// Craig Hananh 60702810 
// craig_hannah@gse.harvard.edu
// 2/12/2012 CSCI-76 HTML5 Staff's Choice, Mobile Local

// Maximum number of location entries to track
var MAX_ENTRIES = 10;
// Number of decimals to display for lat/long
var GEO_DISP_PRECISION = 3;

// Options for getting our geographic location
var GEO_OPTS = {
    enableHighAccuracy : true,
    timeout : 60000,
    maximumAge : 60000
};

var WELCOME_MESSAGE = "Welcome to MobilLocal! <br/>" + 
            "&nbsp;Get the news and weather for here or there!";

// Tracked location entries, persisted from/to from web storage
var myLocations = [];

// Variables used for global message handling
var errorMsgs = "";
var msgs = "";
//*****************************************************************************

/**
 * Initial setup (called on page load)
 * @param None
 * @return Null 
 */
function init() {
    // Ensure that the browser has the necessary functionality
    if(!supports_web_storage()) {
        errorMsgs += "<li>A browser capable of web storage is required</li>";
    }
    if(!supports_geo_location()) {
        errorMsgs += "<li>A browser capable of geo location is required</li>";
    }
    if(errorMsgs !== "") {
        document.getElementById("messages").innerHTML = "<h4>Errors were found</h4>" + "Sadly, the browser you are using does not have the capabilities needed to run this web application." + "Specifically, the errors are:<ul>" + errorMsgs + "</ul>";
        document.getElementById("appdetail").innerHTML = "";
        return;
    }

    // Load data in from web storage
    var myLocationStrings = localStorage.locations;
    if(myLocationStrings !== null) {
        myLocations = JSON.parse(myLocationStrings);
    }

	msg = WELCOME_MESSAGE;
	
    // Display the currently defined locations
    displayLocs();
}

//*****************************************************************************
//* Define the 3 screen interaction entry points

/**
 * Process a location value entered
 * @param None
 * @return False (to prevent form submission) 
 */
function processLoc() {
    if(document.forms.location.cityStateZip.value === "") {
        document.getElementById("messages").innerHTML = "<header>Messages</header><h4>" + "You must provide either a Zip Code or a city and state." + "</h4>";
        return false;
    }
    var locToUse = {};
    locToUse.cityStateZip = document.forms.location.cityStateZip.value;
    resetScreen();
    storeLoc(locToUse);
    expandAndProcessLocation(locToUse);
    return false;
}

/**
 * Handle a request to use our current geographic location
 * @param None
 * @return False (to prevent form submission) 
 */
function getGeo() {
    resetScreen();
    if(navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(geo_handler, geo_error_handler, GEO_OPTS);
    } else {
        errorMsgs="Geolocation not supported by your browser!";
        displayMessages();
    }
    return false;
}

/**
 * Handle a request to reset everything back to the initial state
 * @param None
 * @return False (to prevent form submission) 
 */
function resetHist() {
    resetScreen();
    myLocations = [];
    // Get rid of the locations
    localStorage.removeItem("locations");
    displayLocs();
}

//*****************************************************************************

/**
 * Define the normal geolocation callback handler
 * @param Our position's latitute/longitude
 * @return Null
 */ 
function geo_handler(pos) {
    var locToUse = {};
    locToUse.lat = pos.coords.latitude;
    locToUse.lon = pos.coords.longitude;
    storeLoc(locToUse);
    expandAndProcessLocation(locToUse);
}

/**
 * Define the error geolocation callback handler
 * @param Our position's latitute/longitude
 * @return Null
 */
function geo_error_handler(err) {
    switch(err.code) {
        case err.PERMISSION_DENIED:
            errorMsgs="This page is not allowed to view your position. Message: " + err.message;
            break;
        case err.POSITION_UNAVAILABLE:
            errorMsgs = "Your position is not available. Message: " + err.message;
            break;
        case err.TIMEOUT:
            errorMsgs = "Timeout when determining your location.";
            break;
        default:
            errorMsgs = "Unknown error occurred! Message: " + err.message;
    }
	displayMessages();
}

//*****************************************************************************

/**
 * Get the screen ready to process a new request
 * @param None
 * @return Null
 */
function resetScreen() {
    document.getElementById("news").innerHTML = "";
    document.getElementById("weather").innerHTML = "";
    document.forms.location.cityStateZip.value = "";
}

/**
 * A convenience function to facilitate our history links
 * @param The index into our location array of the entry to process
 * @return Null
 */
function getOldRequest(ind) {
    expandAndProcessLocation(myLocations[ind]);
}

/**
 * Save a location into our global array & persist to web storage
 * @param The location value to save
 * @return the index (relative to 0) of the entry just saved
 */
function storeLoc(loc) {
    // Don't re-add this if it already exists
    for(var i = myLocations.length - 1; i >= 0; i--) {
        if(varEqual(myLocations[i].lat, loc.lat) && varEqual(myLocations[i].lon, loc.lon)) {
            return i;
        }
        if(varEqual(myLocations[i].cityStateZip, loc.cityStateZip) && varEqual(myLocations[i].cityStateZip, loc.cityStateZip)) {
            return i;
        }
    }

    // Add the new entry
    if(myLocations.length >= MAX_ENTRIES) {// Limit # of entries
        myLocations.splice(0, 1);
    }

    var locAddedInd = myLocations.push(loc);
    //Add it
    localStorage.locations = JSON.stringify(myLocations);
    //Resave
    return locAddedInd - 1;
    //Return relative to 0
}

//*****************************************************************************

/**
 * Format all the current locations into a text block & show on screen
 * @param None
 * @return Null
 */
function displayLocs() {

    //Put out any msgs we might have
    displayMessages();
    
    var locStrings = "";
    var locString;
    var header = "<header>Previous locations used:</header> ";
    for( iterLoc = 0; iterLoc < myLocations.length; iterLoc++) {
        locString = "";
        if(myLocations[iterLoc].cityStateZip !== undefined) {
            locString += "Zip/city/state: " + myLocations[iterLoc].cityStateZip;
            if(myLocations[iterLoc].drvd_lat !== undefined) {
                locString += " (Derived latitude: " + roundDecimal(myLocations[iterLoc].drvd_lat, 3) + ", longitude: " + roundDecimal(myLocations[iterLoc].drvd_lon, 3) + ")";
            }
        } else if(myLocations[iterLoc].lat !== undefined && myLocations[iterLoc].lon !== undefined) {
            locString += "Lat: " + myLocations[iterLoc].lat + " Lon: " + myLocations[iterLoc].lon;
            if(myLocations[iterLoc].drvd_csz !== undefined) {
                locString += " (Derived address: " + myLocations[iterLoc].drvd_csz + ")";
            }
        }
        if(locString.length > 0) {
            locStrings += "<li><a onclick='resetScreen(), getOldRequest(" + iterLoc + ");'>" + locString + "</a></li>";
        }
    }

    if(locStrings.length === 0) {
        document.getElementById("usedLocs").innerHTML = header + "<ul><li>None defined</li></ul>";
    } else {
        document.getElementById("usedLocs").innerHTML = header + "<ul>" + locStrings + "</ul>";
    }
}

/**
 * Display any error or information messages we might have to display
 * @param None
 * @return Null
 */
function displayMessages() {
    document.getElementById("messages").innerHTML = "";
    if((errorMsgs !== undefined && errorMsgs.length > 0) || (msgs !== undefined && msgs.length > 0)) {
        dispMsg = "<header>Messages</header>";
        if(errorMsgs !== undefined && errorMsgs.length > 0) {
            dispMsg += "<h4>" + errorMsgs + "</h4>";
            errorMsgs = "";
        }
        if(msgs !== undefined && msgs.length > 0) {
            dispMsg += "<p>" + msgs + "</p>";
            msgs = "";
        }
        document.getElementById("messages").innerHTML = dispMsg;
    }
}

//*****************************************************************************

/**
 * Get the news for the given location
 * @param None
 * @return Null
 */
function processNews(location) {
    var url = "";
    var url1 = "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20rss%20where%20url%3D'http%3A%2F%2Fnews.google.com%2Fnews%3Fgeo%3D"
    var url2 = "%26num%3D10%26output%3Drss%20'&format=json&diagnostics=true"
    if(location != null && location.length > 0) {
        url = url1 + encodeURIComponent(location.replace(/ /g, "+")) + url2;
        console.log(location.replace(/ /g, "+"));
        $.getJSON(url, function(newsResp) {
            var stories = "";
            if(newsResp.query.results == null) {
                stories = "<li>None found</li>"
            } else {
                for(story in newsResp.query.results.item) {
                    stories += "<li><a href=\"" + newsResp.query.results.item[story].link + "\" target=\"_blank\"> " + newsResp.query.results.item[story].title + "</a></li>";
                }
            }
            if(stories.length == 0) {
                document.getElementById("news").innerHTML = "None";
            } else {
                document.getElementById("news").innerHTML = "<header>News for " + location + "</header><ul>" + stories + "</ul>";
            }
        });
    }
}

/**
 * Get the weather for the given location
 * (Uses http://www.worldweatheronline.com/feed-generater.aspx api 8dc5cb0002084635111502)
 * @param A comma separated string of latitude and longitude
 * @param The address to display as a heading for the weather data
 * @return Null
 */
function processWeather(latLongString, addressToDisplay) {
    var url = "";
    var url1 = "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20json%20where%20url%3D'http%3A%2F%2Ffree.worldweatheronline.com%2Ffeed%2Fweather.ashx%3Fq%3D";
    var url2 = "%26format%3Djson%26num_of_days%3D4%26key%3D8dc5cb0002084635111502'&format=json&diagnostics=true";

    if(latLongString != null && latLongString.length > 0) {
        url = url1 + encodeURIComponent(latLongString.replace(/ /g, "+")) + url2;
        $.getJSON(url, function(weatherResp) {
            var currentConditions = "";
            var weatherMessage = "";
            var weatherLocation = "Weather for " + addressToDisplay;
            var weatherForecasts = "";
            if(weatherResp.query.results == null) {
                weatherMessage = "<li>No results found</li>"
            } else if(weatherResp.query.results.data.hasOwnProperty("error")) {
                weatherMessage = "<li>Error - " + weatherResp.query.results.data.error.msg + "</li>";
            } else if(weatherResp.query.results.data.hasOwnProperty("current_condition")) {
                currentConditions = "<li>Current conditions: <ul>" + "<li>Description: " + weatherResp.query.results.data.current_condition.weatherDesc.value + "</li>" + "<li>Temperature: " + weatherResp.query.results.data.current_condition.temp_F + "F, " + weatherResp.query.results.data.current_condition.temp_C + "C</li>" + "<li>Wind speed: " + weatherResp.query.results.data.current_condition.windspeedMiles + " mph, Direction: " + weatherResp.query.results.data.current_condition.winddir16Point + "</li>" + "</ul></li>";
            }
            if(weatherResp.query.results.data.hasOwnProperty("request")) {
                weatherLocation += " (" + weatherResp.query.results.data.request.query + ")";
            }
            if(weatherResp.query.results.data.hasOwnProperty("weather")) {
                var weatherArray = [];
                if(jQuery.isArray(weatherResp.query.results.data.weather)) {
                    weatherArray = weatherResp.query.results.data.weather;
                } else {
                    weatherArray[0] = weatherResp.query.results.data.weather
                }

                for(forecastDay in weatherArray) {
                    weatherForecasts += "<li>Forecast for " + weatherArray[forecastDay].date + "<ul>";
                    weatherForecasts += "<li>Description: " + weatherArray[forecastDay].weatherDesc.value + "</li>";
                    weatherForecasts += "<li>High Temperature: " + weatherArray[forecastDay].tempMaxF + " F, " + weatherArray[forecastDay].tempMaxC + " C </li>";
                    weatherForecasts += "<li>Low Temperature: " + weatherArray[forecastDay].tempMinF + " F, " + weatherArray[forecastDay].tempMinC + " C </li>";
                    weatherForecasts += "<li>Wind speed: " + weatherArray[forecastDay].windspeedMiles + " mph, Direction: " + weatherArray[forecastDay].winddir16Point + "</li>";
                    weatherForecasts += "</ul>";
                }
                weatherForecasts += "</ul>";
            }
            var weatherReport = "<header>" + weatherLocation + "</header><ul>" + weatherMessage + currentConditions + weatherForecasts + "</ul>";
            document.getElementById("weather").innerHTML = weatherReport;
        });
    }
}

//*****************************************************************************

/**
 * Forward or reverse geocode the given location
 * @param location object that contains latitude and longitude, or a city and state or a zip
 * @param The address to display as a heading for the weather data
 * @return Null
 */

function expandAndProcessLocation(requestedLoc) {

    var geocoder = new google.maps.Geocoder();
    var geoParm = [];
    if(requestedLoc.lat !== undefined && requestedLoc.lon !== undefined) {
        geoParm.latLng = new google.maps.LatLng(requestedLoc.lat, requestedLoc.lon);
        geocoder.geocode(geoParm, callBackLL);
    } else if(requestedLoc.cityStateZip !== undefined) {
        geoParm.address = requestedLoc.cityStateZip;
        geocoder.geocode(geoParm, callBackCSZ);
    }

/**
 * The callback function for the reverse geocode request
 * @param The geocode response object
 * @param the geocode request result status
 * @return Null
 */
    function callBackLL(response, status) {
        console.log(response);
        if(status == google.maps.GeocoderStatus.OK) {
            if(response[1]) {
                loc = -1//augmentMyLocLL(requestedLoc.lat, requestedLoc.lon, response[1].formatted_address);
                for(var i = myLocations.length - 1; i >= 0; i--) {
                    if(myLocations[i].lat !== undefined && myLocations[i].lat == requestedLoc.lat && myLocations[i].lon !== undefined && myLocations[i].lon == requestedLoc.lon) {
                        myLocations[i].drvd_csz = response[1].formatted_address;
                        loc = i;
                        break;
                    }
                }
                if(loc < 0) {
                    console.log("callBackCSZ error, unmatched CSZ: " + requestedLoc.cityStateZip);
                } else {
                    displayLocs();
                    processNews(myLocations[loc].drvd_csz);
                    processWeather(requestedLoc.lat + "," + requestedLoc.lon, myLocations[loc].drvd_csz);
                }
            } else {           
				errorMsgs += "Callback for lat/long returned no results<br/>";
				displayMessages();
				}
				} else {
					errorMsgs = "Geocoder failed due to: " + status;
					displayMessages();
				}
    }

/**
 * The callback function for the geocode request
 * @param The geocode response object
 * @param the geocode request result status
 * @return Null
 */
    function callBackCSZ(response, status) {
        console.log(response);
        if(status == google.maps.GeocoderStatus.OK) {
            if(response[0]) {
                loc = -1;
                for(var i = myLocations.length - 1; i >= 0; i--) {
                    if(myLocations[i].cityStateZip !== undefined && myLocations[i].cityStateZip == requestedLoc.cityStateZip) {
                        myLocations[i].drvd_lat = response[0].geometry.location.lat();
                        myLocations[i].drvd_lon = response[0].geometry.location.lng();
                        myLocations[i].drvd_csv = response[0].formatted_address;
                        loc = i;
                        break;
                    }
                }
                if(loc < 0) {
                    console.log("callBackCSZ error, unmatched CSZ: " + requestedLoc.cityStateZip);
                } else {
                    displayLocs();
                    processNews(requestedLoc.cityStateZip);
                    processWeather(myLocations[loc].drvd_lat + "," + myLocations[loc].drvd_lat, myLocations[loc].drvd_csv);
                }
            } else {
                errorMsgs += "Callback for city/state/zip returned no results<br/>";
                displayMessages();
            }
        } else {
            errorMsgs = "Geocoder failed due to: " + status;
            displayMessages();
        }
    }

}

//*****************************************************************************

/**
 * Utility function to check if web storage is supported
 * @param None
 * @return A boolean indicating if web storage is supported
 */
function supports_web_storage() {
    try {
        return 'localStorage' in window && window.localStorage !== null;
    } catch (e) {
        return false;
    }
}

/**
 * Utility function to check if geo location is supported
 * @param None
 * @return A boolean indicating if geo location is supported
 */
function supports_geo_location() {
    return !!navigator.geolocation;
}

/**
 * Utility function to round to a given number of digits
 * @param The number to round
 * @param The number of decimals the result should have
 * @return The rounded number
 */
function roundDecimal(number, digits) {
    adjuster = Math.pow(10, digits);
    return Math.round(number * adjuster) / adjuster;
}

/**
 * Utility function to compare 2 variables
 * (Attempting to make this case indifferent (using toUpperCase) 
 * caused some very flakey results )
 * @param The number to round
 * @param The number of decimals the result should have
 * @return False if they're unequal or either are undefined, otherwise true
 */
function varEqual(var1, var2) {

    if(var1 == undefined || var2 == undefined) {
        return false;
    }
    return (var1 == var2);
}
//*****************************************************************************