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

# Kubestrap Installer
# Usage: curl -sfL https://get.kubestrap.com | bash

DOCKER_IMAGE="damurai/kubestrap:latest"
SERVICE_NAME="kubestrap"
DATA_DIR="/root/.kubestrap"
SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"

info()  { printf "\033[32m[INFO]\033[0m  %s\n" "$*"; }
warn()  { printf "\033[33m[WARN]\033[0m  %s\n" "$*"; }
error() { printf "\033[31m[ERROR]\033[0m %s\n" "$*"; exit 1; }

check_root() {
  if [ "$(id -u)" -ne 0 ]; then
    error "This installer must be run as root. Try: curl -sfL https://get.kubestrap.com | sudo bash"
  fi
}

check_systemd() {
  if [ ! -d /run/systemd/system ]; then
    error "systemd is required but not detected. Kubestrap needs systemd to run as a service."
  fi
}

check_docker() {
  if ! command -v docker >/dev/null 2>&1; then
    warn "Docker is not installed."
    info "Install Docker first: https://docs.docker.com/engine/install/"
    info ""
    info "Quick install (most Linux distros):"
    info "  curl -fsSL https://get.docker.com | sh"
    info ""
    error "Please install Docker and re-run this installer."
  fi

  if ! docker info >/dev/null 2>&1; then
    error "Docker daemon is not running. Start it with: systemctl start docker"
  fi
}

check_existing() {
  if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    info "Kubestrap service is already running. Upgrading..."
    systemctl stop "$SERVICE_NAME"
  fi
}

pull_image() {
  info "Pulling ${DOCKER_IMAGE}..."
  docker pull "$DOCKER_IMAGE"
}

create_data_dir() {
  info "Creating data directory at ${DATA_DIR}..."
  mkdir -p "${DATA_DIR}"
  mkdir -p "${DATA_DIR}/ssh-keys"
  mkdir -p "${DATA_DIR}/kubeconfigs"
  mkdir -p "${DATA_DIR}/reports"
}

install_service() {
  info "Installing systemd service..."
  cat > "$SERVICE_FILE" <<SERVICEEOF
[Unit]
Description=Kubestrap Cluster Launcher
After=docker.service
Requires=docker.service

[Service]
Type=simple
Restart=on-failure
RestartSec=10
ExecStartPre=-/usr/bin/docker stop ${SERVICE_NAME}
ExecStartPre=-/usr/bin/docker rm ${SERVICE_NAME}
ExecStart=/usr/bin/docker run --rm --name ${SERVICE_NAME} \\
    -p 7373:7373 \\
    -v ${DATA_DIR}:/data \\
    -v /root/.ssh:/root/.ssh:ro \\
    --network host \\
    ${DOCKER_IMAGE}
ExecStop=/usr/bin/docker stop ${SERVICE_NAME}

[Install]
WantedBy=multi-user.target
SERVICEEOF

  systemctl daemon-reload
  systemctl enable "$SERVICE_NAME"
}

start_service() {
  info "Starting Kubestrap service..."
  systemctl start "$SERVICE_NAME"
  sleep 2

  if systemctl is-active --quiet "$SERVICE_NAME"; then
    info ""
    info "============================================"
    info "  Kubestrap is running!"
    info "  Open http://localhost:7373 in your browser"
    info "============================================"
    info ""
  else
    warn "Service may still be starting. Check status with:"
    warn "  systemctl status ${SERVICE_NAME}"
    warn "  journalctl -u ${SERVICE_NAME} -f"
  fi
}

main() {
  info "Kubestrap Installer"
  info ""

  check_root
  check_systemd
  check_docker
  check_existing
  pull_image
  create_data_dir
  install_service
  start_service
}

main "$@"