<?php
/**
 * NIS2 Agile - Controlli periodici (control monitoring) — mig.057
 * ----------------------------------------------------------------------------
 * Registro dei controlli RICORRENTI (owner + frequenza + metodo) e relativo
 * REGISTRO DELLE ESECUZIONI (data, esito, note, evidenze) = evidenza del
 * monitoraggio periodico (ISO 27001 §9.1 / A.8.16 — buona prassi, non obbligo).
 * Da un'esecuzione non conforme si genera una NC o un'azione correttiva (AC),
 * riusando non_conformities / capa_actions. La scadenza avanza ad ogni esecuzione
 * e alimenta il Calendario.
 *
 * Distinto da compliance_controls (registro stato), review_schedule (cadenza
 * generica) e internal_audits (audit puntuale). Vedi docs/DESIGN_CONTROLLI_PERIODICI.md.
 *
 * NOTE: Database::query/fetchAll/fetchOne/insert/update/delete; jsonError/Success exit.
 */

require_once __DIR__ . '/BaseController.php';

class PeriodicControlController extends BaseController
{
    private const MANAGE_ROLES = ['org_admin', 'compliance_manager', 'auditor'];
    private const FREQS = ['giornaliero', 'settimanale', 'mensile', 'trimestrale', 'semestrale', 'annuale', 'custom'];

    // ── LETTURE ──────────────────────────────────────────────────────────────
    /** GET /api/periodic-controls/list */
    public function list(): void
    {
        $this->requireOrgAccess();
        $orgId = $this->getCurrentOrgId();
        $rows = Database::fetchAll(
            "SELECT c.id, c.code, c.title, c.category, c.control_ref, c.frequency, c.frequency_days,
                    c.next_due_date, c.last_executed_at, c.status, c.owner_role_id, r.role_name AS owner_role,
                    (SELECT COUNT(*) FROM periodic_control_executions e WHERE e.control_id = c.id) AS n_exec,
                    (SELECT outcome FROM periodic_control_executions e WHERE e.control_id = c.id ORDER BY e.executed_at DESC, e.id DESC LIMIT 1) AS last_outcome
             FROM periodic_controls c
             LEFT JOIN org_roles r ON r.id = c.owner_role_id
             WHERE c.organization_id = ?
             ORDER BY (c.next_due_date IS NULL), c.next_due_date ASC, c.id DESC",
            [$orgId]
        );
        $today = date('Y-m-d');
        $out = array_map(function ($c) use ($today) {
            return [
                'id' => (int) $c['id'], 'code' => $c['code'], 'title' => $c['title'], 'category' => $c['category'],
                'control_ref' => $c['control_ref'], 'frequency' => $c['frequency'], 'frequency_days' => $c['frequency_days'] !== null ? (int) $c['frequency_days'] : null,
                'owner_role_id' => $c['owner_role_id'] !== null ? (int) $c['owner_role_id'] : null, 'owner_role' => $c['owner_role'],
                'next_due_date' => $c['next_due_date'], 'last_executed_at' => $c['last_executed_at'], 'status' => $c['status'],
                'n_exec' => (int) $c['n_exec'], 'last_outcome' => $c['last_outcome'],
                'due_status' => $this->dueStatus($c['next_due_date'], $today, $c['status']),
            ];
        }, $rows);
        $this->jsonSuccess(['controls' => $out]);
    }

    /** GET /api/periodic-controls/{id} */
    public function get(int $id): void
    {
        $this->requireOrgAccess();
        $orgId = $this->getCurrentOrgId();
        $c = Database::fetchOne(
            "SELECT c.*, r.role_name AS owner_role FROM periodic_controls c
             LEFT JOIN org_roles r ON r.id = c.owner_role_id
             WHERE c.id = ? AND c.organization_id = ?",
            [$id, $orgId]
        );
        if (!$c) { $this->jsonError('Controllo non trovato', 404, 'NOT_FOUND'); }
        $exec = Database::fetchAll(
            "SELECT e.id, e.executed_at, e.outcome, e.notes, e.ncr_id, e.created_at,
                    u.full_name AS executed_by_name, n.ncr_code
             FROM periodic_control_executions e
             LEFT JOIN users u ON u.id = e.executed_by
             LEFT JOIN non_conformities n ON n.id = e.ncr_id
             WHERE e.control_id = ? ORDER BY e.executed_at DESC, e.id DESC",
            [$id]
        );
        $this->jsonSuccess([
            'id' => (int) $c['id'], 'code' => $c['code'], 'title' => $c['title'], 'description' => $c['description'],
            'category' => $c['category'], 'control_ref' => $c['control_ref'], 'method' => $c['method'],
            'frequency' => $c['frequency'], 'frequency_days' => $c['frequency_days'] !== null ? (int) $c['frequency_days'] : null,
            'owner_role_id' => $c['owner_role_id'] !== null ? (int) $c['owner_role_id'] : null, 'owner_role' => $c['owner_role'],
            'next_due_date' => $c['next_due_date'], 'last_executed_at' => $c['last_executed_at'], 'status' => $c['status'],
            'executions' => array_map(static fn($e) => [
                'id' => (int) $e['id'], 'executed_at' => $e['executed_at'], 'outcome' => $e['outcome'], 'notes' => $e['notes'],
                'executed_by_name' => $e['executed_by_name'], 'ncr_id' => $e['ncr_id'] !== null ? (int) $e['ncr_id'] : null, 'ncr_code' => $e['ncr_code'],
            ], $exec),
        ]);
    }

    // ── SCRITTURE ────────────────────────────────────────────────────────────
    /** POST /api/periodic-controls/create */
    public function create(): void
    {
        $this->requireOrgRole(self::MANAGE_ROLES);
        $orgId = $this->getCurrentOrgId();
        $b = $this->getJsonBody();

        $title = trim((string) ($b['title'] ?? ''));
        if ($title === '' || mb_strlen($title) > 255) { $this->jsonError('Titolo obbligatorio (max 255)', 422, 'INVALID_TITLE'); }
        $freq = in_array($b['frequency'] ?? '', self::FREQS, true) ? $b['frequency'] : 'mensile';
        $fdays = ($freq === 'custom') ? max(1, (int) ($b['frequency_days'] ?? 0)) : null;
        if ($freq === 'custom' && !$fdays) { $this->jsonError('Per frequenza custom indicare frequency_days', 422, 'INVALID_FREQ'); }
        $ownerRole = $this->validateOwnerRole($b['owner_role_id'] ?? null, $orgId);
        $next = $this->validateDate($b['next_due_date'] ?? null, 'next_due_date');
        if ($next === null) { $next = $this->advance(date('Y-m-d'), $freq, $fdays); }

        // Retry-on-duplicate: il codice CTL-NNN è MAX+1 (race possibile su create concorrenti);
        // la UNIQUE (organization_id, code) blocca i doppioni e qui si rigenera il codice.
        $base = [
            'organization_id' => $orgId, 'title' => $title,
            'description' => $this->nullableStr($b['description'] ?? null), 'category' => $this->nullableStr($b['category'] ?? null, 100),
            'control_ref' => $this->nullableStr($b['control_ref'] ?? null, 32), 'owner_role_id' => $ownerRole,
            'frequency' => $freq, 'frequency_days' => $fdays, 'method' => $this->nullableStr($b['method'] ?? null),
            'next_due_date' => $next, 'status' => in_array($b['status'] ?? '', ['active', 'suspended'], true) ? $b['status'] : 'active',
            'created_by' => $this->getCurrentUserId(),
        ];
        $code = null; $id = 0;
        for ($attempt = 0; ; $attempt++) {
            $code = $this->nextCode($orgId);
            try {
                $id = (int) Database::insert('periodic_controls', ['code' => $code] + $base);
                break;
            } catch (\PDOException $e) {
                if (($e->errorInfo[1] ?? 0) === 1062 && $attempt < 4) { continue; }
                throw $e;
            }
        }
        $this->logAudit('periodic_control_created', 'periodic_control', $id, ['code' => $code, 'title' => $title]);
        $this->jsonSuccess(['id' => $id, 'code' => $code, 'next_due_date' => $next], 'Controllo periodico creato', 201);
    }

    /** PUT /api/periodic-controls/{id} */
    public function update(int $id): void
    {
        $this->requireOrgRole(self::MANAGE_ROLES);
        $orgId = $this->getCurrentOrgId();
        $b = $this->getJsonBody();
        $c = Database::fetchOne('SELECT id, frequency, frequency_days FROM periodic_controls WHERE id = ? AND organization_id = ?', [$id, $orgId]);
        if (!$c) { $this->jsonError('Controllo non trovato', 404, 'NOT_FOUND'); }

        $updates = [];
        if ($this->hasParam('title')) {
            $t = trim((string) ($b['title'] ?? '')); if ($t === '' || mb_strlen($t) > 255) { $this->jsonError('Titolo non valido', 422, 'INVALID_TITLE'); }
            $updates['title'] = $t;
        }
        if ($this->hasParam('description')) { $updates['description'] = $this->nullableStr($b['description'] ?? null); }
        if ($this->hasParam('category')) { $updates['category'] = $this->nullableStr($b['category'] ?? null, 100); }
        if ($this->hasParam('control_ref')) { $updates['control_ref'] = $this->nullableStr($b['control_ref'] ?? null, 32); }
        if ($this->hasParam('method')) { $updates['method'] = $this->nullableStr($b['method'] ?? null); }
        // array_key_exists (non hasParam): distingue "chiave presente = null" (azzera) da "chiave assente" (lascia invariato).
        if (array_key_exists('owner_role_id', $b)) { $updates['owner_role_id'] = $this->validateOwnerRole($b['owner_role_id'], $orgId); }
        if ($this->hasParam('frequency') && in_array($b['frequency'], self::FREQS, true)) {
            $updates['frequency'] = $b['frequency'];
            $updates['frequency_days'] = ($b['frequency'] === 'custom') ? max(1, (int) ($b['frequency_days'] ?? $c['frequency_days'] ?? 30)) : null;
        }
        if (array_key_exists('next_due_date', $b)) { $updates['next_due_date'] = $this->validateDate($b['next_due_date'], 'next_due_date'); }
        if ($this->hasParam('status') && in_array($b['status'], ['active', 'suspended'], true)) { $updates['status'] = $b['status']; }

        if (!empty($updates)) { Database::update('periodic_controls', $updates, 'id = ? AND organization_id = ?', [$id, $orgId]); }
        $this->logAudit('periodic_control_updated', 'periodic_control', $id, array_keys($updates));
        $this->jsonSuccess(['id' => $id, 'updated' => array_keys($updates)], 'Controllo aggiornato');
    }

    /** DELETE /api/periodic-controls/{id} */
    public function delete(int $id): void
    {
        $this->requireOrgRole(['org_admin']);
        $orgId = $this->getCurrentOrgId();
        // Le esecuzioni si cancellano via FK ON DELETE CASCADE; il calendario legge
        // periodic_controls direttamente (CalendarController::srcPeriodicControls),
        // quindi non esiste alcuna riga review_schedule da ripulire.
        $del = Database::delete('periodic_controls', 'id = ? AND organization_id = ?', [$id, $orgId]);
        if ($del === 0) { $this->jsonError('Controllo non trovato', 404, 'NOT_FOUND'); }
        $this->logAudit('periodic_control_deleted', 'periodic_control', $id);
        $this->jsonSuccess(null, 'Controllo eliminato');
    }

    /**
     * POST /api/periodic-controls/{id}/executions
     * Body: {executed_at?, outcome, notes?, generate?: 'none'|'nc'|'ac'}
     * Registra l'esecuzione, avanza la scadenza; su esito negativo può generare NC o NC+azione correttiva.
     */
    public function addExecution(int $id): void
    {
        $this->requireOrgRole(self::MANAGE_ROLES);
        $orgId = $this->getCurrentOrgId();
        $c = Database::fetchOne('SELECT * FROM periodic_controls WHERE id = ? AND organization_id = ?', [$id, $orgId]);
        if (!$c) { $this->jsonError('Controllo non trovato', 404, 'NOT_FOUND'); }
        $b = $this->getJsonBody();

        $outcome = in_array($b['outcome'] ?? '', ['conforme', 'non_conforme', 'parziale', 'non_applicabile'], true) ? $b['outcome'] : null;
        if ($outcome === null) { $this->jsonError('Esito non valido', 422, 'INVALID_OUTCOME'); }
        $execDate = $this->validateDate($b['executed_at'] ?? null, 'executed_at') ?? date('Y-m-d');
        $generate = in_array($b['generate'] ?? 'none', ['none', 'nc', 'ac'], true) ? $b['generate'] : 'none';

        $execId = (int) Database::insert('periodic_control_executions', [
            'control_id' => $id, 'executed_at' => $execDate, 'executed_by' => $this->getCurrentUserId(),
            'outcome' => $outcome, 'notes' => $this->nullableStr($b['notes'] ?? null),
        ]);

        // avanza la scadenza
        $next = $this->advance($execDate, $c['frequency'], $c['frequency_days'] !== null ? (int) $c['frequency_days'] : null);
        Database::update('periodic_controls', ['last_executed_at' => $execDate, 'next_due_date' => $next], 'id = ? AND organization_id = ?', [$id, $orgId]);

        // generazione NC / AC su esito negativo
        $ncr = null;
        if (in_array($outcome, ['non_conforme', 'parziale'], true) && $generate !== 'none') {
            $ncr = $this->generateNc($orgId, $c, $execId, $outcome, $generate === 'ac');
            Database::update('periodic_control_executions', ['ncr_id' => $ncr['id']], 'id = ?', [$execId]);
        }

        $this->logAudit('periodic_control_executed', 'periodic_control', $id, ['execution_id' => $execId, 'outcome' => $outcome, 'ncr' => $ncr['ncr_code'] ?? null]);
        $this->jsonSuccess(['execution_id' => $execId, 'next_due_date' => $next, 'ncr' => $ncr], 'Esecuzione registrata', 201);
    }

    /** GET /api/periodic-controls/{id}/report */
    public function report(int $id): void
    {
        $this->requireOrgAccess();
        $orgId = $this->getCurrentOrgId();
        $c = Database::fetchOne(
            "SELECT c.*, r.role_name AS owner_role, o.name AS org_name FROM periodic_controls c
             LEFT JOIN org_roles r ON r.id = c.owner_role_id JOIN organizations o ON o.id = c.organization_id
             WHERE c.id = ? AND c.organization_id = ?",
            [$id, $orgId]
        );
        if (!$c) { $this->jsonError('Controllo non trovato', 404, 'NOT_FOUND'); }
        $exec = Database::fetchAll(
            "SELECT e.executed_at, e.outcome, e.notes, n.ncr_code, u.full_name AS by_name
             FROM periodic_control_executions e LEFT JOIN non_conformities n ON n.id = e.ncr_id
             LEFT JOIN users u ON u.id = e.executed_by WHERE e.control_id = ? ORDER BY e.executed_at DESC, e.id DESC",
            [$id]
        );
        header('Content-Type: text/html; charset=utf-8');
        echo $this->renderReport($c, $exec);
        exit;
    }

    // ── HELPER ───────────────────────────────────────────────────────────────
    private function dueStatus(?string $next, string $today, string $status): string
    {
        if ($status === 'suspended') { return 'suspended'; }
        if ($next === null) { return 'none'; }
        if ($next < $today) { return 'overdue'; }
        $soon = date('Y-m-d', strtotime($today . ' +14 days'));
        return ($next <= $soon) ? 'due_soon' : 'upcoming';
    }

    /**
     * Avanza una data secondo la frequenza.
     * Per le frequenze a mesi si "ancora" al primo del mese e si rimette il giorno
     * limato all'ultimo valido del mese di destinazione: evita l'overflow di
     * strtotime('+1 month') (es. 31/01 -> 03/03, febbraio saltato).
     */
    private function advance(string $from, string $freq, ?int $days): string
    {
        $months = ['mensile' => 1, 'trimestrale' => 3, 'semestrale' => 6, 'annuale' => 12];
        $d = new DateTimeImmutable($from); // $from è sempre un Y-m-d validato (validateDate / date('Y-m-d'))
        if (isset($months[$freq])) {
            $target = $d->modify('first day of this month')->modify('+' . $months[$freq] . ' months');
            $day = min((int) $d->format('d'), (int) $target->format('t'));
            return $target->setDate((int) $target->format('Y'), (int) $target->format('m'), $day)->format('Y-m-d');
        }
        // giornaliero / settimanale / custom (e qualsiasi freq sconosciuta -> a giorni)
        $simple = ['giornaliero' => '+1 day', 'settimanale' => '+1 week'];
        $mod = $simple[$freq] ?? ('+' . max(1, (int) $days) . ' days');
        if ($freq === 'custom') { $mod = '+' . max(1, (int) $days) . ' days'; }
        return $d->modify($mod)->format('Y-m-d');
    }

    /** Crea una NC (e opzionalmente una prima azione correttiva) da un'esecuzione fallita. */
    private function generateNc(int $orgId, array $ctl, int $execId, string $outcome, bool $withAction): array
    {
        $titleBase = ($ctl['control_ref'] ? '[' . $ctl['control_ref'] . '] ' : '') . 'Controllo periodico: ' . $ctl['title'];
        $title = mb_strlen($titleBase) > 200 ? mb_substr($titleBase, 0, 197) . '...' : $titleBase;
        $sev = $outcome === 'non_conforme' ? 'major' : 'minor';
        $ncrCode = $this->generateCode('NCR');
        $ncrId = (int) Database::insert('non_conformities', [
            'organization_id' => $orgId, 'ncr_code' => $ncrCode, 'title' => $title,
            'description' => "Rilevata dal monitoraggio del controllo periodico {$ctl['code']} ({$ctl['title']}): esito " . str_replace('_', ' ', $outcome) . '.',
            'source' => 'monitoring', 'source_entity_type' => 'periodic_control_execution', 'source_entity_id' => $execId,
            'severity' => $sev, 'status' => 'open', 'identified_by' => $this->getCurrentUserId(),
        ]);
        $out = ['id' => $ncrId, 'ncr_code' => $ncrCode];
        if ($withAction) {
            $capaCode = $this->generateCode('CAPA');
            $capaId = (int) Database::insert('capa_actions', [
                'ncr_id' => $ncrId, 'organization_id' => $orgId, 'capa_code' => $capaCode, 'action_type' => 'corrective',
                'title' => 'Azione correttiva per ' . $title, 'status' => 'planned',
            ]);
            $out['capa_id'] = $capaId; $out['capa_code'] = $capaCode;
        }
        return $out;
    }

    private function nextCode(int $orgId): string
    {
        $row = Database::fetchOne(
            "SELECT MAX(CAST(SUBSTRING_INDEX(code, '-', -1) AS UNSIGNED)) AS n
             FROM periodic_controls WHERE organization_id = ? AND code LIKE 'CTL-%'",
            [$orgId]
        );
        return 'CTL-' . str_pad((string) (((int) ($row['n'] ?? 0)) + 1), 3, '0', STR_PAD_LEFT);
    }

    private function validateOwnerRole($id, int $orgId): ?int
    {
        $id = ($id === null || $id === '') ? null : (int) $id;
        if ($id === null) { return null; }
        $r = Database::fetchOne('SELECT id FROM org_roles WHERE id = ? AND organization_id = ?', [$id, $orgId]);
        if (!$r) { $this->jsonError('Ruolo responsabile non valido', 422, 'INVALID_OWNER'); }
        return $id;
    }

    private function validateDate($v, string $field): ?string
    {
        if ($v === null || $v === '') { return null; }
        $d = trim((string) $v); $dt = DateTime::createFromFormat('Y-m-d', $d);
        if (!$dt || $dt->format('Y-m-d') !== $d) { $this->jsonError("Data $field non valida (AAAA-MM-GG)", 422, 'INVALID_DATE'); }
        return $d;
    }

    private function nullableStr($v, ?int $max = null): ?string
    {
        if ($v === null) { return null; }
        $s = trim((string) $v); if ($s === '') { return null; }
        if ($max !== null && mb_strlen($s) > $max) { $s = mb_substr($s, 0, $max); }
        return $s;
    }

    private function renderReport(array $c, array $exec): string
    {
        $esc = static fn($s) => htmlspecialchars((string) $s, ENT_QUOTES, 'UTF-8');
        $rows = '';
        foreach ($exec as $e) {
            $rows .= '<tr><td>' . $esc($e['executed_at']) . '</td><td>' . $esc(str_replace('_', ' ', $e['outcome'])) . '</td>'
                . '<td>' . $esc($e['by_name'] ?? '') . '</td><td>' . $esc($e['ncr_code'] ?? '') . '</td><td>' . $esc($e['notes'] ?? '') . '</td></tr>';
        }
        if ($rows === '') { $rows = '<tr><td colspan="5" style="color:#888">Nessuna esecuzione registrata.</td></tr>'; }
        $h = '<!DOCTYPE html><html lang="it"><head><meta charset="UTF-8"><title>Controllo periodico ' . $esc($c['code']) . '</title>'
            . '<style>body{font-family:-apple-system,Segoe UI,Roboto,Arial,sans-serif;color:#1e293b;max-width:900px;margin:24px auto;padding:0 16px}'
            . 'h1{font-size:20px;color:#1e40af} .sub{color:#64748b;font-size:13px;margin-bottom:18px} table{width:100%;border-collapse:collapse;font-size:13px;margin-top:8px}'
            . 'th,td{border:1px solid #e2e8f0;padding:7px 10px;text-align:left} th{background:#f8fafc} .meta td{border:none;padding:3px 0}</style></head><body>';
        $h .= '<h1>Scheda controllo periodico ' . $esc($c['code']) . '</h1>';
        $h .= '<div class="sub">' . $esc($c['org_name']) . ' &middot; generato il ' . date('d/m/Y H:i') . '</div>';
        $h .= '<table class="meta">'
            . '<tr><td style="width:200px"><strong>Titolo</strong></td><td>' . $esc($c['title']) . '</td></tr>'
            . '<tr><td><strong>Categoria</strong></td><td>' . $esc($c['category'] ?? '-') . '</td></tr>'
            . '<tr><td><strong>Controllo collegato</strong></td><td>' . $esc($c['control_ref'] ?? '-') . '</td></tr>'
            . '<tr><td><strong>Responsabile</strong></td><td>' . $esc($c['owner_role'] ?? '-') . '</td></tr>'
            . '<tr><td><strong>Frequenza</strong></td><td>' . $esc($c['frequency']) . ($c['frequency'] === 'custom' ? ' (' . $esc($c['frequency_days']) . ' gg)' : '') . '</td></tr>'
            . '<tr><td><strong>Prossima scadenza</strong></td><td>' . $esc($c['next_due_date'] ?? '-') . '</td></tr>'
            . '<tr><td><strong>Metodo</strong></td><td>' . $esc($c['method'] ?? '-') . '</td></tr></table>';
        $h .= '<h2 style="font-size:15px;color:#1e40af;margin-top:22px">Storico esecuzioni (evidenza)</h2>';
        $h .= '<table><thead><tr><th>Data</th><th>Esito</th><th>Eseguito da</th><th>NC</th><th>Note</th></tr></thead><tbody>' . $rows . '</tbody></table>';
        $h .= '<p style="margin-top:30px;color:#9ca3af;font-size:.78rem;">Documento generato da NIS2 Agile. Il monitoraggio periodico dei controlli e\' buona prassi (ISO 27001 §9.1/A.8.16); gli obblighi normativi in Italia derivano da NIS2 / D.Lgs. 138/2024. Strumento di supporto, non un parere legale.</p>';
        $h .= '</body></html>';
        return $h;
    }
}