#!/bin/bash
#
# Copyright Istio Authors
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

set -euo pipefail

display_usage() {
    echo
    echo "USAGE: ./gen-helloworld.sh [--version] [--includeService value] [--includeDeployment value]"
    echo "    -h|--help: Prints usage information"
    echo "    --version: Specifies the version that will be returned by the helloworld service, default: 'v1'"
    echo "    --includeService: If 'true' the service will be included in the YAML, default: 'true'"
    echo "    --includeDeployment: If 'true' the deployment will be included in the YAML, default: 'true'"
}

INCLUDE_SERVICE=${INCLUDE_SERVICE:-"true"}
INCLUDE_DEPLOYMENT=${INCLUDE_DEPLOYMENT:-"true"}
SERVICE_VERSION=${SERVICE_VERSION:-"v1"}
while (( "$#" )); do
  case "$1" in
    -h|--help)
      display_usage
      exit 0
      ;;

    --version)
      SERVICE_VERSION=$2
      shift 2
      ;;

    --includeService)
      INCLUDE_SERVICE=$2
      shift 2
      ;;

    --includeDeployment)
      INCLUDE_DEPLOYMENT=$2
      shift 2
      ;;

    *)
      echo "Error: Unsupported flag $1" >&2
      display_usage
      exit 1
      ;;
  esac
done

SERVICE_YAML=$(cat <<EOF
apiVersion: v1
kind: Service
metadata:
  name: helloworld
  labels:
    app: helloworld
    service: helloworld
spec:
  ports:
  - port: 5000
    name: http
  selector:
    app: helloworld
EOF
)

DEPLOYMENT_YAML=$(cat <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: helloworld-${SERVICE_VERSION}
  labels:
    app: helloworld
    version: ${SERVICE_VERSION}
spec:
  replicas: 1
  selector:
    matchLabels:
      app: helloworld
      version: ${SERVICE_VERSION}
  template:
    metadata:
      labels:
        app: helloworld
        version: ${SERVICE_VERSION}
    spec:
      containers:
      - name: helloworld
        env:
        - name: SERVICE_VERSION
          value: ${SERVICE_VERSION}
        image: docker.io/istio/examples-helloworld-v1
        resources:
          requests:
            cpu: "100m"
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 5000
EOF
)

OUT=""

# Add the service to the output.
if [[ "$INCLUDE_SERVICE" == "true" ]]; then
  OUT="${SERVICE_YAML}"
fi

# Add the deployment to the output.
if [[ "$INCLUDE_DEPLOYMENT" == "true" ]]; then
  # Add a separator
  if [[ -n "$OUT" ]]; then
    OUT+="
---
"
  fi
  OUT+="${DEPLOYMENT_YAML}"
fi

echo "$OUT"