<?php
/*
 * rktpkgs.php
 *
 * Maakt een volledige HTML-index van de Racket package catalogus.
 *
 * Bron:
 *   https://pkgs.racket-lang.org/pkgs-all
 *
 * Output:
 *   Alleen HTML.
 *
 * Package-links:
 *   /package?name=<pkg-name>&next=<id>
 *
 * Regels:
 *   - Geen filterveld.
 *   - Geen git-adressen tonen.
 *   - Geen package-details tonen.
 *   - Geen package-downloads implementeren in dit script.
 *   - De package-naam zelf is de link.
 *   - Eén next-id per gegenereerde HTML-pagina.
 *
 * .htaccess:
 *
 *   Options -MultiViews
 *   RewriteEngine On
 *   RewriteRule ^racket-pkg-index$ rktpkgs.php [L,QSA]
 */

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

require_once __DIR__ . '/private/nexttoken.php';
require_once __DIR__ . '/private/lib/catalog-http.php';
require_once __DIR__ . '/private/lib/racket-data.php';
require_once __DIR__ . '/private/Template.php';

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

@set_time_limit(180);
ignore_user_abort(false);

define('CATALOG_PKGS_ALL', 'https://pkgs.racket-lang.org/pkgs-all');

define('CACHE_DIR', __DIR__ . '/data');
define('CACHE_FILE', CACHE_DIR . '/pkgs-all.rktd');
define('CACHE_META_FILE', CACHE_DIR . '/pkgs-all.meta.json');
define('CACHE_TTL', 3600);

/*
 * Eén next-id voor alle package-links op deze pagina.
 */
$NEXT_ID = $TOKENS->create();

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

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

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

    $query['next'] = $NEXT_ID;

    return current_scheme() . '://' . current_host() . $path . '?' . http_build_query($query);
}

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

function get_pkgs_all_text()
{
    try {
        return catalog_http_fetch_cached(
            CATALOG_PKGS_ALL,
            CACHE_FILE,
            CACHE_META_FILE,
            CACHE_TTL,
            'rktsndbx-rktpkgs/1.0',
            180
        );
    } catch (Throwable $e) {
        fail_html($e->getMessage());
    }
}

function serve_index()
{
    global $NEXT_ID;

    $text = get_pkgs_all_text();
    $names = rktd_extract_top_level_package_names($text);

    if (count($names) === 0) {
        fail_html('Geen package-namen gevonden in pkgs-all.');
    }

    $rows = '';

    foreach ($names as $i => $name) {
        $url = make_url('/package', array('name' => $name));

        $rows .= RacketSandboxTemplate::renderFile('partials/package-index-row.html', array(
            'id' => $name,
            'index' => (string)($i + 1),
            'url' => $url,
            'name' => $name,
        )) . "\n";
    }

    html_response(RacketSandboxTemplate::renderFile('racket-pkg-index.html', array(
        'package_count' => (string)count($names),
        'next_id' => $NEXT_ID,
        'package_rows_html' => $rows,
    )));
}

$TOKENS->check_valid_next('html');
serve_index();