#!/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"

# Input arguments
client_name="$1"

# Global variables
server_pubkey=""
client_pubkey=""
folder_log=""
ips=""
users=""

# ==============================================================================
# 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*' "${WG0_DIR}/wg0.conf" | sed 's/^\s*AllowedIPs\s*=\s*//I; s/\s*$//')
    users=$(grep -i '^\s*# BEGIN_PEER \s*' "${WG0_DIR}/wg0.conf" | sed 's/^\s*# BEGIN_PEER \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
}

# Display QR Code and Generate PNG
display_qr_code() {
    # Derive user folder path from the already established global TOOLS_DIR
    local user_folder_path="${TOOLS_DIR}/logs/${client_name}"
    local base_name="${client_name}"

    # Make sure that the client name doesn't have spaces
    if [[ "$client_name" =~ [[:space:]] ]]; then
        printf "Error: Client name cannot contain spaces. Use underscores instead of spaces.\n"
        exit 1
    elif [[ "$client_name" == "" ]]; then
        printf "Error: Client name argument is mandatory. Please provide one first.\n"
        exit 1
    fi

    # Enforce exact match tags
    local peer_begin="# BEGIN_PEER ${client_name}"

    # Check if client already exists
    if grep -i "^${peer_begin}$" "${WG0_DIR}/wg0.conf"; then
        # Show the qr-code
        if command -v qrencode >/dev/null 2>&1; then
            printf "\n--- Scan QR Code with WireGuard App ---\n\n"
            
            # 1. Output to terminal in large ANSI UTF-8 format
            qrencode -t ansiutf8 < "${user_folder_path}/${client_name}.conf"
            printf "\nOtherwise, a PNG QR-code can be found in the folder '$user_folder_path'.\n"
        else
            printf "\n[Notice] "qrencode" is not installed. QR codes could not be generated.\n\n"
        fi
    else
        printf "Error: Client "%s" doesn't exist\n" "$client_name"
    fi

}

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

    # Print current values
    printf "Public Key of the server: %s\n" "$server_pubkey"
    printf "List of current clients:\n"
    paste -d '|' <(echo "$users") <(echo "$ips") | while IFS='|' read -r user ip; do
        echo "User: $user -> IP: $ip"
    done
    printf "\n"

    # Output QR code to terminal and save PNG
    display_qr_code
}

# Invoke main
main "$@"