<?php
header('Content-Type: application/json');
require_once __DIR__ . '/db/config.php';

/**
 * Generates a random, URL-friendly string of a given length.
 */
function generate_random_id($length = 8) {
    return substr(str_shuffle(str_repeat('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', $length)), 0, $length);
}

$method = $_SERVER['REQUEST_METHOD'];

try {
    $pdo = db();

    if ($method === 'POST') {
        $input = json_decode(file_get_contents('php://input'), true);
        $code = $input['code'] ?? null;

        if (!$code) {
            http_response_code(400); // Bad Request
            echo json_encode(['error' => 'Code content is missing.']);
            exit;
        }

        // Loop to ensure the generated ID is unique
        do {
            $id = generate_random_id();
            $stmt = $pdo->prepare("SELECT id FROM snippets WHERE id = ?");
            $stmt->execute([$id]);
        } while ($stmt->fetchColumn());

        $stmt = $pdo->prepare("INSERT INTO snippets (id, code) VALUES (?, ?)");
        $stmt->execute([$id, $code]);

        http_response_code(201); // Created
        echo json_encode(['id' => $id]);

    } elseif ($method === 'GET') {
        $id = $_GET['id'] ?? null;

        if (!$id) {
            http_response_code(400); // Bad Request
            echo json_encode(['error' => 'Snippet ID is missing.']);
            exit;
        }

        $stmt = $pdo->prepare("SELECT code, created_at FROM snippets WHERE id = ?");
        $stmt->execute([$id]);
        $snippet = $stmt->fetch(PDO::FETCH_ASSOC);

        if ($snippet) {
            echo json_encode($snippet);
        } else {
            http_response_code(404); // Not Found
            echo json_encode(['error' => 'Snippet not found.']);
        }
    } else {
        http_response_code(405); // Method Not Allowed
        echo json_encode(['error' => 'Method not allowed.']);
    }

} catch (PDOException $e) {
    http_response_code(500); // Internal Server Error
    error_log("Database error: " . $e->getMessage());
    echo json_encode(['error' => 'An internal server error occurred.']);
} catch (Exception $e) {
    http_response_code(500); // Internal Server Error
    error_log("General error: " . $e->getMessage());
    echo json_encode(['error' => 'An internal server error occurred.']);
}