#!/usr/bin/env bash
# install-docker.sh
# Docker — Build, ship, and run applications in isolated containers.
# Target: Ubuntu / Debian. Safe to re-run.
# Source guide: devops-hub/tools/docker.html

set -euo pipefail

if [[ $EUID -eq 0 ]]; then
  echo "Run this as a regular sudo-capable user, not root." >&2
  exit 1
fi

echo "==> Remove old versions"
sudo apt-get remove docker docker-engine docker.io containerd runc

echo "==> Set up the apt repository"
sudo apt-get update
sudo apt-get install -y ca-certificates curl gnupg
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

echo "==> Add the repository to Apt sources"
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update

echo "==> Install Docker Engine"
sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

echo "==> Verify"
sudo docker run hello-world

echo "==> Done. Docker installation finished."