<?php
// api.php — Multi-User API mit Legacy-Kompatibilität
// Stand: 2025-09-05

declare(strict_types=1);
header('X-API-Version: 2025-09-05');

/* ------------------------- Fehler als JSON ------------------------- */
set_error_handler(static function ($severity, $message, $file, $line) {
  throw new ErrorException($message, 0, $severity, $file, $line);
});
set_exception_handler(static function (Throwable $e) {
  http_response_code(500);
  header('Content-Type: application/json; charset=utf-8');
  echo json_encode([
    'ok'    => false,
    'error' => 'internal',
    'type'  => get_class($e),
    'msg'   => $e->getMessage(),
    'file'  => basename($e->getFile()),
    'line'  => $e->getLine(),
  ], JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES);
  exit;
});

/* ------------------------- Helpers ------------------------- */
function json_out(array $data, int $code = 200): void {
  http_response_code($code);
  header('Content-Type: application/json; charset=utf-8');
  echo json_encode($data, JSON_UNESCAPED_UNICODE|JSON_UNESCAPED_SLASHES);
  exit;
}
function in_json(): array {
  $raw = file_get_contents('php://input') ?: '';
  if ($raw === '') return [];
  $j = json_decode($raw, true);
  return is_array($j) ? $j : [];
}

/* ------------------------- Config laden ------------------------- */
// Parent /inc/config.php (wie von dir beschrieben)
$cfgFile = dirname(__DIR__) . '/inc/config.php';
if (!is_file($cfgFile)) {
  json_out(['ok'=>false,'error'=>'config_missing','hint'=>'config.php nicht gefunden','path'=>$cfgFile], 500);
}
$CFG = include $cfgFile;
if (!is_array($CFG)) {
  json_out(['ok'=>false,'error'=>'config_invalid','hint'=>'config.php muss ein Array zurückgeben'], 500);
}
$ENV = $CFG['env'] ?? 'prod';

/* ------------------------- PDO-Factories ------------------------- */
function pdo_from_cfg(?array $dbc): ?PDO {
  if (!$dbc) return null;
  $dsn = sprintf(
    'mysql:host=%s;dbname=%s;charset=%s',
    $dbc['db_host']   ?? 'localhost',
    $dbc['db_name']   ?? '',
    $dbc['db_charset']?? 'utf8mb4'
  );
  return new PDO($dsn, $dbc['db_user'] ?? '', $dbc['db_pass'] ?? '', [
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
  ]);
}
$pdoTpl  = pdo_from_cfg($CFG['templates']  ?? null);                 // Template-Daten
$pdoCust = pdo_from_cfg(($CFG['customers'] ?? null) ?: ($CFG['templates'] ?? null)); // Kunden/Users

$TPL_DB  = $CFG['templates']['db_name'] ?? null; // für information_schema

function has_column(PDO $pdo, ?string $db, string $table, string $col): bool {
  if (!$db) return false;
  $st = $pdo->prepare("SELECT 1 FROM information_schema.COLUMNS
                       WHERE TABLE_SCHEMA=:db AND TABLE_NAME=:t AND COLUMN_NAME=:c
                       LIMIT 1");
  $st->execute([':db'=>$db, ':t'=>$table, ':c'=>$col]);
  return (bool)$st->fetchColumn();
}

/* ------------------------- Auth (Helper oder Fallback) ------------------------- */
$authFile = dirname(__DIR__) . '/inc/auth_helpers.php';
$useHelpers = is_file($authFile);
if ($useHelpers) {
  require_once $authFile; // stellt auth_start_session(), auth_require(), auth_logout(), require_role() bereit
} else {
  // interner Fallback – kompatibel zu deinen Erwartungen
  function auth_start_session(array $CFG): void {
    $secure = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
    session_set_cookie_params([
      'httponly' => true,
      'samesite' => 'Lax',
      'secure'   => $secure,
      'path'     => rtrim(dirname($_SERVER['SCRIPT_NAME']),'/').'/'
    ]);
    session_name('et_session');
    if (session_status() !== PHP_SESSION_ACTIVE) session_start();
  }
  function auth_require(array $CFG): void {
    auth_start_session($CFG);
    if (empty($_SESSION['user'])) {
      json_out(['ok'=>false,'error'=>'unauthorized'], 401);
    }
  }
  function auth_logout(array $CFG): void {
    auth_start_session($CFG);
    $_SESSION = [];
    if (ini_get('session.use_cookies')) {
      $p = session_get_cookie_params();
      setcookie(session_name(), '', time()-42000, $p['path'], $p['domain'] ?? '', $p['secure'], $p['httponly']);
    }
    session_destroy();
  }
  function require_role(array $CFG, array $roles): void {
    auth_start_session($CFG);
    $r = $_SESSION['user']['role'] ?? null;
    if (!$r || !in_array($r, $roles, true)) json_out(['ok'=>false,'error'=>'forbidden'], 403);
  }
}

/* ------------------------- Routing + Legacy-Mapping ------------------------- */
$action = $_GET['action'] ?? $_POST['action'] ?? null;

// Alt: ?resource=blocks&action=list|get|create|update|delete|sync
if (!empty($_GET['resource'])) {
  $res = (string)$_GET['resource'];
  $act = (string)($_GET['action'] ?? '');
  $allowed = ['templates','sections','blocks','snippets','assets','template_items','section_items'];
  if (in_array($res, $allowed, true)) {
    if ($act === 'list')   $action = $res.'.list';
    if ($act === 'get')    $action = $res.'.get';
    if ($act === 'create') $action = $res.'.create';
    if ($act === 'update') $action = $res.'.update';
    if ($act === 'delete') $action = $res.'.delete';
    if ($act === 'sync')   $action = $res.'.sync';
  }
}

/* ------------------------- Meta/Health ------------------------- */
if ($action === 'health' || $action === 'ping')     json_out(['ok'=>true,'env'=>$ENV,'time'=>date('c')]);
if ($action === 'version')                          json_out(['ok'=>true,'version'=>'2025-09-05','env'=>$ENV]);

/* ------------------------- Diagnose (leichtgewichtig) ------------------------- */
if ($action === 'debug.diag') {
  $diag = [
    'php'      => PHP_VERSION,
    'pdo'      => extension_loaded('pdo'),
    'pdo_mysql'=> extension_loaded('pdo_mysql'),
    'cfg'      => ['templates'=>!!$pdoTpl, 'customers'=>!!$pdoCust],
  ];
  json_out(['ok'=>true,'diag'=>$diag]);
}

/* ------------------------- STAGING: User-Debug ------------------------- */
if (in_array($action, ['debug.users','debug.users.check','debug.users.setpass','debug.users.peek'], true)) {
  if ($ENV !== 'staging') json_out(['ok'=>false,'error'=>'forbidden'], 403);
  if (!$pdoCust) json_out(['ok'=>false,'error'=>'customers_db_not_configured'], 500);

  if ($action === 'debug.users') {
    $email = isset($_GET['email']) ? trim((string)$_GET['email']) : '';
    if ($email !== '') {
      $st = $pdoCust->prepare("SELECT id, customer_id, email, role, is_active, created_at, updated_at
                               FROM customer_users WHERE email=:email");
      $st->execute([':email'=>$email]);
      $rows = $st->fetchAll();
    } else {
      $st = $pdoCust->query("SELECT id, customer_id, email, role, is_active, created_at, updated_at
                             FROM customer_users ORDER BY id DESC LIMIT 50");
      $rows = $st->fetchAll();
    }
    json_out(['ok'=>true,'items'=>$rows]);
  }

  if ($action === 'debug.users.check') {
    $in  = in_json();
    $email = trim((string)($in['email'] ?? ''));
    $pass  = (string)($in['password'] ?? '');
    if ($email==='' || $pass==='') json_out(['ok'=>false,'error'=>'missing_params'], 400);
    $st = $pdoCust->prepare("SELECT id, customer_id, email, password_hash, role, is_active FROM customer_users
                             WHERE email=:email LIMIT 1");
    $st->execute([':email'=>$email]);
    $u = $st->fetch();
    if (!$u) json_out(['ok'=>true,'exists'=>false,'password_match'=>false]);
    json_out(['ok'=>true,'exists'=>true,'password_match'=>password_verify($pass,$u['password_hash'])]);
  }

  if ($action === 'debug.users.setpass') {
    $in  = in_json();
    $email = trim((string)($in['email'] ?? ''));
    $pass  = (string)($in['password'] ?? '');
    if ($email==='' || $pass==='') json_out(['ok'=>false,'error'=>'missing_params'], 400);
    $st = $pdoCust->prepare("SELECT id FROM customer_users WHERE email=:email LIMIT 1");
    $st->execute([':email'=>$email]);
    $u = $st->fetch();
    if (!$u) json_out(['ok'=>false,'error'=>'user_not_found'], 404);
    $hash = password_hash($pass, PASSWORD_DEFAULT);
    $upd  = $pdoCust->prepare("UPDATE customer_users SET password_hash=:h, is_active=1 WHERE id=:id");
    $upd->execute([':h'=>$hash, ':id'=>$u['id']]);
    json_out(['ok'=>true,'set'=>true]);
  }

  if ($action === 'debug.users.peek') {
    $email = isset($_GET['email']) ? trim((string)$_GET['email']) : '';
    if ($email==='') json_out(['ok'=>false,'error'=>'missing_email'], 400);
    $st = $pdoCust->prepare("SELECT id, customer_id, email, LENGTH(password_hash) len
                             FROM customer_users WHERE email=:email");
    $st->execute([':email'=>$email]);
    json_out(['ok'=>true,'user'=>$st->fetch()]);
  }
}

/* ------------------------- AUTH: Login / Logout / Me ------------------------- */
if ($action === 'auth.login') {
  $in = in_json();
  $email = trim(strtolower((string)($in['email'] ?? '')));
  $pass  = (string)($in['password'] ?? '');
  if ($email==='' || $pass==='') json_out(['ok'=>false,'error'=>'missing_credentials'], 400);
  if (!$pdoCust) json_out(['ok'=>false,'error'=>'customers_db_not_configured'], 500);

  // Mehrfachkunden mit gleicher Mail erlauben → best match über password_verify
  $st = $pdoCust->prepare("SELECT cu.id, cu.customer_id, cu.email, cu.password_hash, cu.role, cu.is_active,
                                  c.slug AS customer_slug, c.plan, c.status
                           FROM customer_users cu
                           JOIN customers c ON c.id = cu.customer_id
                           WHERE cu.email=:email");
  $st->execute([':email'=>$email]);
  $rows = $st->fetchAll();

  $match = null;
  foreach ($rows as $r) {
    if ((int)$r['is_active'] === 1 && !empty($r['password_hash']) && password_verify($pass, $r['password_hash'])) {
      $match = $r; break;
    }
  }
  if (!$match) json_out(['ok'=>false,'error'=>'invalid_credentials'], 401);
  if (($match['status'] ?? 'active') !== 'active') json_out(['ok'=>false,'error'=>'customer_inactive'], 403);

  auth_start_session($CFG);
  $_SESSION['user'] = [
    'id'            => (int)$match['id'],
    'email'         => $match['email'],
    'role'          => $match['role'],
    'customer_id'   => (int)$match['customer_id'],
    'customer_slug' => $match['customer_slug'],
    'plan'          => $match['plan'] ?? null,
  ];
  json_out(['ok'=>true,'user'=>$_SESSION['user']]);
}

if ($action === 'auth.logout') { auth_logout($CFG); json_out(['ok'=>true]); }

if ($action === 'auth.me') {
  auth_start_session($CFG);
  json_out(['ok'=>!empty($_SESSION['user']), 'user'=>$_SESSION['user'] ?? null]);
}

/* ------------------------- ab hier: geschützt ------------------------- */
$public = ['auth.login','auth.logout','auth.me','health','ping','version','debug.diag','debug.users','debug.users.check','debug.users.setpass','debug.users.peek'];
if (!in_array($action, $public, true)) auth_require($CFG);

$customerId = (int)($_SESSION['user']['customer_id'] ?? 0);

/* ------------------------- Templates ------------------------- */
if ($action === 'templates.list') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $st = $pdoTpl->prepare("SELECT id, name, updated_at
                          FROM emailtemplate_templates
                          WHERE customer_id = :cid
                          ORDER BY updated_at DESC, id DESC
                          LIMIT 1000");
  $st->execute([':cid'=>$customerId]);
  json_out(['ok'=>true,'items'=>$st->fetchAll()]);
}

if ($action === 'templates.get') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $id = isset($_GET['id']) ? (int)$_GET['id'] : (int)($_POST['id'] ?? 0);
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);
  $hasHtml = has_column($pdoTpl, $TPL_DB, 'emailtemplate_templates', 'html');
  $cols = $hasHtml ? "id, customer_id, name, html, updated_at" : "id, customer_id, name, NULL AS html, updated_at";
  $st = $pdoTpl->prepare("SELECT $cols FROM emailtemplate_templates WHERE id=:id AND customer_id=:cid LIMIT 1");
  $st->execute([':id'=>$id, ':cid'=>$customerId]);
  $row = $st->fetch();
  if (!$row) json_out(['ok'=>false,'error'=>'not_found'], 404);
  json_out(['ok'=>true,'item'=>$row]);
}

if ($action === 'templates.create') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in = in_json();
  $name = trim((string)($in['name'] ?? ''));
  $html = (string)($in['html'] ?? '');
  if ($name==='') json_out(['ok'=>false,'error'=>'name_required'], 400);
  $hasHtml = has_column($pdoTpl, $TPL_DB, 'emailtemplate_templates', 'html');

  if ($hasHtml) {
    $st = $pdoTpl->prepare("INSERT INTO emailtemplate_templates (customer_id,name,html,created_at,updated_at)
                            VALUES (:cid,:name,:html,NOW(),NOW())");
    $st->execute([':cid'=>$customerId, ':name'=>$name, ':html'=>$html]);
  } else {
    $st = $pdoTpl->prepare("INSERT INTO emailtemplate_templates (customer_id,name,created_at,updated_at)
                            VALUES (:cid,:name,NOW(),NOW())");
    $st->execute([':cid'=>$customerId, ':name'=>$name]);
  }
  json_out(['ok'=>true,'id'=>(int)$pdoTpl->lastInsertId()]);
}

if ($action === 'templates.update') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in = in_json();
  $id   = (int)($in['id'] ?? 0);
  $name = array_key_exists('name',$in) ? trim((string)$in['name']) : null;
  $html = array_key_exists('html',$in) ? (string)$in['html'] : null;
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);

  $hasHtml = has_column($pdoTpl, $TPL_DB, 'emailtemplate_templates', 'html');
  $sets=[]; $p=[':id'=>$id, ':cid'=>$customerId];
  if ($name!==null) { $sets[]="name=:name"; $p[':name']=$name; }
  if ($hasHtml && $html!==null) { $sets[]="html=:html"; $p[':html']=$html; }
  if (!$sets) json_out(['ok'=>false,'error'=>'nothing_to_update'], 400);

  $sql = "UPDATE emailtemplate_templates SET ".implode(',',$sets).", updated_at=NOW() WHERE id=:id AND customer_id=:cid";
  $st  = $pdoTpl->prepare($sql);
  $st->execute($p);
  json_out(['ok'=>true,'updated'=>$st->rowCount()]);
}

if ($action === 'templates.delete') {
  require_role($CFG, ['owner','admin']);
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in = in_json(); $id=(int)($in['id'] ?? 0);
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);
  $pdoTpl->beginTransaction();
  try {
    $pdoTpl->prepare("DELETE FROM emailtemplate_template_items WHERE template_id=:id AND customer_id=:cid")->execute([':id'=>$id, ':cid'=>$customerId]);
    $pdoTpl->prepare("DELETE FROM emailtemplate_templates      WHERE id=:id AND customer_id=:cid")->execute([':id'=>$id, ':cid'=>$customerId]);
    $pdoTpl->commit();
    json_out(['ok'=>true]);
  } catch (Throwable $e) { $pdoTpl->rollBack(); throw $e; }
}

/* ------------------------- Sections ------------------------- */
if ($action === 'sections.list') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $templateId = isset($_GET['template_id']) ? (int)$_GET['template_id'] : 0;
  if ($templateId>0) {
    $st = $pdoTpl->prepare("SELECT id, template_id, name, z_index, type, updated_at
                            FROM emailtemplate_sections
                            WHERE customer_id=:cid AND template_id=:tid
                            ORDER BY z_index ASC, id ASC
                            LIMIT 1000");
    $st->execute([':cid'=>$customerId, ':tid'=>$templateId]);
  } else {
    $st = $pdoTpl->prepare("SELECT id, template_id, name, z_index, type, updated_at
                            FROM emailtemplate_sections
                            WHERE customer_id=:cid
                            ORDER BY template_id ASC, z_index ASC, id ASC
                            LIMIT 1000");
    $st->execute([':cid'=>$customerId]);
  }
  json_out(['ok'=>true,'items'=>$st->fetchAll()]);
}

if ($action === 'sections.get') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $id = isset($_GET['id']) ? (int)$_GET['id'] : (int)($_POST['id'] ?? 0);
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);
  $st = $pdoTpl->prepare("SELECT id, customer_id, template_id, name, z_index, type, updated_at
                          FROM emailtemplate_sections
                          WHERE id=:id AND customer_id=:cid
                          LIMIT 1");
  $st->execute([':id'=>$id, ':cid'=>$customerId]);
  $row = $st->fetch();
  if (!$row) json_out(['ok'=>false,'error'=>'not_found'], 404);
  json_out(['ok'=>true,'item'=>$row]);
}

/* ------------------------- Blocks ------------------------- */
if ($action === 'blocks.list') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $st = $pdoTpl->prepare("SELECT id, name, category, updated_at
                          FROM emailtemplate_blocks
                          WHERE customer_id=:cid
                          ORDER BY name ASC
                          LIMIT 1000");
  $st->execute([':cid'=>$customerId]);
  json_out(['ok'=>true,'items'=>$st->fetchAll()]);
}

if ($action === 'blocks.get') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $id = isset($_GET['id']) ? (int)$_GET['id'] : (int)($_POST['id'] ?? 0);
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);
  $st = $pdoTpl->prepare("SELECT id, customer_id, name, category, updated_at
                          FROM emailtemplate_blocks
                          WHERE id=:id AND customer_id=:cid
                          LIMIT 1");
  $st->execute([':id'=>$id, ':cid'=>$customerId]);
  $row = $st->fetch();
  if (!$row) json_out(['ok'=>false,'error'=>'not_found'], 404);
  json_out(['ok'=>true,'item'=>$row]);
}

if ($action === 'blocks.create') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in=in_json(); $name=trim((string)($in['name']??'')); $cat=trim((string)($in['category']??''));
  if ($name==='') json_out(['ok'=>false,'error'=>'name_required'], 400);
  $st=$pdoTpl->prepare("INSERT INTO emailtemplate_blocks (customer_id,name,category,created_at,updated_at)
                        VALUES (:cid,:name,COALESCE(NULLIF(:cat,''),'Default'),NOW(),NOW())");
  $st->execute([':cid'=>$customerId, ':name'=>$name, ':cat'=>$cat]);
  json_out(['ok'=>true,'id'=>(int)$pdoTpl->lastInsertId()]);
}

if ($action === 'blocks.update') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in=in_json(); $id=(int)($in['id']??0); $name=trim((string)($in['name']??'')); $cat=trim((string)($in['category']??''));
  if ($id<=0 || $name==='') json_out(['ok'=>false,'error'=>'invalid_params'], 400);
  $st=$pdoTpl->prepare("UPDATE emailtemplate_blocks
                        SET name=:name, category=COALESCE(NULLIF(:cat,''),category), updated_at=NOW()
                        WHERE id=:id AND customer_id=:cid");
  $st->execute([':name'=>$name, ':cat'=>$cat, ':id'=>$id, ':cid'=>$customerId]);
  json_out(['ok'=>true,'updated'=>$st->rowCount()]);
}

if ($action === 'blocks.delete') {
  require_role($CFG, ['owner','admin']);
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in=in_json(); $id=(int)($in['id']??0);
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);
  $st=$pdoTpl->prepare("DELETE FROM emailtemplate_blocks WHERE id=:id AND customer_id=:cid");
  $st->execute([':id'=>$id, ':cid'=>$customerId]);
  json_out(['ok'=>true,'deleted'=>$st->rowCount()]);
}

/* ------------------------- Snippets ------------------------- */
if ($action === 'snippets.list') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $st=$pdoTpl->prepare("SELECT id, name, category, updated_at
                        FROM emailtemplate_snippets
                        WHERE customer_id=:cid
                        ORDER BY name ASC
                        LIMIT 1000");
  $st->execute([':cid'=>$customerId]);
  json_out(['ok'=>true,'items'=>$st->fetchAll()]);
}

if ($action === 'snippets.get') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $id = isset($_GET['id']) ? (int)$_GET['id'] : (int)($_POST['id'] ?? 0);
  if ($id<=0) json_out(['ok'=>false,'error'=>'missing_id'], 400);
  $st=$pdoTpl->prepare("SELECT id, customer_id, name, category, updated_at
                        FROM emailtemplate_snippets
                        WHERE id=:id AND customer_id=:cid
                        LIMIT 1");
  $st->execute([':id'=>$id, ':cid'=>$customerId]);
  $row=$st->fetch();
  if (!$row) json_out(['ok'=>false,'error'=>'not_found'], 404);
  json_out(['ok'=>true,'item'=>$row]);
}

/* ------------------------- Assets (READ) ------------------------- */
if ($action === 'assets.list') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $st=$pdoTpl->prepare("SELECT id, name, type, mime_type, size_bytes, public_url, updated_at
                        FROM emailtemplate_assets
                        WHERE customer_id=:cid
                        ORDER BY updated_at DESC, id DESC
                        LIMIT 200");
  $st->execute([':cid'=>$customerId]);
  json_out(['ok'=>true,'items'=>$st->fetchAll()]);
}

/* ------------------------- Editor-Referenzen (Placeholders) ------------------------- */
if ($action === 'template_items.sync') { json_out(['ok'=>true]); }
if ($action === 'section_items.sync')  { json_out(['ok'=>true]); }

/* ------------------------- Render (Fallback) ------------------------- */
if ($action === 'render.preview') {
  if (!$pdoTpl) json_out(['ok'=>false,'error'=>'templates_db_not_configured'], 500);
  $in = in_json();
  $templateId = (int)($in['template_id'] ?? 0);
  if ($templateId<=0) json_out(['ok'=>false,'error'=>'template_id_required'], 400);
  $st = $pdoTpl->prepare("SELECT id, name FROM emailtemplate_templates WHERE id=:id AND customer_id=:cid LIMIT 1");
  $st->execute([':id'=>$templateId, ':cid'=>$customerId]);
  $tpl = $st->fetch();
  if (!$tpl) json_out(['ok'=>false,'error'=>'not_found'], 404);
  $html = "<!-- preview {$tpl['name']} (#{$tpl['id']}) -->\n<div style=\"padding:16px;font:14px/1.4 system-ui\">Preview okay.</div>";
  json_out(['ok'=>true, 'template'=>$tpl, 'html'=>$html]);
}

/* ------------------------- Fallback ------------------------- */
json_out(['ok'=>false,'error'=>'unknown_action','action'=>$action], 404);