<?php

/**
 * POP3 stream access
 *
 * Creates POP3 URL handlers for accessing POP3 accounts and emails.
 *
 * LICENSE: Free for non-commercial usage. For commercial usage, contact the author.
 *
 * @author Rick Hodger <rick@fuzzi.org.uk>
 * @version 1.2
 * @package pop3_stream
 * @example example.php
 *
 * HISTORY
 * 1.0 - Initial release
 * 1.1 - Implemented stream_stat to allow usage with copy() and file().
 *     - For directory reading, we now close the connection immediatly. This avoids
 *       problems with locking POP3 servers.
 * 1.2 - Removed imap_uid() call, it causes errors.
 *     - Added Secure POP3 for gmail usage, via pop3s://
 * 1.3 - Experimental IMAP support. Does not work at this time.
 */

class pop3_stream {

    var $ih;
    var $host;
    var $port;
    var $username;
    var $password;
    var $path;
    // stuff for dir reading
    var $dir;
    var $pos;
    // stuff for file reading
    var $data;
    var $gotbody;
    var $size;
    var $time;

    /* Ignore the $mode, we're only interested in the path */
    function stream_open($path,$mode,$options,$opened_path) {
        // parse URL
        $url=parse_url($path);
        $this->host=$url['host'];
        if (!empty($url['port'])) {
            $this->port=$url['port'];
        } else {
            if ($url['scheme']==='imap') {
                $this->port=143;
            } else {
                $this->port=110;
            }
        }
        $this->username=$url['user'];
        $this->password=$url['pass'];
        $this->path=substr($url['path'],1);

        // do we have a path?
        if (empty($this->path) && $mode!=='np') {
            return false;
        }

        // open IMAP connection
        switch($url['scheme']) {
            case "pop3s":
                $this->ih=imap_open("{".$this->host.":".$this->port."/pop3/ssl/novalidate-cert}INBOX",$this->username,$this->password);
                break;
            case "pop3":
                $this->ih=imap_open("{".$this->host.":".$this->port."/pop3}INBOX",$this->username,$this->password);
                break;
            case "imap":
                $this->ih=imap_open("{".$this->host.":".$this->port."}INBOX",$this->username,$this->password);
                break;
        }
        if ($this->ih) {
            if (!empty($this->path)) {
                list($stats,)=imap_fetch_overview($this->ih,$this->path);
                $this->size=$stats->size;
                $this->time=strtotime($stats->date);
            }
            return true;
        } else {
            return false;
        }
    }

    function stream_close() {
        imap_close($this->ih);
    }

    /* Smart reader, at first it only downloads the header to memory, but if a read request is made
       beyond the header, we download the rest of the body */
    function stream_read($count) {
        // smart... only download the header WHEN data is requested
        if (empty($this->data)) {
            $this->pos=0; $this->gotbody=false;
            $this->data = imap_fetchheader($this->ih,$this->path);
        }
        // only download the body once we read past the header
        if ($this->gotbody==false && ($this->pos+$count > strlen($this->data))) {
            $this->gotbody=true;
            $this->data .= imap_body($this->ih,$this->path);
            $this->size=strlen($this->data);
        }
        if ($this->pos >= $this->size) {
            return false;
        } else {
            $d=substr($this->data,$this->pos,$count);
            if ($this->pos+$count > strlen($this->data)) {
                $this->pos=strlen($this->data);
            } else {
                $this->pos = $this->pos+$count+1;
            }
            return $d;
        }
    }

    /* Can't write to POP3 */
    function stream_write($data) {
        return false;
    }

    function stream_eof() {
        if ($this->pos == $this->size) {
            return true;
        } else {
            return false;
        }
    }

    function stream_tell() {
        return $this->pos;
    }

    function stream_seek($offset,$whence) {
        switch($whence) {
            case SEEK_SET:
                $this->pos = $offset;
                break;
            case SEEK_CUR:
                $this->pos = $this->pos+$offset;
                break;
            case SEEK_END:
                $this->pos = $this->size+$offset;
                break;
        }
    }

    function stream_stat() {
        $keys = array(
            'dev'     => 0,
            'ino'     => 0,
            'mode'    => 33216,
            'nlink'   => 0,
            'uid'     => 0,
            'gid'     => 0,
            'rdev'    => 0,
            'size'    => $this->size,
            'atime'   => $this->time,
            'mtime'   => $this->time,
            'ctime'   => $this->time,
            'blksize' => 0,
            'blocks'  => 0
        );
        return $keys;
    }

    function dir_opendir($path,$options) {
        // setting mode to 'np' avoids the path check
        if ($this->stream_open($path,'np',$options,'')) {
            $this->dir = imap_num_msg($this->ih);
            $this->pos=1;
            $this->stream_close();
            return true;
        } else {
            return false;
        }
    }

    function dir_closedir() {
        // do nothing.
    }

    function url_stat($path,$flags) {
        if ($this->stream_open($path,'','','')) {
            $stats=array();
            list($stats,)=imap_fetch_overview($this->ih,$this->path);
            $time=strtotime($stats->date);
            $keys = array(
                'dev'     => 0,
                'ino'     => 0,
                'mode'    => 33216,
                'nlink'   => 0,
                'uid'     => 0,
                'gid'     => 0,
                'rdev'    => 0,
                'size'    => $stats->size,
                'atime'   => $time,
                'mtime'   => $time,
                'ctime'   => $time,
                'blksize' => 0,
                'blocks'  => 0
            );
            $this->stream_close();
            return $keys;
        } else {
            return false;
        }        
    }

    function dir_readdir() {
        if ($this->pos>$this->dir) {
            return false;
        } else {
            $x=$this->pos;
            $this->pos++;
        }
        return $x;
    }

    function dir_rewinddir() {
        $this->pos=1;
    }

    /* Delete an email from the mailbox */
    function unlink($path) {
        if ($this->stream_open($path,'','','')) {
            imap_delete($this->ih,$this->path);
            imap_expunge($this->ih);
            $this->stream_close();
            return true;
        } else {
            return false;
        }
    }

}

stream_wrapper_register('pop3','pop3_stream')
    or die('Failed to register POP3 protocol!');
stream_wrapper_register('pop3s','pop3_stream')
    or die('Failed to register secure POP3 protocol!');
stream_wrapper_register('imap','pop3_stream')
    or die('Failed to register IMAP protocol!');
?>