<?php

declare(strict_types=1);

/**
 * -------------------------------------------------------------------------
 * UrBackup plugin for GLPI
 * -------------------------------------------------------------------------
 *
 * Based on urbackup-server-python-web-api-wrapper by uroni
 * Reference: https://github.com/uroni/urbackup-server-python-web-api-wrapper
 */

namespace GlpiPlugin\Urbackup;

use RuntimeException;

class UrbackupApiClient
{
    private object $server;

    private string $base_url;

    private string $username;

    private string $password;

    private bool $ignore_ssl;

    private int $timeout = 10;

    private string $session = '';

    private bool $logged_in = false;

    private int $lastlogid = 0;

    private string $server_version = '';

    private bool $is_version_2_4_or_higher = false;

    /**
     * Constructor.
     *
     * @param Server|object $server UrBackup server object
     */
    public function __construct(object $server)
    {
        $this->server = $server;
        $this->base_url = rtrim($server->getWebInterfaceUrl(), '/') . '/x';
        $this->username = (string) ($server->fields['api_username'] ?? '');
        $this->password = (string) ($server->fields['api_password'] ?? '');
        $this->ignore_ssl = ((int) ($server->fields['ignore_ssl'] ?? 0)) === 1;
        $this->server_version = (string) ($server->fields['server_version'] ?? '');
        $this->is_version_2_4_or_higher = $this->detectVersion2_4OrHigher();
    }

    private function detectVersion2_4OrHigher(): bool
    {
        if ($this->server_version === '') {
            return false;
        }

        $parts = explode('.', $this->server_version);
        if (count($parts) < 2) {
            return false;
        }

        $major = (int) $parts[0];
        $minor = (int) $parts[1];

        if ($major > 2) {
            return true;
        }
        if ($major === 2 && $minor >= 4) {
            return true;
        }

        return false;
    }

    /**
     * Get internet mode setting key based on server version.
     *
     * @return string
     */
    public function getInternetModeSettingKey(): string
    {
        return $this->is_version_2_4_or_higher ? 'internet_mode_enabled' : 'internet_mode';
    }

    /**
     * Extract setting value from 2.5+ structured format or simple value.
     *
     * @param mixed $setting Setting value
     * @param mixed $default Default value
     *
     * @return mixed
     */
    public function extractSettingValue(mixed $setting, mixed $default = null): mixed
    {
        if (is_array($setting) && array_key_exists('value', $setting)) {
            return $setting['value'];
        }

        return $setting ?? $default;
    }

    /**
     * Test API connection.
     *
     * @return array<string, mixed>
     */
    public function testConnection(): array
    {
        try {
            $this->login();
            $identity = $this->getServerIdentity();

            return [
                'success' => true,
                'message' => $identity !== ''
                    ? sprintf(__('Connection successful. Server identity: %s', 'urbackup'), $identity)
                    : __('Connection successful.', 'urbackup'),
                'identity' => $identity,
            ];
        } catch (RuntimeException $e) {
            return [
                'success' => false,
                'message' => $e->getMessage(),
                'identity' => '',
            ];
        }
    }

    /**
     * Login to UrBackup web API.
     *
     * @return bool
     */
    public function login(): bool
    {
        if ($this->logged_in) {
            return true;
        }

        $login = $this->request('login', [], 'POST', false);

        if (!$login || !isset($login['success']) || $login['success'] !== true) {
            $salt = $this->request('salt', ['username' => $this->username], 'POST', false);

            if (!$salt || !isset($salt['ses']) || $salt['ses'] === '') {
                if (isset($salt['error']) && $salt['error'] === 1) {
                    throw new RuntimeException(__('Username does not exist on UrBackup server.', 'urbackup'));
                }
                throw new RuntimeException(__('Unable to get salt from UrBackup server.', 'urbackup'));
            }

            $this->session = (string) $salt['ses'];

            if (isset($salt['salt'])) {
                $password_md5 = $this->buildPasswordHash($this->password, $salt);

                $login = $this->request('login', [
                    'username' => $this->username,
                    'password' => $password_md5,
                    'ses'      => $this->session,
                ], 'POST', false);

                if (!$login || !isset($login['success']) || $login['success'] !== true) {
                    throw new RuntimeException(__('Unable to authenticate against UrBackup server. Password may be wrong.', 'urbackup'));
                }

                $this->logged_in = true;
                return true;
            }

            throw new RuntimeException(__('Salt response missing salt field.', 'urbackup'));
        }

        $this->session = (string) ($login['session'] ?? '');
        $this->logged_in = true;
        return true;
    }

    /**
     * Build password hash for authentication.
     *
     * @param string $password Plain password
     * @param array  $salt     Salt response from server
     *
     * @return string
     */
    private function buildPasswordHash(string $password, array $salt): string
    {
        $salt_str = (string) ($salt['salt'] ?? '');
        $rnd = (string) ($salt['rnd'] ?? '');
        $pbkdf2_rounds = (int) ($salt['pbkdf2_rounds'] ?? 0);

        $passwordMd5Bin = md5($salt_str . $password, true);
        $passwordMd5 = bin2hex($passwordMd5Bin);

        if ($pbkdf2_rounds > 0 && function_exists('hash_pbkdf2')) {
            $passwordMd5 = hash_pbkdf2(
                'sha256',
                $passwordMd5Bin,
                $salt_str,
                $pbkdf2_rounds,
                0,
                false
            );
        }

        return md5($rnd . $passwordMd5);
    }

    /**
     * Get server identity.
     *
     * @return string
     */
    public function getServerIdentity(): string
    {
        $data = $this->apiAction('server_identity');

        if (isset($data['server_identity'])) {
            return (string) $data['server_identity'];
        }

        if (isset($data['identity'])) {
            return (string) $data['identity'];
        }

        if (isset($data['name'])) {
            return (string) $data['name'];
        }

        return '';
    }

    /**
     * Get all client statuses.
     *
     * @return array<int, array<string, mixed>>
     */
    public function getStatus(): array
    {
        $data = $this->apiAction('status');

        if (isset($data['status']) && is_array($data['status'])) {
            return array_values($data['status']);
        }

        if (isset($data['clients']) && is_array($data['clients'])) {
            return array_values($data['clients']);
        }

        if (array_is_list($data)) {
            return $data;
        }

        return [];
    }

    /**
     * Get client status by GLPI asset name.
     *
     * @param string $client_name Client name
     *
     * @return array<string, mixed>|null
     */
    public function getClientStatusByName(string $client_name): ?array
    {
        foreach ($this->getStatus() as $client) {
            $name = (string) ($client['name'] ?? $client['clientname'] ?? $client['hostname'] ?? '');

            if (strcasecmp($name, $client_name) === 0) {
                return $client;
            }
        }

        return null;
    }

    /**
     * Get client ID by name.
     *
     * @param string $client_name Client name
     *
     * @return int
     */
    public function getClientIdByName(string $client_name): int
    {
        $client = $this->getClientStatusByName($client_name);

        if ($client === null) {
            return 0;
        }

        return (int) ($client['id'] ?? $client['clientid'] ?? $client['client_id'] ?? 0);
    }

    /**
     * Get client settings.
     *
     * @param string $client_name Client name
     *
     * @return array<string, mixed>
     */
    public function getClientSettings(string $client_name): array
    {
        $client_id = $this->getClientIdByName($client_name);

        if ($client_id <= 0) {
            return [];
        }

        $data = $this->apiAction('settings', [
            'sa'        => 'clientsettings',
            't_clientid' => $client_id,
        ]);

        if (isset($data['settings']) && is_array($data['settings'])) {
            return $data['settings'];
        }

        return $data;
    }

    /**
     * Change a client setting.
     *
     * @param string $client_name Client name
     * @param string $key         Setting key
     * @param mixed  $value       New value
     *
     * @return bool
     */
    public function changeClientSetting(string $client_name, string $key, mixed $value): bool
    {
        $client_id = $this->getClientIdByName($client_name);

        if ($client_id <= 0) {
            return false;
        }

        $data = $this->apiAction('settings', [
            'sa'           => 'clientsettings_save',
            't_clientid'   => $client_id,
            'overwrite'    => 'true',
            $key           => (string) $value,
        ]);

        return $this->responseIsSuccess($data);
    }

    public function updateClientSettings(string $client_name, string $key, string $value): bool
    {
        $client_id = $this->getClientIdByName($client_name);

        if ($client_id <= 0) {
            return false;
        }

        $data = $this->apiAction('settings', [
            'sa'           => 'clientsettings_save',
            't_clientid'   => $client_id,
            'overwrite'    => 'true',
            $key           => $value,
        ]);

        return $this->responseIsSuccess($data);
    }

    public function saveInternetMode(string $client_name, bool $enabled): bool
    {
        $client_id = $this->getClientIdByName($client_name);

        if ($client_id <= 0) {
            return false;
        }

        $key = $this->getInternetModeSettingKey();

        $params = [
            'sa'         => 'clientsettings_save',
            't_clientid' => $client_id,
            'overwrite'  => 'true',
            $key         => $enabled ? 'true' : 'false',
        ];

        $data = $this->apiAction('settings', $params);

        return $this->responseIsSuccess($data);
    }

    /**
     * Get client internet authentication key.
     *
     * @param string $client_name Client name
     *
     * @return string
     */
    public function getClientAuthKey(string $client_name): string
    {
        $settings = $this->getClientSettings($client_name);

        $raw = $settings['internet_authkey'] ?? $settings['internetAuthkey'] ?? '';

        if (is_array($raw) && isset($raw['value'])) {
            return (string) $raw['value'];
        }

        if (is_array($raw)) {
            return '';
        }

        return (string) $raw;
    }

    /**
     * Add a client to UrBackup server.
     *
     * @param string $client_name Client name
     *
     * @return bool
     */
    public function addClient(string $client_name): bool
    {
        $data = $this->apiAction('add_client', [
            'clientname' => $client_name,
        ]);

        return $this->responseIsSuccess($data);
    }

    /**
     * Remove a client from UrBackup server.
     *
     * @param string $client_name Client name
     *
     * @return bool
     */
    public function removeClient(string $client_name): bool
    {
        $client_id = $this->getClientIdByName($client_name);

        $payload = [
            'clientname' => $client_name,
        ];

        if ($client_id > 0) {
            $payload['clientid'] = $client_id;
        }

        $data = $this->apiAction('remove_client', $payload);

        return $this->responseIsSuccess($data);
    }

    /**
     * Start incremental file backup.
     *
     * @param string $client_name Client name
     *
     * @return bool
     */
    public function startIncrementalFileBackup(string $client_name): bool
    {
        return $this->startBackup($client_name, 'incr_file');
    }

    /**
     * Start full file backup.
     *
     * @param string $client_name Client name
     *
     * @return bool
     */
    public function startFullFileBackup(string $client_name): bool
    {
        return $this->startBackup($client_name, 'full_file');
    }

    /**
     * Start incremental image backup.
     *
     * @param string $client_name Client name
     *
     * @return bool
     */
    public function startIncrementalImageBackup(string $client_name): bool
    {
        return $this->startBackup($client_name, 'incr_image');
    }

    /**
     * Start full image backup.
     *
     * @param string $client_name Client name
     *
     * @return bool
     */
    public function startFullImageBackup(string $client_name): bool
    {
        return $this->startBackup($client_name, 'full_image');
    }

    /**
     * Get recent backups.
     *
     * @param string $client_name Client name
     * @param int    $limit       Limit
     *
     * @return array<int, array<string, mixed>>
     */
    public function getRecentBackups(string $client_name, int $limit = 40): array
    {
        $client_id = $this->getClientIdByName($client_name);

        if ($client_id <= 0) {
            return [];
        }

        $data = $this->apiAction('backups', [
            'sa'      => 'backups',
            'clientid' => $client_id,
        ]);

        $rows = [];

        foreach (($data['backups'] ?? []) as $backup) {
            if (is_array($backup)) {
                $backup['backup_type'] = __('File backup', 'urbackup');
                $rows[] = $backup;
            }
        }

        foreach (($data['backup_images'] ?? []) as $backup) {
            if (is_array($backup)) {
                $backup['backup_type'] = __('Image backup', 'urbackup');
                $rows[] = $backup;
            }
        }

        usort($rows, static function (array $a, array $b): int {
            $timeA = (int) ($a['time'] ?? $a['backuptime'] ?? $a['backup_time'] ?? $a['created'] ?? 0);
            $timeB = (int) ($b['time'] ?? $b['backuptime'] ?? $b['backup_time'] ?? $b['created'] ?? 0);
            return $timeB <=> $timeA;
        });

        return array_slice($rows, 0, $limit);
    }

    /**
     * Get client log rows.
     *
     * @param string $client_name Client name
     * @param int    $limit       Limit
     *
     * @return array<int, array<string, mixed>>
     */
    public function getClientLogs(string $client_name, int $limit = 50): array
    {
        $client_id = $this->getClientIdByName($client_name);

        $data = $this->apiAction('livelog', [
            'clientid' => $client_id,
            'lastid'   => $this->lastlogid,
        ]);

        $logs = [];

        foreach (($data['logdata'] ?? []) as $row) {
            if (is_array($row)) {
                $logs[] = $row;
            }
        }

        if (count($logs) > 0) {
            $last_entry = end($logs);
            $this->lastlogid = (int) ($last_entry['id'] ?? 0);
        }

        return array_slice($logs, 0, $limit);
    }

    /**
     * Start backup command.
     *
     * @param string $client_name Client name
     * @param string $type        Backup type
     *
     * @return bool
     */
    private function startBackup(string $client_name, string $type): bool
    {
        $client_id = $this->getClientIdByName($client_name);

        if ($client_id <= 0) {
            return false;
        }

        $data = $this->apiAction('start_backup', [
            'start_client' => $client_id,
            'start_type'   => $type,
        ]);

        if (isset($data['result']) && is_array($data['result'])) {
            foreach ($data['result'] as $result) {
                if (isset($result['start_ok']) && $result['start_ok'] === true) {
                    return true;
                }
            }
        }

        return $this->responseIsSuccess($data);
    }

    /**
     * Execute an authenticated API action.
     *
     * @param string               $action Action name
     * @param array<string, mixed> $params Parameters
     *
     * @return array<string, mixed>
     */
    private function apiAction(string $action, array $params = []): array
    {
        if (!$this->logged_in) {
            $this->login();
        }

        $params['ses'] = $this->session;

        return $this->request($action, $params, 'POST', true);
    }

    /**
     * Execute HTTP request.
     *
     * @param string               $action          API action
     * @param array<string, mixed> $params          Parameters
     * @param string               $method          HTTP method (GET/POST)
     * @param bool                 $require_success Require successful HTTP
     *
     * @return array<string, mixed>
     */
    private function request(string $action, array $params, string $method = 'POST', bool $require_success = true): array
    {
        if (!function_exists('curl_init')) {
            throw new RuntimeException(__('PHP cURL extension is required for UrBackup API.', 'urbackup'));
        }

        $ch = curl_init();

        if ($ch === false) {
            throw new RuntimeException(__('Unable to initialize cURL.', 'urbackup'));
        }

        $url = $this->base_url . '?a=' . urlencode($action);

        if ($method === 'GET') {
            $url .= '&' . http_build_query($params);
        }

        $options = [
            CURLOPT_RETURNTRANSFER  => true,
            CURLOPT_TIMEOUT         => $this->timeout,
            CURLOPT_SSL_VERIFYPEER  => !$this->ignore_ssl,
            CURLOPT_SSL_VERIFYHOST  => $this->ignore_ssl ? 0 : 2,
            CURLOPT_HTTPHEADER      => [
                'Accept: application/json',
                'Content-Type: application/x-www-form-urlencoded; charset=UTF-8',
            ],
        ];

        if ($method === 'POST') {
            $options[CURLOPT_POST] = true;
            $options[CURLOPT_POSTFIELDS] = http_build_query($params);
        }

        $options[CURLOPT_URL] = $url;

        curl_setopt_array($ch, $options);

        $raw = curl_exec($ch);

        if ($raw === false) {
            $error = curl_error($ch);
            curl_close($ch);

            throw new RuntimeException(
                sprintf(__('UrBackup API request failed: %s', 'urbackup'), $error)
            );
        }

        $http_code = (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);

        curl_close($ch);

        if ($require_success && ($http_code < 200 || $http_code >= 300)) {
            throw new RuntimeException(
                sprintf(__('UrBackup API returned HTTP status %d.', 'urbackup'), $http_code)
            );
        }

        if ($raw === '' || $raw === 'null') {
            return [];
        }

        $decoded = json_decode($raw, true);

        if (!is_array($decoded)) {
            if (str_starts_with(trim($raw), '<')) {
                throw new RuntimeException(
                    sprintf(__('UrBackup API returned non-JSON response (HTML). Check server URL and authentication.', 'urbackup'))
                );
            }

            return [
                'raw' => $raw,
                'success' => $http_code >= 200 && $http_code < 300,
            ];
        }

        return $decoded;
    }

    /**
     * Evaluate generic API success response.
     *
     * @param array<string, mixed> $data Response
     *
     * @return bool
     */
    private function responseIsSuccess(array $data): bool
    {
        if (isset($data['success']) && $data['success'] === true) {
            return true;
        }

        if (isset($data['ok']) && $data['ok'] === true) {
            return true;
        }

        if (isset($data['saved_ok']) && $data['saved_ok'] === true) {
            return true;
        }

        if (isset($data['result']) && $data['result'] === 'ok') {
            return true;
        }

        if (isset($data['start_ok']) && $data['start_ok'] === true) {
            return true;
        }

        return false;
    }
}