#!/bin/bash
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
TOFU_ROOT="$(dirname "$SCRIPT_DIR")"
PROJECT_ROOT="$(dirname "$TOFU_ROOT")"

usage() {
  cat <<EOF
Usage: $0 <cluster> --envtype <dev|prod|workload>

  Fetch (or reuse) a kubeconfig for the given cluster.
  Platform is read from the cluster prefix (<platform>-...).
  Env type must be supplied explicitly — it is no longer inferred
  from the cluster name, so names like 'upc-forte-group' work.

  Examples:
    $0 aks-dev          --envtype dev
    $0 upc-forte-group  --envtype prod
    $0 eks-workload     --envtype workload
EOF
  exit "${1:-0}"
}

CLUSTER=""
ENVTYPE=""
while [[ $# -gt 0 ]]; do
  case "$1" in
    --envtype)    ENVTYPE="${2:-}"; shift 2 ;;
    --envtype=*)  ENVTYPE="${1#*=}"; shift ;;
    -h|--help)    usage 0 ;;
    -*)           echo "Unknown option: $1"; usage 1 ;;
    *)
      if [[ -z "$CLUSTER" ]]; then
        CLUSTER="$1"; shift
      else
        echo "Error: unexpected argument '$1'"; usage 1
      fi
      ;;
  esac
done

[[ -z "$CLUSTER" ]] && { echo "Error: <cluster> argument required"; usage 1; }
[[ -z "$ENVTYPE" ]] && { echo "Error: --envtype <dev|prod|workload> required"; usage 1; }

case "$ENVTYPE" in
  dev|prod|workload) ;;
  *) echo "Error: invalid --envtype '$ENVTYPE'. Expected: dev, prod, workload"; exit 1 ;;
esac

PLATFORM="${CLUSTER%%-*}"
ENV="$ENVTYPE"

case "$PLATFORM" in
  aks|eks|gke|upc) ;;
  *) echo "Error: unknown platform '$PLATFORM'. Expected: aks, eks, gke, upc"; exit 1 ;;
esac

KUBECONFIG_FILE="$PROJECT_ROOT/private/$CLUSTER/kubeconfig"

if [[ -f "$KUBECONFIG_FILE" ]]; then
  echo "Kubeconfig already exists: $KUBECONFIG_FILE"
  echo ""
  echo "  export KUBECONFIG=$KUBECONFIG_FILE"
else
  echo "No cached kubeconfig. Fetching from platform..."

  # Load platform credentials
  ENV_FILE="$TOFU_ROOT/configs/$PLATFORM.env"
  if [[ -f "$ENV_FILE" ]]; then
    set -a; source "$ENV_FILE"; set +a
  fi

  TOFU_DIR="$TOFU_ROOT/platforms/$PLATFORM/$ENV"
  mkdir -p "$(dirname "$KUBECONFIG_FILE")"

  case "$PLATFORM" in
    aks)
      cd "$TOFU_DIR"
      RG=$(tofu output -raw resource_group_name 2>/dev/null || echo "$CLUSTER-rg")
      NAME=$(tofu output -raw cluster_name 2>/dev/null || echo "$CLUSTER")
      az aks get-credentials --resource-group "$RG" --name "$NAME" --file "$KUBECONFIG_FILE" --overwrite-existing
      ;;
    eks)
      cd "$TOFU_DIR"
      NAME=$(tofu output -raw cluster_name 2>/dev/null || echo "$CLUSTER")
      REGION=$(tofu output -raw aws_region 2>/dev/null || echo "${AWS_REGION:-eu-west-1}")
      aws eks update-kubeconfig --name "$NAME" --region "$REGION" --kubeconfig "$KUBECONFIG_FILE"
      ;;
    gke)
      cd "$TOFU_DIR"
      NAME=$(tofu output -raw cluster_name 2>/dev/null || echo "$CLUSTER")
      REGION=$(tofu output -raw region 2>/dev/null || echo "${GCP_REGION:-europe-west4}")
      PROJECT=$(tofu output -raw project_id 2>/dev/null || echo "${GCP_PROJECT_ID:-}")
      gcloud container clusters get-credentials "$NAME" --region "$REGION" --project "$PROJECT"
      cp ~/.kube/config "$KUBECONFIG_FILE"
      ;;
    upc)
      cd "$TOFU_DIR"
      CLUSTER_ID=$(tofu output -raw cluster_id 2>/dev/null || echo "${UPCLOUD_CLUSTER_ID:-}")
      upctl kubernetes config "$CLUSTER_ID" > "$KUBECONFIG_FILE"
      ;;
  esac

  chmod 600 "$KUBECONFIG_FILE"
  echo "Kubeconfig saved: $KUBECONFIG_FILE"
  echo ""
  echo "  export KUBECONFIG=$KUBECONFIG_FILE"
fi