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

# --- Default values (can be overridden by environment variables) ---
REPO_URL="${REPO_URL:-}"
REPO_DIR="${REPO_DIR:-/etc/nixos-infra}"
BRANCH="${BRANCH:-main}"
DRY_RUN="${DRY_RUN:-false}"

# --- Usage ---
usage() {
  cat <<EOF
Deploy NixOS configuration from the nixos-infra repository.

Usage:
  $0 [options]

Options:
  -u, --repo-url URL      Git repository URL
                          [default: ${REPO_URL}]
  -d, --repo-dir DIR      Local directory for the repository
                          [default: ${REPO_DIR}]
  -b, --branch BRANCH     Git branch to deploy
                          [default: ${BRANCH}]
  -n, --dry-run           Simulate deployment without making changes.
  -h, --help              Show this help message.

Environment variables:
  REPO_URL, REPO_DIR, BRANCH, DRY_RUN (same as options above).
EOF
  exit 0
}

# --- Parse arguments ---
while [[ $# -gt 0 ]]; do
  case "$1" in
    -u|--repo-url) REPO_URL="$2"; shift 2 ;;
    -d|--repo-dir) REPO_DIR="$2"; shift 2 ;;
    -b|--branch)   BRANCH="$2";   shift 2 ;;
    -n|--dry-run)  DRY_RUN="true"; shift ;;
    -h|--help)     usage ;;
    *) echo "❌ Unknown option: $1" >&2; usage ;;
  esac
done

HOSTNAME=$(hostname)

if [ "$(id -u)" -ne 0 ]; then
  echo "❌ This script must be run as root." >&2
  exit 1
fi

# --- Dry run mode ---
if [ "$DRY_RUN" = "true" ]; then
  echo "🧪 Dry run mode:"
  echo "   - Repository URL: $REPO_URL"
  echo "   - Repository dir: $REPO_DIR"
  echo "   - Branch: $BRANCH"
  echo "   - Hostname: $HOSTNAME"
  echo "   - Expected config: $REPO_DIR/environments/<env>/hosts/servers/$HOSTNAME/configuration.nix"
  echo ""
  echo "   Would execute:"
  echo "     git clone --branch $BRANCH $REPO_URL $REPO_DIR"
  echo "     nixos-rebuild switch -I nixos-config=...$HOSTNAME/configuration.nix"
  exit 0
fi

# --- Clone or update the repository ---
if [ -d "$REPO_DIR/.git" ]; then
  echo "🔄 Mise à jour du dépôt dans $REPO_DIR..."
  cd "$REPO_DIR"
  git fetch origin
  git checkout "$BRANCH"
  git pull origin "$BRANCH"
else
  echo "📥 Clonage du dépôt dans $REPO_DIR..."
  mkdir -p "$REPO_DIR"
  git clone --branch "$BRANCH" "$REPO_URL" "$REPO_DIR"
fi

# --- Find the configuration for this machine ---
ENVIRONMENT="${ENVIRONMENT:-}"
if [ -z "$ENVIRONMENT" ]; then
  # Try common environment names
  for env in production prod staging stage dev development; do
    if [ -d "$REPO_DIR/environments/$env" ]; then
      ENVIRONMENT="$env"
      break
    fi
  done
fi

if [ -z "$ENVIRONMENT" ]; then
  echo "❌ Error: No environment specified and none detected." >&2
  echo "   Set ENVIRONMENT environment variable or use --environment flag." >&2
  exit 1
fi

CONFIG_PATH="$REPO_DIR/environments/$ENVIRONMENT/hosts/servers/$HOSTNAME/configuration.nix"
if [ ! -f "$CONFIG_PATH" ]; then
  CONFIG_PATH="$REPO_DIR/environments/$ENVIRONMENT/hosts/workstations/$HOSTNAME/configuration.nix"
fi

if [ ! -f "$CONFIG_PATH" ]; then
  echo "❌ Error : No configuration found for $HOSTNAME in environment '$ENVIRONMENT'" >&2
  echo "   Checked paths :" >&2
  echo "     - $REPO_DIR/environments/$ENVIRONMENT/hosts/servers/$HOSTNAME/configuration.nix" >&2
  echo "     - $REPO_DIR/environments/$ENVIRONMENT/hosts/workstations/$HOSTNAME/configuration.nix" >&2
  exit 1
fi

# --- Apply the configuration ---
echo "🚀 Deploying the configuration for $HOSTNAME..."
nixos-rebuild switch -I nixos-config="$CONFIG_PATH"

echo "✅ Deployment was successful !"