<?php
/*
 * Simpele Racket bootstrap.
 *
 * .htaccess:
 *
 *   FallbackResource /index.php
 *
 * Bestanden:
 *
 *   config/racket.zip
 *   data/          bevat vooraf gemaakte parts
 *
 * Routes:
 *
 *   /bootstrap-racket?next=...
 *      Leest de vooraf gemaakte parts in data/ en toont een HTML-index
 *      met links.
 *
 *   /bootstrap-racket-part?n=000001&next=...
 *      Geeft text/plain met base64 van precies één binair part.
 *
 * Regels:
 *
 *   - Indexen/lijsten zijn HTML.
 *   - Payload/downloads zijn text/plain.
 *   - Payload/downloads zijn altijd base64.
 *   - Geen .bin, .zip of bestandsnaam in download-URL’s.
 *   - next=... is alleen cache-busting.
 *   - Per gegenereerde HTML-pagina wordt één next-id gemaakt en voor alle
 *     links op die pagina gebruikt.
 */

require_once __DIR__ . '/config/reporting.php';

require_once __DIR__ . '/private/nexttoken.php';
require_once __DIR__ . '/private/base64config.php';
require_once __DIR__ . '/private/racketzip.php';
require_once __DIR__ . '/private/Template.php';

$TOKENS = new NextTokenStore(__DIR__ . '/data/racket-sandbox.sqlite');

@set_time_limit(300);
ignore_user_abort(false);

$chunkConfig = load_base64_chunk_config();
$racketZipMaxBase64Kb = (int)($chunkConfig['racket_zip_max_base64_kb'] ?? 8192);

if ($racketZipMaxBase64Kb < 1) {
    $racketZipMaxBase64Kb = 1;
}

define('RACKET_ZIP_MAX_BASE64_KB', $racketZipMaxBase64Kb);
define('RACKET_ZIP_MAX_BASE64_BYTES', RACKET_ZIP_MAX_BASE64_KB * 1024);
define('RACKET_ZIP_BINARY_CHUNK_BYTES', racket_zip_binary_chunk_bytes_for_base64_kib(RACKET_ZIP_MAX_BASE64_KB));

if (RACKET_ZIP_BINARY_CHUNK_BYTES < 3) {
    fail_html('Ongeldige racket.zip base64 chunk-instelling.');
}

/*
 * Eén next-id voor alle URLs die deze request genereert.
 */
$NEXT_ID = $TOKENS->create();

function path_only()
{
    $p = parse_url($_SERVER['REQUEST_URI'] ?? '/', PHP_URL_PATH);
    $p = '/' . trim($p ?: '/', '/');
    return $p === '/' ? '/' : $p;
}

function scheme()
{
    if (!empty($_SERVER['HTTP_X_FORWARDED_PROTO'])) {
        return strtolower(trim(explode(',', $_SERVER['HTTP_X_FORWARDED_PROTO'])[0]));
    }

    return (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') ? 'https' : 'http';
}

function host_name()
{
    return $_SERVER['HTTP_HOST'] ?? 'localhost';
}

function make_url($path, $query = array())
{
    global $NEXT_ID;

    $query['next'] = $NEXT_ID;

    return scheme() . '://' . host_name() . $path . '?' . http_build_query($query);
}

function h($s)
{
    return htmlspecialchars((string)$s, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
}

function html_response($html, $status = 200)
{
    http_response_code($status);
    header('Content-Type: text/html; charset=utf-8');
    header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0');
    header('Pragma: no-cache');
    echo $html;
    exit;
}

function text_response($text, $status = 200)
{
    http_response_code($status);
    header('Content-Type: text/plain; charset=us-ascii');
    header('Content-Disposition: inline');
    header('X-Content-Type-Options: nosniff');
    header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0');
    header('Pragma: no-cache');

    echo $text;

    if ($text === '' || substr($text, -1) !== "\n") {
        echo "\n";
    }

    exit;
}

function fail_html($message, $status = 500)
{
    html_response(
        RacketSandboxTemplate::renderFile('protocol-error.html', array(
            'title' => 'Error',
            'message' => $message,
        )),
        $status
    );
}

function fail_text($message, $status = 500)
{
    text_response("error: " . $message . "\n", $status);
}

function load_parts()
{
    try {
        $manifest = load_racket_zip_parts_manifest();
    } catch (Throwable $e) {
        fail_html($e->getMessage() . "\n\nSla de configuratiepagina op om racket.zip in parts te verdelen.");
    }

    if (!racket_zip_parts_current($manifest, RACKET_ZIP_MAX_BASE64_KB)) {
        fail_html(
            "racket.zip parts ontbreken of passen niet bij de huidige chunk-grootte.\n\n" .
            "Sla de configuratiepagina op om de parts opnieuw te maken."
        );
    }

    $parts = array();

    foreach (($manifest['parts'] ?? array()) as $part) {
        $number = (string)($part['number'] ?? '');
        $parts[] = array(
            'number' => $number,
            'name' => (string)($part['name'] ?? racket_zip_part_name((int)$number)),
            'size' => (int)($part['size'] ?? 0),
            'url' => make_url('/bootstrap-racket-part', array('n' => $number)),
        );
    }

    $manifest['parts'] = $parts;

    return $manifest;
}

function serve_bootstrap()
{
    global $NEXT_ID;

    $manifest = load_parts();
    $parts = $manifest['parts'];

    $rows = '';

    foreach ($parts as $i => $part) {
        $rows .= RacketSandboxTemplate::renderFile('partials/racket-part-row.html', array(
            'index' => (string)($i + 1),
            'number' => $part['number'],
            'size' => (string)$part['size'],
            'url' => $part['url'],
        )) . "\n";
    }

    $zipSize = (int)($manifest['source_bytes'] ?? 0);

    $pkg_url = make_url('/racket-pkg-index');

    html_response(RacketSandboxTemplate::renderFile('bootstrap-racket.html', array(
        'pkg_url' => $pkg_url,
        'zip_size' => (string)$zipSize,
        'max_base64_kb' => (string)RACKET_ZIP_MAX_BASE64_KB,
        'max_base64_bytes' => (string)RACKET_ZIP_MAX_BASE64_BYTES,
        'binary_chunk_bytes' => (string)RACKET_ZIP_BINARY_CHUNK_BYTES,
        'part_count' => (string)count($parts),
        'created_at' => (string)($manifest['created_at'] ?? ''),
        'next_id' => $NEXT_ID,
        'part_rows_html' => $rows,
    )));
}

function serve_part()
{
    $n = $_GET['n'] ?? '';

    if (!is_string($n) || !preg_match('/^[0-9]{6}$/', $n)) {
        fail_text('ongeldig partnummer; gebruik bijvoorbeeld n=000001', 400);
    }

    $file = racket_zip_part_file($n);

    if (!is_file($file) || !is_readable($file)) {
        fail_text('part ontbreekt of is niet leesbaar: ' . $n, 404);
    }

    $bin = file_get_contents($file);

    if ($bin === false) {
        fail_text('kan part niet lezen: ' . $n, 500);
    }

    text_response(base64_encode($bin));
}

$path = path_only();

if ($path === '/' || $path === '/index.php') {
    header('Location: ' . make_url('/bootstrap-racket'), true, 302);
    exit;
}

if ($path === '/bootstrap-racket') {
    $TOKENS->check_valid_next('html');
    serve_bootstrap();
}

if ($path === '/bootstrap-racket-part') {
    $TOKENS->check_valid_next('text');
    serve_part();
}

fail_html('Onbekende route: ' . $path, 404);