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

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $survey_id = filter_input(INPUT_POST, 'survey_id', FILTER_VALIDATE_INT);
    $answers = $_POST['answers'] ?? [];

    if (!$survey_id) {
        http_response_code(400);
        die('Bad request: survey_id is required.');
    }

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

        // 1. Create a new survey response
        $stmt = $pdo->prepare("INSERT INTO survey_responses (survey_id) VALUES (?)");
        $stmt->execute([$survey_id]);
        $response_id = $pdo->lastInsertId();

        // 2. Save each answer
        $stmt = $pdo->prepare("INSERT INTO survey_answers (response_id, question_id, answer_text) VALUES (?, ?, ?)");
        foreach ($answers as $question_id => $answer_text) {
            if (is_array($answer_text)) {
                // For checkboxes, implode the array into a string
                $answer_text = implode(', ', $answer_text);
            }
            $stmt->execute([$response_id, $question_id, $answer_text]);
        }

        $pdo->commit();

        // Redirect to a success page
        header('Location: survey_success.php?response=true');
        exit;

    } catch (PDOException $e) {
        if ($pdo->inTransaction()) {
            $pdo->rollBack();
        }
        // In a real app, you'd log this error
        http_response_code(500);
        die('Database error: ' . $e->getMessage());
    }
} else {
    http_response_code(405);
    die('Method not allowed.');
}