const data = require("./_data/simple-icons.json");
const { htmlFriendlyToTitle } = require("./scripts/utils.js");
const getBounds = require("svg-path-bounding-box");

const titleRegexp = /(.+) icon$/;
const svgRegexp = /^<svg( [^\s]*=".*"){3}><title>.*<\/title><path d=".*"\/><\/svg>\r?\n?$/;

const iconSize = 24;
const iconFloatPrecision = 3;
const iconTolerance = 0.001;
const iconIgnored = require("./.svglint-ignored.json");

module.exports = {
    rules: {
        elm: {
            "svg": 1,
            "svg > title": 1,
            "svg > path": 1,
            "*": false,
        },
        attr: [
            { // ensure that the SVG elm has the appropriate attrs
                "role": "img",
                "viewBox": `0 0 ${iconSize} ${iconSize}`,
                "xmlns": "http://www.w3.org/2000/svg",

                "rule::selector": "svg",
                "rule::whitelist": true,
            },
            { // ensure that the title elm has the appropriate attr
                "rule::selector": "svg > title",
                "rule::whitelist": true,
            },
            { // ensure that the path element only has the 'd' attr (no style, opacity, etc.)
                "d": /^[,a-zA-Z0-9\. -]+$/,
                "rule::selector": "svg > path",
                "rule::whitelist": true,
            }
        ],
        custom: [
          function(reporter, $, ast) {
            reporter.name = "icon-title";

            const iconTitleText = $.find("title").text();
            if (!titleRegexp.test(iconTitleText)) {
              reporter.error("<title> should follow the format \"[ICON_NAME] icon\"");
            } else {
              const titleMatch = iconTitleText.match(titleRegexp);
              // titleMatch = [ "[ICON_NAME] icon", "[ICON_NAME]" ]
              const rawIconName = titleMatch[1];
              const iconName = htmlFriendlyToTitle(rawIconName);
              const icon = data.icons.find(icon => icon.title === iconName);
              if (icon === undefined) {
                reporter.error(`No icon with title "${iconName}" found in simple-icons.json`);
              }
            }
          },
          function(reporter, $, ast) {
            reporter.name = "icon-size";

            const iconPath = $.find("path").attr("d");
            if (iconIgnored.size.hasOwnProperty(iconPath)) {
              return;
            }

            const bounds = getBounds(iconPath);
            const width = +bounds.width.toFixed(iconFloatPrecision);
            const height = +bounds.height.toFixed(iconFloatPrecision);

            if (width === 0 && height === 0) {
              reporter.error("Path bounds were reported as 0 x 0; check if the path is valid");
            } else if (width !== iconSize && height !== iconSize) {
              reporter.error(`Size of <path> must be exactly ${iconSize} in one dimension; the size is currently ${width} x ${height}`);
            }
          },
          function(reporter, $, ast) {
            reporter.name = "extraneous";

            const rawSVG = $.html();
            if (!svgRegexp.test(rawSVG)) {
              reporter.error("Unexpected character(s), most likely extraneous whitespace, detected in SVG markup");
            }
          },
          function(reporter, $, ast) {
            reporter.name = "icon-centered";
            const iconPath = $.find("path").attr("d");
            const bounds = getBounds(iconPath);

            if (
              iconIgnored.size.hasOwnProperty(iconPath) ||
              iconIgnored.center.hasOwnProperty(iconPath)
            ) {
              return;
            }

            const targetCenter = iconSize / 2;
            const centerX = +((bounds.minX + bounds.maxX) / 2).toFixed(iconFloatPrecision);
            const devianceX = centerX - targetCenter;
            const centerY = +((bounds.minY + bounds.maxY) / 2).toFixed(iconFloatPrecision);
            const devianceY = centerY - targetCenter;

            if (
              Math.abs(devianceX) > iconTolerance ||
              Math.abs(devianceY) > iconTolerance
            ) {
              reporter.error(`<path> must be centered at (${targetCenter}, ${targetCenter}); the center is currently (${centerX}, ${centerY})`);
            }
          }
        ]
    }
};