<?php
require_once 'db/config.php';

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    header('Location: create_survey.php');
    exit;
}

$title = trim($_POST['title'] ?? '');
$description = trim($_POST['description'] ?? '');
$questions = $_POST['questions'] ?? [];

if (empty($title) || empty($questions)) {
    // Basic validation: Title and at least one question are required.
    // In a real app, you'd want more robust validation and user feedback.
    die('Error: Survey title and at least one question are required.');
}

try {
    $pdo = db();
    $pdo->beginTransaction();

    // 1. Insert the survey
    $stmt = $pdo->prepare("INSERT INTO surveys (title, description) VALUES (?, ?)");
    $stmt->execute([$title, $description]);
    $surveyId = $pdo->lastInsertId();

    // 2. Insert the questions
    $questionStmt = $pdo->prepare(
        "INSERT INTO questions (survey_id, question_text, question_type, options) VALUES (?, ?, ?, ?)"
    );

    foreach ($questions as $question) {
        $text = trim($question['text'] ?? '');
        $type = trim($question['type'] ?? '');
        $options = $question['options'] ?? [];

        if (empty($text) || empty($type)) {
            // Skip invalid/empty questions
            continue;
        }

        // For choice-based questions, ensure options are provided and encode them as JSON
        $optionsJson = null;
        if (($type === 'multiple-choice' || $type === 'checkboxes')) {
            // Filter out empty option strings
            $validOptions = array_filter($options, function($val) {
                return trim($val) !== '';
            });
            if (empty($validOptions)) {
                // If no valid options, skip this question
                continue;
            }
            $optionsJson = json_encode($validOptions);
        }

        $questionStmt->execute([$surveyId, $text, $type, $optionsJson]);
    }

    $pdo->commit();

    // Redirect to a success page
    header("Location: survey_success.php?id=" . $surveyId);
    exit;

} catch (PDOException $e) {
    // If anything goes wrong, roll back the transaction
    if ($pdo->inTransaction()) {
        $pdo->rollBack();
    }
    // In a real app, log this error instead of showing it to the user
    die("Database error: " . $e->getMessage());
} catch (Exception $e) {
    die("An unexpected error occurred: " . $e->getMessage());
}