(function() {
    'use strict';

// *****************************************
// reusable heat-map chart
// *****************************************

    d3.eesur.heatmap = function module() {

        // input vars for getter setters
        var startYear = 2013,
            endYear = 2016,
            colourRangeStart = '#fae9e9',
            colourRangeEnd = '#d62728',
            width = 950,
            height = 475;

        var dispatch = d3.dispatch('_hover');

        function exports(_selection) {
            _selection.each(function(nestedData) {

                var colour = d3.scale.linear()
                    .range([colourRangeStart, colourRangeEnd]);

                var margin = {top: 20, right: 30, bottom: 20, left: 20};
                // update width and height to use margins for axis
                width = width - margin.left - margin.right;
                height = height - margin.top - margin.bottom;

                var years = d3.range(startYear, endYear).reverse(),
                    sizeByYear = height/years.length+1,
                    sizeByDay = d3.min([sizeByYear/8,width/54]),
                    day = function(d) { return (d.getDay() + 6) % 7; },
                    week = d3.time.format('%W'),
                    date = d3.time.format('%b %d');
                    
                var svg = d3.select(this)
                    .append('svg')
                        .attr({
                           class: 'chart',
                           width: width + margin.left + margin.right,
                           height: height + margin.top + margin.bottom
                        })
                    .append('g')
                        .attr('transform', 'translate(' + margin.left + ',' + margin.top + ')');

                var year = svg.selectAll('.year')
                    .data(years)
                    .enter().append('g')
                        .attr('class', 'year')
                        .attr('transform', function(d,i) { return 'translate(30,' + i * sizeByYear + ')'; });

                year.append('text')
                    .attr({
                        class: 'year-title',
                        transform: 'translate(-38,' + sizeByDay * 3.5 + ')rotate(-90)',
                        'text-anchor': 'middle',
                        'font-weight': 'bold'
                    })
                    .text(function(d) { return d; });

                var rect = year.selectAll('.day')
                    .data(function (d) { 
                      return (d === moment().year()) ? d3.time.days(new Date(d, 0, 1), new Date(d , moment().month(), moment().date())) : d3.time.days(new Date(d, 0, 1), new Date(d + 1, 0, 1)); 
                    })
                    .enter().append('rect')
                        .attr({
                            class: 'day',
                            width: sizeByDay,
                            height: sizeByDay,
                            x: function(d) { return week(d) * sizeByDay; },
                            y: function(d) { return day(d) * sizeByDay; }
                        });

                year.selectAll('.month')
                    .data(function (d) { 
                        return d3.time.months(new Date(d, 0, 1), new Date(d + 1, 0, 1)); 
                    })
                    .enter().append('path')
                        .attr({
                            class: 'month',
                            d: monthPath
                        });

                // day and week titles
                var chartTitles = (function() {

                    var weekDays = ['Mon','Tue','Wed','Thu','Fri','Sat','Sun'],
                        month = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'];

                    var titlesDays = svg.selectAll('.year')
                        .selectAll('.titles-day')
                        .data(weekDays)
                        .enter().append('g')
                        .attr('class', 'titles-day')
                        .attr('transform', function (d, i) {
                            return 'translate(-5,' + sizeByDay*(i+1) + ')';
                        });
                    
                    titlesDays.append('text')
                        .attr('class', function (d,i) { return weekDays[i]; })
                        .style('text-anchor', 'end')
                        .attr('dy', '-.25em')
                        .text(function (d, i) { return weekDays[i]; }); 

                    var titlesMonth = svg.selectAll('.year')
                        .selectAll('.titles-month')
                            .data(month)
                        .enter().append('g')
                            .attr('class', 'titles-month')
                            .attr('transform', function (d, i) { 
                                return 'translate(' + (((i+1) * (width/12) )-30) + ',-5)'; 
                            });

                    titlesMonth.append('text')
                        .attr('class', function (d,i) { return month[i]; })
                        .style('text-anchor', 'end')
                        .text(function (d,i) { return month[i]; });

                })();

                function monthPath(t0) {
                    var t1 = new Date(t0.getFullYear(), 
                        t0.getMonth() + 1, 0),
                        d0 = +day(t0), w0 = +week(t0),
                        d1 = +day(t1), w1 = +week(t1);

                    return 'M' + (w0 + 1) * sizeByDay + ',' + d0 * sizeByDay + 'H' + w0 * sizeByDay + 'V' + 7 * sizeByDay + 'H' + w1 * sizeByDay + 'V' + (d1 + 1) * sizeByDay + 'H' + (w1 + 1) * sizeByDay + 'V' + 0 + 'H' + (w0 + 1) * sizeByDay + 'Z';
                }

                // apply the heatmap colours
                colour.domain(d3.extent(d3.values(nestedData)));

                rect.filter(function (d) { 
                        return d in nestedData; 
                    })
                    .style('fill', function (d) { 
                        return colour(nestedData[d]); 
                    })
                    .on('mouseover', dispatch._hover);
            });
        }
        
        // overrides getter/setters
        exports.startYear = function(value) {
            if (!arguments.length) return startYear;
            startYear = value;
            return this;
        };
        exports.endYear = function(value) {
            if (!arguments.length) return endYear;
            endYear = value;
            return this;
        };
        exports.colourRangeStart = function(value) {
            if (!arguments.length) return colourRangeStart;
            colourRangeStart = value;
            return this;
        };
        exports.colourRangeEnd = function(value) {
            if (!arguments.length) return colourRangeEnd;
            colourRangeEnd = value;
            return this;
        };
        exports.width = function(value) {
            if (!arguments.length) return width;
            width = value;
            return this;
        };
        exports.height = function(value) {
            if (!arguments.length) return height;
            height = value;
            return this;
        };

        d3.rebind(exports, dispatch, 'on');
        return exports;

    };


}());