#!/bin/bash
# Provisions a droplet on DigitalOcean to download a given torrent file, then reupload to a given rclone remote
# Prints estimated USD cost of transaction when complete
# uses your user's rclone.conf, so set up the remote locally and make sure it works
# torrentdl.sh https://releases.ubuntu.com/20.04/ubuntu-20.04.1-live-server-amd64.iso.torrent b2:my-linux-isos/ubuntu/
echo "Checking dependencies (wget, installed doctl, configured rclone)"
[ -s "$HOME/.config/rclone/rclone.conf" ] || (echo "Set up rclone (from rclone.org, not from package manager) with a remote, or write to ~/.config/rclone/rclone.conf, then run this script again"; exit)

if type doctl >/dev/null 2>&1; then
        if ! doctl compute droplet list >/dev/null 2>&1; then
                echo doctl not authenticated, running doctl auth init
                doctl auth init
        fi
else
        echo 'doctl not found, attempting to install with "go get github.com/digitalocean/doctl/cmd/doctl"'
        if ! go version >/dev/null 2>&1; then
                echo golang-go not found, installing gvm and go1.15.6 to ~/.gvm in 5 seconds. Ctrl-C to abort
                sleep 5
                bash < <(curl -s -S -L https://raw.githubusercontent.com/moovweb/gvm/master/binscripts/gvm-installer)
                source ~/.gvm/scripts/gvm
                gvm install go1.4 -B
                gvm use go1.4
                export GOROOT_BOOTSTRAP=$GOROOT
                gvm install go1.15.6
                gvm use --default go1.15.6
        fi
        go get github.com/digitalocean/doctl/cmd/doctl
        doctl auth init
fi

IMAGE="ubuntu-20-04-x64"
REGION="sgp1"
HOSTNAME="torrent-dl"
URLREGEX='^(https?|ftp|file)://[-A-Za-z0-9\+&@#/%?=~_|!:,.;]*[-A-Za-z0-9\+&@#/%=~_|]$'
TORRENT="$1"
DESTREMOTE="$2"
if [[ $TORRENT =~ $URLREGEX ]]; then
        if ! type wget >/dev/null 2>&1; then
                echo wget not found for downloading torrent file from url, installing from apt using sudo.
                echo "If this isn't right for your environment, install wget before running script again"
                sudo apt-get install -y wget || exit
        fi
        echo Downloading torrent from url...
        wget "$TORRENT" -c
        export TORRENT=`basename "$TORRENT"`
fi

TORRENTSIZE=`head -1 "$TORRENT" | grep -aoE '6:lengthi[0-9]+' | cut -di -f2 | awk '{s+=$1} END {print s}'`
if (($TORRENTSIZE<=30000000000)); then # 30GB
        SIZE="s-1vcpu-2gb"
elif (($TORRENTSIZE<=60000000000)); then # 60GB
        SIZE="s-2vcpu-4gb"
elif (($TORRENTSIZE<=140000000000)); then # 140GB
        SIZE="s-4vcpu-8gb"
else # up to 300GB
        SIZE="s-8vcpu-16gb"
fi

if [ -v $1 ]; then
        echo Usage: $0 https://releases.ubuntu.com/20.04/ubuntu-20.04.1-live-server-amd64.iso.torrent b2:my-linux-isos/ubuntu/
        exit
fi

echo "Downloading '$TORRENT' on $REGION:$IMAGE:$SIZE with hostname $HOSTNAME, then uploading to '$DESTREMOTE'"
read -p "Press enter to continue, ctrl-c to abort..."

echo "Started at `date`"
export STARTTIME=`date +%s`

echo "Provisioning droplet..."
export SSHKEYS=`doctl compute ssh-key list --no-header --format ID | tr '\n' ',' | sed 's/,$/\n/'`
export IP=$( set -x; doctl compute droplet create $HOSTNAME --ssh-keys $SSHKEYS --region $REGION --size $SIZE --image $IMAGE --wait --no-header --format PublicIPv4 )

echo -n "Droplet at $IP, waiting for connection"
until (ssh -o StrictHostKeyChecking=no root@$IP mkdir -p /root/.config/rclone /root/t 2>/dev/null >/dev/null); do
        echo -n "."
        sleep 1
done
ssh-keyscan -H $IP 2>/dev/null >> ~/.ssh/known_hosts
echo

echo Copying rclone conf and torrent to droplet...
scp ~/.config/rclone/rclone.conf root@$IP:/root/.config/rclone/rclone.conf
scp "$TORRENT" root@$IP:/root/t/

echo Installing dependencies...
ssh -t root@$IP "apt-get update; apt-get install -y aria2; curl https://rclone.org/install.sh | sudo bash"
echo Downloading torrent...
ssh -t root@$IP aria2c -d "/root/t/" --enable-dht=false --enable-peer-exchange=false --seed-time=0 "/root/t/*.torrent"
echo Uploading torrent to rclone remote...
ssh -t root@$IP rclone copy /root/t/ "$DESTREMOTE" -P --fast-list --transfers=$(($LINES-5))
echo Job complete, deleting droplet
$(set -x; doctl compute droplet delete -f $HOSTNAME)

echo "Finished at `date`"
export ENDTIME=`date +%s`
echo "Total run time: $(($ENDTIME-$STARTTIME))"
echo -n "Total (estimated) cost: USD $"
doctl compute size list | grep $SIZE | awk '{print $5}' | while read p; do python3 -c "print(($p/2592000)*($ENDTIME-$STARTTIME))"; done