/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for 
 * full list of contributors). Published under the Clear BSD license.  
 * See http://svn.openlayers.org/trunk/openlayers/license.txt for the
 * full text of the license. */
 
/** 
 * @requires OpenLayers/Control.js
 */
 
/**
 * Class: OpenLayers.Control.LayerSwitcher
 * The LayerSwitcher control displays a table of contents for the map. This 
 * allows the user interface to switch between BaseLasyers and to show or hide
 * Overlays. By default the switcher is shown minimized on the right edge of 
 * the map, the user may expand it by clicking on the handle.
 *
 * To create the LayerSwitcher outside of the map, pass the Id of a html div 
 * as the first argument to the constructor.
 * 
 * Inherits from:
 *  - <OpenLayers.Control>
 */
OpenLayers.Control.LayerSwitcher = 
  OpenLayers.Class(OpenLayers.Control, {
 
    /**
     * APIProperty: roundedCorner
     * {Boolean} If true the Rico library is used for rounding the corners
     *     of the layer switcher div, defaults to true.
     */
    roundedCorner: true,
 
    /**  
     * APIProperty: roundedCornerColor
     * {String} The color of the rounded corners, only applies if roundedCorner
     *     is true, defaults to "darkblue".
     */
    roundedCornerColor: "darkblue",
    
    /**  
     * Property: layerStates 
     * {Array(Object)} Basically a copy of the "state" of the map's layers 
     *     the last time the control was drawn. We have this in order to avoid
     *     unnecessarily redrawing the control.
     */
    layerStates: null,
    
 
  // DOM Elements
  
    /**
     * Property: layersDiv
     * {DOMElement} 
     */
    layersDiv: null,
    
    /** 
     * Property: baseLayersDiv
     * {DOMElement}
     */
    baseLayersDiv: null,
 
    /** 
     * Property: baseLayers
     * {Array(<OpenLayers.Layer>)}
     */
    baseLayers: null,
    
    
    /** 
     * Property: dataLbl
     * {DOMElement} 
     */
    dataLbl: null,
    
    /** 
     * Property: dataLayersDiv
     * {DOMElement} 
     */
    dataLayersDiv: null,
 
    /** 
     * Property: dataLayers
     * {Array(<OpenLayers.Layer>)} 
     */
    dataLayers: null,
 
 
    /** 
     * Property: minimizeDiv
     * {DOMElement} 
     */
    minimizeDiv: null,
 
    /** 
     * Property: maximizeDiv
     * {DOMElement} 
     */
    maximizeDiv: null,
    
    /**
     * APIProperty: ascending
     * {Boolean} 
     */
    ascending: true,
 
    /**
     * Constructor: OpenLayers.Control.LayerSwitcher
     * 
     * Parameters:
     * options - {Object}
     */
    initialize: function(options) {
        OpenLayers.Control.prototype.initialize.apply(this, arguments);
        this.layerStates = [];
    },
 
    /**
     * APIMethod: destroy 
     */    
    destroy: function() {
        
        OpenLayers.Event.stopObservingElement(this.div);
 
        OpenLayers.Event.stopObservingElement(this.minimizeDiv);
        OpenLayers.Event.stopObservingElement(this.maximizeDiv);
 
        //clear out layers info and unregister their events 
        this.clearLayersArray("base");
        this.clearLayersArray("data");
        
        this.map.events.un({
            "addlayer": this.redraw,
            "changelayer": this.redraw,
            "removelayer": this.redraw,
            "changebaselayer": this.redraw,
            scope: this
        });
        
        OpenLayers.Control.prototype.destroy.apply(this, arguments);
    },
 
    /** 
     * Method: setMap
     *
     * Properties:
     * map - {<OpenLayers.Map>} 
     */
    setMap: function(map) {
        OpenLayers.Control.prototype.setMap.apply(this, arguments);
 
        this.map.events.on({
            "addlayer": this.redraw,
            "changelayer": this.redraw,
            "removelayer": this.redraw,
            "changebaselayer": this.redraw,
            scope: this
        });
    },
 
    /**
     * Method: draw
     *
     * Returns:
     * {DOMElement} A reference to the DIV DOMElement containing the 
     *     switcher tabs.
     */  
    draw: function() {
        OpenLayers.Control.prototype.draw.apply(this);
 
        // create layout divs
        this.loadContents();
 
        // set mode to minimize
        if(!this.outsideViewport) {
            this.minimizeControl();
        }
 
        // populate div with current info
        this.redraw();    
 
        return this.div;
    },
 
    /** 
     * Method: clearLayersArray
     * User specifies either "base" or "data". we then clear all the
     *     corresponding listeners, the div, and reinitialize a new array.
     * 
     * Parameters:
     * layersType - {String}  
     */
    clearLayersArray: function(layersType) {
        var layers = this[layersType + "Layers"];
        if (layers) {
            for(var i=0, len=layers.length; i<len ; i++) {
                var layer = layers[i];
                OpenLayers.Event.stopObservingElement(layer.inputElem);
                OpenLayers.Event.stopObservingElement(layer.labelSpan);
            }
        }
        this[layersType + "LayersDiv"].innerHTML = "";
        this[layersType + "Layers"] = [];
    },
 
 
    /**
     * Method: checkRedraw
     * Checks if the layer state has changed since the last redraw() call.
     * 
     * Returns:
     * {Boolean} The layer state changed since the last redraw() call. 
     */
    checkRedraw: function() {
        var redraw = false;
        if ( !this.layerStates.length ||
             (this.map.layers.length != this.layerStates.length) ) {
            redraw = true;
        } else {
            for (var i=0, len=this.layerStates.length; i<len; i++) {
                var layerState = this.layerStates[i];
                var layer = this.map.layers[i];
                if ( (layerState.name != layer.name) || 
                     (layerState.inRange != layer.inRange) || 
                     (layerState.id != layer.id) || 
                     (layerState.visibility != layer.visibility) ) {
                    redraw = true;
                    break;
                }    
            }
        }    
        return redraw;
    },
    
    /** 
     * Method: redraw
     * Goes through and takes the current state of the Map and rebuilds the
     *     control to display that state. Groups base layers into a 
     *     radio-button group and lists each data layer with a checkbox.
     *
     * Returns: 
     * {DOMElement} A reference to the DIV DOMElement containing the control
     */  
    redraw: function() {
        //if the state hasn't changed since last redraw, no need 
        // to do anything. Just return the existing div.
        if (!this.checkRedraw()) { 
            return this.div; 
        } 
 
        //clear out previous layers 
        this.clearLayersArray("base");
        this.clearLayersArray("data");
        
        var containsOverlays = false;
        var containsBaseLayers = false;
        
        // Save state -- for checking layer if the map state changed.
        // We save this before redrawing, because in the process of redrawing
        // we will trigger more visibility changes, and we want to not redraw
        // and enter an infinite loop.
        var len = this.map.layers.length;
        this.layerStates = new Array(len);
        for (var i=0; i <len; i++) {
            var layer = this.map.layers[i];
            this.layerStates[i] = {
                'name': layer.name, 
                'visibility': layer.visibility,
                'inRange': layer.inRange,
                'id': layer.id
            };
        }    
 
        var layers = this.map.layers.slice();
        if (!this.ascending) { layers.reverse(); }
        for(var i=0, len=layers.length; i<len; i++) {
            var layer = layers[i];
            var baseLayer = layer.isBaseLayer;
 
            if (layer.displayInLayerSwitcher) {
 
                if (baseLayer) {
                    containsBaseLayers = true;
                } else {
                    containsOverlays = true;
                }    
 
                // only check a baselayer if it is *the* baselayer, check data
                //  layers if they are visible
                var checked = (baseLayer) ? (layer == this.map.baseLayer)
                                          : layer.getVisibility();
    
                // create input element
                var inputElem = document.createElement("input");
                inputElem.id = this.id + "_input_" + layer.name;
                inputElem.name = (baseLayer) ? this.id + "_baseLayers" : layer.name;
                inputElem.type = (baseLayer) ? "radio" : "checkbox";
                inputElem.value = layer.name;
                inputElem.checked = checked;
                inputElem.defaultChecked = checked;
 
                if (!baseLayer && !layer.inRange) {
                    inputElem.disabled = true;
                }
                var context = {
                    'inputElem': inputElem,
                    'layer': layer,
                    'layerSwitcher': this
                };
                OpenLayers.Event.observe(inputElem, "mouseup", 
                    OpenLayers.Function.bindAsEventListener(this.onInputClick,
                                                            context)
                );
                
                // create span
                var labelSpan = document.createElement("span");
                OpenLayers.Element.addClass(labelSpan, "labelSpan")
                if (!baseLayer && !layer.inRange) {
                    labelSpan.style.color = "gray";
                }
                labelSpan.innerHTML = layer.name;
                labelSpan.style.verticalAlign = (baseLayer) ? "bottom" 
                                                            : "baseline";
                OpenLayers.Event.observe(labelSpan, "click", 
                    OpenLayers.Function.bindAsEventListener(this.onInputClick,
                                                            context)
                );
                // create line break
                var br = document.createElement("br");
    
                
                var groupArray = (baseLayer) ? this.baseLayers
                                             : this.dataLayers;
                groupArray.push({
                    'layer': layer,
                    'inputElem': inputElem,
                    'labelSpan': labelSpan
                });
                                                     
    
                var groupDiv = (baseLayer) ? this.baseLayersDiv
                                           : this.dataLayersDiv;
                groupDiv.appendChild(inputElem);
                groupDiv.appendChild(labelSpan);
                groupDiv.appendChild(br);
            }
        }
 
        // if no overlays, dont display the overlay label
        this.dataLbl.style.display = (containsOverlays) ? "" : "none";        
        
        // if no baselayers, dont display the baselayer label
        this.baseLbl.style.display = (containsBaseLayers) ? "" : "none";        
 
        return this.div;
    },
 
    /** 
     * Method:
     * A label has been clicked, check or uncheck its corresponding input
     * 
     * Parameters:
     * e - {Event} 
     *
     * Context:  
     *  - {DOMElement} inputElem
     *  - {<OpenLayers.Control.LayerSwitcher>} layerSwitcher
     *  - {<OpenLayers.Layer>} layer
     */
 
    onInputClick: function(e) {
 
        if (!this.inputElem.disabled) {
            if (this.inputElem.type == "radio") {
                this.inputElem.checked = true;
                this.layer.map.setBaseLayer(this.layer);
            } else {
                this.inputElem.checked = !this.inputElem.checked;
                this.layerSwitcher.updateMap();
            }
        }
        OpenLayers.Event.stop(e);
    },
    
    /**
     * Method: onLayerClick
     * Need to update the map accordingly whenever user clicks in either of
     *     the layers.
     * 
     * Parameters: 
     * e - {Event} 
     */
    onLayerClick: function(e) {
        this.updateMap();
    },
 
 
    /** 
     * Method: updateMap
     * Cycles through the loaded data and base layer input arrays and makes
     *     the necessary calls to the Map object such that that the map's 
     *     visual state corresponds to what the user has selected in 
     *     the control.
     */
    updateMap: function() {
 
        // set the newly selected base layer        
        for(var i=0, len=this.baseLayers.length; i<len; i++) {
            var layerEntry = this.baseLayers[i];
            if (layerEntry.inputElem.checked) {
                this.map.setBaseLayer(layerEntry.layer, false);
            }
        }
 
        // set the correct visibilities for the overlays
        for(var i=0, len=this.dataLayers.length; i<len; i++) {
            var layerEntry = this.dataLayers[i];   
            layerEntry.layer.setVisibility(layerEntry.inputElem.checked);
        }
 
    },
 
    /** 
     * Method: maximizeControl
     * Set up the labels and divs for the control
     * 
     * Parameters:
     * e - {Event} 
     */
    maximizeControl: function(e) {
 
        // set the div's width and height to empty values, so
        // the div dimensions can be controlled by CSS
        this.div.style.width = "";
        this.div.style.height = "";
 
        this.showControls(false);
 
        if (e != null) {
            OpenLayers.Event.