#!/usr/bin/env bash

set -euo pipefail

# init_k3s_registry.sh
# Purpose:
# - Configure k3s/containerd to allow access to the Knoe registry
# - Writes /etc/rancher/k3s/registries.yaml on the k3s node

SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
# shellcheck disable=SC1090
source "$SCRIPT_DIR/knoe_cfg.sh"

ACTION=${1:-apply}

registry_host_from_url() {
  local value="${1:-}"
  value="${value#http://}"
  value="${value#https://}"
  value="${value%%/*}"
  value="${value%%:*}"
  printf '%s' "$value"
}

K3S_REGISTRY_HOST=${K3S_REGISTRY_HOST:-$(registry_host_from_url "${PROLE_K3S_SERVER:-${K3S_SERVER_URL:-}}")}
K3S_REGISTRY_PORT=${K3S_REGISTRY_PORT:-5000}
K3S_REGISTRY_NAMESPACE=${K3S_REGISTRY_NAMESPACE:-${REGISTRY_NAMESPACE:-${SERVICE_NAMESPACE:-${PROLE_NAMESPACE:-default}}}}
K3S_REGISTRY_FILE=${K3S_REGISTRY_FILE:-/etc/rancher/k3s/registries.yaml}
K3S_REGISTRY_SCHEME=${K3S_REGISTRY_SCHEME:-}

if [[ -z "${K3S_REGISTRY_SCHEME}" ]]; then
  # Internal Knoe registry endpoints are plain HTTP by default.
  # Set K3S_REGISTRY_SCHEME=https explicitly when TLS is configured.
  K3S_REGISTRY_SCHEME="http"
fi

ensure_root() {
  if [[ "$(id -u)" -ne 0 ]]; then
    echo "ERROR: must run as root to write $K3S_REGISTRY_FILE" >&2
    exit 1
  fi
}

render_registries_yaml() {
  local host="$1"
  local port="$2"
  local ns="$3"
  local scheme="$4"

  if [[ "$scheme" == "http" ]]; then
    cat <<EOF
mirrors:
  "${host}:${port}":
    endpoint:
      - "http://${host}:${port}"
  "registry.${ns}.svc.cluster.local:${port}":
    endpoint:
      - "http://${host}:${port}"
EOF
    return 0
  fi
  cat <<EOF
mirrors:
  "${host}:${port}":
    endpoint:
      - "${scheme}://${host}:${port}"
  "registry.${ns}.svc.cluster.local:${port}":
    endpoint:
      - "${scheme}://${host}:${port}"
configs:
  "${host}:${port}":
    tls:
      insecure_skip_verify: true
  "registry.${ns}.svc.cluster.local:${port}":
    tls:
      insecure_skip_verify: true
EOF
}

case "$ACTION" in
  apply|update)
    if [[ -z "${K3S_REGISTRY_HOST:-}" ]]; then
      echo "ERROR: K3S_REGISTRY_HOST is empty (set PROLE_K3S_SERVER or K3S_REGISTRY_HOST)." >&2
      exit 2
    fi
    ensure_root
    mkdir -p "$(dirname "$K3S_REGISTRY_FILE")"
    render_registries_yaml "$K3S_REGISTRY_HOST" "$K3S_REGISTRY_PORT" "$K3S_REGISTRY_NAMESPACE" "$K3S_REGISTRY_SCHEME" >"$K3S_REGISTRY_FILE"
    echo "Wrote $K3S_REGISTRY_FILE for ${K3S_REGISTRY_SCHEME}://${K3S_REGISTRY_HOST}:${K3S_REGISTRY_PORT}"
    echo "Restart k3s to apply: sudo systemctl restart k3s"
    ;;
  status)
    if [[ -f "$K3S_REGISTRY_FILE" ]]; then
      echo "Found $K3S_REGISTRY_FILE"
      cat "$K3S_REGISTRY_FILE"
    else
      echo "No registries.yaml at $K3S_REGISTRY_FILE"
      exit 1
    fi
    ;;
  *)
    echo "Usage: $0 {apply|status}" >&2
    exit 2
    ;;
esac