import * as d3 from "d3";
import {hexbin as d3hexbin} from "d3-hexbin";
import Utils from "../Utils.js";

/**
 * Charting operations.
 *
 * @author tlwr [toby@toby.com]
 * @copyright Crown Copyright 2016
 * @license Apache-2.0
 *
 * @namespace
 */
const Charts = {
    /**
     * @constant
     * @default
     */
    RECORD_DELIMITER_OPTIONS: ["Line feed", "CRLF"],


    /**
     * @constant
     * @default
     */
    FIELD_DELIMITER_OPTIONS: ["Space", "Comma", "Semi-colon", "Colon", "Tab"],


    /**
     * Gets values from input for a scatter plot.
     *
     * @param {string} input
     * @param {string} recordDelimiter
     * @param {string} fieldDelimiter
     * @param {boolean} columnHeadingsAreIncluded - whether we should skip the first record
     * @returns {Object[]}
     */
    _getScatterValues(input, recordDelimiter, fieldDelimiter, columnHeadingsAreIncluded) {
        let headings;
        const values = [];

        input
            .split(recordDelimiter)
            .forEach((row, rowIndex) => {
                let split = row.split(fieldDelimiter);

                if (split.length !== 2) throw "Each row must have length 2.";

                if (columnHeadingsAreIncluded && rowIndex === 0) {
                    headings = {};
                    headings.x = split[0];
                    headings.y = split[1];
                } else {
                    let x = split[0],
                        y = split[1];

                    x = parseFloat(x, 10);
                    if (Number.isNaN(x)) throw "Values must be numbers in base 10.";

                    y = parseFloat(y, 10);
                    if (Number.isNaN(y)) throw "Values must be numbers in base 10.";

                    values.push([x, y]);
                }
            });

        return { headings, values};
    },


    /**
     * Hex Bin chart operation.
     *
     * @param {string} input
     * @param {Object[]} args
     * @returns {html}
     */
    runHexDensityChart: function (input, args) {
        const recordDelimiter = Utils.charRep[args[0]],
            fieldDelimiter = Utils.charRep[args[1]],
            radius = args[2],
            columnHeadingsAreIncluded = args[3],
            dimension = 500;

        let xLabel = args[4],
            yLabel = args[5],
            { headings, values } = Charts._getScatterValues(
                input,
                recordDelimiter,
                fieldDelimiter,
                columnHeadingsAreIncluded
            );

        if (headings) {
            xLabel = headings.x;
            yLabel = headings.y;
        }

        let svg = document.createElement("svg");
        svg = d3.select(svg)
            .attr("width", "100%")
            .attr("height", "100%")
            .attr("viewBox", `0 0 ${dimension} ${dimension}`);

        let margin = {
                top: 0,
                right: 0,
                bottom: 30,
                left: 30,
            },
            width = dimension - margin.left - margin.right,
            height = dimension - margin.top - margin.bottom,
            marginedSpace = svg.append("g")
                .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

        let hexbin = d3hexbin()
            .radius(radius)
            .extent([0, 0], [width, height]);

        let hexPoints = hexbin(values),
            maxCount = Math.max(...hexPoints.map(b => b.length));

        let xExtent = d3.extent(hexPoints, d => d.x),
            yExtent = d3.extent(hexPoints, d => d.y);
        xExtent[0] -= 2 * radius;
        xExtent[1] += 2 * radius;
        yExtent[0] -= 2 * radius;
        yExtent[1] += 2 * radius;

        let xAxis = d3.scaleLinear()
            .domain(xExtent)
            .range([0, width]);
        let yAxis = d3.scaleLinear()
            .domain(yExtent)
            .range([height, 0]);

        let color = d3.scaleSequential(d3.interpolateLab("white", "steelblue"))
            .domain([0, maxCount]);

        marginedSpace.append("clipPath")
            .attr("id", "clip")
            .append("rect")
            .attr("width", width)
            .attr("height", height);

        marginedSpace.append("g")
            .attr("class", "hexagon")
            .attr("clip-path", "url(#clip)")
            .selectAll("path")
            .data(hexPoints)
            .enter()
            .append("path")
            .attr("d", d => {
                return `M${xAxis(d.x)},${yAxis(d.y)} ${hexbin.hexagon(radius * 0.75)}`;
            })
            .attr("fill", (d) => color(d.length))
            .append("title")
            .text(d => {
                let count = d.length,
                    perc = 100.0 * d.length / values.length,
                    CX = d.x,
                    CY = d.y,
                    xMin = Math.min(...d.map(d => d[0])),
                    xMax = Math.max(...d.map(d => d[0])),
                    yMin = Math.min(...d.map(d => d[1])),
                    yMax = Math.max(...d.map(d => d[1])),
                    tooltip = `Count: ${count}\n
                               Percentage: ${perc.toFixed(2)}%\n
                               Center: ${CX.toFixed(2)}, ${CY.toFixed(2)}\n
                               Min X: ${xMin.toFixed(2)}\n
                               Max X: ${xMax.toFixed(2)}\n
                               Min Y: ${yMin.toFixed(2)}\n
                               Max Y: ${yMax.toFixed(2)}
                    `.replace(/\s{2,}/g, "\n");
                return tooltip;
            });

        marginedSpace.append("g")
            .attr("class", "axis axis--y")
            .call(d3.axisLeft(yAxis).tickSizeOuter(-width));

        svg.append("text")
            .attr("transform", "rotate(-90)")
            .attr("y", -margin.left)
            .attr("x", -(height / 2))
            .attr("dy", "1em")
            .style("text-anchor", "middle")
            .text(yLabel);

        marginedSpace.append("g")
            .attr("class", "axis axis--x")
            .attr("transform", "translate(0," + height + ")")
            .call(d3.axisBottom(xAxis).tickSizeOuter(-height));

        svg.append("text")
            .attr("x", width / 2)
            .attr("y", dimension)
            .style("text-anchor", "middle")
            .text(xLabel);

        return svg._groups[0][0].outerHTML;
    },
};

export default Charts;