<?php
header('Content-Type: application/json');
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

require_once(__DIR__ . '/class/db-functions.php');

try {
    $db = DBHandlerSelect::getInstance();
    $pdo = $db->getConnection();

    $data = json_decode(file_get_contents("php://input"), true);

    if (!$data || !isset($data['template_id'], $data['xls_headers'])) {
        echo json_encode(["success" => false, "message" => "Invalid or missing data"]);
        exit;
    }

    $templateId = (int)$data['template_id'];
    $xlsHeaders = $data['xls_headers'];

    $headerRow = isset($data['header_row']) && $data['header_row'] !== ''
        ? (int)$data['header_row']
        : null;

    $startColumn = isset($data['start_column']) && $data['start_column'] !== ''
        ? (int)$data['start_column']
        : null;

    $xlsSheetIndex = isset($data['xls_sheet_index']) && $data['xls_sheet_index'] !== ''
        ? (int)$data['xls_sheet_index']
        : null;

    if ($templateId <= 0) {
        echo json_encode(["success" => false, "message" => "Invalid template ID"]);
        exit;
    }

    if ($xlsHeaders === '') {
        echo json_encode(["success" => false, "message" => "XLS headers cannot be empty"]);
        exit;
    }

    if ($headerRow !== null && $headerRow <= 0) {
        echo json_encode(["success" => false, "message" => "Header row must be greater than 0"]);
        exit;
    }

    if ($startColumn !== null && $startColumn <= 0) {
        echo json_encode(["success" => false, "message" => "Start column must be greater than 0"]);
        exit;
    }

    if ($xlsSheetIndex !== null && $xlsSheetIndex < 0) {
        echo json_encode(["success" => false, "message" => "XLS sheet number cannot be negative"]);
        exit;
    }

    $sql = "UPDATE excel_templates SET xls_headers = ?";
    $params = [$xlsHeaders];

    if ($headerRow !== null) {
        $sql .= ", header_row = ?";
        $params[] = $headerRow;
    }

    if ($startColumn !== null) {
        $sql .= ", start_column = ?";
        $params[] = $startColumn;
    }

    if ($xlsSheetIndex !== null) {
        $sql .= ", xls_sheet_index = ?";
        $params[] = $xlsSheetIndex;
    }

    $sql .= ", updated_at = NOW()";
    $sql .= " WHERE id = ?";
    $params[] = $templateId;

    $stmt = $pdo->prepare($sql);
    $result = $stmt->execute($params);

    if (!$result) {
        echo json_encode(["success" => false, "message" => "Database update failed"]);
        exit;
    }

    echo json_encode([
        "success" => true,
        "message" => "XLS headers saved successfully",
        "debug" => [
            "template_id" => $templateId,
            "header_row" => $headerRow,
            "start_column" => $startColumn,
            "xls_sheet_index" => $xlsSheetIndex
        ]
    ]);
} catch (Exception $e) {
    echo json_encode(["success" => false, "message" => "Error: " . $e->getMessage()]);
}

exit;