<?php
/**
 * controllers/updateSoilSpecification.php
 *
 * AJAX POST handler: updates a single cell in soil_specifications.
 * Returns JSON { success: true } or { success: false, error: "..." }.
 */

if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

require_once __DIR__ . '/../config/database.php';
require_once __DIR__ . '/../lib/auth.php';
require_once __DIR__ . '/../lib/csrf.php';

header('Content-Type: application/json');

if (!isLoggedIn()) {
    http_response_code(401);
    echo json_encode(['success' => false, 'error' => 'Not authenticated']);
    exit;
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    echo json_encode(['success' => false, 'error' => 'Method not allowed']);
    exit;
}

if (!verifyCsrfToken($_POST['csrf_token'] ?? '')) {
    http_response_code(403);
    echo json_encode(['success' => false, 'error' => 'Invalid CSRF token']);
    exit;
}

$specId = (int)($_POST['spec_id'] ?? 0);
$column = (string)($_POST['column'] ?? '');
$value  = trim((string)($_POST['value'] ?? ''));

if (!$specId || $column === '') {
    http_response_code(400);
    echo json_encode(['success' => false, 'error' => 'Missing required fields']);
    exit;
}

// Allowlist — only columns present in soil_specifications (excluding system cols)
$allowed = [
    'soil_type',
    'cec', 'NO3_N', 'NH3_N',
    'p_mehlick', 'p_bray2', 'p_morgan', 'p_colwell',
    'k_morgan', 'ca_morgan', 'mg_morgan', 'na_morgan',
    'ch_h2o', 'ocarbon', 'omatter', 'fe', 'ec',
    'ph_cacl2', 'ph_h2o', 's_morgan',
    'b_cacl2', 'mn_dtpa', 'zn_dtpa', 'fe_dtpa', 'cu_dtpa',
    'al', 'sl_cacl2', 'm_dtpa', 'co_dtpa', 'se',
    'ca_mehlick3', 'mg_mehlick3', 'k_mehlick3', 'na_mehlick3', 'al_mehlick3',
    'BS_ca2', 'BS_ca_ppm', 'BS_mg2', 'BS_mg_ppm',
    'BS_k', 'BS_k_ppm', 'BS_na', 'BS_na_ppm',
    'BS_al3', 'BS_ob', 'BS_h',
    'ca_mg_ratio', 'c_n_ratio',
    // spec-range columns
    'ca_ppm_min', 'ca_ppm_max', 'mg_ppm_min', 'mg_ppm_max',
    'k_ppm_min',  'k_ppm_max',  'na_ppm_min', 'na_ppm_max',
    'cabs_min',   'cabs_max',   'mgbs_min',   'mgbs_max',
    'kbs_min',    'kbs_max',    'nabs_min',   'nabs_max',
    'ob_rec', 'h_rec', 'ca_mg_ratio', 'c_n_ratio', 'ph',
];

if (!in_array($column, $allowed, true)) {
    http_response_code(400);
    echo json_encode(['success' => false, 'error' => 'Column not editable']);
    exit;
}

try {
    $pdo    = getDBConnection();
    $userId = getCurrentUserId();

    // The backtick-quoted column name is safe because it is validated against the allowlist above.
    $stmt = $pdo->prepare("UPDATE soil_specifications SET `{$column}` = ? WHERE id = ? AND modx_user_id = ?");
    $stmt->execute([$value, $specId, $userId]);

    if ($stmt->rowCount() === 0) {
        http_response_code(404);
        echo json_encode(['success' => false, 'error' => 'Record not found']);
        exit;
    }

    echo json_encode(['success' => true]);

} catch (PDOException $e) {
    error_log('DB error in updateSoilSpecification.php: ' . $e->getMessage());
    http_response_code(500);
    echo json_encode(['success' => false, 'error' => 'Database error']);
}
exit;