#!/usr/bin/env bash
set -euo pipefail

# ──────────────────────────────
# Config & helpers
# ──────────────────────────────
LOGFILE="${LOGFILE:-/var/log/docker-install.log}"
: > "$LOGFILE" || { echo "Cannot write $LOGFILE (need root?)"; exit 1; }

if [[ ${EUID:-$(id -u)} -ne 0 ]]; then SUDO="sudo"; else SUDO=""; fi
TARGET_USER="${SUDO_USER:-$USER}"

GREEN=$(tput setaf 2 || true); CYAN=$(tput setaf 6 || true); RESET=$(tput sgr0 || true)
BOLD=$(tput bold || true); NORM=$(tput sgr0 || true)

log() { echo -e "${CYAN}$*${RESET}" | tee -a "$LOGFILE"; }
ok()  { echo -e "${GREEN}$*${RESET}" | tee -a "$LOGFILE"; }
run() { eval "$@" >>"$LOGFILE" 2>&1; }

ascii="
${CYAN}
                      =++++
                      *####
                      -====
          .****:-****.=***+
          :####-=####.*####           :
          .====.:==== -====          -##=
     +***=.****:-****.=***+ ****=    ####*
     ####*:####-=####.*#### ####+    *####*###*=
     ====-.====.:==== -==== ====:    -########*.
  -+++++++++++++++++++++++++++++++**#####==-:
  =#####################################:
  :###################################*.
   *#################################=
   .*##############################+.
     +##########################*-
      .=*####################+-.
         .-=+**######**+=-:.
${RESET}"

clear
echo -e "$ascii"

# ──────────────────────────────
# Arguments
# ──────────────────────────────
ACTION="install"     # install | uninstall
PURGE_REPO="no"      # yes | no

for arg in "${@:-}"; do
  case "$arg" in
    --uninstall|-u) ACTION="uninstall" ;;
    --purge-repo)   PURGE_REPO="yes"   ;;
    --help|-h)
      cat <<USAGE
Usage:
  $0                 # installs Docker (default)
  $0 --uninstall     # uninstalls Docker (keeps /opt/docker)
  $0 -u --purge-repo # uninstalls Docker + removes APT repo and GPG key
Logs: ${LOGFILE}
USAGE
      exit 0
      ;;
  esac
done

# ──────────────────────────────
# OS Detection
# ──────────────────────────────
if [[ -r /etc/os-release ]]; then . /etc/os-release; else
  echo "Cannot detect distribution (missing /etc/os-release)." >&2; exit 1; fi

case "${ID:-}" in
  ubuntu) BASE_URL="https://download.docker.com/linux/ubuntu" ;;
  debian) BASE_URL="https://download.docker.com/linux/debian" ;;
  *) echo "Unsupported distribution: ${ID:-unknown}. (Ubuntu/Debian only)"; exit 1 ;;
esac

CODENAME="${VERSION_CODENAME:-}"
if [[ -z "$CODENAME" ]] && command -v lsb_release >/dev/null 2>&1; then CODENAME="$(lsb_release -cs)"; fi
if [[ -z "$CODENAME" ]]; then echo "Unable to determine codename (VERSION_CODENAME)." >&2; exit 1; fi

ARCH="$(dpkg --print-architecture)"
PRETTY="${PRETTY_NAME:-$ID}"
LISTFILE="/etc/apt/sources.list.d/docker.list"
KEYFILE="/etc/apt/keyrings/docker.asc"
REPO_LINE="deb [arch=${ARCH} signed-by=${KEYFILE}] ${BASE_URL} ${CODENAME} stable"

echo -e "Mode: ${CYAN}${BOLD}${ACTION^^}${RESET} | ${BOLD}${PRETTY}${RESET} (${BOLD}${CODENAME}${RESET}), arch=${CYAN}${ARCH}${RESET}"
echo -e "Detailed logs: ${CYAN}${LOGFILE}${RESET}\n"

# ──────────────────────────────
# INSTALL Functions
# ──────────────────────────────
install_docker() {
  echo -e "${CYAN}1) Installing prerequisites (ca-certificates, curl, gnupg, acl)${RESET}"
  run "$SUDO apt-get update -y"
  run "$SUDO apt-get install -y ca-certificates curl gnupg acl"

  echo -e "${CYAN}2) Preparing Docker keyring${RESET}"
  run "$SUDO install -m 0755 -d /etc/apt/keyrings"
  if [[ ! -f "$KEYFILE" ]]; then
    run "$SUDO curl -fsSL ${BASE_URL}/gpg -o ${KEYFILE}"
    run "$SUDO chmod a+r ${KEYFILE}"
  fi

  echo -e "${CYAN}3) Adding Docker APT repository (stable)${RESET}"
  echo "$REPO_LINE" | $SUDO tee "$LISTFILE" >/dev/null
  run "$SUDO apt-get update -y"

  echo -e "${CYAN}4) Installing Docker Engine + Buildx + Compose${RESET}"
  run "$SUDO apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin"

  echo -e "${CYAN}5) Enabling Docker service${RESET}"
  run "$SUDO systemctl enable --now docker"

  echo -e "${CYAN}6) Managing docker group and adding user${RESET}"
  if ! getent group docker >/dev/null 2>&1; then run "$SUDO groupadd docker"; fi
  if ! id -nG "$TARGET_USER" | grep -qw docker; then run "$SUDO usermod -aG docker '$TARGET_USER'"; fi

  echo -e "${CYAN}7) Creating and setting permissions for /opt/docker${RESET}"
  run "$SUDO mkdir -p /opt/docker"
  run "$SUDO chown root:docker /opt/docker"
  run "$SUDO chmod 2770 /opt/docker"
  run "$SUDO setfacl -R -m g:docker:rwx /opt/docker"
  run "$SUDO setfacl -R -d -m g:docker:rwx /opt/docker"

  echo -e "${CYAN}8) Verifying installation (hello-world)${RESET}"
  run "$SUDO docker run --rm hello-world"

  echo ""; ok "✅ Docker installation and verification completed."
  echo -e "Log out and log back in (${BOLD}logout/login${NORM}) to use Docker without sudo."
}

# ──────────────────────────────
# UNINSTALL Functions
# ──────────────────────────────
uninstall_docker() {
  echo -e "${CYAN}1) Stopping Docker service (if running)${RESET}"
  if $SUDO systemctl is-active --quiet docker; then run "$SUDO systemctl stop docker"; fi
  run "$SUDO systemctl disable docker || true"

  echo -e "${CYAN}2) Removing Docker packages${RESET}"
  PKGS="docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin docker-ce-rootless-extras docker-scan-plugin docker.io"
  run "$SUDO DEBIAN_FRONTEND=noninteractive apt-get purge -y $PKGS || true"
  echo -e "${CYAN}3) Cleaning up dependencies${RESET}"
  run "$SUDO apt-get autoremove -y --purge || true"

  if [[ "$PURGE_REPO" == "yes" ]]; then
    echo -e "${CYAN}4) Removing Docker APT repo and GPG key${RESET}"
    run "$SUDO rm -f '$LISTFILE' || true"
    run "$SUDO rm -f '$KEYFILE' || true"
    run "$SUDO apt-get update -y || true"
    STEP_NEXT=5
  else
    STEP_NEXT=4
  fi

  echo -e "${CYAN}${STEP_NEXT}) Keeping local data and /opt/docker (no deletion)${RESET}"
  echo -e "${CYAN}   → /opt/docker, /var/lib/docker, and /var/lib/containerd are NOT touched.${RESET}"

  echo ""; ok "🧹 Docker uninstallation complete (packages removed, data kept)."
  echo -e "You can manually delete ${BOLD}/var/lib/docker${NORM} and ${BOLD}/var/lib/containerd${NORM} if you want a full cleanup."
}

# ──────────────────────────────
# Main
# ──────────────────────────────
case "$ACTION" in
  install)   install_docker   ;;
  uninstall) uninstall_docker ;;
esac