// Validate dbAdmin Role
if (db.hostInfo().ok == 0) {
  user = db.runCommand({connectionStatus : 1}).authInfo.authenticatedUsers[0].user
  print (`\nUser '${user}' does not have the 'dbAdmin' role required to collect this information.\n`);

} else {

  // Compare Data Sizes
  // listDatabases reports storageSize + indexSize
  // the dataSize is uncompressed

  var totalStorageSize = 0;
  var totalDataSize = 0;
  var printDatabaseDetails = false;

  db.getSiblingDB("admin")
    .runCommand({ listDatabases: 1 })
    .databases.forEach(function (database) {
      // Get sizes
      storageSize = db.getSiblingDB(database.name).stats().storageSize;
      sizeOnDisk = database.sizeOnDisk;
      dataSize = db.getSiblingDB(database.name).stats().dataSize;
      compression = ((1 - storageSize / dataSize) * 100).toFixed(2);

      // Convert to MB
      sizeOnDiskMB = (sizeOnDisk / 1024 / 1024).toFixed(3);
      dataSizeMB = (dataSize / 1024 / 1024).toFixed(3);

      // Print
      if (printDatabaseDetails) {
        print(database.name);
        print(`  ${sizeOnDiskMB} MB - sizeOnDisk (compressed data & indexes)`);
        print(`  ${dataSizeMB} MB - dataSize (uncompressed)`);
        print(`  ${compression}% compression (dataSize -> storageSize)`);
        print();
      }

      totalStorageSize += storageSize;
      totalDataSize += dataSize;
    });

  var totalStorageSizeGB = (
    db.getSiblingDB("admin").runCommand({ listDatabases: 1 }).totalSize /
    1024 /
    1024 /
    1024
  ).toFixed(3);
  var totalCompression = ((1 - totalStorageSize / totalDataSize) * 100).toFixed(
    2
  );
  var fsUsedSizeGB = (
    db.getSiblingDB("admin").runCommand({ dbStats: 1 }).fsUsedSize /
    1024 /
    1024 /
    1024
  ).toFixed(1);
  var fsTotalSizeGB = (
    db.getSiblingDB("admin").runCommand({ dbStats: 1 }).fsTotalSize /
    1024 /
    1024 /
    1024
  ).toFixed(3);
  var percentFsUsed = ((fsUsedSizeGB / fsTotalSizeGB) * 100).toFixed(2);

  print("\n=== Cluster Totals ===");

  print("\n-- Host Information --> Map to AtlasCluster Tier\n");
  var mem = Math.ceil(db.hostInfo().system.memSizeMB / 1024);
  var cores = db.hostInfo().system.numCores;
  print(`RAM \t Storage \t vCPU`);
  print(`----- \t ------- \t ----`);
  print(`${mem} GB \t ${Math.ceil(fsTotalSizeGB)} GB \t ${cores}`);

  replSet = db.isMaster().hosts == null ? false : true;

  print("\nElectable Nodes");
  print("---------------");
  if (replSet) {
    nodes = db.isMaster().hosts.length;
  } else {
    nodes = 1;
  }
  print(nodes);

  // Print oplog information
  if (replSet) {
    replInfo = db.getReplicationInfo();
    avgOplogMBPerHour = (replInfo.usedMB / replInfo.timeDiffHours).toFixed(0);

    print("\nOpLog Stats");
    print("-----------");
    print(`${replInfo.logSizeMB} MB \t\t - Total OpLog size`);
    print(`${replInfo.usedMB.toFixed(0)} MB \t\t - Used Oplog`);
    print(`${replInfo.timeDiffHours.toFixed(0)} Hours \t - OpLog window`);
    print(`${avgOplogMBPerHour} MB \t\t - Average OpLog MBs per hour`);
  }

  print("\n-- Backup Information --> For calculating backup costs");

  print("\nData Size");
  print("---------");
  print(`${(totalDataSize / 1024 / 1024 / 1024).toFixed(3)} GB`);

  print("\n--- Additional Information of Potential Interest ---");

  print("\nDB Storage");
  print("----------");
  print(
    `${totalStorageSizeGB} GB \t - Total size on disk (compressed data & indexes)`
  );
  print(
    `${(totalDataSize / 1024 / 1024 / 1024).toFixed(
      3
    )} GB \t - Total dataSize (uncompressed)`
  );
  print(
    `${totalCompression}% \t\t - compression (total dataSize -> total size on disk)`
  );

  print("\nDisk Space Used");
  print("---------------");
  print(`${fsUsedSizeGB} GB \t - Total File System Used`);
  print(`${Math.ceil(fsTotalSizeGB)} GB \t - Total File System Size`);
  print(`${percentFsUsed}% \t - Percent File System Used `);
  print();
}