<?php
# $Id$
# http://www.mapbender.org/index.php/
# Copyright (C) 2002 CCGIS 
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

require_once(dirname(__FILE__)."/../../core/globalSettings.php");

require_once(dirname(__FILE__)."/../classes/class_wms.php");
require_once(dirname(__FILE__)."/../classes/class_bbox.php");

require_once(dirname(__FILE__)."/../extensions/DifferenceEngine.php");

define("MONITOR_DEFAULT_SCALE", 500000);
define("MONITOR_IMG_WIDTH", 20);
define("MONITOR_IMG_HEIGHT", 20);
define("MB_RESOLUTION", 28.35);

class Monitor {
	/**
	 *  1 = reachable and in sync with db
	 *  0 = reachable and out of sync with db
	 * -1 = unreachable
	 * -2 = monitoring in progress
	 * 
	 */
	var $result = -1;

	/**
	 * 1  = the get map request DEFINITELY returns a valid map image
	 * 0  = the WMS doesn't support XML error format. Who knows if the image is really a map?
	 * -1 = the get map request doesn't return an image
	 */
	var $returnsImage;

	var $comment = "";
	var $updated = "0";
	var $supportsXMLException = false;
	
	var $timestamp;
	var $capabilitiesURL;
	var $mapURL;
	
	var $remoteXML;
	var $localXML;
	var $capabilitiesDiff;
	
	function __construct($wmsId, $uploadId, $autoUpdate) {
		$this->wmsId = $wmsId;
		$this->uploadId = $uploadId;
		$this->autoUpdate = $autoUpdate;

		$this->capabilitiesURL = $this->getUploadURL($this->wmsId, $this->uploadId);

		set_time_limit(TIME_LIMIT);
		
		
		$this->timestamp = time();
		
		if ($this->capabilitiesURL) {
		
			$remoteWms = new wms();
			$remoteWms->createObjFromXML($this->capabilitiesURL);
			$this->remoteXML = $remoteWms->wms_getcapabilities_doc;  
			$this->localXML = $this->getCapabilitiesDocByWMS($this->wmsId);

			// service unreachable
			if (!$this->remoteXML) {
				$this->result = -1;
				$this->comment = "Connection failed.";
			}
			/*
			 * service available;
			 * no local copy of capabilities file,
			 * so it has to be updated anyway
			 */
			elseif (!$this->localXML) {
				$this->result = 0;
			}
			/*
			 * service available;
			 * check if local copy is different
			 * to remote capabilties document
			 */
			else {
				/*
				 * compare to local capabilities document
				 */
				// capabilities files match
				if ($this->localXML == $this->remoteXML) {
					$this->result = 1;
					$this->comment = "WMS is stable.";
				}
				// capabilities files don't match
				else {
					$this->result = 0;
					$localXMLArray = explode("\n", htmlentities($this->localXML));
					$remoteXMLArray = explode("\n", htmlentities($this->remoteXML));
					$this->capabilitiesDiff = $this->outputDiffHtml($localXMLArray,$remoteXMLArray);
				}
			}
			/*
			 * if the WMS is available,
			 * 1) get a map image
			 * 2) update the local backup of the capabilities doc if necessary
			 */
			if ($this->result != -1) {
				
				$this->mapURL = $this->getMapRequest($this->wmsId);
				
				if ($this->isImage($this->mapURL)) {
					$this->returnsImage = 1;
				}
				else {
					$this->returnsImage = -1;
				}
		
				/*
				 * if the local backup of the capabilities document
				 * is deprecated, update the local backup
				 */
				if ($this->result == 0) {
					$mywms = new wms();
		
					/* 
					 * if the capabilities document is valid,
					 * update it OR mark it as "not up to date"
					 */ 
					if ($mywms->createObjFromXML($this->capabilitiesURL)) {
						if ($this->autoUpdate) {
							$mywms->updateObjInDB($this->wmsId);
							$this->updated = "1";
							$this->comment = "WMS has been updated.";
						}
						else {
							$this->comment = "WMS is not up to date.";
						}
					}
					// capabilities document is invalid
					else {
						$this->result = -1;
						$this->comment = "Invalid getCapabilities request/document or service exception.";
					}    
				}
			}
		}
		else {
			$this->result = -1;
			$this->comment = "Invalid upload URL.";
		}
		$e = new mb_notice("class_monitor: constructor: result = " . $this->result);
		$e = new mb_notice("class_monitor: constructor: comment = " . $this->comment);
		$e = new mb_notice("class_monitor: constructor: returnsImage = " . $this->returnsImage);
	}
	
	/**
	 * 
	 */
	public function __toString() {
		$str = "";
		$str .= "wmsid: " . $this->wmsId . "\nupload_id: " . $this->uploadId . "\n";
		$str .= "autoupdate: " . $this->autoUpdate . "\n";
		$str .= "result: " . $this->result . "\ncomment: " . $this->comment . "\n";
		$str .= "timestamp: " . $this->timestamp . " (".date("F j, Y, G:i:s", $this->timestamp).")\n";
		$str .= "getCapabilities URL: " . $this->capabilitiesURL . "\nupdated: " . $this->updated . "\n\n";
		$str .= "getMap URL: " . $this->mapURL . "\nis image: " . $this->returnsImage . "\n\n";
		$str .= "-------------------------------------------------------------------\n";
		$str .= "remote XML:\n\n" . $this->remoteXML . "\n\n";
		$str .= "-------------------------------------------------------------------\n";
		$str .= "local XML:\n\n" . $this->localXML . "\n\n";
		$str .= "-------------------------------------------------------------------\n";
		$str .= "diff:\n\n" . $this->capabilitiesDiff . "\n\n";
		$str .= "-------------------------------------------------------------------\n";		
		return (string) $str;
	}

	/**
	 * Update database
	 */
	function updateInDB() {
		$sql = "UPDATE mb_monitor SET updated = $1, status = $2, image = $3, status_comment = $4, upload_url = $5, timestamp_end = $6, map_url = $7, timestamp_begin = $8, caps_diff = $9 WHERE upload_id = $10 AND fkey_wms_id = $11";
		$v = array($this->updated, $this->result, $this->returnsImage, $this->comment, $this->capabilitiesURL, time(), $this->mapURL, $this->timestamp, $this->capabilitiesDiff, $this->uploadId, $this->wmsId);
		$t = array('s', 'i', 'i', 's', 's', 's', 's', 's', 's', 's', 'i');
		$res = db_prep_query($sql,$v,$t);		
	}

	/*
	 * Checks if the mapUrl returns an image or an exception
	 */
	private function isImage($url) {
		$headers = get_headers($url, 1);
		$e = new mb_notice("class_monitor: isImage: map URL is " . $url);
		$e = new mb_notice("class_monitor: isImage: Content-Type is " . $headers["Content-Type"]);
		if (preg_match("/xml/", $headers["Content-Type"])) {
			return false;
		}
		return true;
	}

	/**
	 * Returns the upload url of some WMS
 	 */
	private function getUploadURL($wmsId, $upload_id) {
		$e = new mb_notice("class_monitor: getUploadURL: wms = " . $wmsId);
		$e = new mb_notice("class_monitor: getUploadURL: upload_id = " . $upload_id);
		$sql = "SELECT upload_url FROM mb_monitor WHERE fkey_wms_id = $1 AND upload_id = $2";
		$v = array($wmsId, $upload_id);
		$t = array('i', 'i');
		$res = db_prep_query($sql,$v,$t);
		$someArray = db_fetch_array($res);
		$e = new mb_notice("class_monitor: getUploadURL: url = " . $someArray["upload_url"]);
		return $someArray["upload_url"];
	}
	
	/**
	 * Returns the character that needs to be appended to 
	 * a given online resource, in order to append other GET 
	 * parameters.
	 * 
	 * Possible characters: "?", "&", ""
	 */
	private function mb_getConjunctionCharacter($onlineresource){
		// index of character ? in online resource
		$indexOfChar = mb_strpos($onlineresource,"?");
	
		if($indexOfChar) {
			// no conjunction character needed
			if($indexOfChar == mb_strlen($onlineresource)-1){ 
				return "";
			}
			// no conjunction character needed
			else if (mb_substr($onlineresource, mb_strlen($onlineresource)-1) == "&") {
				return "";
			}
			else{
				return "&";
			}
		}
		return "?";
	}
	
	/**
	 * retrieves all information necessary to build a map request, 
	 * concatenates them and returns a valid get map request
	 */
	private function getMapRequest($wmsId) {
	
		// get map (wms_getmap)
		// version (wms_version)
		$sql = "SELECT wms_getmap, wms_version FROM wms WHERE wms_id = $1";
		$res = db_prep_query($sql, array($wmsId), array('i'));
		$row = db_fetch_array($res);
		$getmap = $row["wms_getmap"];
		$version = $row["wms_version"];
		
		//map format
		$sql = "SELECT * FROM wms_format WHERE data_type = 'map' AND fkey_wms_id = $1";
		$res = db_prep_query($sql, array($wmsId), array('i'));
		$row = db_fetch_array($res);
		$mapFormat = "";
		while ($row = db_fetch_array($res)) {
			$mapFormat = urlencode($row["data_format"]);
			if (preg_match("/png/", $mapFormat) || preg_match("/gif/", $mapFormat) || preg_match("/jp.{1}g/", $mapFormat)) {
				break;
			}
		}
	
		// layers (all layers)
		$sql = "SELECT layer_name FROM layer WHERE fkey_wms_id = $1 AND layer_parent <> '' AND layer_pos > 0";
		$res = db_prep_query($sql, array($wmsId), array('i'));
		$layerArray = array();
		while ($row = db_fetch_array($res)) {
			array_push($layerArray, urlencode($row["layer_name"]));
		}
		$layerList = implode(",", $layerArray);
		
		// srs (layer_epsg: epsg)
		// bbox (layer_epsg: minx, miny, maxx, maxy)
		$sql = "SELECT epsg, minx, miny, maxx, maxy ";
		$sql .= "FROM layer_epsg, (SELECT fkey_wms_id, layer_id FROM layer WHERE fkey_wms_id = $1 AND layer_parent = '' AND layer_pos = 0) AS l ";
		$sql .= "WHERE l.layer_id = layer_epsg.fkey_layer_id AND l.fkey_wms_id = $1";
		$res = db_prep_query($sql, array($wmsId), array('i'));
		$bboxArray = array();
		while ($row = db_fetch_array($res)) {
			array_push($bboxArray, new Mapbender_bbox($row["minx"], $row["miny"], $row["maxx"], $row["maxy"], $row["epsg"]));
		}
	
		// get a bbox in a preferably non WGS84 epsg to use the scalehints
		for ($i=0; $i < count($bboxArray); $i++) {
			$bbox = $bboxArray[$i];			
			if ($bboxArray[$i]->epsg != "EPSG:4326") {
				break;
			}
		}
		
		/*
		 * transform to 31466 if is 4326
		 * TODO: extend to other EPSG apart from 31466
		 */
		if ($bbox->epsg == "EPSG:4326") {
			$bbox->transform("EPSG:31466");
		}
		
		/*
		 * get map and check if result is image 
		 */
		// check if this WMS supports exception type XML
		$sql = "SELECT data_format FROM wms_format WHERE fkey_wms_id = $1 AND data_type = 'exception'";
		$v = array($wmsId);
		$t = array('i');
		$res = db_prep_query($sql,$v,$t);
		while ($row = db_fetch_array($res)) {
			$exceptionFormat = $row["data_format"];
			// set the exception type to xml (if possible)
			if (preg_match('/xml/', $exceptionFormat)) {
				$this->supportsXMLException = true;
				break; 
			}
		}

		// correct bbox according to scale
		$scale = $this->getScaleForWMS($wmsId);
		$bbox = $this->getBBoxInScale($bbox, $scale);

		return $this->concatenateMapRequest($getmap, $version, $mapFormat, $layerList, $bbox, MONITOR_IMG_WIDTH, MONITOR_IMG_HEIGHT, $exceptionFormat);			 
	}
	
	/**
	 * updates a given BBox according to a given scale
	 * 
	 * @param bbox 
	 * @param scale 
	 */
	private function getBBoxInScale($bbox, $scale) {
		$e = new mb_notice("class_monitor: getMapRequest: old bbox = " . $bbox);
		$e = new mb_notice("class_monitor: getMapRequest: old bbox = " . $bbox->min->x . "," . $bbox->min->y . "," . $bbox->max->x . "," . $bbox->max->y);
		$e = new mb_notice("class_monitor: getMapRequest: scale = " . $scale);
		if ($scale) {
			$center = $bbox->min->plus($bbox->max)->times(0.5);
			$e = new mb_notice("class_monitor: getMapRequest: center = " . $center);
			
			/*
			 * TODO: this formula should have documentation
			 */
			$offset =  MONITOR_IMG_WIDTH / (MB_RESOLUTION * 100 * 2) * $scale;
			$offsetPoint = new Mapbender_point($offset, $offset, $bbox->epsg);
			$min = $center->minus($offsetPoint);
			$max = $center->plus($offsetPoint);
			$bbox->min = $min;
			$bbox->max = $max;
			$e = new mb_notice("class_monitor: getMapRequest: new bbox = " . $bbox);
			$e = new mb_notice("class_monitor: getMapRequest: new bbox = " . $bbox->min->x . "," . $bbox->min->y . "," . $bbox->max->x . "," . $bbox->max->y);
		}
		return $bbox;
	}
	
	
	/**
	 * Returns an online resource representing a get map request
	 */
	private function concatenateMapRequest(	$getmap, $wmsVersion, $mapFormat, $layerList, 
							$bbox, $width, $height, $exceptionFormat) {
		/*
		 * getMap URL
		 */
		$mapRequest = $getmap;
		$mapRequest .= $this->mb_getConjunctionCharacter($getmap);
		
		/*
		 * WMS version
		 */
		if ($wmsVersion == "1.0.0") {
			$mapRequest .= "WMTVER=" . $wmsVersion . "&REQUEST=map&";
		}
		else {
			$mapRequest .= "VERSION=" . $wmsVersion . "&REQUEST=GetMap&SERVICE=WMS&";
		}
		
		/*
		 * Layer list
		 */
		$mapRequest .= "LAYERS=" . $layerList . "&";
		
		/*
		 * Format
		 */
		 $mapRequest .= "FORMAT=" . $mapFormat . "&";
		 
		/*
		 * SRS and BBox
		 */
		$mapRequest .= "SRS=" . $bbox->epsg . "&";
		$mapRequest .= "BBOX=" . $bbox->min->x . "," . $bbox->min->y . "," . $bbox->max->x . "," . $bbox->max->y . "&";
		 
		/*
		 * Width and height
		 */
		$mapRequest .= "WIDTH=" . $width . "&";
		$mapRequest .= "HEIGHT=" . $height . "&";
		 
		/*
		 * BGColor
		 */
		$mapRequest .= "BGCOLOR=0xffffff&";
	
		/*
		 * Transparency
		 */
		if (preg_match("/png/", $mapFormat) || preg_match("/gif/", $mapFormat)) {
			$mapRequest .= "TRANSPARENT=TRUE&";
		}
		 
		/*
		 * Exception format
		 */
		$mapRequest .= "EXCEPTIONS=" . $exceptionFormat . "&";
		
//		return urlencode($mapRequest);	
		return $mapRequest;	
	}
	
	/**
	 * Checks if the given WMS has ScaleHints. If yes, a scale is selected and returned.
	 */
	private function getScaleForWMS($wmsId) {
		// get the scalehints
		$sql = "SELECT layer_minscale, layer_maxscale FROM layer WHERE fkey_wms_id = $1 AND layer_pos = 0 AND layer_parent = '' AND layer_minscale <> layer_maxscale LIMIT 1";
		$v = array($wmsId);
		$t = array('i');
		$res = db_prep_query($sql,$v,$t);
		$scaleHintArray = db_fetch_array($res);
		
		/*
		 *  determine the scalehint
		 */
		// if a scalehint exists 
		if ($scaleHintArray) {
			// if upper boundary
			if ($scaleHintArray["layer_minscale"] < $scaleHintArray["layer_maxscale"]) {
				// TODO: find a better algorithm with a less obscure scale
				$scaleHint = round($scaleHintArray["layer_maxscale"] - $scaleHintArray["layer_minscale"]) / 2;				
			}
			// if lower boundary
			else {
				if ($scaleHintArray["layer_minscale"] < MONITOR_DEFAULT_SCALE) {
					$scaleHint = MONITOR_DEFAULT_SCALE;
				}
				else {
					// TODO: find a better algorithm with a less obscure scale
					$scaleHint = $scaleHintArray["layer_minscale"] + 1000;
				}
			}
		}
		// otherwise, use a default value
		else {
			$scaleHint = MONITOR_DEFAULT_SCALE;
		}
		return $scaleHint;
	}
	
	/**
	 * Returns the local backup of the given WMS' capabilities document
	 */
	private function getCapabilitiesDocByWMS($wmsId) {
		$sql = "SELECT wms_getcapabilities_doc FROM wms WHERE wms_id = $1";
		$v = array($wmsId);
		$t = array('i');
		$res = db_prep_query($sql,$v,$t);
		$someArray = db_fetch_array($res);
		return $someArray["wms_getcapabilities_doc"];
	}
	/*
	* creates a html diff of the xml documents
	*/
	private function outputDiffHtml($localXMLArray,$remoteXMLArray) {
		$diffObj = new Diff($localXMLArray,$remoteXMLArray);
		$dft = new TableDiffFormatter();
		return $dft->format($diffObj);
	}		
	
}
?>