~pkunal-parmar/ubuntu-calendar-app/ICalImport

/*

 * Copyright (C) 2013-2014 Canonical Ltd

 *

 * This file is part of Ubuntu Calendar App

 *

 * Ubuntu Calendar App is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 3 as

 * published by the Free Software Foundation.

 *

 * Ubuntu Calendar App 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, see <http://www.gnu.org/licenses/>.

 */

WorkerScript.onMessage = function(events) {

    //returns sorted array of schedules

    //schedule is start time and duration

    var allSchs = processEvents(events);

    while( allSchs.length > 0) {

        var sch = allSchs.shift();

        //finds all schedules overlapping with current schedule and remove from original array

        var schs = findOverlappingSchedules(sch, allSchs);

        //insert original schedule first, so array remain sorted

        schs.unshift(sch);

        //assign position to schedules with respest to their duration and  start time

        var array = [];

        var maxDepth = assignDepth(schs, array);

        WorkerScript.sendMessage({ 'schedules': array,"maxDepth":maxDepth});

    }

}

function getMinutes(time) {

    return time.getHours() * 60 + time.getMinutes();

}

function getDuration(event) {

    var start = getMinutes(event.startDateTime);

    var end = getMinutes(event.endDateTime);

    return end - start;

}

function processEvents(events) {

    var array = [];

    for( var i = 0; i < events.length ; ++i) {

        var event = events[i]

        var sch = {};

        sch["start"] = getMinutes(event.startDateTime);

        sch["duration"] = getDuration(event);

        sch["id"] = event.id;

        sch["depth"] = 0;

        sortedInsert(array,sch);

    }

    return array;

}

//insert in to array using insertion sort

function sortedInsert(array, sch) {

    for(var i = array.length-1; i >=0 ; --i) {

        var temp = array[i];

        if( sch.duration < array[i].duration) {

            array.splice(i+1,0,sch);

            return;

        }

    }

    array.push(sch);

}

//find all overlapping schedules respect to provided schedule

function findOverlappingSchedules( sch, schs) {

    var array = [];

    var i = 0;

    while( i < schs.length && schs.length > 0) {

        var otherSch = schs[i];

        if( doesOverlap(sch, otherSch) ) {

            schs.splice(i,1);

            array.push(otherSch);

            sch = mergeSchedules(sch,otherSch);

        } else {

            i++;

        }

    }

    return array;

}

//merges tow schedules and creates a schedule which is long engouth to contain both the of them

function mergeSchedules(sch1,sch2) {

    var sch = {};

    sch["start"] = Math.min(sch1.start,sch2.start);

    sch["duration"] = Math.max(sch1.duration,sch2.duration);

    sch["depth"] = 1;

    sch["id"] = "DUMMY";

    return sch;

}

//check if two schedules overlap each other

//is start time of one schedule is between

//start and end time of other schedule then it's considered as overlap

function doesOverlap( sch1, sch2) {

    if( sch1.start >= sch2.start && sch1.start < sch2.start + sch2.duration ) {

        return true;

    }

    if( sch2.start >= sch1.start && sch2.start < sch1.start + sch1.duration ) {

        return true;

    }

    return false;

}

//assign depth(position) of schedule with respect to other

function assignDepth(schs, array) {

    var maxDepth = 0;

    while( schs.length > 0 ) {

        var sch = schs.shift()

        array.push(sch);

        var depth = findDepth(sch, schs);

        maxDepth = Math.max(maxDepth,depth);

    }

    return maxDepth;

}

function findDepth( sch, schs) {

    var maxDepth = 0;

    for( var i = 0; i < schs.length ; ++i) {

        var otherSch = schs[i];

        if( doesOverlap(sch, otherSch) ) {

            otherSch.depth ++;

            maxDepth = Math.max(maxDepth,otherSch.depth);

            sch = mergeSchedules(sch,otherSch);

        }

    }

    return maxDepth;

}