import readdir from "readdir-enhanced";
import fs from "fs";
import crypto from "crypto";
import multimatch from "multimatch";

function applyExcludeFilter(stat, excludeFilters) {
  // match exclude, return immediatley
  if (excludeFilters.length > 0) {
      // todo this could be a performance problem...
      const pathWithFolderSlash = stat.path + (stat.isDirectory() ? "/" : "");
      const excludeMatch = multimatch(pathWithFolderSlash, excludeFilters, { matchBase: true, dot: true });

      if (excludeMatch.length > 0) {
          return false;
      }
  }

  return true;
}

/**
 * @param algorithm : "md5" | "sha1" | "sha256" | "sha512"
 */
async function fileHash(filename, algorithm) {
  return new Promise((resolve, reject) => {
      // Algorithm depends on availability of OpenSSL on platform
      // Another algorithms: "sha1", "md5", "sha256", "sha512" ...
      let shasum = crypto.createHash(algorithm);
      try {
          let s = fs.createReadStream(filename);
          s.on("data", function (data) {
              shasum.update(data)
          });

          s.on("error", function (error) {
              reject(error);
          });

          // making digest
          s.on("end", function () {
              const hash = shasum.digest("hex")
              return resolve(hash);
          });
      }
      catch (error) {
          return reject("calc fail");
      }
  });
}

function createLocalState(localFiles, args) {
  console.log(`Creating local state at ${args["local-dir"]}${args["state-name"]}`);
  fs.writeFileSync(`${args["local-dir"]}${args["state-name"]}`, JSON.stringify(localFiles, undefined, 4), { encoding: "utf8" });
  console.log("Local state created");
}
async function getLocalFiles(args) {
  const files = await readdir.async(args["local-dir"], { deep: true, stats: true, sep: "/", filter: (stat) => applyExcludeFilter(stat, args.exclude) });
  let records = [];

  for (let stat of files) {
      if (stat.isDirectory()) {
          records.push({
              type: "folder",
              name: stat.path,
              size: undefined
          });

          continue;
      }

      if (stat.isFile()) {
          records.push({
              type: "file",
              name: stat.path,
              size: stat.size,
              hash: await fileHash(args["local-dir"] + stat.path, "sha256")
          });

          continue;
      }

      if (stat.isSymbolicLink()) {
          console.warn("This script is currently unable to handle symbolic links - please add a feature request if you need this");
      }
  }

  return {
      description: 'Don\'t delete',
      version: '1.0.0',
      generatedTime: new Date().getTime(),
      data: records
  };
}

try {
  const filename = ".generate-file-hash.json";
  const _args = {
    'local-dir': './',
    'state-name': filename,
    'exclude': [
      '**/node_modules/**',
      '**/.git*/**',
      '**/.git*/**',
      filename,
    ]
  };
  const localFiles = await getLocalFiles(_args);
  createLocalState(localFiles, _args);
  } catch (error) {
  console.log(error);
}