var pca_result = [];
var colours = [];
var annotations = [];
var colour_column = 2;
var data_start = 5;

function compute_pca(data, data_start) {
    // actual data used for PCA computation
    var numerical_data = filter_numerical_values(data, data_start, data[0].length);

    var vectors = PCA.getEigenVectors(numerical_data);
    var adData = PCA.computeAdjustedData(numerical_data,vectors[0],vectors[1],vectors[2])
    return PCA.transpose(adData.adjustedData)
}

function get_colours(colour_column, data) {
    return unpack(data, colour_column).slice(1, data.length)
}

function filter_numerical_values(data, data_start, data_end) {
    var numerical_data = [];
    for(var i = 1; i < data.length; i++){
      numerical_data.push(data[i].slice(data_start, data_end));
    }
    return numerical_data
}

function compute_annotations(data, data_start) {
    var headers = data[0].slice(0, data_start);
    var annotations = [];
    for(var i = 1; i < data.length; i++){
      var line  = data[i].slice(0, data_start);
      var annotation = ''
      for(var j = 0; j < headers.length; j++){
        annotation += `<b>${headers[j]}</b>: ${line[j]}<br>`
      }
      annotations.push(annotation);
    }
    return annotations
}

function unpack(rows, key) {
    return rows.map(function(row)
        { return row[key]; }
  );
}

function onlyUnique(value, index, self) {
    return self.indexOf(value) === index;
}

function update_options() {
    var arr_options = [];
    if (colour_column >= data_start) {
        colour_column = data_start - 1;
        colours = get_colours(colour_column, data);
        create_plot(pca_result, colours, annotations);
    }
    for (var i=0; i < data_start; i++) {
        if (colour_column == i) {
            var selected = ' selected';
        } else {
            var selected = '';
        }
        arr_options.push("<option value='" + i + "'" + selected + ">" + header[i] + "</option>");
    }
    document.getElementById("colour_column").innerHTML = arr_options;
}

function colour_changed() {
    colour_column = document.getElementById("colour_column").value
    colours = get_colours(colour_column, data);
    create_plot(pca_result, colours, annotations);
}

function data_start_changed() {
    data_start = document.getElementById("data_start").value;
    update_options();
    annotations = compute_annotations(data, data_start);
    pca_result = compute_pca(data, data_start);
    create_plot(pca_result, colours, annotations);
}

function filter_based_on_colour(data, colours, target_colour) {
    var result = [];
    for (var j = 0; j < colours.length; j++){
        if (colours[j] == target_colour){
            result.push(data[j])
        }
    }
    return result
}

function create_plot(pca_result, colours, annotations) {
    var layout = {
        hoverlabel: { bgcolor: "#FFF" },
        scene: {
            xaxis: {title: 'PC 0', zerolinecolor: "rgb(210, 210, 210)"},
            yaxis: {title: 'PC 1', zerolinecolor: "rgb(210, 210, 210)"},
            zaxis: {title: 'PC 2', zerolinecolor: "rgb(210, 210, 210)"}
        },
        margin: {
            l: 0,
            r: 0,
            b: 0,
            t: 20,
        }
    };

    var data = [];
    var unique_colours = colours.filter(onlyUnique);

    for (var i = 0; i < unique_colours.length; i++){
        var trace_data = filter_based_on_colour(pca_result, colours, unique_colours[i])
        var trace_annotations = filter_based_on_colour(annotations, colours, unique_colours[i])

        var trace = {
            x:unpack(trace_data, 0), y: unpack(trace_data, 1), z: unpack(trace_data, 2),
            mode: 'markers',
            name: unique_colours[i],
            marker: {
                size: 8,
                color: i,
                opacity: 0.8,
                colorscale: 'Jet'},
            text: trace_annotations,
            showlegend: true,
            hovertemplate: '%{text}' +
                           '<br>PC 0: %{x:.5f}' +
                           '<br>PC 1: %{y:.5f}' +
                           '<br>PC 2: %{z:.5f}' +
                           '<extra></extra>',
            type: 'scatter3d'
        };
        data.push(trace);
    }

    var gd3 = d3.select("div[id='visualisation']");
    var res_graph = gd3.node();
    try {
        Plotly.newPlot(res_graph, data, layout);
    } catch (error) {
        // FF fails to render datapoints here because of this bug:
        // https://bugzilla.mozilla.org/show_bug.cgi?id=941146
        // So we silently fail since FF also triggers the "onresize" which works.
    }
    window.onresize = function() { Plotly.Plots.resize(res_graph); };
}

function load_visualisation() {
    // PCA
    pca_result = compute_pca(data, data_start);
    // create colours of individual data points
    colours = get_colours(colour_column, data);
    // add metadata to hover text of individual data points
    annotations = compute_annotations(data, data_start);

    create_plot(pca_result, colours, annotations);
}

document.addEventListener("DOMContentLoaded", load_visualisation);