#!/bin/bash

# ==============================================================================
# 1. SETTINGS & GLOBALS
# ==============================================================================
# Exit immediately if a command exits with a non-zero status
set -e 

# Determine the directory where this script resides
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
cd "$SCRIPT_DIR"

# Global variables
server_pubkey=""
ips=""

# ==============================================================================
# 2. HELPER FUNCTIONS
# ==============================================================================
# Load environment variable of the script
environment_var() {
    echo "--- Starting Environment & Pre-flight Checks ---"
    # --- .env LOADING ---
    # This safely loads the variables from .env without touching other files
    if [ -f "$SCRIPT_DIR/.env" ]; then
        set -a
        source "$SCRIPT_DIR/.env"
        set +a
        echo "[✔] Environment variables loaded."
    else
        echo "[!] No .env file found. Using defaults."
    fi

    # --- Variable Checks ---
    server_pubkey=$(cat ${WG0_DIR}/publickey)
    ips=$(grep -i '^\s*AllowedIPs\s*=\s*' "${WG0_DIR}/wg0.conf" | sed 's/^\s*AllowedIPs\s*=\s*//I; s/\s*$//')
}

# Find the last registered client IP
find_last_ip() {
    # Find the last ip an create the next ip
    if [ -n "$ips" ]; then
        last=$(printf '%s\n' "$ips" | tail -1)
        addr=${last%/*}   # strip /32 if present
        IFS=. read -r a b c d <<< "$addr"
        next_ip="10.0.0.$((d + 1))"
        printf 'Last CIDR: %s\nNext IP: %s/32\n' "$last" "$next_ip"
    else
        next_ip="10.0.0.2"
        printf 'No peers found, starting at %s/32\n' "$next_ip"
    fi
}

# Show the template of the client's configuration file
client_show_template() {
    # Show template from .client_template file
    template_file="${TOOLS_DIR}/client_template"

    if [ -f "$template_file" ]; then
        printf "\n--- Wireguard client template (generated from %s) ---\n" "$template_file"

        # Process template: replace placeholders
        sed -e "s|<%CLIENT_IP%>|${next_ip}|g" \
            -e "s|<%SERVER_PUBLIC_KEY%>|${server_pubkey}|g" \
            -e "s|<%DOMAIN_NAME%>|${DOMAIN_NAME}|g" \
            "$template_file"
    else
        printf "\n--- Error: Template file %s not found ---\n" "$template_file"
        exit 1
    fi
}

# ==============================================================================
# 3. MAIN LOGIC
# ==============================================================================
main() {
    # Load environment variables first
    environment_var

    # Print current values
    printf 'Public Key of the server: %s\n' "$server_pubkey"
    printf 'List of current clients: %s\n' "$ips"

    # Find the last IP
    find_last_ip
    # Show client template
    client_show_template
}

# Invoke main
main "$@"