<?php

namespace App\Services;
use Exception;
class LxdService
{    
    private string $baseUrl; 

    public function __construct() {
        $this->baseUrl = $_ENV['LXD_API_URL'] ?? 'https://localhost:8443';
    }

    private function curlInit($url, $method = '') {
        $ch = curl_init($url);
        
        // Paths to client certificate and key for TLS authentication
        $clientCert = $_ENV['LXD_CLIENT_CERT'] ?? '/etc/ssl/lxdapp/client.crt';
        $clientKey  = $_ENV['LXD_CLIENT_KEY']  ?? '/etc/ssl/lxdapp/client.key';


        curl_setopt($ch, CURLOPT_SSLCERT, $clientCert);
        curl_setopt($ch, CURLOPT_SSLKEY, $clientKey);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        if($method) curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method);
        return $ch;
    }
    
    /**
     * Sends an HTTP request to the LXD API.
     *
     * @param string $method HTTP method (GET, POST, PUT, etc.)
     * @param string $endpoint API endpoint
     * @param array $body Request body (optional)
     * @return array Response from the API
     * @throws Exception
     */
    private function request(string $method, string $endpoint, array $body = []): array {
        $ch = $this->curlInit("{$this->baseUrl}{$endpoint}", $method);
        if (!empty($body)) {
            curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($body));
            curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
        }
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);

        // Check if curl_exec failed
        if (curl_errno($ch)) {
            throw new Exception("Curl error: " . curl_error($ch));
        }

        curl_close($ch);

        if (!$response) {
            throw new Exception("LXD API error or not reachable.");
        }

        $json = json_decode($response, true);
        
        if ($httpCode >= 400) {
            throw new Exception("LXD API Error: " . ($json['error'] ?? 'Unknown'));
        }

        return $json;
    }

    /**
     * Sends a GET request and returns raw (non-JSON) response.
     *
     * @param string $endpoint API endpoint
     * @return string Raw response body
     * @throws Exception
     */
    private function requestRaw(string $endpoint): string {
        $url = "{$this->baseUrl}{$endpoint}";
        $ch = $this->curlInit($url);

        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
        $curlError = curl_error($ch);
        curl_close($ch);

        if ($response === false || $response === null) {
            throw new \Exception("Raw LXD API call failed: $curlError");
        }

        if ($httpCode >= 400) {
            throw new \Exception("LXD raw API returned HTTP $httpCode");
        }

        return $response;
    }


    /**
     * Retrieves the status of a container.
     *
     * @param string $name Container name
     * @return array|null Container status or null if an error occurs
     */
    public function getContainerState(string $name) {
        try {
            return $this->request('GET', "/1.0/instances/$name/state");
        } catch (\Throwable $e) {
            return null;
            // echo 'Error: ' . $e->getMessage();
        }
    }

    /**
     * Checks if a container exists.
     *
     * @param string $name Container name
     * @return bool True if the container exists, false otherwise
     */
    public function containerExists(string $name): bool {
        return $this->getContainerState($name) !== null;
    }
 
    /**
     * Starts a container.
     *
     * @param string $name Container name
     * @return array Response from the API
     * @throws Exception
     */
    public function startContainer(string $name): array {
        $startResponse = $this->request('PUT', "/1.0/instances/$name/state", [
            "action" => "start",
            "timeout" => 30,
            "force" => true
        ]);
        
        if (!isset($startResponse['operation'])) {
            throw new \Exception("Failed to start container, please try again.");
        }

        return $startResponse;        
    }
 
    /**
     * Stops a container.
     *
     * @param string $name Container name
     * @return array Response from the API
     */
    public function stopContainer(string $name): array {
        $response = $this->request('PUT', "/1.0/instances/$name/state", [
            "action" => "stop",
            "timeout" => 30,
            "force" => true
        ]);

        return $response;
    }


    /**
     * Retrieves the IPv4 address of a container.
     *
     * @param string $name Container name
     * @return string|null IPv4 address or null if not found
     */
    public function getContainerIP($name)
    {
        $container = $this->getContainerState($name);
        return $this->getIPv4FromMetadata($container['metadata']);
    }

    /**
     * Extracts the IPv4 address from container metadata.
     *
     * @param array $metadata Container metadata
     * @return string|null IPv4 address or null if not found
     */
    public function getIPv4FromMetadata(array $metadata): ?string
    {
        if (
            isset($metadata['network']['eth0']['addresses']) &&
            is_array($metadata['network']['eth0']['addresses'])
        ) {
            foreach ($metadata['network']['eth0']['addresses'] as $addr) {
                if (isset($addr['family']) && $addr['family'] === 'inet' && isset($addr['address'])) {
                    return $addr['address'];
                }
            }
        }
        return null;
    }

    // public function isServiceRunning(string $container, string $service): string
    // {
    //     $lxcPath = $_ENV['LXC_PATH'] ?: 'lxc';
    //     $cmd = "$lxcPath exec {$container} -- systemctl is-active {$service} 2>&1";
    //     $output = shell_exec($cmd);
    //     return trim($output);
    // }

    public function getContainerServiceStatus(string $container, string $service): string
    {
        // Step 1: Prepare exec command
        $execPayload = [
            "command" => ["systemctl", "is-active", $service],
            "wait-for-websocket" => false,
            "record-output" => true,
            "interactive" => false
        ];

        // Step 2: Start exec operation
        $execResponse = $this->request('POST', "/1.0/instances/{$container}/exec", $execPayload);
        $operationUrl = $execResponse['operation'] ?? null;

        if (!$operationUrl) {
            throw new \Exception("Failed to create exec operation");
        }

        // Step 3: Wait for operation to complete
        $waitResponse = $this->request('GET', "{$operationUrl}/wait?timeout=10");
        $metadata = $waitResponse['metadata']['metadata'] ?? [];

        $outputPaths = $metadata['output'] ?? [];
        $stdoutPath = $outputPaths['1'] ?? null;

        if (!$stdoutPath) {
            throw new \Exception("No stdout path returned by LXD");
        }

        // Step 4: Fetch raw stdout output
        $rawOutput = $this->requestRaw($stdoutPath);
        
        return trim($rawOutput); // Expected: 'active', 'inactive', etc.
    }


}