#!/bin/bash
# WireGuard Secure Installer
# Copyright (c) 2025 Muhammad Fadhila Abiyyu Faris
# GitHub: [github.com/fadhila36/wireguard-secure-installer](https://github.com/fadhila36/wireguard-secure-installer)

check_os() {
    if [ -f /etc/os-release ]; then
        . /etc/os-release
        OS=$ID
        VERSION_ID=$VERSION_ID
    else
        fatal_error "Cannot detect OS. /etc/os-release not found."
    fi

    log_info "Detected OS: $OS $VERSION_ID"

    case "$OS" in
        ubuntu|debian)
            PKG_MANAGER="apt-get"
            UPDATE_CMD="apt-get update"
            INSTALL_CMD="apt-get install -y"
            ;;
        centos|rhel|rocky|almalinux)
            PKG_MANAGER="dnf"
            UPDATE_CMD="dnf check-update" # dnf update is slow, check-update is enough to refresh metadata
            INSTALL_CMD="dnf install -y"
            ;;
        *)
            fatal_error "Unsupported OS: $OS. Supported: Ubuntu, Debian, CentOS, Rocky, AlmaLinux."
            ;;
    esac
}

install_dependencies() {
    log_info "Installing dependencies..."
    
    $UPDATE_CMD >> "$LOG_FILE" 2>&1

    case "$OS" in
        ubuntu|debian)
            $INSTALL_CMD wireguard qrencode curl iptables >> "$LOG_FILE" 2>&1
            ;;
        centos|rhel|rocky|almalinux)
            $INSTALL_CMD epel-release >> "$LOG_FILE" 2>&1
            $INSTALL_CMD wireguard-tools qrencode curl iptables-services >> "$LOG_FILE" 2>&1
            ;;
    esac

    if ! command -v wg >/dev/null; then
        fatal_error "WireGuard installation failed."
    fi
}