'use strict';

const core = require('@capsizecss/core');

function useDeclare(declaration, Declaration) {
  function declareOne([prop, value]) {
    declaration.after(
      new Declaration({
        prop: prop.replace(/[A-Z]/g, (r) => `-${r.toLowerCase()}`),
        value
      })
    );
  }
  function declare(props) {
    Object.entries(props).forEach(declareOne);
  }
  return declare;
}
function useParentDeclare(parent, Declaration, Rule) {
  function declareOnParent([selector, props]) {
    parent.after(
      new Rule({
        selector: parent.selector + selector,
        source: parent.source,
        nodes: Object.entries(props).map(
          ([prop, value]) => new Declaration({
            prop: prop.replace(/[A-Z]/g, (r) => `-${r.toLowerCase()}`),
            value: String(value)
          })
        )
      })
    );
  }
  function declareAllOnParent(props) {
    Object.entries(props).forEach(declareOnParent);
  }
  return declareAllOnParent;
}
const plugin = (ctx) => {
  const { metrics = {} } = ctx || {};
  const fontFamilies = Object.keys(metrics);
  const matcher = new RegExp(
    `^(?<size>\\d+)px (?<family>(${fontFamilies.join("|")})) (?<gap>\\d+)px$`
  );
  function addCapsizedRules(fontConfig, source, helpers) {
    const { size, fontFamily, gap } = fontConfig;
    const { Declaration, Rule } = helpers;
    const declare = useDeclare(source, Declaration);
    const declareOnParent = useParentDeclare(
      source.parent,
      Declaration,
      Rule
    );
    const values = core.createStyleObject({
      fontMetrics: metrics[fontFamily],
      fontSize: Number(size),
      lineGap: Number(gap)
    });
    declare({
      lineHeight: values.lineHeight
    });
    declareOnParent({
      "::before": values["::before"],
      "::after": values["::after"]
    });
    source.remove();
  }
  return {
    postcssPlugin: "postcss-capsize",
    Declaration: {
      "font-metrics": (declaration, helpers) => {
        const {
          size,
          family: fontFamily,
          gap
        } = declaration.value.match(matcher)?.groups || {};
        if (!size || !fontFamily || !gap) {
          throw new Error(
            "Correct syntax is `font-metrics: [font-size]px [font-family] [line-gap]px;"
          );
        }
        const declare = useDeclare(declaration, helpers.Declaration);
        declare({
          fontFamily,
          fontSize: `${size}px`
        });
        addCapsizedRules({ size, fontFamily, gap }, declaration, helpers);
      },
      "line-gap": (declaration, helpers) => {
        let fontFamily;
        let size;
        const gap = (declaration.value.match(/^(\d+)px$/) || [])[1];
        declaration.parent?.walkDecls("font-family", (d) => {
          fontFamily = d.value.split(",").map((val) => val.trim().replace(/['"]/g, "")).find((val) => fontFamilies.includes(val));
        });
        declaration.parent?.walkDecls("font-size", (d) => {
          size = (d.value.match(/^(\d+)px$/) || [])[1];
        });
        addCapsizedRules({ size, fontFamily, gap }, declaration, helpers);
      }
    }
  };
};
plugin.postcss = true;

module.exports = plugin;