#!/bin/bash

# ModelGrid Uninstaller
#
# install.sh installs this script beside the executable, in the installation directory
# (/opt/modelgrid unless --install-dir chose another). It removes the systemd service, the
# command link and that installation directory: the executable, its third-party notices and
# this script. The configuration in /etc/modelgrid is removed only on request; the cluster state
# in /var/lib/modelgrid and the logs in /var/log/modelgrid stay.
#
# Usage:
#   sudo modelgrid uninstall
#   sudo bash /opt/modelgrid/uninstall.sh
#
# Environment (set by `modelgrid uninstall`):
#   REMOVE_CONFIG=yes|no    remove /etc/modelgrid without asking
#   MODELGRID_CLI_CALL=true called by the CLI, which has already asked its questions

set -euo pipefail

if [[ "$EUID" -ne 0 ]]; then
  echo "Please run as root (sudo modelgrid uninstall or sudo bash $0)"
  exit 1
fi

REMOVE_CONFIG="${REMOVE_CONFIG:-no}"
MODELGRID_CLI_CALL="${MODELGRID_CLI_CALL:-}"
SERVICE_FILE="/etc/systemd/system/modelgrid.service"
CONFIG_DIR="/etc/modelgrid"
BIN_LINKS=("/usr/local/bin/modelgrid" "/usr/bin/modelgrid")

# The installation directory is the directory this script lives in.
INSTALL_DIR="$(cd "$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")" && pwd -P)"
EXECUTABLE="$INSTALL_DIR/modelgrid"

# Refuse to delete a directory that is not a ModelGrid installation, such as a source checkout.
if [[ ! -f "$EXECUTABLE" ]]; then
  echo "Error: $INSTALL_DIR holds no ModelGrid executable (modelgrid); refusing to remove it." >&2
  echo "Run the uninstall.sh that install.sh placed in the installation directory." >&2
  exit 1
fi
if [[ "$INSTALL_DIR" == "/" ]]; then
  echo "Error: refusing to remove /" >&2
  exit 1
fi

echo "ModelGrid Uninstaller"
echo "====================="
echo "Removing ModelGrid installed in $INSTALL_DIR"

# 1. The systemd service.
if command -v systemctl >/dev/null 2>&1; then
  if systemctl is-active --quiet modelgrid.service 2>/dev/null; then
    echo "Stopping the ModelGrid service..."
    systemctl stop modelgrid.service
  fi
  if systemctl is-enabled --quiet modelgrid.service 2>/dev/null; then
    echo "Disabling the ModelGrid service..."
    systemctl disable modelgrid.service
  fi
fi
if [[ -f "$SERVICE_FILE" ]]; then
  echo "Removing $SERVICE_FILE"
  rm -f "$SERVICE_FILE"
  if command -v systemctl >/dev/null 2>&1; then
    systemctl daemon-reload
  fi
fi

# 2. The command links that point into this installation.
for link in "${BIN_LINKS[@]}"; do
  if [[ -L "$link" ]]; then
    target="$(readlink -f "$link" || true)"
    if [[ "$target" == "$INSTALL_DIR/"* ]]; then
      echo "Removing $link"
      rm -f "$link"
    fi
  fi
done

# 3. The configuration, on request.
if [[ "$REMOVE_CONFIG" == "yes" ]]; then
  echo "Removing $CONFIG_DIR"
  rm -rf "$CONFIG_DIR"
elif [[ -z "$MODELGRID_CLI_CALL" && -d "$CONFIG_DIR" && -t 0 ]]; then
  read -r -p "Remove the ModelGrid configuration in $CONFIG_DIR? (y/N) " reply || reply=""
  if [[ "$reply" =~ ^[Yy]$ ]]; then
    echo "Removing $CONFIG_DIR"
    rm -rf "$CONFIG_DIR"
  fi
fi

# 4. The installation directory: the executable, its notices and this script. Bash has the
# script open, so it finishes after the file is gone.
echo "Removing $INSTALL_DIR"
rm -rf -- "$INSTALL_DIR"

echo
echo "ModelGrid has been uninstalled."
if [[ -d "$CONFIG_DIR" ]]; then
  echo "The configuration in $CONFIG_DIR was kept."
fi
if [[ -d /var/lib/modelgrid || -d /var/log/modelgrid ]]; then
  echo "Cluster state in /var/lib/modelgrid and logs in /var/log/modelgrid were kept; remove them by hand if no longer needed."
fi