var postmileList = [];  // the list of postmiles saved from the json file.
var chosenColor = "yellow"; // stores color that user picks, initial default yellow

// function to find differences between two arrays
Array.prototype.diff = function(a) {
    return this.filter(function(i) {return a.indexOf(i) < 0;});
};

    // Build a solid colored icon to use instead of the classic pin
    function dotSymbol(color) 
    {
        var iconPath = iconVDSwhite;
        if (color == 'red')
        {
           iconPath = iconVDSred;
        }
        else if (color == 'yellow')
        {
            iconPath = iconVDSyellow;
        }
        else if (color == 'lime')
        {
            iconPath = iconVDSgreen;
        }
        return {
            url: iconPath, 
            anchor: new google.maps.Point(6, 6)
        };
    }

    // Load the map data from a json file and style all the points
    function loadVDSlayer()
    {
        // Load the static map data and call saveCoords when done
        map.data.loadGeoJson(kMapStartupFile, null, saveCoords)
        // Style the map data by applying the desired properties to each feature (marker)
        // The function will be called every time a feature's properties are updated.
        map.data.setStyle(function(feature)
        {
            // Get the postmile id 
            var name = feature.getId();
            // Get the desired color value
            var ptColor = feature.getProperty("color");
            var street = feature.getProperty("street");
            // Build the marker
            var iconSymbol = dotSymbol(ptColor);
            // return the StyleOptions
            return {
                icon: iconSymbol,
                title: name + " @" + street, // set rollover text
                // set zIndex for slowed traffic to a higher value so they overlap
                zIndex: colorZvalues[ptColor]
            };
        });
        var clicked = false; 
        var first = []; // stores first dot
        var asc = false; //ascending
        //var color_arr = []; 
        var white_arr = []; //stores all white dots
        // Initialize the current time to zero
        var currentTime = new Date(0);
        currentTime.setHours(0);
        currentTime.setMinutes(0);
        currentTime.setSeconds(0);

        map.data.addListener('click', function(event) 
        {
            var event_arr = event.feature.getId().split(/[ ,]+/);
            // if user has already made the first click and the second click is 
            // on the same highway and same direction
            if (clicked && event_arr[0] === first[0] && event_arr[1] === first[1])
            {
                // compute range between the two clicked dots
                var range = Math.abs(parseFloat(event_arr[2]) - parseFloat(first[2]));
                var clicked_dots = [];
                // checks highway direction to determine if postmiles are ascending or descending 
                if (parseFloat(event_arr[2]) < parseFloat(first[2]))
                {
                    asc = false;
                }
                else 
                {
                    asc = true;
                }
                // searches map for all dots between the two clicked dots and adds it to list "clicked_dots"
                map.data.forEach(function (marker) 
                {
                    var marker_arr = marker.getId().split(/[ ,]+/);
                    // if the dot in the map matches the highway and direction of the clicked dot
                    if (marker_arr[0] === event_arr[0] && marker_arr[1] === event_arr[1])
                    {
                        // compute distance based on direction of highway
                        if (asc)
                        {
                            var dist = parseFloat(marker_arr[2]) - parseFloat(first[2]);
                        }
                        else 
                        {
                            var dist = parseFloat(parseFloat(first[2]) - (marker_arr[2]));
                        }
                        // if dist within range of the two clicked dots, add to list "clicked_dots"
                        if (dist <= range && dist >= 0)
                        {
                            clicked_dots.push(marker);
                        }
                    }
                });
                //color_arr.push(clicked_dots);
                //console.log(clicked_dots);
                //console.log(range);
                // extracts ids for all the white dots
                var white_arr_ids = white_arr.map(function (marker) {
                    return marker.id;
                });
                // extracts ids for all the clicked dots
                var clicked_dots_ids = clicked_dots.map(function (marker) {
                    return marker.getId();
                });
                // computes difference between the white dots and clicked dots to find the unused dots
                var unused_ids = white_arr_ids.diff(clicked_dots_ids);
                //console.log("Unused: ",unused_ids, "White: ",white_arr_ids);
                // change the dot color of all the unused white dots back to their previous color
                unused_ids.forEach(function (id){
                    var marker = white_arr.filter(function (dot) {
                        return dot.id === id;
                    })[0];
                    var feature = map.data.getFeatureById(marker.id);  
                    feature.setProperty("color", marker.color);
                });
                white_arr = [];
                // change the color of all the dots between the two clicked dots to the user picked color
                if (chosenColor)
                {
                    clicked_dots.forEach(function (dot) {
                        dot.setProperty("color", chosenColor);
                    });
                }
                // Increment the time by one-half minute (30 seconds)
                var millisecs = currentTime.getTime();
                millisecs += 30000;  
                currentTime = new Date(millisecs);

                // Create a printable string for the time (HH:MM:SS)
                var printableTime = currentTime.toLocaleTimeString('it-IT');

                // Assemble the line to be written to the events file
                var lineOut = "101   " + printableTime + "\t" + first[0] + "\t" + 
                first[1] + "\t" + first[2] + "\t" + range.toFixed(3) + "\t" 
                + getColorAbbr(chosenColor);
                console.log(lineOut);

                // Using Ajax POST to send the data 
                var xhr = new XMLHttpRequest();
                xhr.open("POST", "../../cgi-bin/saveTrafficEvent.py", true);
                xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
                // send the collected data 
                xhr.send("msg="+lineOut + "\n")
            }
            // if user has not yet clicked on a dot
            else if (!clicked)
            {
                first = event_arr;

                // turns relevant dots white
                selectedID = event.feature.getId();  // get the id of the clicked dot
                curr = postmileList.indexOf(selectedID); // find the id in the postmile list
                var firstBlank = postmileList[curr].indexOf(" ", 0);  // find direction substring
                var secondBlank = firstBlank+2;  
                var direction = postmileList[curr].charAt(firstBlank+1); // extract direction
                target = event.feature.getId().substring(0,secondBlank); // extract target string
                //console.log("making white dots from " + selectedID + " in direction "+direction)
                // Decide whether to increment or decrement based on direction of hwy;
                //  N and E increment,  S and W decrement 
                if (direction == 'N' || direction == 'E')
                {
                    // Process all dots with same hwy and direction
                    while  (postmileList[curr].startsWith(target) && curr < postmileList.length)
                    {
                        // turn the dot white
                        currFeat = map.data.getFeatureById(postmileList[curr]);
                        white_arr.push({id : currFeat.getId(), color : currFeat.getProperty("color")});         
                        currFeat.setProperty("color", "white");  
                        curr++;
                
                    } 
                }
                else
                {
                    // Process all dots with same hwy and direction
                    while  (postmileList[curr].startsWith(target) && curr > 0)
                    {
                        currFeat = map.data.getFeatureById(postmileList[curr]);
                        white_arr.push({id : currFeat.getId(), color : currFeat.getProperty("color")});
                        // turn the dot white
                        currFeat.setProperty("color", "white");  
                        curr--;
                    }                 
                }
            }
            // if the user's second click is made on a dot not on the first dot's highway
            else 
            {
                console.log('wrong choice');
                clicked = !clicked;
            }
            clicked = !clicked;
        });
    }
    // callback when load GeoJson completes
    // save each feature's Point as the original coordinates for later reference
    function saveCoords(features)
    {
        // Iterate over all the features in the map
        features.forEach(function(feature)
        {
            var pt = feature.getGeometry().get();
            vds_coords[feature.getId()] = pt; // save the Point in a dictionary
            postmileList.push(feature.getId()); // save the postmile in a list
        });
        // update the dot colors from the dynamic json data 
        updateVDSlayer();
        // go adjust the marker coordinates so dots don't overlap
        adjustCoords(calcDistanceFactor());
    } 

    // magic formula controls distance between dots proportionate to zoom factor
    function calcDistanceFactor()
    {
        // 15 is maximum zoom, the point at which no adjustment is needed
        return (.0005 * (15 - map.getZoom()));
    }

    // Adjust the coordinates of dots so they appear side-by-side
    // The perpendicular vector for each dot has been provided,
    // so we just need to multiply by a scaling factor (adjAmount) 
    // @param adjAmount amount by which to adjust coordinate 
    function adjustCoords(adjAmount)
    {
        // Adjust the NB points a slight amount
        map.data.forEach(function(feature)
        {
            // get the name of the current feature
            var name = feature.getId();
            // lookup the original coordinates for this feature
            var coords = vds_coords[name];

            //retrieve the perpendicular vector (precomputed)
            var perpx = feature.getProperty("perpx")
            var perpy = feature.getProperty("perpy")
                // Make adjustment and save it
            var myLat = coords.lat() + perpy * adjAmount
            var myLong = coords.lng() + perpx * adjAmount
            feature.setGeometry(
            {
                lat: myLat,
                lng: myLong
            });
        });
    }

    // update the color (as needed) for a given marker
    function updateMarker(marker)
    {
        target = marker.id;
        newColor = marker.properties.color;
        // see if new color is different than current color
        currentFeature = map.data.getFeatureById(target);
        if (currentFeature) {
            currentColor = currentFeature.getProperty("color");
            // if a new color is desired then assign it to the feature's color property
            if (currentColor != newColor)
            {
                currentFeature.setProperty("color", newColor);
                // set zIndex for slowed traffic to a higher value so they overlap
                currentFeature.setProperty("zIndex", colorZvalues[newColor]);
            }
        }
    }

    // Load the highways dynamic json file and update the map
    function updateVDSlayer()
    {
        eventIndex = -1;
        var parsed_JSON;
        loadJSON(kVDSstatusFile, function(response)
        {
            // Parse JSON string into object
            parsed_JSON = JSON.parse(response);
            // Process each new marker - lookup in current map
            parsed_JSON.features.forEach(updateMarker);
        });
    }

    function getColorName(str){
        if (str === "R\r" || str === "R")
            return "red";
        else if (str === "Y\r" || str === "Y")
            return "yellow";
        else if (str === "G\r" || str === "G")
            return "lime";
    }

    // gets the starting letter of a given color
    function getColorAbbr(str){
        if (str === "red")
            return "R";
        else if (str === "yellow")
            return "Y";
        else if (str === "lime")
            return "G";
    }

function initColorButtons()
{
    // add the respective color buttons onto the map
    var redColor = document.getElementById('redButton');
    var greenColor = document.getElementById('greenButton');
    var yellowColor = document.getElementById('yellowButton');
    map.controls[google.maps.ControlPosition.BOTTOM_CENTER].push(redColor);
    map.controls[google.maps.ControlPosition.BOTTOM_CENTER].push(greenColor);
    map.controls[google.maps.ControlPosition.BOTTOM_CENTER].push(yellowColor);
    // store the user picked color in "chosenColor"
    
    redColor.addEventListener('click', function() {
        chosenColor = "red";
        redColor.style.background = "red";
        greenColor.style.background = "gray";
        yellowColor.style.background = "gray";
        
    });
    greenColor.addEventListener('click', function() {
        chosenColor = "lime";
        greenColor.style.background = "green";
        redColor.style.background = "gray";
        yellowColor.style.background = "gray";        
    });
    yellowColor.addEventListener('click', function(){
        chosenColor = "yellow";
        yellowColor.style.background = "yellow";
        redColor.style.background = "gray";
        greenColor.style.background = "gray";     
    });
        // set default button on
    yellowColor.style.background = "yellow";    
}