"use strict";
const fs = require("fs");
const zlib = require("zlib");
const path = require("path");

(async () => {
  console.log(
    [
      "ログファイル",
      "リージョン",
      "時間",
      "バケット名",
      "ファイル名",
      "イベント",
      "userAgent",
      "署名バージョン"
    ].join()
  );
  const files = await find_files("./s3logs/");
  for (let i = 0; i < files.length; i++) {
    const result = await load_event_file(files[i]);
    for (let j = 0; j < result.length; j++) {
      const ev = result[j];
      if (
        ev.eventSource === "s3.amazonaws.com" &&
        ev.additionalEventData.SignatureVersion != null &&
        ev.additionalEventData.SignatureVersion === "SigV2"
      ) {
        const date = new Date(ev.eventTime);
        let column = [];
        column.push(
          files[i],
          `${date.toLocaleDateString()} ${date.toLocaleTimeString()}`,
          ev.awsRegion,
          ev.requestParameters.bucketName,
          ev.requestParameters.key,
          ev.eventName,
          ev.userAgent,
          ev.additionalEventData.SignatureVersion
        );
        console.log(column.join());
        //console.log(ev);
      }
    }
  }
})();

async function find_files(dirpath) {
  let file_list = [];
  const fromDir = startPath => {
    const files = fs.readdirSync(startPath);
    for (let i = 0; i < files.length; i++) {
      const filename = path.join(startPath, files[i]);
      const stat = fs.lstatSync(filename);
      if (stat.isDirectory()) {
        fromDir(filename); //recurse
      } else if (filename.indexOf("json.gz") >= 0) {
        file_list.push(filename);
      }
    }
  };
  fromDir(dirpath);
  return file_list;
}

async function load_event_file(file_name) {
  const gzipContent = fs.readFileSync(file_name);
  const result = await new Promise((resolv, reject) => {
    zlib.gunzip(gzipContent, (err, binary) => {
      if (err) {
        reject(err);
      }
      const string = JSON.parse(binary.toString("utf-8"));
      resolv(string.Records);
    });
  });
  return result;
}