const mkdirp = require("mkdirp");
const usercssMeta = require("usercss-meta");

const fs = require("fs");
const path = require("path");

/****/

const inputFile = process.argv[2];
const outputDir = process.argv[3];

if (!fs.existsSync(inputFile)) {
  console.log("input does not exist");
  process.exit(1);
}
if (!fs.existsSync(outputDir)) mkdirp.sync(outputDir);

const css = fs.readFileSync(inputFile, "utf8");

const files = {};

const preprocessors = {
  default: true,
  uso: true,
};

const usercssParser = usercssMeta.createParser({
  mandatoryKeys: [],
  validateKey: {
    preprocessor: (state) => {
      const preprocessor = state.value ?? "default";
      if (!preprocessors[preprocessor])
        throw new usercssMeta.ParseError({
          message: `Unsupported preprocessor: ${preprocessor}`,
          code: "unknownPreprocessor",
          args: [state.value],
          index: state.valueIndex,
        });
    },
  },
  validateVar: {
    select: (state) => {
      if (state.varResult.options.every((o) => o.name !== state.value)) {
        throw new usercssMeta.ParseError({
          code: "invalidSelectValueMismatch",
          index: state.valueIndex,
        });
      }
    },
  },
});

/****/

try {
  //parser won't parse \r
  const cssUnixEndings = css.replace(/\r/g, "");

  const parsed = usercssParser.parse(cssUnixEndings);
  if (!parsed?.metadata || Object.keys(parsed.metadata).length == 0) {
    console.log("UserCSS file has no valid metadata.");
    process.exit(1);
  }

  if (parsed.errors.length > 0) {
    console.log("UserCSS parsed with errors:");
    for (const error of parsed.errors) {
      console.log(error);
    }
  }

  files["base"] = cssUnixEndings.match(
    /\/\* BASE THEME START \*\/(.*?)\/\* BASE THEME END \*\//s
  )[1];

  for (const key of Object.keys(parsed.metadata.vars)) {
    const setting = parsed.metadata.vars[key];
    if (setting.type != "select") continue;
    const options = setting.options.filter((x) => x.value != "");
    if (options.length > 1) {
      for (const option of options) {
        files[
          key.replace("xmc_", "") +
            "/" +
            option.name.toLowerCase().replace(/ /g, "_")
        ] = option.value;
      }
    } else {
      files[key.replace("xmc_", "")] = options[0].value;
    }
  }
} catch (err) {
  console.log("UserCSS parsing failed: " + err);
  process.exit(1);
}

/****/

try {
  for (const filePath of Object.keys(files)) {
    const contents = files[filePath];
    if (filePath.indexOf("/") > -1) {
      const [subfolder, name] = filePath.split("/");
      if (!fs.existsSync(path.join(outputDir, subfolder)))
        mkdirp.sync(path.join(outputDir, subfolder));

      fs.writeFileSync(
        path.join(outputDir, subfolder, name + ".css"),
        contents
      );
    } else {
      fs.writeFileSync(path.join(outputDir, filePath + ".css"), contents);
    }
  }
} catch (err) {
  console.log("Failed to write files: " + err);
  process.exit(1);
}