#!/bin/sh

# We built on top of tiny-cloud
. /etc/conf.d/tiny-cloud

# extract user-data args and cloud meta-data into /var/lib/cloud/meta-data
get_meta_data() {
  if [ ! -f /var/lib/cloud/meta-data ]; then
  	[ -f /var/lib/cloud/user-data ] && bash /var/lib/cloud/user-data get_meta_data || echo "Error trying to extract cloud meta-data" >&2
  fi

  . /var/lib/cloud/meta-data
}

# archive orig /var, mount new var on top and restore orig var
copy_and_mount() {
  local dev=$1

  tar cf /tmp/var.tar /var 2>/dev/null
  mount -t xfs -o noatime "$dev" /var
  tar xf /tmp/var.tar -C / && rm -f /tmp/var.tar
}

setup_var() {
  for d in $(find /dev/sd?); do
    # resolve to a valid block device
    dev="$(realpath "$d")"
    [ -b "$dev" ] || continue

    # already mounted
    mount | grep -q "$dev" && continue

    case "$CLOUD" in
      aws)
        # on AWS look for sdx 
        if [ "$d" = "/dev/sdx" ]; then
          # check volume for existing filesystem
          type=$(file -Lbs $d)
          if [[ "$type" =~ "XFS filesystem" ]]; then
            xfs_repair $d >/dev/null 2>&1
          else
            mkfs.xfs -qf $d >/dev/null
          fi
          copy_and_mount "$dev"
          grep -q "$dev" /etc/fstab || echo "$dev /var xfs defaults,noatime,nofail 0 2" >> /etc/fstab
        fi
        ;;
      *)
        echo "Unsupported Cloud '$CLOUD'" >&2
        exit 1
        ;;
    esac
  done
}

attach_ebs() {
  local volId="$1"
  local device="$2"

  local tries=30
  while true; do
    _json="$(aws ec2 describe-volumes --volume-ids $volId --region $REGION --output json)"
    rc=$?; [ $rc -ne 0 ] && return $rc

    vol_status=$(echo "$_json" | jq -r .Volumes[].State)
    attachId=$(echo "$_json" | jq -r .Volumes[].Attachments[].InstanceId)

    [ "$attachId" = "$INSTANCE_ID" ] && break

    if [ "$vol_status" = "available" ]; then
      aws ec2 attach-volume --volume-id "$volId" --instance-id "$INSTANCE_ID" --region "$REGION" --device "$device" > /dev/null
      rc=$?; [ $rc -ne 0 ] && return $rc
      break
    fi

    # if attached but not to us -> detach
    if [ "$vol_status" = "in-use" ]; then
      aws ec2 detach-volume --volume-id "$volId" --region "$REGION" --force
      rc=$?; [ $rc -ne 0 ] && return $rc
    fi

    ((tries=tries-1))
    [ $tries -eq 0 ] && return 1
    sleep 5
  done
}

_parse_volume() {
  # Todo: proper checks once all is yaml
  # For now just replace ':'
  echo $1 | sed -e 's/:/ /g'
}

# mount optional remote volumes
mount_volumes() {
  local volumes="$1"

  for vol in $volumes; do
    # Todo: check volume type and call matching func
    read volType volId volDevice volPath < <(_parse_volume $vol)

    [ "$volType" != "ebs" ] && { echo "Unknown volume type $volType"; break; }
    attach_ebs $volId $volDevice
    rc=$?
    [ $rc -ne 0 ] && { ewarn "error trying to attach $volId"; break; }

    # wait for the block device to become available
    while true; do
      mdev -s
      test -b $volDevice && break
      sleep 1
    done

    # check volume for existing filesystem
    type=$(file -Lbs $volDevice)
    if [[ "$type" =~ "XFS filesystem" ]]; then
      xfs_repair $volDevice >/dev/null 2>&1
    else
      mkfs.xfs -qf $volDevice >/dev/null
    fi

    # mount
    mkdir -p $volPath
    mount -t xfs -o noatime $volDevice $volPath
  done
}

unmount_volumes() {
  local volumes="$1"

  for vol in $volumes; do
    read volType volId volDevice volPath < <(_parse_volume $vol)

    umount $volPath && aws ec2 detach-volume --volume-id "$volId" --instance-id $INSTANCE_ID --region $REGION > /dev/null
  done
}