stages:
  - package
  - build-image
  - push
  - deploy

variables:
  # ---------- Gradle ----------
  GRADLE_IMAGE: gradle:8.14.4-jdk21
  GRADLE_USER_HOME: ${CI_PROJECT_DIR}/.gradle

  # ---------- Docker ----------
  DOCKER_IMAGE: docker:27.5.1
  DOCKER_SERVICE: docker:27.5.1-dind
  DOCKER_HOST: tcp://docker:2375
  DOCKER_TLS_CERTDIR: ""

  # ---------- Application ----------
  APP_NAME: delta-force-guide-server

  # ---------- Image tags ----------
  IMAGE_TAG: ${CI_REGISTRY_IMAGE}:${CI_COMMIT_SHORT_SHA}
  LATEST_TAG: ${CI_REGISTRY_IMAGE}:latest

  # ---------- CI Dockerfile ----------
  CI_DOCKERFILE: Dockerfile.ci

cache:
  key: ${CI_COMMIT_REF_SLUG}
  paths:
    - .gradle/wrapper
    - .gradle/caches
  policy: pull-push

# ====================================================================
# Reusable template for Docker jobs
# ====================================================================
.docker:
  image: ${DOCKER_IMAGE}
  services:
    - name: ${DOCKER_SERVICE}
      command: ["--tls=false"]
  variables:
    DOCKER_HOST: tcp://docker:2375
    DOCKER_TLS_CERTDIR: ""

# Trigger the pipeline for MRs, the default branch, and tags
workflow:
  rules:
    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
    - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'
    - if: '$CI_COMMIT_TAG'

# ====================================================================
# Stage 1 — Package: build the JAR with Gradle
# ====================================================================
package:
  stage: package
  image: ${GRADLE_IMAGE}
  script:
    - ./gradlew build
  artifacts:
    name: "${CI_JOB_NAME}-${CI_COMMIT_SHORT_SHA}"
    paths:
      - build/libs/*.jar
    expire_in: 1 hour

# ====================================================================
# Stage 2 — Build Docker image using the pre-built JAR artifact
# ====================================================================
build-image:
  stage: build-image
  extends: .docker
  script:
    # Resolve the actual JAR path
    - JAR_FILE=$(ls build/libs/delta-force-guide-server-*.jar | head -1)
    - echo "Packaging JAR: ${JAR_FILE}"

    # Build image with the CI-specific single-stage Dockerfile
    - |
      docker build \
        --build-arg JAR_FILE="${JAR_FILE}" \
        -f ${CI_DOCKERFILE} \
        -t ${IMAGE_TAG} \
        -t ${LATEST_TAG} \
        .

    # Save the image as a CI artefact for the next stage
    - docker save ${IMAGE_TAG} ${LATEST_TAG} > image.tar
  artifacts:
    paths:
      - image.tar
    expire_in: 1 hour
  needs:
    - package

# ====================================================================
# Stage 3 — Push image to GitLab Container Registry
# ====================================================================
push:
  stage: push
  extends: .docker
  script:
    - docker load < image.tar
    - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} ${CI_REGISTRY}
    - docker push ${IMAGE_TAG}
    - docker push ${LATEST_TAG}
  needs:
    - build-image
  rules:
    - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'
    - if: '$CI_COMMIT_TAG'

# ====================================================================
# Stage 4 — Deploy on the target server via SSH
# ====================================================================
deploy:
  stage: deploy
  image: alpine:latest
  before_script:
    - apk add --no-cache openssh-client
    - eval "$(ssh-agent -s)"
    - echo "${DEPLOY_SSH_PRIVATE_KEY}" | tr -d '\r' | ssh-add -
    - mkdir -p ~/.ssh
    - chmod 700 ~/.ssh
  script:
    - |
      ssh -o StrictHostKeyChecking=no ${DEPLOY_USER}@${DEPLOY_HOST} "
        set -e

        echo '=== Pulling image ==='
        echo ${CI_REGISTRY_PASSWORD} | docker login -u ${CI_REGISTRY_USER} --password-stdin ${CI_REGISTRY}
        docker pull ${IMAGE_TAG}

        echo '=== Stopping old container ==='
        docker stop ${APP_NAME} || true
        docker rm ${APP_NAME} || true

        echo '=== Starting new container ==='
        docker run -d \
          --name ${APP_NAME} \
          --restart unless-stopped \
          -p ${DEPLOY_PORT:-8080}:8080 \
          ${IMAGE_TAG}

        echo '=== Cleaning up old images ==='
        docker image prune -f

        echo '=== Deployment complete ==='
      "
  needs:
    - push
  environment:
    name: production
    url: http://${DEPLOY_HOST}:${DEPLOY_PORT:-8080}
  rules:
    - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'