import * as path from "path";
import { relative, resolve } from "path";
import * as url from "url";

export type StringifySheetOptions = {
  resolveUrl?: (url: string) => string;
  uri?: string;
};

export const stringifyCSSSheet = (
  sheet,
  options: StringifySheetOptions = {}
) => {
  return sheet.rules
    .map((rule) => stringifyCSSRule(rule, options))
    .join("\n\n");
};

export const stringifyCSSRule = (rule, options: StringifySheetOptions = {}) => {
  switch (rule.kind) {
    case "Charset":
      return `@charset "${rule.value}"; `;
    case "Style":
      return stringifyStyleRule(rule, options);
    case "Page":
    case "Supports":
    case "Media":
      return stringifyConditionRule(rule, options);
    case "FontFace":
      return stringifyFontFaceRule(rule, options);
    case "Keyframes":
      return stringifyKeyframesRule(rule, options);
  }
};

const stringifyConditionRule = (
  { name, conditionText, rules },
  options: StringifySheetOptions
) => {
  return `@${name} ${conditionText} {\n${rules
    .map((style) => stringifyCSSRule(style, options))
    .join("\n")}\n}`;
};

const stringifyKeyframesRule = (
  { name, rules },
  options: StringifySheetOptions
) => {
  return `@keyframes ${name} {\n${rules
    .map((style) => stringifyKeyframeRule(style, options))
    .join("\n")}\n}`;
};

const stringifyKeyframeRule = (
  { key, style },
  options: StringifySheetOptions
) => {
  return `${key} {\n${style
    .map((style) => stringifyStyle(style, options))
    .join("\n")}\n}`;
};

const stringifyFontFaceRule = ({ style }, options: StringifySheetOptions) => {
  return `@font-face {\n${style
    .map((style) => stringifyStyle(style, options))
    .join("\n")}\n}`;
};

const stringifyStyleRule = (
  { selectorText, style, ...rest },
  options: StringifySheetOptions
) => {
  return `${selectorText} {\n${style
    .map((style) => stringifyStyle(style, options))
    .join("\n")}\n}`;
};

const stringifyStyle = (
  { name, value },
  { uri, resolveUrl }: StringifySheetOptions
) => {
  if (value) {
    // required for bundling, otherwise file protocol is maintained
    if (uri) {
      const urls = value.match(/(file:\/\/.*?)(?=['")])/g) || [];
      const selfPathname = url.fileURLToPath(uri);
      for (const foundUrl of urls) {
        const pathname = url.fileURLToPath(foundUrl);
        let relativePath = path.relative(path.dirname(selfPathname), pathname);
        if (relativePath.charAt(0) !== ".") {
          relativePath = "./" + relativePath;
        }

        value = value.replace(foundUrl, relativePath);
      }
    }

    if (value && resolveUrl) {
      if (value.includes("file:")) {
        const url = value.match(/(file:\/\/[^)]+)/)[1];
        value = value.replace(url, resolveUrl(url));
      } else if (value.includes("url(")) {
        const parts = value.match(/url\(['"]?(.*?)['"]?\)/);
        const url = parts && parts[1];
        if (url && !url.includes("http")) {
          value = value.replace(url, resolveUrl(url));
        }
      }
    }
  }

  return `  ${name.trim()}:${value};`;
};