<?php
error_reporting(E_ALL);
set_time_limit(0);
ob_implicit_flush();

// Based on:
// gemini://glasgow.social/gemini-php

class Gemini {
	function __construct($config) {
		if (empty($config['certificate_file'])) {
			die('Missing certificate file. Edit config.php\n');
		}

		$this->ip = '0';
		$this->port = '1965';
		$this->data_dir = 'hosts/';
		$this->default_host_dir = 'default/';
		$this->default_index_file = 'index.gmi';
		$this->logging = 1;
		$this->log_file = "logs/gemini-php.log";
		$this->log_sep = "\t";

		$settings = array(
			'ip', 'port',
			'data_dir',
			'default_host_dir',
			'default_index_file',
			'certificate_file',
			'certificate_passphrase'
		);

		foreach ($settings as $setting_key) {
			if (!empty($config[$setting_key])) {
				$this->$setting_key = $config[$setting_key];
			}
		}

		// Append the required filepath slashes if they're missing
		if (substr($this->data_dir, -1) != "/") {
			$this->data_dir .= "/";
		}
		if (substr($this->default_host_dir, -1) != "/") {
			$this->default_host_dir .= "/";
		}
		if ($this->logging) {
			if (!file_exists($this->log_file)) {
				$this->log_to_file("Log created", null, null, null, null);
			}
			if (!is_writable($this->log_file)) {
				die("{$this->log_file} is not writable.\n");
			}
		}
		if (!is_readable($this->certificate_file)) {
			die("Certificate file {$this->certificate_file} not readable.\n");
		}
	}

	function parse_request($request) {
		$url = trim($request); // Strip <CR><LF> from the end
		return parse_url($url);
	}

	function get_valid_hosts() {
		$dirs = array_map('basename', glob($this->data_dir . '*', GLOB_ONLYDIR));
		return $dirs;
	}

	function get_status_code($filepath) {
		if (is_file($filepath) and file_exists($filepath)) {
			return '20';
		}
		if (!file_exists($filepath)) {
			//echo("File $filepath doesn't exist\n");
			return '51';
		}
		return '50';
	}

	function get_mime_type($filepath) {
		$type = mime_content_type($filepath);
		// We need a way to detect gemini file types, which PHP doesn't
		// so.. if it ends with gemini (or if it has no extension), assume
		$path_parts = pathinfo($filepath);

		if (empty($path_parts['extension'])
				or $path_parts['extension'] === 'gemini'
				or $path_parts['extension'] === 'gmi'
			) {
			$type = 'text/gemini';
		}
		return $type;
	}

	/**
	* Gets the full file path (assumes directory structure based on host)
	*
	* This function determines where the requested file is stored
	* based on the hostname supplied in the request from the client.
	* If no host is supplied, the default directory is assumed.
	*
	* @param array $url An array returned by the parse_request() method
	*
	* @return string
	*/
	function get_filepath($url) {
		$hostname = '';

		if (!is_array($url)) {
			return false;
		}
		if (!empty($url['host'])) {
			$hostname = $url['host'];
		}

		$valid_hosts = $this->get_valid_hosts();

		if (!in_array($hostname, $valid_hosts)) {
			$hostname = 'default';
		}

		// Kristall Browser is adding "__" to the end of the filenames
		// wtf am I missing?
		// also removing ".." to mitigate against directory traversal
		$url['path'] = str_replace(array('..', '__'), '', $url['path']);

		// Force an index file to be appended if a filename is missing
		if (empty($url['path'])) {
			$url['path'] = '/' . $this->default_index_file;
		} elseif(substr($url['path'], -1) === '/') {
			$url['path'] .= $this->default_index_file;
		}

		$valid_data_dir = dirname(__FILE__) . '/' . $this->data_dir;
		$return_path = $this->data_dir.$hostname.$url['path'];

		if (is_link($return_path)) {
			return $return_path;
		}

		// Check the real path is in the data_dir (path traversal sanity check)
		if (substr(realpath($return_path), 0, strlen($valid_data_dir)) === $valid_data_dir) {
			return $return_path;
		}
		return false;
	}

	function log_to_file($ip, $status_code, $meta, $filepath, $filesize) {
		$ts = date("Y-m-d H:i:s", strtotime('now'));
		$this->log_sep;

		$str = $ts.$this->log_sep . $ip . $this->log_sep
			. $status_code . $this->log_sep
			.	$meta.$this->log_sep . $filepath . $this->log_sep
			. $filesize . "\n";
		file_put_contents($this->log_file, $str, FILE_APPEND);
	}
}