var map;

// this global (we tried a closure but it was returning a function pointer instead of a value) is used to 
// determine whether we submit form lpf (true) or not (false) once we have coordinates returned.
var atl_submit_on_success = false;

// global that is either 'search' or 'manage' which is used to modify messages intended for searchers, or people managing products
var atl_scenario = 'search';

// global defaults
var default_latitude = 0;
var default_longitude = 0;
var default_accuracy = 0;

function find_location () {

    var latitude = '';
    var longitude = '';
    var accuracy = '';
    // lookup the cookie - if available
    var last_location = get_location_cookie();
    if (last_location) {
	latitude = (last_location.latitude === '') ? default_latitude : last_location.latitude;
	longitude = (last_location.longitude === '') ? default_longitude : last_location.longitude;
	accuracy = (last_location.accuracy === '') ? default_accuracy : last_location.accuracy;
    } else {
	latitude = default_latitude;
	longitude = default_longitude;
	accuracy = default_accuracy;
    }
    document.lpf.lat.value = latitude;
    document.lpf.lon.value = longitude;
    document.lpf.acc.value = accuracy;

    if (navigator.geolocation) {
	document.getElementById("location_message").innerHTML = ''; //Click the "Share Location" button above to begin Geolocating...';
        navigator.geolocation.getCurrentPosition(location_func_pointer);
    } else {
	document.getElementById("location_message").innerHTML = 'Zoom into your location by clicking on this map';
	//alert('****latitude = ' + latitude + ' longitude = ' + longitude + ' accuracy = ' + accuracy + '****');
	initialize_map(latitude,longitude,accuracy);
    }
    return;
}

function location_func_pointer (position) {
    document.lpf.lat.value = position.coords.latitude;
    document.lpf.lon.value = position.coords.longitude;
    var accuracy = position.coords.accuracy;
    if (accuracy) {
	if (document.lpf.acc) {
	    document.lpf.acc.value = accuracy;
	}
	if(accuracy >= 0) {  //TODO: can make this 1000
	    location_found_message(accuracy, 'geo');
	    //initialize_map(position.coords.latitude, position.coords.longitude, accuracy);	
	} else {
	    if (atl_submit_on_success == true) {
		document.lpf.submit();
	    } else {
		location_found_message(accuracy, 'geo');
	    }
	}
    } else {
	document.getElementById("location_message").innerHTML = "Sorry, but your location could not be found!";
    }
    return;
}

function map_finish_mesage() {
    var finish_message = '';
    if (atl_submit_on_success == false) {
	if (atl_scenario == 'manage') {
	    // special message while editing shop data
	    finish_message = "You are ready to continue";
	} else {
	    finish_message = "Ready to find products."; //"You are ready to find products from this location";
	    document.lpf.s.focus();
	}
    } else {
	finish_message = "Finding products from this location now...";
    }
    return finish_message;
}
	
function initialize_map(lat, long, accuracy) {
    var hybrid_cutoff = 14; // zoom level at which to become a hybrid map
    if (isNaN(lat)) {
	lat = 0;
    }
    if (isNaN(long)) {
	long = 0;
    }
    if (isNaN(accuracy)) {
	accuracy = 0;
    }
    //alert('****latitude = ' + lat + ' longitude = ' + long + ' accuracy = ' + accuracy + '****');
    var start_zoomlevel;
    if (accuracy && accuracy != 0) {
	//alert ('zoomed map - accuracy is true -- accuracy="' + accuracy + '"');
	// note this zoomlevel is recalculated in get_limits_from_radius() for compatible browsers 
	start_zoomlevel = 15;
	map_message();
    } else {
	//alert ('world map - accuracy is false');
	start_zoomlevel = 1;
	world_map_message();
    }
    if (GBrowserIsCompatible()) {
      	document.getElementById('map_canvas').style.display = 'block';
        map = new GMap2(document.getElementById("map_canvas"));
        map.setCenter(new GLatLng(lat, long), start_zoomlevel);
        map.setUIToDefault();

	// set the zoom level accurately depending on the browser type
	get_limits_from_radius(accuracy, lat, long);

	// set the map type depending on the zoom level too 
	zoomlevel = map.getZoom();
	if (zoomlevel > hybrid_cutoff) {
	    map.setMapType(G_HYBRID_MAP);
	} else {
	    map.setMapType(G_NORMAL_MAP);
	}

	// Recenter Map and add Coords by clicking the map
	GEvent.addListener(map, 'click', function(overlay, point) {
		document.lpf.lat.value=point.y;
		document.lpf.lon.value=point.x;
		zoomlevel = map.getZoom();
		if (zoomlevel > hybrid_cutoff) {
		    map.setMapType(G_HYBRID_MAP);
		} else {
		    map.setMapType(G_NORMAL_MAP);
		}
		var zoomin = 4;
		if (zoomlevel > 8) {
		    zoomin = 2;
		}
		if (zoomlevel > 12) {
		    zoomin = 1;
		}
		if(zoomlevel > 17) { // was 16
		    close_map();
		} else {
		    map.setCenter(new GLatLng(point.y, point.x), zoomlevel + zoomin);		//Zoom in
		}
	    });
    }
}

function close_map() {
    document.getElementById('map_canvas').style.display = 'none';
    document.lpf.acc.value=calculate_accuracy_from_zoomlevel();
    location_found_message( document.lpf.acc.value || 0, 'map' );
    if (atl_submit_on_success == true) {
	document.lpf.submit();
    }
    return;
}
function calculate_accuracy_from_zoomlevel() {
    var bounds = map.getBounds();
    var southWest = bounds.getSouthWest();
    var northEast = bounds.getNorthEast();
    //var lngSpan = northEast.lng() - southWest.lng();
    var latSpan = northEast.lat() - southWest.lat();
    // Now convert the latitude from decimal degrees into metres
    // lat/360 = delta-y/circumference of world 
    // => delta-y = lat * circum-world/360 = lat * 2piR/360 = lat * piR/180
    var piR_over_180 = 111195; //= (3.1415927*6371000)/180 in metres
    var delta_y = latSpan * piR_over_180;
    var radius = parseInt(delta_y / 2); 
    return radius;
}

function get_limits_from_radius(radius_meters, latitude, longitude) {

    //Function sets $this->top_left_latitude = 90.0;
    //		$this->top_left_longitude = -180.0;
    //		$this->bottom_right_longitude = 180.0;
    //		$this->bottom_right_latitude = -90.0;	
    //with a square around latitude/longitude based on the radius
    //Radius = 6371 km (≈3,959 mi).

    var bottom_right_longitude;
    var top_left_longitude;
    var top_left_latitude;
    var bottom_right_latitude;

    if ( ! radius_meters) {

	//alert ('no radius_meters = ' + radius_meters);

	// Special case entry - set the map to world size
	//bottom_right_longitude = 180;
	//top_left_longitude = -180;
	//top_left_latitude = 90;
	//bottom_right_latitude = -90;

	//alert ('about to hardcode the map to zoom level 1');
	map.setZoom(1);	

    } else {

	//alert ('radius_meters = ' + radius_meters);

	radius = radius_meters/1000;	//Get km

	pi = 3.1415927;
	two_pi_r_by_360 = 0;
	c360_by_two_pi_r = 0.008993216; //= 360/(2*3.1415927*6371)

	pi_over_180 = 0.0174533; //pi/180 is the degree to radian converter		


	//get the latitude of the current position in radians so
	//it can be used in cos(lat) to calculate how much to scale x
	lat_radians = latitude * pi_over_180;

	//y deg = dist * 360 / 2 PI R
	//x deg = dist * cos (latitude) * 360 / 2 PI R
	dx = (c360_by_two_pi_r * Math.cos(lat_radians)) * radius; //in km units
	dy = c360_by_two_pi_r * radius; //in km units

	//alert ('dx = ' + dx + ' dy = ' + dy);
	//alert ('longitude = ' + longitude + ' latitude = ' + latitude);
	//alert ('longitude + dx = ' + (longitude + dx));
	//alert ('longitude - dx = ' + (longitude - dx));
	//alert ('latitude + dy = ' + (latitude + dy));
	//alert ('latitude - dy = ' + (latitude - dy));
	//echo "Dx= $dx  Dy=$dy";
	// The following (+number) convert strings into numbers
	// stupid javascript was concatenating strings instead of adding numbers
	bottom_right_longitude = (+longitude) + (+dx);
	top_left_longitude = (+longitude) - (+dx);
	top_left_latitude = (+latitude) + (+dy);
	bottom_right_latitude = (+latitude) - (+dy);
		
	//Change zoom level to size of place
	nw = new GLatLng(top_left_latitude, top_left_longitude , true);
	se = new GLatLng(bottom_right_latitude, bottom_right_longitude , true);
	//alert ('nw = ' + nw + ' se = ' + se);
	bounds = new GLatLngBounds(nw, se);
	//alert('About to set the map to zoom level: ' + map.getBoundsZoomLevel(bounds));
	map.setZoom(map.getBoundsZoomLevel(bounds));

    }
		
    return; 
}

function location_found_message(accuracy, via_map_or_geo) {
    // accuracy is in metres, via_map_or_geo is how this location was found (geolocation, or from clicking on a map)
    var readable_accuracy;
    var fine_tune_vs_edit = (accuracy >= 1000) ? 'Fine-tune your location' : 'Change your location';
    if (accuracy > 1000) {
	// round the accuracy to the nearest km
	readable_accuracy = parseInt((accuracy + 500) / 1000) + ' km';
    } else {
	readable_accuracy = parseInt(accuracy) + ' meters';
    }
    var location_verb = (via_map_or_geo == 'geo') ? 'Geolocated' : 'located';
    var location_sentence = 'Accuracy: ' + readable_accuracy + '.';
    // Turn off location sentence if the accuracy is sufficiently high
    //if (accuracy < 1000) { 
    //	location_sentence = ''; 
    //}
    // Turn off location sentence if the user clicked on a map
    if (via_map_or_geo == 'map') { 
	location_sentence = ''; 
    }
    document.getElementById("location_message").innerHTML = map_finish_mesage() + ' ' + location_sentence + '<br/><button onclick="set_location_cookie((document.lpf.lat.value || 0), (document.lpf.lon.value || 0), (document.lpf.acc.value || 0)); return false;" style="margin:3px; font-weight:normal"><small>Remember location</small></button><button onclick="initialize_map((document.lpf.lat.value || 0), (document.lpf.lon.value || 0), (document.lpf.acc.value || 0)); return false;" style="margin:3px; font-weight:normal"><small>' + fine_tune_vs_edit + '</small></button>';

    return;
}

function map_message() {
    document.getElementById("location_message").innerHTML = "Keep clicking on your location to zoom in<br/>" + clear_location_link() + ' ' + close_map_link();
    return;
}

function world_map_message() {
    document.getElementById("location_message").innerHTML = "Keep clicking on your location to zoom in<br/>" + clear_location_link() + ' ' + close_map_link();
    return;
}

function close_map_link() {
    return "<button onclick=\"close_map(); return false;\" style=\"margin:3px; font-weight:normal\"><small>Finish</small></button>";
}

function clear_location_link() {
    return "<button onclick=\"document.lpf.lat.value=0;document.lpf.lon.value=0;document.lpf.acc.value=0;initialize_map(0,0,0); clear_location_cookie(); return false;\" style=\"margin:3px; font-weight:normal\"><small>Reset</small></button>";
}

function get_location_cookie() {

    var location = {}; // hash with latitude, longitude, accuracy properties
    if (document.cookie) {
       var reg_exp = /latitude=([^\;]*)/; // match cookie format "latitude=..." for example
       var match = reg_exp.exec(document.cookie);
       if (match) {
	   location.latitude = match[1];
       }
       reg_exp = /longitude=([^\;]*)/; // match cookie format "longitude=..." for example
       match = reg_exp.exec(document.cookie);
       if (match) {
	   location.longitude = match[1];
       }
       reg_exp = /accuracy=([^\;]*)/; // match cookie format "accuracy=..." for example
       match = reg_exp.exec(document.cookie);
       if (match) {
	   location.accuracy = match[1];
       }
    }

    return (location);
}

function set_location_cookie(latitude, longitude, accuracy, gmapzoom) {

    // set the cookie expiration date far in future.
    document.cookie = 'latitude=' + latitude + ';path=/;expires=Thu,31-Dec-2020 00:00:00 GMT;';
    document.cookie = 'longitude=' + longitude + ';path=/;expires=Thu,31-Dec-2020 00:00:00 GMT;';
    document.cookie = 'accuracy=' + accuracy + ';path=/;expires=Thu,31-Dec-2020 00:00:00 GMT;';

}

function clear_location_cookie() {

    // delete the cookies by setting an expiration date in the past.
    if (document.cookie) {
	document.cookie = 'latitude=;patth=/;expires=Sat,1-Jan-2000 00:00:00 GMT;';
	document.cookie = 'longitude=;path=/;expires=Sat,1-Jan-2000 00:00:00 GMT;';
	document.cookie = 'accuracy=;path=/;expires=Sat,1-Jan-2000 00:00:00 GMT;';
    };
    return;
}