<?php

namespace App\Http\Controllers;

use App\Models\VpnConfig;
use Illuminate\Http\Request;

class VpnConfigController extends Controller
{
    public function index()
    {
        $vpns = VpnConfig::orderBy('partner_name')->paginate(15);
        return view('vpns.index', compact('vpns'));
    }

    // Handle Add Form Submission
    public function store(Request $request)
    {
        $validated = $request->validate([
            'partner_name' => 'required|string|max:255',
            'status' => 'required|in:Active,Inactive',
            'local_ip' => 'required|ip',
            'peer_ip' => 'required|ip',
            'encryption_domain_local' => 'nullable|string|max:255',
            'encryption_domain_remote' => 'nullable|string|max:255',
            'preshared_key' => 'required|string',            
            'local_device' => 'nullable|string|max:255',
            'peer_device' => 'nullable|string|max:255',
            'ike_version' => 'required|integer',
            'phase1_encryption' => 'required|string|max:50',
            'phase1_hash' => 'required|string|max:50',
            'phase1_dh_group' => 'required|string|max:50',
            'phase1_lifetime' => 'required|integer',
            'phase2_encryption' => 'required|string|max:50',
            'phase2_hash' => 'required|string|max:50',
            'phase2_dh_group' => 'nullable|string|max:50',
            'phase2_lifetime' => 'required|integer',
            'pfs_enabled' => 'boolean',
        ]);

        VpnConfig::create($validated);

        return response()->json(['success' => true, 'message' => 'VPN configuration added successfully.']);
    }

    // Fetch data for the Edit Modal
    public function show($id)
    {
        $vpn = VpnConfig::findOrFail($id);
        
        // Hide the pre-shared key from being sent back in the JSON response for security
        $vpn->makeHidden('preshared_key'); 
        
        return response()->json($vpn);
    }

    // Handle Edit Form Submission
    public function update(Request $request, $id)
    {
        $vpn = VpnConfig::findOrFail($id);

        $validated = $request->validate([
            'partner_name' => 'required|string|max:255',
            'status' => 'required|in:Active,Inactive',
            'local_ip' => 'required|ip',
            'peer_ip' => 'required|ip',
            'encryption_domain_local' => 'nullable|string|max:255',
            'encryption_domain_remote' => 'nullable|string|max:255',
            'preshared_key' => 'nullable|string', 
            'local_device' => 'nullable|string|max:255',
            'peer_device' => 'nullable|string|max:255',
            'ike_version' => 'required|integer',
            'phase1_encryption' => 'required|string|max:50',
            'phase1_hash' => 'required|string|max:50',
            'phase1_dh_group' => 'required|string|max:50',
            'phase1_lifetime' => 'required|integer',
            'phase2_encryption' => 'required|string|max:50',
            'phase2_hash' => 'required|string|max:50',
            'phase2_dh_group' => 'nullable|string|max:50',
            'phase2_lifetime' => 'required|integer',
            'pfs_enabled' => 'boolean',
        ]);


        // If the PSK field is empty, remove it so we don't overwrite the existing key
        if (empty($validated['preshared_key'])) {
            unset($validated['preshared_key']);
        }

        $vpn->update($validated);

        return response()->json(['success' => true, 'message' => 'VPN configuration updated successfully.']);
    }

    // Export the company's global standard VPN parameters
    public function downloadStandardTemplate()
    {
        $template = "=================================================\n";
        $template .= " Click Mobile VPN Configuration Parameters\n";
        $template .= "=================================================\n\n";
        
        $template .= "! Phase 1 (IKE / ISAKMP)\n";
        $template .= " Encryption Algorithm: AES-256\n";
        $template .= " Hash Algorithm: SHA-256\n";
        $template .= " Authentication Method: Pre-Shared Key (PSK)\n";
        $template .= " Diffie-Hellman Group: Group 14\n";
        $template .= " Lifetime: 86400 seconds\n\n";
        
        $template .= "! Phase 2 (IPsec)\n";
        $template .= " Protocol: ESP\n";
        $template .= " Encryption Algorithm: AES-256\n";
        $template .= " Hash Algorithm: SHA-256\n";
        $template .= " Perfect Forward Secrecy (PFS): Group 14\n";
        $template .= " Lifetime: 3600 seconds\n\n";
        
        $template .= "! Gateway Details\n";
        $template .= " Our Public Gateway IP: [216.55.137.19]\n";
        $template .= " Our Encryption Domain: [10.199.0.0/24]\n";

        return response($template)
            ->header('Content-Type', 'text/plain')
            ->header('Content-Disposition', 'attachment; filename="standard_vpn_parameters.txt"');
    }

    // Fetch data to populate the Partner Export Modal
    public function generateTemplate($id)
    {
        $vpn = VpnConfig::findOrFail($id);
        
        $template = "=================================================\n";
        $template .= " VPN Configuration for Partner: {$vpn->partner_name}\n";
        $template .= "=================================================\n\n";
        $template .= "! Phase 1 (IKE)\n";
        $template .= "crypto isakmp policy 10\n";
        $template .= " encr aes 256\n";
        $template .= " hash sha256\n";
        $template .= " authentication pre-share\n";
        $template .= " group 14\n";
        $template .= "crypto isakmp key {$vpn->preshared_key} address {$vpn->local_ip}\n\n";
        $template .= "! Phase 2 (IPsec)\n";
        $template .= "crypto ipsec transform-set TS-AES256-SHA256 esp-aes 256 esp-sha256-hmac\n";
        $template .= "crypto map VPNMAP 10 ipsec-isakmp\n";
        $template .= " set peer {$vpn->local_ip}\n";
        $template .= " set transform-set TS-AES256-SHA256\n";
        $template .= " match address 100\n\n";
        $template .= "! Access Control List (Encryption Domains)\n";
        $template .= "access-list 100 permit ip {$vpn->encryption_domain_remote} {$vpn->encryption_domain_local}\n";

        return response()->json(['template' => $template, 'partner_name' => $vpn->partner_name]);
    }

    // Process the edited text and force a file download
    public function download(Request $request)
    {
        $request->validate([
            'config_content' => 'required|string',
            'partner_name' => 'required|string',
        ]);

        $filename = str_replace(' ', '_', strtolower($request->partner_name)) . '_vpn_config.txt';

        return response($request->config_content)
            ->header('Content-Type', 'text/plain')
            ->header('Content-Disposition', "attachment; filename=\"{$filename}\"");
    }
}