#!/bin/sh

set -eu

if [ "$(id -u)" -ne 0 ]; then
    echo "This script should be run as root. Aborting..." > /dev/stderr
    exit 1
fi

SUPPORTED_ARCH="amd64 armhf arm64"
ARCH=$(dpkg --print-architecture)

echo "Checking system architecture..."
if echo "${SUPPORTED_ARCH}" | grep -w "${ARCH}" > /dev/null; then
    echo "Architecture ${ARCH} supported."
else
    echo "Architecture ${ARCH} not supported! Aborting..."
    exit 1
fi

# REPO SETUP

# Update the apt package index and install packages to allow apt to use a
# repository over HTTPS:
echo "Updating apt package index..."
apt-get update > /dev/null

echo "Installing prerequisites..."
apt-get -q -y -o Dpkg::Use-Pty=0 install \
    apt-transport-https \
    ca-certificates \
    curl \
    gnupg-agent \
    software-properties-common

# Add Docker’s official GPG key:
echo "Adding Docker's repo key..."
curl -fsSL https://download.docker.com/linux/debian/gpg | sudo apt-key add -

# Verify that you now have the key with the fingerprint
# 9DC8 5822 9FC7 DD38 854A E2D8 8D81 803C 0EBF CD88, by searching for the last
# 8 characters of the fingerprint.
apt-key fingerprint 0EBFCD88

# Use the following command to set up the stable repository. To add the
# nightly or test repository, add the word nightly or test (or both) after
# the word stable in the commands below.
echo "Adding Docker repo..."
add-apt-repository \
    "deb [arch=${ARCH}] https://download.docker.com/linux/debian \
    $(lsb_release -cs) \
    stable"

# INSTALLATION

# Update the apt package index, and install the latest version of Docker Engine
# and containerd, or go to the next step to install a specific version:
echo "Updating apt package index again..."
apt-get update > /dev/null
echo "Installing Docker..."
apt-get -q -y -o Dpkg::Use-Pty=0 install docker-ce docker-ce-cli containerd.io

echo "Done."
exit 0