<?php
/**
 * NIS2 Agile - Audit Controller
 *
 * Controlli compliance, evidenze, audit logs, mapping ISO 27001.
 */

require_once __DIR__ . '/BaseController.php';
require_once APP_PATH . '/services/ReportService.php';

class AuditController extends BaseController
{
    public function listControls(): void
    {
        $this->requireOrgAccess();

        $controls = Database::fetchAll(
            'SELECT cc.*, u.full_name as responsible_name
             FROM compliance_controls cc
             LEFT JOIN users u ON u.id = cc.responsible_user_id
             WHERE cc.organization_id = ?
             ORDER BY cc.control_code',
            [$this->getCurrentOrgId()]
        );

        $this->jsonSuccess($controls);
    }

    public function updateControl(int $id): void
    {
        $this->requireOrgRole(['org_admin', 'compliance_manager', 'auditor']);

        $updates = [];
        foreach (['status', 'implementation_percentage', 'evidence_description', 'responsible_user_id', 'next_review_date'] as $field) {
            if ($this->hasParam($field)) {
                $updates[$field] = $this->getParam($field);
            }
        }

        if (isset($updates['status']) && $updates['status'] === 'verified') {
            $updates['last_verified_at'] = date('Y-m-d H:i:s');
        }

        if (!empty($updates)) {
            Database::update('compliance_controls', $updates, 'id = ? AND organization_id = ?', [$id, $this->getCurrentOrgId()]);
            $this->logAudit('control_updated', 'compliance_control', $id, $updates);
        }

        $this->jsonSuccess($updates, 'Controllo aggiornato');
    }

    public function uploadEvidence(): void
    {
        $this->requireOrgRole(['org_admin', 'compliance_manager', 'auditor']);

        if (!isset($_FILES['file'])) {
            $this->jsonError('File non fornito', 400, 'NO_FILE');
        }

        $file = $_FILES['file'];
        $maxSize = 10 * 1024 * 1024; // 10MB

        if ($file['size'] > $maxSize) {
            $this->jsonError('File troppo grande (max 10MB)', 400, 'FILE_TOO_LARGE');
        }

        $orgId = $this->getCurrentOrgId();
        $uploadDir = UPLOAD_PATH . "/evidence/{$orgId}";

        if (!is_dir($uploadDir)) {
            mkdir($uploadDir, 0755, true);
        }

        $ext = pathinfo($file['name'], PATHINFO_EXTENSION);
        $filename = uniqid('ev_') . '.' . $ext;
        $filePath = $uploadDir . '/' . $filename;

        if (!move_uploaded_file($file['tmp_name'], $filePath)) {
            $this->jsonError('Errore caricamento file', 500, 'UPLOAD_ERROR');
        }

        $evidenceId = Database::insert('evidence_files', [
            'organization_id' => $orgId,
            'control_id'      => $this->getParam('control_id'),
            'entity_type'     => $this->getParam('entity_type'),
            'entity_id'       => $this->getParam('entity_id'),
            'file_name'       => $file['name'],
            'file_path'       => "evidence/{$orgId}/{$filename}",
            'file_size'       => $file['size'],
            'mime_type'       => $file['type'],
            'uploaded_by'     => $this->getCurrentUserId(),
        ]);

        $this->logAudit('evidence_uploaded', 'evidence', $evidenceId);
        $this->jsonSuccess(['id' => $evidenceId], 'Evidenza caricata', 201);
    }

    public function listEvidence(): void
    {
        $this->requireOrgAccess();

        $where = 'organization_id = ?';
        $params = [$this->getCurrentOrgId()];

        if ($this->hasParam('control_id')) {
            $where .= ' AND control_id = ?';
            $params[] = $this->getParam('control_id');
        }
        if ($this->hasParam('entity_type') && $this->hasParam('entity_id')) {
            $where .= ' AND entity_type = ? AND entity_id = ?';
            $params[] = $this->getParam('entity_type');
            $params[] = $this->getParam('entity_id');
        }

        $evidence = Database::fetchAll(
            "SELECT ef.*, u.full_name as uploaded_by_name
             FROM evidence_files ef
             LEFT JOIN users u ON u.id = ef.uploaded_by
             WHERE ef.{$where}
             ORDER BY ef.created_at DESC",
            $params
        );

        $this->jsonSuccess($evidence);
    }

    public function generateReport(): void
    {
        $this->requireOrgAccess();
        $orgId = $this->getCurrentOrgId();

        $org = Database::fetchOne('SELECT * FROM organizations WHERE id = ?', [$orgId]);
        $controls = Database::fetchAll('SELECT * FROM compliance_controls WHERE organization_id = ? ORDER BY control_code', [$orgId]);
        $lastAssessment = Database::fetchOne('SELECT * FROM assessments WHERE organization_id = ? AND status = "completed" ORDER BY completed_at DESC LIMIT 1', [$orgId]);
        $riskCount = Database::count('risks', 'organization_id = ? AND status != "closed"', [$orgId]);
        $incidentCount = Database::count('incidents', 'organization_id = ?', [$orgId]);
        $policyCount = Database::count('policies', 'organization_id = ? AND status IN ("approved","published")', [$orgId]);

        $totalControls = count($controls);
        $implemented = count(array_filter($controls, fn($c) => in_array($c['status'], ['implemented', 'verified'])));

        $this->jsonSuccess([
            'organization'       => $org,
            'report_date'        => date('Y-m-d H:i:s'),
            'compliance_summary' => [
                'total_controls'       => $totalControls,
                'implemented_controls' => $implemented,
                'compliance_percentage' => $totalControls > 0 ? round($implemented / $totalControls * 100) : 0,
            ],
            'controls'           => $controls,
            'last_assessment'    => $lastAssessment,
            'risk_count'         => $riskCount,
            'incident_count'     => $incidentCount,
            'policy_count'       => $policyCount,
        ]);
    }

    public function getAuditLogs(): void
    {
        $this->requireOrgRole(['org_admin', 'auditor']);
        $pagination = $this->getPagination(50);

        $total = Database::count('audit_logs', 'organization_id = ?', [$this->getCurrentOrgId()]);

        $logs = Database::fetchAll(
            "SELECT al.*, u.full_name
             FROM audit_logs al
             LEFT JOIN users u ON u.id = al.user_id
             WHERE al.organization_id = ?
             ORDER BY al.created_at DESC
             LIMIT {$pagination['per_page']} OFFSET {$pagination['offset']}",
            [$this->getCurrentOrgId()]
        );

        $this->jsonPaginated($logs, $total, $pagination['page'], $pagination['per_page']);
    }

    public function getIsoMapping(): void
    {
        $this->requireOrgAccess();

        $mapping = [
            ['nis2' => '21.2.a', 'iso27001' => 'A.5.1, A.5.2, A.8.1, A.8.2', 'title' => 'Risk analysis and security policies'],
            ['nis2' => '21.2.b', 'iso27001' => 'A.5.24, A.5.25, A.5.26, A.6.8', 'title' => 'Incident handling'],
            ['nis2' => '21.2.c', 'iso27001' => 'A.5.29, A.5.30', 'title' => 'Business continuity'],
            ['nis2' => '21.2.d', 'iso27001' => 'A.5.19, A.5.20, A.5.21, A.5.22', 'title' => 'Supply chain security'],
            ['nis2' => '21.2.e', 'iso27001' => 'A.8.25, A.8.26, A.8.27, A.8.28', 'title' => 'System acquisition and development'],
            ['nis2' => '21.2.f', 'iso27001' => 'A.5.35, A.5.36', 'title' => 'Effectiveness assessment'],
            ['nis2' => '21.2.g', 'iso27001' => 'A.6.3, A.6.6', 'title' => 'Cyber hygiene and training'],
            ['nis2' => '21.2.h', 'iso27001' => 'A.8.24', 'title' => 'Cryptography and encryption'],
            ['nis2' => '21.2.i', 'iso27001' => 'A.5.15, A.5.16, A.5.17, A.5.18, A.6.1, A.6.2', 'title' => 'HR security, access control, asset management'],
            ['nis2' => '21.2.j', 'iso27001' => 'A.8.5', 'title' => 'Multi-factor authentication'],
        ];

        $this->jsonSuccess($mapping);
    }

    /**
     * GET /api/audit/executive-report
     * Genera report esecutivo HTML (stampabile come PDF)
     */
    public function executiveReport(): void
    {
        $this->requireOrgRole(['org_admin', 'compliance_manager', 'board_member']);

        $reportService = new ReportService();
        $html = $reportService->generateExecutiveReport($this->getCurrentOrgId());

        header('Content-Type: text/html; charset=utf-8');
        echo $html;
        exit;
    }

    /**
     * GET /api/audit/export/{type}
     * Esporta dati in CSV
     */
    public function export(int $type = 0): void
    {
        $this->requireOrgRole(['org_admin', 'compliance_manager', 'auditor']);

        $exportType = $_GET['type'] ?? 'controls';
        $orgId = $this->getCurrentOrgId();
        $reportService = new ReportService();

        $csv = match ($exportType) {
            'risks'     => $reportService->exportRisksCSV($orgId),
            'incidents' => $reportService->exportIncidentsCSV($orgId),
            'controls'  => $reportService->exportControlsCSV($orgId),
            'assets'    => $reportService->exportAssetsCSV($orgId),
            default     => $reportService->exportControlsCSV($orgId),
        };

        $filename = "nis2_{$exportType}_" . date('Y-m-d') . '.csv';

        header('Content-Type: text/csv; charset=utf-8');
        header('Content-Disposition: attachment; filename="' . $filename . '"');
        echo $csv;
        exit;
    }

    /**
     * GET /api/audit/chain-verify
     * Verifica l'integrità dell'hash chain per l'organizzazione corrente.
     * Risponde con: valid, total, hashed, coverage_pct, broken_at, last_hash
     */
    public function chainVerify(): void
    {
        $this->requireOrgRole(['org_admin', 'auditor']);
        $orgId = $this->getCurrentOrgId();

        $db     = Database::getInstance();
        $result = AuditService::verifyChain($db, $orgId);

        // Se la catena è rotta, registra la violazione
        if (!$result['valid'] && $result['broken_at'] !== null) {
            $performer = $this->currentUser['email'] ?? 'system';
            try {
                $ins = $db->prepare(
                    "INSERT INTO audit_violations
                     (organization_id, detected_by, broken_at_id, chain_length, notes)
                     VALUES (:org, :by, :bid, :len, :notes)"
                );
                $ins->execute([
                    'org'   => $orgId,
                    'by'    => $performer,
                    'bid'   => $result['broken_at'],
                    'len'   => $result['total'],
                    'notes' => 'Violazione rilevata tramite API chain-verify',
                ]);
            } catch (Throwable $e) {
                error_log('[AuditController] chain violation log error: ' . $e->getMessage());
            }

            $this->logAudit('audit.chain_broken', 'audit_logs', $result['broken_at'], [
                'total'        => $result['total'],
                'coverage_pct' => $result['coverage_pct'],
            ]);
        }

        $this->jsonSuccess($result);
    }

    /**
     * GET /api/audit/export-certified
     * Genera un export JSON certificato con hash SHA-256 dell'intero contenuto.
     * Adatto per ispezioni ACN, audit NIS2 Art.32, certificazione ISO 27001.
     */
    public function exportCertified(): void
    {
        $this->requireOrgRole(['org_admin', 'auditor']);
        $orgId  = $this->getCurrentOrgId();
        $userId = $this->getCurrentUserId();
        $email  = $this->currentUser['email'] ?? 'system';

        $db     = Database::getInstance();
        $result = AuditService::exportCertified(
            $db,
            $orgId,
            $userId,
            $email,
            $_GET['purpose'] ?? 'export_certificato',
            $_GET['from']    ?? null,
            $_GET['to']      ?? null
        );

        $this->logAudit('audit.export_certified', 'audit_logs', null, [
            'records_count' => $result['records_count'],
            'chain_valid'   => $result['chain_valid'],
            'export_hash'   => $result['export_hash'],
        ]);

        header('Content-Disposition: attachment; filename="nis2_audit_certified_' . date('Y-m-d') . '.json"');
        $this->jsonSuccess($result);
    }
}