOOK_URL="DISCORD_WEBHOOK_URL"

# Temp file to store the VPN connection status
STATUS_FILE="/tmp/vpn_status.log"

# Function to send VPN down alert
vpn_down_alert() {
curl -H "Content-Type: application/json" -X POST --data @- "$WEBHOOK_URL" <<EOF
{
  "content": null,
  "embeds": [
    {
      "title": "VPN Connectivity - WARNING",
      "description": "\"$(hostname)\" is not going through a Mullvad VPN connection",
      "color": 13238272,
      "fields": [
        {
          "name": "Date and Time of Test:",
          "value": "$(date +'%Y-%m-%d %H:%M:%S')"
        },
        {
          "name": "Current ISP",
          "value": "$ORG"
        },
        {
          "name": "Current IP",
          "value": "$IP"
        }
      ]
    }
  ],
  "attachments": []
}
EOF
}

# Function to send VPN restored alert
vpn_up_alert() {
curl -H "Content-Type: application/json" -X POST --data @- "$WEBHOOK_URL" <<EOF
{
  "content": null,
  "embeds": [
    {
      "title": "VPN Connectivity - RESTORED",
      "description": "\"$(hostname)\" is now going through a Mullvad VPN connection",
      "color": 3066993,
      "fields": [
        {
          "name": "Date and Time of Test:",
          "value": "$(date +'%Y-%m-%d %H:%M:%S')"
        },
        {
          "name": "Current ISP",
          "value": "$ORG"
        },
        {
          "name": "Current IP",
          "value": "$IP"
        }
      ]
    }
  ],
  "attachments": []
}
EOF
}

# Function to check the VPN status and act accordingly
check_vpn_status() {
    mullvad_exit_ip="$1"

    # Check the current status (true for VPN, false for no VPN)
    if [ "$mullvad_exit_ip" = "false" ]; then
        echo "VPN not connected, sending alert..."
        
        # Send alert if VPN was connected last time
        if [ "$previous_status" = "true" ]; then
            vpn_down_alert
            echo "VPN down alert sent!"
        fi

        # Log the current status
        echo "false" > "$STATUS_FILE"
    else
        echo "VPN connected."

        # Send a "VPN restored" alert if VPN was not connected last time
        if [ "$previous_status" = "false" ]; then
            vpn_up_alert
            echo "VPN restored alert sent!"
        fi

        # Log the current status
        echo "true" > "$STATUS_FILE"
    fi
}

# Fetch JSON data from Mullvad API
json=$(curl -s https://ipv4.am.i.mullvad.net/json)

# Get Reported IP and ISP
IP=$(echo "$json" | grep -oE '"ip":\s*"[^"]+"' | grep -oE '[0-9.]+')
ORG=$(echo "$json" | grep -oP '(?<="organization":")[^"]+')

# Parse JSON and extract "mullvad_exit_ip" (true if VPN, false if not)
mullvad_exit_ip=$(jq -r '.mullvad_exit_ip' <<< "$json")

# Check if the status log file exists, if not create it with a default value (false)
if [ ! -f "$STATUS_FILE" ]; then
    echo "false" > "$STATUS_FILE"
fi

# Read the previous VPN status from the log file
previous_status=$(cat "$STATUS_FILE")

# Check the current VPN status and take action
check_vpn_status "$mullvad_exit_ip"