<?php
use function MicroHTML\FORM;
use function MicroHTML\INPUT;

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* Misc                                                                      *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

const DATA_DIR = "data";


function mtimefile(string $file): string
{
    $data_href = get_base_href();
    $mtime = filemtime($file);
    return "$data_href/$file?$mtime";
}

function get_theme(): string
{
    global $config;
    $theme = $config->get_string(SetupConfig::THEME, "default");
    if (!file_exists("themes/$theme")) {
        $theme = "default";
    }
    return $theme;
}

function contact_link(): ?string
{
    global $config;
    $text = $config->get_string('contact_link');
    if (is_null($text)) {
        return null;
    }

    if (
        startsWith($text, "http:") ||
        startsWith($text, "https:") ||
        startsWith($text, "mailto:")
    ) {
        return $text;
    }

    if (strpos($text, "@")) {
        return "mailto:$text";
    }

    if (strpos($text, "/")) {
        return "http://$text";
    }

    return $text;
}

/**
 * Check if HTTPS is enabled for the server.
 */
function is_https_enabled(): bool
{
    return (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
}

/**
 * Compare two Block objects, used to sort them before being displayed
 */
function blockcmp(Block $a, Block $b): int
{
    if ($a->position == $b->position) {
        return 0;
    } else {
        return ($a->position > $b->position);
    }
}

/**
 * Figure out PHP's internal memory limit
 */
function get_memory_limit(): int
{
    global $config;

    // thumbnail generation requires lots of memory
    $default_limit = 8*1024*1024;	// 8 MB of memory is PHP's default.
    $shimmie_limit = parse_shorthand_int($config->get_int(MediaConfig::MEM_LIMIT));

    if ($shimmie_limit < 3*1024*1024) {
        // we aren't going to fit, override
        $shimmie_limit = $default_limit;
    }

    /*
    Get PHP's configured memory limit.
    Note that this is set to -1 for NO memory limit.

    http://ca2.php.net/manual/en/ini.core.php#ini.memory-limit
    */
    $memory = parse_shorthand_int(ini_get("memory_limit"));

    if ($memory == -1) {
        // No memory limit.
        // Return the larger of the set limits.
        return max($shimmie_limit, $default_limit);
    } else {
        // PHP has a memory limit set.
        if ($shimmie_limit > $memory) {
            // Shimmie wants more memory than what PHP is currently set for.

            // Attempt to set PHP's memory limit.
            if (ini_set("memory_limit", $shimmie_limit) === false) {
                /*  We can't change PHP's limit, oh well, return whatever its currently set to */
                return $memory;
            }
            $memory = parse_shorthand_int(ini_get("memory_limit"));
        }

        // PHP's memory limit is more than Shimmie needs.
        return $memory; // return the current setting
    }
}

/**
 * Get the currently active IP, masked to make it not change when the last
 * octet or two change, for use in session cookies and such
 */
function get_session_ip(Config $config): string
{
    $mask = $config->get_string("session_hash_mask", "255.255.0.0");
    $addr = $_SERVER['REMOTE_ADDR'];
    $addr = inet_ntop(inet_pton($addr) & inet_pton($mask));
    return $addr;
}


/**
 * A shorthand way to send a TextFormattingEvent and get the results.
 */
function format_text(string $string): string
{
    $tfe = new TextFormattingEvent($string);
    send_event($tfe);
    return $tfe->formatted;
}

/**
 * Generates the path to a file under the data folder based on the file's hash.
 * This process creates subfolders based on octet pairs from the file's hash.
 * The calculated folder follows this pattern data/$base/octet_pairs/$hash
 * @param string $base
 * @param string $hash
 * @param bool $create
 * @param int $splits The number of octet pairs to split the hash into. Caps out at strlen($hash)/2.
 * @return string
 */
function warehouse_path(string $base, string $hash, bool $create=true, int $splits = WH_SPLITS): string
{
    $dirs =[DATA_DIR, $base];
    $splits = min($splits, strlen($hash) / 2);
    for ($i = 0; $i < $splits; $i++) {
        $dirs[] = substr($hash, $i * 2, 2);
    }
    $dirs[] = $hash;

    $pa = join_path(...$dirs);

    if ($create && !file_exists(dirname($pa))) {
        mkdir(dirname($pa), 0755, true);
    }
    return $pa;
}

/**
 * Determines the path to the specified file in the data folder.
 */
function data_path(string $filename, bool $create = true): string
{
    $filename = join_path("data", $filename);
    if ($create&&!file_exists(dirname($filename))) {
        mkdir(dirname($filename), 0755, true);
    }
    return $filename;
}

function transload(string $url, string $mfile): ?array
{
    global $config;

    if ($config->get_string("transload_engine") === "curl" && function_exists("curl_init")) {
        $ch = curl_init($url);
        $fp = fopen($mfile, "w");

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_VERBOSE, 1);
        curl_setopt($ch, CURLOPT_HEADER, 1);
        curl_setopt($ch, CURLOPT_REFERER, $url);
        curl_setopt($ch, CURLOPT_USERAGENT, "Shimmie-".VERSION);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);

        $response = curl_exec($ch);

        $header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
        $headers = http_parse_headers(implode("\n", preg_split('/\R/', rtrim(substr($response, 0, $header_size)))));
        $body = substr($response, $header_size);

        curl_close($ch);
        fwrite($fp, $body);
        fclose($fp);

        return $headers;
    }

    if ($config->get_string("transload_engine") === "wget") {
        $s_url = escapeshellarg($url);
        $s_mfile = escapeshellarg($mfile);
        system("wget --no-check-certificate $s_url --output-document=$s_mfile");

        return file_exists($mfile) ? ["ok"=>"true"] : null;
    }

    if ($config->get_string("transload_engine") === "fopen") {
        $fp_in = @fopen($url, "r");
        $fp_out = fopen($mfile, "w");
        if (!$fp_in || !$fp_out) {
            return null;
        }
        $length = 0;
        while (!feof($fp_in) && $length <= $config->get_int('upload_size')) {
            $data = fread($fp_in, 8192);
            $length += strlen($data);
            fwrite($fp_out, $data);
        }
        fclose($fp_in);
        fclose($fp_out);

        $headers = http_parse_headers(implode("\n", $http_response_header));

        return $headers;
    }

    return null;
}

/**
 * Get the active contents of a .php file
 */
function manual_include(string $fname): ?string
{
    static $included = [];

    if (!file_exists($fname)) {
        return null;
    }

    if (in_array($fname, $included)) {
        return null;
    }

    $included[] = $fname;

    print "$fname\n";

    $text = file_get_contents($fname);

    // we want one continuous file
    $text = str_replace('<'.'?php', '', $text);
    $text = str_replace('?'.'>', '', $text);

    // most requires are built-in, but we want /lib separately
    $text = str_replace('require_', '// require_', $text);
    $text = str_replace('// require_once "lib', 'require_once "lib', $text);

    // @include_once is used for user-creatable config files
    $text = preg_replace('/@include_once "(.*)";/e', "manual_include('$1')", $text);

    return $text;
}


function path_to_tags(string $path): string
{
    $matches = [];
    $tags = [];
    if (preg_match("/\d+ - (.+)\.([a-zA-Z0-9]+)/", basename($path), $matches)) {
        $tags = explode(" ", $matches[1]);
    }

    $path = dirname($path);
    $path = str_replace(";", ":", $path);
    $path = str_replace("__", " ", $path);


    $category = "";
    foreach (explode("/", $path) as $dir) {
        $category_to_inherit = "";
        foreach (explode(" ", $dir) as $tag) {
            $tag = trim($tag);
            if ($tag=="") {
                continue;
            }
            if (substr_compare($tag, ":", -1) === 0) {
                // This indicates a tag that ends in a colon,
                // which is for inheriting to tags on the subfolder
                $category_to_inherit = $tag;
            } else {
                if ($category!=""&&strpos($tag, ":") === false) {
                    // This indicates that category inheritance is active,
                    // and we've encountered a tag that does not specify a category.
                    // So we attach the inherited category to the tag.
                    $tag = $category.$tag;
                }
                $tags[] = $tag;
            }
        }
        // Category inheritance only works on the immediate subfolder,
        // so we hold a category until the next iteration, and then set
        // it back to an empty string after that iteration
        $category = $category_to_inherit;
    }

    return implode(" ", $tags);
}


function join_url(string $base, string ...$paths)
{
    $output = $base;
    foreach ($paths as $path) {
        $output = rtrim($output, "/");
        $path = ltrim($path, "/");
        $output .= "/".$path;
    }
    return $output;
}

function get_dir_contents(string $dir): array
{
    if (empty($dir)) {
        throw new Exception("dir required");
    }
    if (!is_dir($dir)) {
        return [];
    }
    $results = array_diff(
        scandir(
            $dir
        ),
        ['..', '.']
    );

    return $results;
}

/**
 * Returns amount of files & total size of dir.
 */
function scan_dir(string $path): array
{
    $bytestotal = 0;
    $nbfiles = 0;

    $ite = new RecursiveDirectoryIterator(
        $path,
        FilesystemIterator::KEY_AS_PATHNAME |
        FilesystemIterator::CURRENT_AS_FILEINFO |
        FilesystemIterator::SKIP_DOTS
    );
    foreach (new RecursiveIteratorIterator($ite) as $filename => $cur) {
        try {
            $filesize = $cur->getSize();
            $bytestotal += $filesize;
            $nbfiles++;
        } catch (RuntimeException $e) {
            // This usually just means that the file got eaten by the import
            continue;
        }
    }

    $size_mb = $bytestotal / 1048576; // to mb
    $size_mb = number_format($size_mb, 2, '.', '');
    return ['path' => $path, 'total_files' => $nbfiles, 'total_mb' => $size_mb];
}


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* Debugging functions                                                       *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

// SHIT by default this returns the time as a string. And it's not even a
// string representation of a number, it's two numbers separated by a space.
// What the fuck were the PHP developers smoking.
$_shm_load_start = microtime(true);

/**
 * Collects some debug information (execution time, memory usage, queries, etc)
 * and formats it to stick in the footer of the page.
 */
function get_debug_info(): string
{
    global $cache, $config, $_shm_event_count, $database, $_shm_load_start;

    $i_mem = sprintf("%5.2f", ((memory_get_peak_usage(true)+512)/1024)/1024);

    if ($config->get_string("commit_hash", "unknown") == "unknown") {
        $commit = "";
    } else {
        $commit = " (".$config->get_string("commit_hash").")";
    }
    $time = sprintf("%.2f", microtime(true) - $_shm_load_start);
    $dbtime = sprintf("%.2f", $database->dbtime);
    $i_files = count(get_included_files());
    $hits = $cache->get_hits();
    $miss = $cache->get_misses();

    $debug = "<br>Took $time seconds (db:$dbtime) and {$i_mem}MB of RAM";
    $debug .= "; Used $i_files files and {$database->query_count} queries";
    $debug .= "; Sent $_shm_event_count events";
    $debug .= "; $hits cache hits and $miss misses";
    $debug .= "; Shimmie version ". VERSION . $commit; // .", SCore Version ". SCORE_VERSION;

    return $debug;
}


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* Request initialisation stuff                                              *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/** @privatesection */

function _version_check(): void
{
    if (MIN_PHP_VERSION) {
        if (version_compare(phpversion(), MIN_PHP_VERSION, ">=") === false) {
            print "
Shimmie (SCore Engine) does not support versions of PHP lower than ".MIN_PHP_VERSION."
(PHP reports that it is version ".phpversion().")
If your web host is running an older version, they are dangerously out of
date and you should plan on moving elsewhere.
";
            exit;
        }
    }
}

function _sanitise_environment(): void
{
    global $_tracer;

    if (TIMEZONE) {
        date_default_timezone_set(TIMEZONE);
    }

    # ini_set('zend.assertions', 1);  // generate assertions
    ini_set('assert.exception', 1);  // throw exceptions when failed
    if (DEBUG) {
        error_reporting(E_ALL);
    }

    $_tracer = new EventTracer();

    if (COVERAGE) {
        _start_coverage();
        register_shutdown_function("_end_coverage");
    }

    ob_start();

    if (PHP_SAPI === 'cli' || PHP_SAPI == 'phpdbg') {
        if (isset($_SERVER['REMOTE_ADDR'])) {
            die("CLI with remote addr? Confused, not taking the risk.");
        }
        $_SERVER['REMOTE_ADDR'] = "0.0.0.0";
        $_SERVER['HTTP_HOST'] = "<cli command>";
    }
}


function _get_themelet_files(string $_theme): array
{
    $base_themelets = [];
    if (file_exists('themes/'.$_theme.'/custompage.class.php')) {
        $base_themelets[] = 'themes/'.$_theme.'/custompage.class.php';
    }
    $base_themelets[] = 'themes/'.$_theme.'/layout.class.php';
    $base_themelets[] = 'themes/'.$_theme.'/themelet.class.php';

    $ext_themelets = zglob("ext/{".Extension::get_enabled_extensions_as_string()."}/theme.php");
    $custom_themelets = zglob('themes/'.$_theme.'/{'.Extension::get_enabled_extensions_as_string().'}.theme.php');

    return array_merge($base_themelets, $ext_themelets, $custom_themelets);
}


/**
 * Used to display fatal errors to the web user.
 */
function _fatal_error(Exception $e): void
{
    $version = VERSION;
    $message = $e->getMessage();
    $phpver = phpversion();

    //$hash = exec("git rev-parse HEAD");
    //$h_hash = $hash ? "<p><b>Hash:</b> $hash" : "";
    //'.$h_hash.'

    if (PHP_SAPI === 'cli' || PHP_SAPI == 'phpdbg') {
        print("Trace: ");
        $t = array_reverse($e->getTrace());
        foreach ($t as $n => $f) {
            $c = $f['class'] ?? '';
            $t = $f['type'] ?? '';
            $a = implode(", ", array_map("stringer", $f['args']));
            print("$n: {$f['file']}({$f['line']}): {$c}{$t}{$f['function']}({$a})\n");
        }

        print("Message: $message\n");

        if (isset($e->query)) {
            print("Query:   {$e->query}\n");
        }

        print("Version: $version (on $phpver)\n");
    } else {
        $q = (!isset($e->query) || is_null($e->query)) ? "" : "<p><b>Query:</b> " . html_escape($e->query);
        header("HTTP/1.0 500 Internal Error");
        echo '
<html>
	<head>
		<title>Internal error - SCore-'.$version.'</title>
	</head>
	<body>
		<h1>Internal Error</h1>
		<p><b>Message:</b> '.html_escape($message).'
		'.$q.'
		<p><b>Version:</b> '.$version.' (on '.$phpver.')
	</body>
</html>
';
    }
}

/**
 * Turn ^^ into ^ and ^s into /
 *
 * Necessary because various servers and various clients
 * think that / is special...
 */
function _decaret(string $str): string
{
    $out = "";
    $length = strlen($str);
    for ($i=0; $i<$length; $i++) {
        if ($str[$i] == "^") {
            $i++;
            if ($str[$i] == "^") {
                $out .= "^";
            }
            if ($str[$i] == "s") {
                $out .= "/";
            }
            if ($str[$i] == "b") {
                $out .= "\\";
            }
        } else {
            $out .= $str[$i];
        }
    }
    return $out;
}

function _get_user(): User
{
    global $config, $page;
    $my_user = null;
    if ($page->get_cookie("user") && $page->get_cookie("session")) {
        $tmp_user = User::by_session($page->get_cookie("user"), $page->get_cookie("session"));
        if (!is_null($tmp_user)) {
            $my_user = $tmp_user;
        }
    }
    if (is_null($my_user)) {
        $my_user = User::by_id($config->get_int("anon_id", 0));
    }
    assert(!is_null($my_user));

    return $my_user;
}

function _get_query(): string
{
    return (@$_POST["q"]?:@$_GET["q"])?:"/";
}


/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* Code coverage                                                             *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

function _start_coverage(): void
{
    if (function_exists("xdebug_start_code_coverage")) {
        #xdebug_start_code_coverage(XDEBUG_CC_UNUSED|XDEBUG_CC_DEAD_CODE);
        xdebug_start_code_coverage(XDEBUG_CC_UNUSED);
    }
}

function _end_coverage(): void
{
    if (function_exists("xdebug_get_code_coverage")) {
        // Absolute path is necessary because working directory
        // inside register_shutdown_function is unpredictable.
        $absolute_path = dirname(dirname(__FILE__)) . "/data/coverage";
        if (!file_exists($absolute_path)) {
            mkdir($absolute_path);
        }
        $n = 0;
        $t = time();
        while (file_exists("$absolute_path/$t.$n.log")) {
            $n++;
        }
        file_put_contents("$absolute_path/$t.$n.log", gzdeflate(serialize(xdebug_get_code_coverage())));
    }
}

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
* HTML Generation                                                           *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/**
 * Give a HTML string which shows an IP (if the user is allowed to see IPs),
 * and a link to ban that IP (if the user is allowed to ban IPs)
 *
 * FIXME: also check that IP ban ext is installed
 */
function show_ip(string $ip, string $ban_reason): string
{
    global $user;
    $u_reason = url_escape($ban_reason);
    $u_end = url_escape("+1 week");
    $ban = $user->can(Permissions::BAN_IP) ? ", <a href='".make_link("ip_ban/list", "c_ip=$ip&c_reason=$u_reason&c_expires=$u_end#create")."'>Ban</a>" : "";
    $ip = $user->can(Permissions::VIEW_IP) ? $ip.$ban : "";
    return $ip;
}

/**
 * Make a form tag with relevant auth token and stuff
 */
function make_form(string $target, string $method="POST", bool $multipart=false, string $form_id="", string $onsubmit=""): string
{
    global $user;
    if ($method == "GET") {
        $link = html_escape($target);
        $target = make_link($target);
        $extra_inputs = "<input type='hidden' name='q' value='$link'>";
    } else {
        $extra_inputs = $user->get_auth_html();
    }

    $extra = empty($form_id) ? '' : 'id="'. $form_id .'"';
    if ($multipart) {
        $extra .= " enctype='multipart/form-data'";
    }
    if ($onsubmit) {
        $extra .= ' onsubmit="'.$onsubmit.'"';
    }
    return '<form action="'.$target.'" method="'.$method.'" '.$extra.'>'.$extra_inputs;
}

function SHM_FORM(string $target, string $method="POST", bool $multipart=false, string $form_id="", string $onsubmit="")
{
    global $user;

    $attrs = [
        "action"=>$target,
        "method"=>$method
    ];

    if ($form_id) {
        $attrs["id"] = $form_id;
    }
    if ($multipart) {
        $attrs["enctype"] = 'multipart/form-data';
    }
    if ($onsubmit) {
        $attrs["onsubmit"] = $onsubmit;
    }
    $f = FORM(
        $attrs,
        INPUT(["type"=>"hidden", "name"=>"q", "value"=>$target]),
        $method != "GET" ? "" : $user->get_auth_html()
    );

    return $f;
}