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

# Kubesman Installer
# Usage: curl -sfL https://get.kubesman.org | bash
#        curl -sfL https://get.kubesman.org | bash -s -- [OPTIONS]
#
# Options:
#   --version <tag>    Docker image tag (default: latest)
#   --dry-run          Preview commands without executing
#   --uninstall        Remove Kubesman service, container, and data

# ── Defaults ──
DOCKER_IMAGE="damurai/kubesman"
IMAGE_TAG="latest"
SERVICE_NAME="kubesman"
DATA_DIR="/root/.kubesman"
SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"
DRY_RUN=false
UNINSTALL=false

# ── Colors ──
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; }

# ── Helpers ──
command_exists() { command -v "$1" >/dev/null 2>&1; }

run() {
  if [ "$DRY_RUN" = true ]; then
    info "[DRY-RUN] $*"
  else
    "$@"
  fi
}

# ── Environment checks ──
detect_wsl() {
  if [ -f /proc/version ] && grep -qi "microsoft" /proc/version 2>/dev/null; then
    warn "WSL detected. systemd may not be available in your WSL distribution."
    warn "If installation fails, enable systemd in WSL:"
    warn "  https://learn.microsoft.com/en-us/windows/wsl/systemd"
    echo ""
  fi
}

detect_macos() {
  case "$(uname -s)" in
    Darwin)
      error "macOS detected. Kubesman requires Linux with systemd and Docker.
  Run it on a Linux server or VM instead."
      ;;
  esac
}

check_root() {
  if [ "$(id -u)" -ne 0 ]; then
    if command_exists sudo; then
      warn "Not running as root. Re-running with sudo..."
      exec sudo bash "$0" "$@"
    else
      error "This installer must be run as root. Try: curl -sfL https://get.kubesman.org | sudo bash"
    fi
  fi
}

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

check_docker() {
  if ! command_exists docker; 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
}

# ── Uninstall ──
do_uninstall() {
  info "Uninstalling Kubesman..."
  echo ""

  if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    info "Stopping service..."
    run systemctl stop "$SERVICE_NAME"
  fi

  if systemctl is-enabled --quiet "$SERVICE_NAME" 2>/dev/null; then
    info "Disabling service..."
    run systemctl disable "$SERVICE_NAME"
  fi

  if [ -f "$SERVICE_FILE" ]; then
    info "Removing service file..."
    run rm -f "$SERVICE_FILE"
    run systemctl daemon-reload
  fi

  if docker ps -a --format '{{.Names}}' 2>/dev/null | grep -q "^${SERVICE_NAME}\$"; then
    info "Removing container..."
    run docker rm -f "$SERVICE_NAME"
  fi

  if docker images "${DOCKER_IMAGE}" --format '{{.Repository}}:{{.Tag}}' 2>/dev/null | grep -q .; then
    info "Removing Docker image..."
    run docker rmi "${DOCKER_IMAGE}:${IMAGE_TAG}" 2>/dev/null || true
  fi

  if [ -d "$DATA_DIR" ]; then
    warn "Data directory exists at ${DATA_DIR}"
    warn "To remove all data (configs, keys, reports), run:"
    warn "  rm -rf ${DATA_DIR}"
    echo ""
  fi

  info "Kubesman has been uninstalled."
}

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

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

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

install_service() {
  info "Installing systemd service..."
  if [ "$DRY_RUN" = true ]; then
    info "[DRY-RUN] Would write service file to ${SERVICE_FILE}"
  else
    cat > "$SERVICE_FILE" <<SERVICEEOF
[Unit]
Description=Kubesman 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 \\
    ${DOCKER_IMAGE}:${IMAGE_TAG}
ExecStop=/usr/bin/docker stop ${SERVICE_NAME}

[Install]
WantedBy=multi-user.target
SERVICEEOF
  fi

  run systemctl daemon-reload
  run systemctl enable "$SERVICE_NAME"
}

start_service() {
  info "Starting Kubesman service..."
  run systemctl start "$SERVICE_NAME"

  if [ "$DRY_RUN" = true ]; then
    info "[DRY-RUN] Would verify service status"
    return
  fi

  sleep 2
  if systemctl is-active --quiet "$SERVICE_NAME"; then
    info ""
    info "============================================"
    info "  Kubesman 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
}

do_install() {
  check_root "$@"
  detect_macos
  detect_wsl
  check_systemd
  check_docker
  check_existing
  pull_image
  create_data_dir
  install_service
  start_service
}

# ── Argument parsing ──
parse_args() {
  while [ $# -gt 0 ]; do
    case "$1" in
      --version)
        IMAGE_TAG="${2:-}"
        if [ -z "$IMAGE_TAG" ]; then
          error "--version requires a tag argument (e.g., --version v1.2.0)"
        fi
        shift 2
        ;;
      --dry-run)
        DRY_RUN=true
        shift
        ;;
      --uninstall)
        UNINSTALL=true
        shift
        ;;
      --help|-h)
        echo "Kubesman Installer"
        echo ""
        echo "Usage: curl -sfL https://get.kubesman.org | bash -s -- [OPTIONS]"
        echo ""
        echo "Options:"
        echo "  --version <tag>    Docker image tag (default: latest)"
        echo "  --dry-run          Preview commands without executing"
        echo "  --uninstall        Remove Kubesman service, container, and data"
        echo "  --help             Show this help message"
        exit 0
        ;;
      *)
        error "Unknown option: $1 (use --help for usage)"
        ;;
    esac
  done
}

# ── Main ──
main() {
  parse_args "$@"

  info "Kubesman Installer"
  if [ "$DRY_RUN" = true ]; then
    warn "Dry-run mode — no changes will be made"
  fi
  info ""

  if [ "$UNINSTALL" = true ]; then
    check_root "$@"
    do_uninstall
  else
    do_install
  fi
}

main "$@"